Based on the datasheet found here:
http://www.richtek.com/download_ds.jsp?p=RT9455
Signed-off-by: Anda-Maria Nicolae <[email protected]>
---
.../devicetree/bindings/power/rt9455_charger.txt | 38 +
.../devicetree/bindings/vendor-prefixes.txt | 1 +
drivers/power/Kconfig | 6 +
drivers/power/Makefile | 1 +
drivers/power/rt9455_charger.c | 1770 ++++++++++++++++++++
5 files changed, 1816 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/rt9455_charger.txt
create mode 100644 drivers/power/rt9455_charger.c
diff --git a/Documentation/devicetree/bindings/power/rt9455_charger.txt b/Documentation/devicetree/bindings/power/rt9455_charger.txt
new file mode 100644
index 0000000..f716cf6
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/rt9455_charger.txt
@@ -0,0 +1,38 @@
+Binding for RT rt9455 battery charger
+
+Required properties:
+- compatible: Should contain one of the following:
+ * "rt,rt9455"
+
+- reg: integer, i2c address of the device.
+- rt,ICHRG: integer, output charge current in uA.
+- rt,IEOC_PERCENTAGE: integer, the percent of the output charge current (ICHRG).
+ When the current in constant-voltage phase drops below
+ ICHRG x IEOC_PERCENTAGE, charge is terminated.
+- rt,VOREG: integer, battery regulation voltage in uV.
+
+Optional properties:
+- rt,VMIVR: integer, minimum input voltage regulation in uV.
+ Prevents input voltage drop due to insufficient current
+ provided by the power source.
+- rt,IAICR: integer, input current regulation in uA.
+
+Example:
+
+rt9455@22 {
+ compatible = "rt,rt9455";
+ reg = <0x22>;
+
+ interrupt-parent = <&gpio1>;
+ interrupts = <0 1>;
+
+ interrupt-gpio = <&gpio1 0 1>;
+ reset-gpio = <&gpio1 1 1>;
+
+ rt,ICHRG = <500000>;
+ rt,IEOC_PERCENTAGE = <10>;
+ rt,VOREG = <4200000>;
+
+ rt,VMIVR = <4500000>;
+ rt,IAICR = <500000>;
+};
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 389ca13..dc868ed 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -148,6 +148,7 @@ raidsonic RaidSonic Technology GmbH
ralink Mediatek/Ralink Technology Corp.
ramtron Ramtron International
realtek Realtek Semiconductor Corp.
+rt Richtek Technology Corporation
renesas Renesas Electronics Corporation
ricoh Ricoh Co. Ltd.
rockchip Fuzhou Rockchip Electronics Co., Ltd
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 4091fb0..39f208d 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -439,6 +439,12 @@ config BATTERY_RT5033
The fuelgauge calculates and determines the battery state of charge
according to battery open circuit voltage.
+config CHARGER_RT9455
+ tristate "Richtek RT9455 battery charger driver"
+ depends on I2C && GPIOLIB
+ help
+ Say Y to enable support for the Richtek RT9455 battery charger.
+
source "drivers/power/reset/Kconfig"
endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b7b0181..e49abbf 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_BATTERY_MAX17040) += max17040_battery.o
obj-$(CONFIG_BATTERY_MAX17042) += max17042_battery.o
obj-$(CONFIG_BATTERY_Z2) += z2_battery.o
obj-$(CONFIG_BATTERY_RT5033) += rt5033_battery.o
+obj-$(CONFIG_CHARGER_RT9455) += rt9455_charger.o
obj-$(CONFIG_BATTERY_S3C_ADC) += s3c_adc_battery.o
obj-$(CONFIG_BATTERY_TWL4030_MADC) += twl4030_madc_battery.o
obj-$(CONFIG_CHARGER_88PM860X) += 88pm860x_charger.o
diff --git a/drivers/power/rt9455_charger.c b/drivers/power/rt9455_charger.c
new file mode 100644
index 0000000..57bb97d
--- /dev/null
+++ b/drivers/power/rt9455_charger.c
@@ -0,0 +1,1770 @@
+/*
+ * Driver for Richtek RT9455WSC battery charger.
+ *
+ * Copyright (C) 2015 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/power_supply.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/usb/phy.h>
+
+#define RT9455_MANUFACTURER "Richtek"
+#define RT9455_MODEL_NAME "RT9455"
+#define RT9455_DRIVER_NAME "rt9455-charger"
+
+#define RT9455_IRQ_NAME "interrupt"
+
+#define RT9455_PWR_RDY_DELAY 1 /* 1 second */
+#define RT9455_MAX_CHARGING_TIME 21600 /* 6 hrs */
+#define RT9455_BATT_PRESENCE_DELAY 60 /* 60 seconds */
+
+#define RT9455_CHARGE_MODE 0x00
+#define RT9455_BOOST_MODE 0x01
+
+#define RT9455_FAULT 0x03
+
+#define RT9455_IAICR_100MA 0x00
+#define RT9455_IAICR_500MA 0x01
+#define RT9455_IAICR_NO_LIMIT 0x03
+
+#define RT9455_CHARGE_DISABLE 0x00
+#define RT9455_CHARGE_ENABLE 0x01
+
+#define RT9455_PWR_FAULT 0x00
+#define RT9455_PWR_GOOD 0x01
+
+#define RT9455_REG_CTRL1 0x00 /* Control1 */
+#define RT9455_REG_CTRL1_STAT_MASK (BIT(5) | BIT(4))
+#define RT9455_REG_CTRL1_STAT_SHIFT 4
+#define RT9455_REG_CTRL1_BOOST_MASK BIT(3)
+#define RT9455_REG_CTRL1_BOOST_SHIFT 3
+#define RT9455_REG_CTRL1_PWR_RDY_MASK BIT(2)
+#define RT9455_REG_CTRL1_PWR_RDY_SHIFT 2
+#define RT9455_REG_CTRL1_OTG_PIN_POLARITY_MASK BIT(1)
+#define RT9455_REG_CTRL1_OTG_PIN_POLARITY_SHIFT 1
+
+#define RT9455_REG_CTRL2 0x01 /* Control2 */
+#define RT9455_REG_CTRL2_IAICR_MASK (BIT(7) | BIT(6))
+#define RT9455_REG_CTRL2_IAICR_SHIFT 6
+#define RT9455_REG_CTRL2_TE_SHDN_EN_MASK BIT(5)
+#define RT9455_REG_CTRL2_TE_SHDN_EN_SHIFT 5
+#define RT9455_REG_CTRL2_HIGHER_OCP_MASK BIT(4)
+#define RT9455_REG_CTRL2_HIGHER_OCP_SHIFT 4
+#define RT9455_REG_CTRL2_TE_MASK BIT(3)
+#define RT9455_REG_CTRL2_TE_SHIFT 3
+#define RT9455_REG_CTRL2_IAICR_INT_MASK BIT(2)
+#define RT9455_REG_CTRL2_IAICR_INT_SHIFT 2
+#define RT9455_REG_CTRL2_HIZ_MASK BIT(1)
+#define RT9455_REG_CTRL2_HIZ_SHIFT 1
+#define RT9455_REG_CTRL2_OPA_MODE_MASK BIT(0)
+#define RT9455_REG_CTRL2_OPA_MODE_SHIFT 0
+
+#define RT9455_REG_CTRL3 0x02 /* Control3 */
+#define RT9455_REG_CTRL3_VOREG_MASK (BIT(7) | BIT(6) | BIT(5) | \
+ BIT(4) | BIT(3) | BIT(2))
+#define RT9455_REG_CTRL3_VOREG_SHIFT 2
+#define RT9455_REG_CTRL3_OTG_PL_MASK BIT(1)
+#define RT9455_REG_CTRL3_OTG_PL_SHIFT 1
+#define RT9455_REG_CTRL3_OTG_EN_MASK BIT(0)
+#define RT9455_REG_CTRL3_OTG_EN_SHIFT 0
+
+#define RT9455_REG_DEV_ID 0x03 /* Device ID */
+#define RT9455_REG_DEV_ID_VENDOR_ID_MASK (BIT(7) | BIT(6) | BIT(5) | \
+ BIT(4))
+#define RT9455_REG_DEV_ID_VENDOR_ID_SHIFT 4
+#define RT9455_REG_DEV_ID_CHIP_REV_MASK (BIT(3) | BIT(2) | BIT(1) | \
+ BIT(0))
+#define RT9455_REG_DEV_ID_CHIP_REV_SHIFT 0
+
+#define RT9455_REG_CTRL4 0x04 /* Control4 */
+#define RT9455_REG_CTRL4_RST_MASK BIT(7)
+#define RT9455_REG_CTRL4_RST_SHIFT 7
+
+#define RT9455_REG_CTRL5 0x05 /* Control5 */
+#define RT9455_REG_CTRL5_TMR_EN_MASK BIT(7)
+#define RT9455_REG_CTRL5_TMR_EN_SHIFT 7
+#define RT9455_REG_CTRL5_VMIVR_MASK (BIT(5) | BIT(4))
+#define RT9455_REG_CTRL5_VMIVR_SHIFT 4
+#define RT9455_REG_CTRL5_IPREC_MASK (BIT(3) | BIT(2))
+#define RT9455_REG_CTRL5_IPREC_SHIFT 2
+#define RT9455_REG_CTRL5_IEOC_PERCENTAGE_MASK (BIT(1) | BIT(0))
+#define RT9455_REG_CTRL5_IEOC_PERCENTAGE_SHIFT 0
+
+#define RT9455_REG_CTRL6 0x06 /* Control6 */
+#define RT9455_REG_CTRL6_IAICR_SEL_MASK BIT(7)
+#define RT9455_REG_CTRL6_IAICR_SEL_SHIFT 7
+#define RT9455_REG_CTRL6_ICHRG_MASK (BIT(6) | BIT(5) | BIT(4))
+#define RT9455_REG_CTRL6_ICHRG_SHIFT 4
+#define RT9455_REG_CTRL6_VPREC_MASK (BIT(2) | BIT(1) | BIT(0))
+#define RT9455_REG_CTRL6_VPREC_SHIFT 0
+
+#define RT9455_REG_CTRL7 0x07 /* Control7 */
+#define RT9455_REG_CTRL7_BATD_EN_MASK BIT(6)
+#define RT9455_REG_CTRL7_BATD_EN_SHIFT 6
+#define RT9455_REG_CTRL7_CHG_EN_MASK BIT(4)
+#define RT9455_REG_CTRL7_CHG_EN_SHIFT 4
+#define RT9455_REG_CTRL7_VMREG_MASK (BIT(3) | BIT(2) | BIT(1) | \
+ BIT(0))
+#define RT9455_REG_CTRL7_VMREG_SHIFT 0
+
+#define RT9455_REG_IRQ1 0x08 /* IRQ1 */
+#define RT9455_REG_IRQ1_TSDI_MASK BIT(7)
+#define RT9455_REG_IRQ1_TSDI_SHIFT 7
+#define RT9455_REG_IRQ1_VINOVPI_MASK BIT(6)
+#define RT9455_REG_IRQ1_VINOVPI_SHIFT 6
+#define RT9455_REG_IRQ1_BATAB_MASK BIT(0)
+#define RT9455_REG_IRQ1_BATAB_SHIFT 0
+
+#define RT9455_REG_IRQ2 0x09 /* IRQ2 */
+#define RT9455_REG_IRQ2_CHRVPI_MASK BIT(7)
+#define RT9455_REG_IRQ2_CHRVPI_SHIFT 7
+#define RT9455_REG_IRQ2_CHBATOVI_MASK BIT(5)
+#define RT9455_REG_IRQ2_CHBATOVI_SHIFT 5
+#define RT9455_REG_IRQ2_CHTERMI_MASK BIT(4)
+#define RT9455_REG_IRQ2_CHTERMI_SHIFT 4
+#define RT9455_REG_IRQ2_CHRCHGI_MASK BIT(3)
+#define RT9455_REG_IRQ2_CHRCHGI_SHIFT 3
+#define RT9455_REG_IRQ2_CH32MI_MASK BIT(2)
+#define RT9455_REG_IRQ2_CH32MI_SHIFT 2
+#define RT9455_REG_IRQ2_CHTREGI_MASK BIT(1)
+#define RT9455_REG_IRQ2_CHTREGI_SHIFT 1
+#define RT9455_REG_IRQ2_CHMIVRI_MASK BIT(0)
+#define RT9455_REG_IRQ2_CHMIVRI_SHIFT 0
+
+#define RT9455_REG_IRQ3 0x0A /* IRQ3 */
+#define RT9455_REG_IRQ3_BSTBUSOVI_MASK BIT(7)
+#define RT9455_REG_IRQ3_BSTBUSOVI_SHIFT 7
+#define RT9455_REG_IRQ3_BSTOLI_MASK BIT(6)
+#define RT9455_REG_IRQ3_BSTOLI_SHIFT 6
+#define RT9455_REG_IRQ3_BSTLOWVI_MASK BIT(5)
+#define RT9455_REG_IRQ3_BSTLOWVI_SHIFT 5
+#define RT9455_REG_IRQ3_BST32SI_MASK BIT(3)
+#define RT9455_REG_IRQ3_BST32SI_SHIFT 3
+
+#define RT9455_REG_MASK1 0x0B /* MASK1 */
+#define RT9455_REG_MASK1_TSDM_MASK BIT(7)
+#define RT9455_REG_MASK1_TSDM_SHIFT 7
+#define RT9455_REG_MASK1_VINOVPIM_MASK BIT(6)
+#define RT9455_REG_MASK1_VINOVPIM_SHIFT 6
+#define RT9455_REG_MASK1_BATABM_MASK BIT(0)
+#define RT9455_REG_MASK1_BATABM_SHIFT 0
+
+#define RT9455_REG_MASK2 0x0C /* MASK2 */
+#define RT9455_REG_MASK2_CHRVPIM_MASK BIT(7)
+#define RT9455_REG_MASK2_CHRVPIM_SHIFT 7
+#define RT9455_REG_MASK2_CHBATOVIM_MASK BIT(5)
+#define RT9455_REG_MASK2_CHBATOVIM_SHIFT 5
+#define RT9455_REG_MASK2_CHTERMIM_MASK BIT(4)
+#define RT9455_REG_MASK2_CHTERMIM_SHIFT 4
+#define RT9455_REG_MASK2_CHRCHGIM_MASK BIT(3)
+#define RT9455_REG_MASK2_CHRCHGIM_SHIFT 3
+#define RT9455_REG_MASK2_CH32MIM_MASK BIT(2)
+#define RT9455_REG_MASK2_CH32MIM_SHIFT 2
+#define RT9455_REG_MASK2_CHTREGIM_MASK BIT(1)
+#define RT9455_REG_MASK2_CHTREGIM_SHIFT 1
+#define RT9455_REG_MASK2_CHMIVRIM_MASK BIT(0)
+#define RT9455_REG_MASK2_CHMIVRIM_SHIFT 0
+
+#define RT9455_REG_MASK3 0x0D /* MASK3 */
+#define RT9455_REG_MASK3_BSTVINOVIM_MASK BIT(7)
+#define RT9455_REG_MASK3_BSTVINOVIM_SHIFT 7
+#define RT9455_REG_MASK3_BSTOLIM_MASK BIT(6)
+#define RT9455_REG_MASK3_BSTOLIM_SHIFT 6
+#define RT9455_REG_MASK3_BSTLOWVIM_MASK BIT(5)
+#define RT9455_REG_MASK3_BSTLOWVIM_SHIFT 5
+#define RT9455_REG_MASK3_BST32SIM_MASK BIT(3)
+#define RT9455_REG_MASK3_BST32SIM_SHIFT 3
+
+/*
+ * Each array initialised below shows the possible real-world values for a
+ * group of bits belonging to RT9455 registers. The arrays are sorted in
+ * ascending order. The index of each real-world value represents the value
+ * that is encoded in the group of bits belonging to RT9455 registers.
+ */
+/* REG06[6:4] (ICHRG) in uAh */
+static const int rt9455_ichrg_values[] = {
+ 500000, 650000, 800000, 950000, 1100000, 1250000, 1400000, 1550000
+};
+
+/* REG02[7:2] (VOREG) in uV */
+static const int rt9455_voreg_values[] = {
+ 3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
+ 3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
+ 3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
+ 3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
+ 4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
+ 4300000, 4330000, 4350000, 4370000, 4390000, 4410000, 4430000, 4450000,
+ 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000,
+ 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000
+};
+
+/* REG07[3:0] (VMREG) in uV */
+static const int rt9455_vmreg_values[] = {
+ 4200000, 4220000, 4240000, 4260000, 4280000, 4300000, 4320000, 4340000,
+ 4360000, 4380000, 4400000, 4430000, 4450000, 4450000, 4450000, 4450000
+};
+
+/* REG05[5:4] (IEOC_PERCENTAGE) */
+static const int rt9455_ieoc_percentage_values[] = {
+ 10, 30, 20, 30
+};
+
+/* REG05[1:0] (VMIVR) in uV */
+static const int rt9455_vmivr_values[] = {
+ 4000000, 4250000, 4500000, 5000000
+};
+
+/* REG05[1:0] (IAICR) in uA */
+static const int rt9455_iaicr_values[] = {
+ 100000, 500000, 1000000, 2000000
+};
+
+struct rt9455_info {
+ struct i2c_client *client;
+ struct power_supply *charger;
+#if IS_ENABLED(CONFIG_USB_PHY)
+ struct usb_phy *usb_phy;
+ struct notifier_block nb;
+#endif
+ struct gpio_desc *gpiod_irq;
+ unsigned int gpio_irq;
+ struct delayed_work pwr_rdy_work;
+ struct delayed_work max_charging_time_work;
+ struct delayed_work batt_presence_work;
+};
+
+/* I2C read/write API */
+static int rt9455_read(struct rt9455_info *info, u8 reg, u8 *data)
+{
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(info->client, reg);
+ if (ret < 0)
+ return ret;
+
+ *data = ret;
+ return 0;
+}
+
+static int rt9455_write(struct rt9455_info *info, u8 reg, u8 data)
+{
+ return i2c_smbus_write_byte_data(info->client, reg, data);
+}
+
+static int rt9455_read_mask(struct rt9455_info *info, u8 reg,
+ u8 mask, u8 shift, u8 *data)
+{
+ u8 v;
+ int ret;
+
+ ret = rt9455_read(info, reg, &v);
+ if (ret < 0)
+ return ret;
+
+ v &= mask;
+ v >>= shift;
+ *data = v;
+
+ return 0;
+}
+
+static int rt9455_write_mask(struct rt9455_info *info, u8 reg,
+ u8 mask, u8 shift, u8 data)
+{
+ u8 v;
+ int ret;
+
+ ret = rt9455_read(info, reg, &v);
+ if (ret < 0)
+ return ret;
+
+ v &= ~mask;
+ v |= ((data << shift) & mask);
+
+ return rt9455_write(info, reg, v);
+}
+
+/*
+ * Iterate through each element of the 'tbl' array until an element whose value
+ * is greater than v is found. Return the index of the respective element,
+ * or the index of the last element in the array, if no such element is found.
+ */
+static u8 rt9455_find_idx(const int tbl[], int tbl_size, int v)
+{
+ int i;
+
+ /* No need to iterate until the last index in the table because
+ * if no element greater than v is found in the table,
+ * or if only the last element is greater than v,
+ * function returns the index of the last element.
+ */
+ for (i = 0; i < tbl_size - 1; i++)
+ if (v <= tbl[i])
+ return i;
+
+ return (tbl_size - 1);
+}
+
+static int rt9455_get_field_val(struct rt9455_info *info,
+ u8 reg, u8 mask, u8 shift,
+ const int tbl[], int tbl_size,
+ int *val)
+{
+ u8 v;
+ int ret;
+
+ ret = rt9455_read_mask(info, reg, mask, shift, &v);
+ if (ret)
+ return ret;
+
+ v = (v >= tbl_size) ? (tbl_size - 1) : v;
+ *val = tbl[v];
+
+ return 0;
+}
+
+static int rt9455_set_field_val(struct rt9455_info *info,
+ u8 reg, u8 mask, u8 shift,
+ const int tbl[], int tbl_size,
+ int val)
+{
+ u8 idx;
+
+ idx = rt9455_find_idx(tbl, tbl_size, val);
+
+ return rt9455_write_mask(info, reg, mask, shift, idx);
+}
+
+static int rt9455_register_reset(struct rt9455_info *info)
+{
+ struct device *dev = &info->client->dev;
+ int ret, limit = 100;
+ u8 v;
+
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL4,
+ RT9455_REG_CTRL4_RST_MASK,
+ RT9455_REG_CTRL4_RST_SHIFT,
+ 0x1);
+ if (ret) {
+ dev_err(dev, "Failed to set RST bit\n");
+ return ret;
+ }
+
+ /* To make sure that reset operation has finished, loop until RST bit
+ * is set to 0.
+ */
+ do {
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL4,
+ RT9455_REG_CTRL4_RST_MASK,
+ RT9455_REG_CTRL4_RST_SHIFT,
+ &v);
+ if (ret) {
+ dev_err(dev, "Failed to read RST bit\n");
+ return ret;
+ }
+
+ if (!v)
+ break;
+
+ usleep_range(10, 100);
+ } while (--limit);
+
+ if (!limit)
+ return -EIO;
+
+ return 0;
+}
+
+/* Charger power supply property routines */
+static enum power_supply_property rt9455_charger_properties[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_HEALTH,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
+ POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
+ POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+ POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
+ POWER_SUPPLY_PROP_SCOPE,
+ POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+ POWER_SUPPLY_PROP_MODEL_NAME,
+ POWER_SUPPLY_PROP_MANUFACTURER,
+};
+
+static char *rt9455_charger_supplied_to[] = {
+ "main-battery",
+};
+
+static int rt9455_charger_get_status(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int ret;
+ u8 v;
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL1,
+ RT9455_REG_CTRL1_STAT_MASK,
+ RT9455_REG_CTRL1_STAT_SHIFT,
+ &v);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read STAT bits\n");
+ return ret;
+ }
+
+ switch (v) {
+ case 0:
+ val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ break;
+ case 1:
+ val->intval = POWER_SUPPLY_STATUS_CHARGING;
+ break;
+ case 2:
+ val->intval = POWER_SUPPLY_STATUS_FULL;
+ break;
+ default:
+ val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+ break;
+ }
+
+ return 0;
+}
+
+static int rt9455_charger_get_health(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+ u8 v;
+
+ val->intval = POWER_SUPPLY_HEALTH_GOOD;
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL1,
+ RT9455_REG_CTRL1_STAT_MASK,
+ RT9455_REG_CTRL1_STAT_SHIFT,
+ &v);
+ if (ret) {
+ dev_err(dev, "Failed to read STAT bits\n");
+ return ret;
+ }
+
+ if (v == RT9455_FAULT) {
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ return 0;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_IRQ1, &v);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ1 register\n");
+ return ret;
+ }
+
+ if (v & RT9455_REG_IRQ1_TSDI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ1_VINOVPI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ1_BATAB_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ return 0;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_IRQ2, &v);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ2 register\n");
+ return ret;
+ }
+
+ if (v & RT9455_REG_IRQ2_CHBATOVI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ2_CH32MI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+ return 0;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_IRQ3, &v);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ3 register\n");
+ return ret;
+ }
+
+ if (v & RT9455_REG_IRQ3_BSTBUSOVI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ3_BSTOLI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ3_BSTLOWVI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ return 0;
+ }
+ if (v & RT9455_REG_IRQ3_BST32SI_MASK) {
+ val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+ return 0;
+ }
+
+ return 0;
+}
+
+static int rt9455_charger_get_battery_presence(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int ret;
+ u8 v;
+
+ ret = rt9455_read_mask(info, RT9455_REG_IRQ1,
+ RT9455_REG_IRQ1_BATAB_MASK,
+ RT9455_REG_IRQ1_BATAB_SHIFT,
+ &v);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read BATAB bit\n");
+ return ret;
+ }
+
+ /* Since BATAB is 1 when battery is NOT present and 0 otherwise,
+ * we return !BATAB.
+ */
+ val->intval = !v;
+
+ return 0;
+}
+
+static int rt9455_charger_get_online(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int ret;
+ u8 v;
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL1,
+ RT9455_REG_CTRL1_PWR_RDY_MASK,
+ RT9455_REG_CTRL1_PWR_RDY_SHIFT,
+ &v);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
+ return ret;
+ }
+
+ val->intval = v;
+
+ return 0;
+}
+
+static int rt9455_charger_get_current(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int ret, curr;
+
+ ret = rt9455_get_field_val(info, RT9455_REG_CTRL6,
+ RT9455_REG_CTRL6_ICHRG_MASK,
+ RT9455_REG_CTRL6_ICHRG_SHIFT,
+ rt9455_ichrg_values,
+ ARRAY_SIZE(rt9455_ichrg_values),
+ &curr);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read ICHRG value\n");
+ return ret;
+ }
+
+ val->intval = curr;
+
+ return 0;
+}
+
+static int rt9455_charger_get_current_max(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int idx = ARRAY_SIZE(rt9455_ichrg_values) - 1;
+
+ val->intval = rt9455_ichrg_values[idx];
+
+ return 0;
+}
+
+static int rt9455_charger_get_voltage(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int voltage, ret;
+
+ ret = rt9455_get_field_val(info, RT9455_REG_CTRL3,
+ RT9455_REG_CTRL3_VOREG_MASK,
+ RT9455_REG_CTRL3_VOREG_SHIFT,
+ rt9455_voreg_values,
+ ARRAY_SIZE(rt9455_voreg_values),
+ &voltage);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read VOREG value\n");
+ return ret;
+ }
+
+ val->intval = voltage;
+
+ return 0;
+}
+
+static int rt9455_charger_get_voltage_max(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ int voltage_max, ret;
+
+ ret = rt9455_get_field_val(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_VMREG_MASK,
+ RT9455_REG_CTRL7_VMREG_SHIFT,
+ rt9455_vmreg_values,
+ ARRAY_SIZE(rt9455_vmreg_values),
+ &voltage_max);
+ if (ret) {
+ dev_err(&info->client->dev, "Failed to read VMREG value\n");
+ return ret;
+ }
+
+ val->intval = voltage_max;
+
+ return 0;
+}
+
+static int rt9455_charger_get_term_current(struct rt9455_info *info,
+ union power_supply_propval *val)
+{
+ struct device *dev = &info->client->dev;
+ int ichrg, ieoc_percentage, ret;
+
+ ret = rt9455_get_field_val(info, RT9455_REG_CTRL6,
+ RT9455_REG_CTRL6_ICHRG_MASK,
+ RT9455_REG_CTRL6_ICHRG_SHIFT,
+ rt9455_ichrg_values,
+ ARRAY_SIZE(rt9455_ichrg_values),
+ &ichrg);
+ if (ret) {
+ dev_err(dev, "Failed to read ICHRG value\n");
+ return ret;
+ }
+
+ ret = rt9455_get_field_val(info, RT9455_REG_CTRL5,
+ RT9455_REG_CTRL5_IEOC_PERCENTAGE_MASK,
+ RT9455_REG_CTRL5_IEOC_PERCENTAGE_SHIFT,
+ rt9455_ieoc_percentage_values,
+ ARRAY_SIZE(rt9455_ieoc_percentage_values),
+ &ieoc_percentage);
+ if (ret) {
+ dev_err(dev, "Failed to read IEOC value\n");
+ return ret;
+ }
+
+ val->intval = ichrg * ieoc_percentage / 100;
+
+ return 0;
+}
+
+static int rt9455_charger_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct rt9455_info *info = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ return rt9455_charger_get_status(info, val);
+ case POWER_SUPPLY_PROP_HEALTH:
+ return rt9455_charger_get_health(info, val);
+ case POWER_SUPPLY_PROP_PRESENT:
+ return rt9455_charger_get_battery_presence(info, val);
+ case POWER_SUPPLY_PROP_ONLINE:
+ return rt9455_charger_get_online(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+ return rt9455_charger_get_current(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+ return rt9455_charger_get_current_max(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+ return rt9455_charger_get_voltage(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+ return rt9455_charger_get_voltage_max(info, val);
+ case POWER_SUPPLY_PROP_SCOPE:
+ val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
+ return 0;
+ case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+ return rt9455_charger_get_term_current(info, val);
+ case POWER_SUPPLY_PROP_MODEL_NAME:
+ val->strval = RT9455_MODEL_NAME;
+ return 0;
+ case POWER_SUPPLY_PROP_MANUFACTURER:
+ val->strval = RT9455_MANUFACTURER;
+ return 0;
+ default:
+ return -ENODATA;
+ }
+}
+
+static int rt9455_charger_set_current(struct rt9455_info *info,
+ const union power_supply_propval *val)
+{
+ return rt9455_set_field_val(info, RT9455_REG_CTRL6,
+ RT9455_REG_CTRL6_ICHRG_MASK,
+ RT9455_REG_CTRL6_ICHRG_SHIFT,
+ rt9455_ichrg_values,
+ ARRAY_SIZE(rt9455_ichrg_values),
+ val->intval);
+}
+
+static int rt9455_charger_set_voltage(struct rt9455_info *info,
+ const union power_supply_propval *val)
+{
+ return rt9455_set_field_val(info, RT9455_REG_CTRL3,
+ RT9455_REG_CTRL3_VOREG_MASK,
+ RT9455_REG_CTRL3_VOREG_SHIFT,
+ rt9455_voreg_values,
+ ARRAY_SIZE(rt9455_voreg_values),
+ val->intval);
+}
+
+static int rt9455_charger_set_voltage_max(struct rt9455_info *info,
+ const union power_supply_propval *val)
+{
+ return rt9455_set_field_val(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_VMREG_MASK,
+ RT9455_REG_CTRL7_VMREG_SHIFT,
+ rt9455_voreg_values,
+ ARRAY_SIZE(rt9455_voreg_values),
+ val->intval);
+}
+
+static int rt9455_charger_set_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ const union power_supply_propval *val)
+{
+ struct rt9455_info *info = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+ return rt9455_charger_set_current(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+ return rt9455_charger_set_voltage(info, val);
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+ return rt9455_charger_set_voltage_max(info, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int rt9455_charger_property_is_writeable(struct power_supply *psy,
+ enum power_supply_property psp)
+{
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static int rt9455_hw_init(struct rt9455_info *info, u32 ichrg,
+ u32 ieoc_percentage, u32 voreg,
+ u32 vmivr, u32 iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ ret = rt9455_register_reset(info);
+ if (ret) {
+ dev_err(dev, "Power On Reset failed\n");
+ return ret;
+ }
+
+ /* Set TE bit in order to enable end of charge detection */
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_TE_MASK,
+ RT9455_REG_CTRL2_TE_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to set TE bit\n");
+ return ret;
+ }
+
+ /* Set TE_SHDN_EN bit in order to enable end of charge detection */
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_TE_SHDN_EN_MASK,
+ RT9455_REG_CTRL2_TE_SHDN_EN_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to set TE_SHDN_EN bit\n");
+ return ret;
+ }
+
+ /* Set BATD_EN bit in order to enable battery detection
+ * when charging is done
+ */
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_BATD_EN_MASK,
+ RT9455_REG_CTRL7_BATD_EN_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to set BATD_EN bit\n");
+ return ret;
+ }
+
+ /* Disable Safety Timer. In charge mode, this timer terminates charging
+ * if no read or write via I2C is done within 32 minutes. This timer
+ * avoids overcharging the baterry when the OS is not loaded and the
+ * charger is connected to a power source.
+ * In boost mode, this timer triggers BST32SI interrupt if no read or
+ * write via I2C is done within 32 seconds.
+ * When the OS is loaded and the charger driver is inserted, we use
+ * delayed_work, named max_charging_time_work, to avoid overcharging
+ * the battery.
+ */
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL5,
+ RT9455_REG_CTRL5_TMR_EN_MASK,
+ RT9455_REG_CTRL5_TMR_EN_SHIFT,
+ 0x00);
+ if (ret) {
+ dev_err(dev, "Failed to disable Safety Timer\n");
+ return ret;
+ }
+
+ /* Set ICHRG to value retrieved from device-specific data */
+ ret = rt9455_set_field_val(info, RT9455_REG_CTRL6,
+ RT9455_REG_CTRL6_ICHRG_MASK,
+ RT9455_REG_CTRL6_ICHRG_SHIFT,
+ rt9455_ichrg_values,
+ ARRAY_SIZE(rt9455_ichrg_values), ichrg);
+ if (ret) {
+ dev_err(dev, "Failed to set ICHRG value\n");
+ return ret;
+ }
+
+ /* Set IEOC Percentage to value retrieved from device-specific data */
+ ret = rt9455_set_field_val(info, RT9455_REG_CTRL5,
+ RT9455_REG_CTRL5_IEOC_PERCENTAGE_MASK,
+ RT9455_REG_CTRL5_IEOC_PERCENTAGE_SHIFT,
+ rt9455_ieoc_percentage_values,
+ ARRAY_SIZE(rt9455_ieoc_percentage_values),
+ ieoc_percentage);
+ if (ret) {
+ dev_err(dev, "Failed to set IEOC Percentage value\n");
+ return ret;
+ }
+
+ /* Set VOREG to value retrieved from device-specific data */
+ ret = rt9455_set_field_val(info, RT9455_REG_CTRL3,
+ RT9455_REG_CTRL3_VOREG_MASK,
+ RT9455_REG_CTRL3_VOREG_SHIFT,
+ rt9455_voreg_values,
+ ARRAY_SIZE(rt9455_voreg_values), voreg);
+ if (ret) {
+ dev_err(dev, "Failed to set VOREG value\n");
+ return ret;
+ }
+
+ /* Set VMIVR to value retrieved from device-specific data.
+ * If no value is specified, default value for VMIVR is 4.5V.
+ */
+ if (vmivr == -1)
+ vmivr = 4500000;
+
+ ret = rt9455_set_field_val(info, RT9455_REG_CTRL5,
+ RT9455_REG_CTRL5_VMIVR_MASK,
+ RT9455_REG_CTRL5_VMIVR_SHIFT,
+ rt9455_vmivr_values,
+ ARRAY_SIZE(rt9455_vmivr_values), vmivr);
+ if (ret) {
+ dev_err(dev, "Failed to set VMIVR value\n");
+ return ret;
+ }
+
+ /* Set IAICR to value retrieved from device-specific data.
+ * If no value is specified, default value for IAICR is 500 mA.
+ */
+ if (iaicr == -1)
+ iaicr = 500000;
+
+ ret = rt9455_set_field_val(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ rt9455_iaicr_values,
+ ARRAY_SIZE(rt9455_iaicr_values), iaicr);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR value\n");
+ return ret;
+ }
+
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_INT_MASK,
+ RT9455_REG_CTRL2_IAICR_INT_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR_INT bit\n");
+ return ret;
+ }
+
+ ret = rt9455_write_mask(info, RT9455_REG_MASK2,
+ RT9455_REG_MASK2_CHMIVRIM_MASK,
+ RT9455_REG_MASK2_CHMIVRIM_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to mask CHMIVRI interrupt\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rt9455_irq_handler_check_irq1_register(struct rt9455_info *info,
+ bool *_is_battery_absent,
+ bool *_alert_userspace)
+{
+ u8 irq1, mask1, mask2;
+ struct device *dev = &info->client->dev;
+ bool is_battery_absent = false;
+ bool alert_userspace = false;
+ int ret;
+
+ ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ1 register\n");
+ return ret;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_MASK1, &mask1);
+ if (ret) {
+ dev_err(dev, "Failed to read MASK1 register\n");
+ return ret;
+ }
+
+ if (irq1 & RT9455_REG_IRQ1_TSDI_MASK) {
+ dev_err(dev, "Thermal shutdown fault occurred\n");
+ alert_userspace = true;
+ }
+
+ if (irq1 & RT9455_REG_IRQ1_VINOVPI_MASK) {
+ dev_err(dev, "Overvoltage input occurred\n");
+ alert_userspace = true;
+ }
+
+ if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
+ dev_err(dev, "Battery absence occurred\n");
+ is_battery_absent = true;
+ alert_userspace = true;
+
+ if ((mask1 & RT9455_REG_MASK1_BATABM_MASK) == 0) {
+ ret = rt9455_write_mask(info, RT9455_REG_MASK1,
+ RT9455_REG_MASK1_BATABM_MASK,
+ RT9455_REG_MASK1_BATABM_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to mask BATAB interrupt\n");
+ return ret;
+ }
+ }
+
+ ret = rt9455_read(info, RT9455_REG_MASK2, &mask2);
+ if (ret) {
+ dev_err(dev, "Failed to read MASK2 register\n");
+ return ret;
+ }
+
+ if ((mask2 & RT9455_REG_MASK2_CHTERMIM_MASK)) {
+ ret = rt9455_write_mask(info, RT9455_REG_MASK2,
+ RT9455_REG_MASK2_CHTERMIM_MASK,
+ RT9455_REG_MASK2_CHTERMIM_SHIFT,
+ 0x00);
+ if (ret) {
+ dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
+ return ret;
+ }
+ }
+
+ if ((mask2 & RT9455_REG_MASK2_CHRCHGIM_MASK)) {
+ ret = rt9455_write_mask(info, RT9455_REG_MASK2,
+ RT9455_REG_MASK2_CHRCHGIM_MASK,
+ RT9455_REG_MASK2_CHRCHGIM_SHIFT,
+ 0x00);
+ if (ret) {
+ dev_err(dev, "Failed to unmask CHRCHGI interrupt\n");
+ return ret;
+ }
+ }
+
+ /* When the battery is absent, max_charging_time_work is
+ * cancelled, since no charging is done.
+ */
+ cancel_delayed_work_sync(&info->max_charging_time_work);
+ /* Since no interrupt is triggered when the battery is
+ * reconnected, max_charging_time_work is not rescheduled.
+ * Therefore, batt_presence_work is scheduled to check whether
+ * the battery is still absent or not.
+ */
+ schedule_delayed_work(&info->batt_presence_work,
+ RT9455_BATT_PRESENCE_DELAY * HZ);
+ }
+
+ *_is_battery_absent = is_battery_absent;
+
+ if (alert_userspace)
+ *_alert_userspace = alert_userspace;
+
+ return 0;
+}
+
+static int rt9455_irq_handler_check_irq2_register(struct rt9455_info *info,
+ bool is_battery_absent,
+ bool *_alert_userspace)
+{
+ u8 irq2, mask2;
+ struct device *dev = &info->client->dev;
+ bool alert_userspace = false;
+ int ret;
+
+ ret = rt9455_read(info, RT9455_REG_IRQ2, &irq2);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ2 register\n");
+ return ret;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_MASK2, &mask2);
+ if (ret) {
+ dev_err(dev, "Failed to read MASK2 register\n");
+ return ret;
+ }
+
+ if (irq2 & RT9455_REG_IRQ2_CHRVPI_MASK) {
+ dev_dbg(dev, "Charger fault occurred\n");
+ alert_userspace = true;
+ /* CHRVPI bit is set in 2 cases:
+ * 1. when the power source is connected to the charger.
+ * 2. when the power source is disconnected from the charger.
+ * To identify the case, PWR_RDY bit is checked. Because
+ * PWR_RDY bit is set / cleared after CHRVPI interrupt is
+ * triggered, we use delayed_work to later read PWR_RDY bit.
+ */
+ schedule_delayed_work(&info->pwr_rdy_work,
+ RT9455_PWR_RDY_DELAY * HZ);
+ }
+ if (irq2 & RT9455_REG_IRQ2_CHBATOVI_MASK) {
+ dev_err(dev, "Battery OVP occurred\n");
+ alert_userspace = true;
+ }
+ if (irq2 & RT9455_REG_IRQ2_CHTERMI_MASK) {
+ dev_dbg(dev, "Charge terminated\n");
+ alert_userspace = true;
+
+ if (!is_battery_absent) {
+ if ((mask2 & RT9455_REG_MASK2_CHTERMIM_MASK) == 0) {
+ ret = rt9455_write_mask(info, RT9455_REG_MASK2,
+ RT9455_REG_MASK2_CHTERMIM_MASK,
+ RT9455_REG_MASK2_CHTERMIM_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to mask CHTERMI interrupt\n");
+ return ret;
+ }
+ }
+ cancel_delayed_work_sync(&info->max_charging_time_work);
+ }
+ }
+ if (irq2 & RT9455_REG_IRQ2_CHRCHGI_MASK) {
+ dev_dbg(dev, "Recharge request\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_CHG_EN_MASK,
+ RT9455_REG_CTRL7_CHG_EN_SHIFT,
+ 0x01);
+ if (ret) {
+ dev_err(dev, "Failed to enable charging\n");
+ return ret;
+ }
+ if (mask2 & RT9455_REG_MASK2_CHTERMIM_MASK) {
+ ret = rt9455_write_mask(info, RT9455_REG_MASK2,
+ RT9455_REG_MASK2_CHTERMIM_MASK,
+ RT9455_REG_MASK2_CHTERMIM_SHIFT,
+ 0x00);
+ if (ret) {
+ dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
+ return ret;
+ }
+ }
+ if (!is_battery_absent) {
+ schedule_delayed_work(&info->max_charging_time_work,
+ RT9455_MAX_CHARGING_TIME * HZ);
+ alert_userspace = true;
+ }
+ }
+ if (irq2 & RT9455_REG_IRQ2_CH32MI_MASK) {
+ dev_err(dev, "Charger fault. 32 mins timeout occurred\n");
+ alert_userspace = true;
+ }
+ if (irq2 & RT9455_REG_IRQ2_CHTREGI_MASK) {
+ dev_warn(dev,
+ "Charger warning. Thermal regulation loop active\n");
+ alert_userspace = true;
+ }
+ if (irq2 & RT9455_REG_IRQ2_CHMIVRI_MASK) {
+ dev_dbg(dev,
+ "Charger warning. Input voltage MIVR loop active\n");
+ }
+
+ if (alert_userspace)
+ *_alert_userspace = alert_userspace;
+
+ return 0;
+}
+
+static int rt9455_irq_handler_check_irq3_register(struct rt9455_info *info,
+ bool *_alert_userspace)
+{
+ u8 irq3, mask3;
+ struct device *dev = &info->client->dev;
+ bool alert_userspace = false;
+ int ret;
+
+ ret = rt9455_read(info, RT9455_REG_IRQ3, &irq3);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ3 register\n");
+ return ret;
+ }
+
+ ret = rt9455_read(info, RT9455_REG_MASK3, &mask3);
+ if (ret) {
+ dev_err(dev, "Failed to read MASK3 register\n");
+ return ret;
+ }
+
+ if (irq3 & RT9455_REG_IRQ3_BSTBUSOVI_MASK) {
+ dev_err(dev, "Boost fault. Overvoltage input occurred\n");
+ alert_userspace = true;
+ }
+ if (irq3 & RT9455_REG_IRQ3_BSTOLI_MASK) {
+ dev_err(dev, "Boost fault. Overload\n");
+ alert_userspace = true;
+ }
+ if (irq3 & RT9455_REG_IRQ3_BSTLOWVI_MASK) {
+ dev_err(dev, "Boost fault. Battery voltage too low\n");
+ alert_userspace = true;
+ }
+ if (irq3 & RT9455_REG_IRQ3_BST32SI_MASK) {
+ dev_err(dev, "Boost fault. 32 seconds timeout occurred.\n");
+ alert_userspace = true;
+ }
+
+ if (alert_userspace) {
+ dev_dbg(dev, "Boost fault occurred, therefore the charger goes into charge mode\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ RT9455_CHARGE_MODE);
+ if (ret) {
+ dev_err(dev, "Failed to set charger in charge mode\n");
+ return ret;
+ }
+ *_alert_userspace = alert_userspace;
+ }
+
+ return 0;
+}
+
+static irqreturn_t rt9455_irq_handler_thread(int irq, void *data)
+{
+ struct rt9455_info *info = data;
+ struct device *dev = &info->client->dev;
+ bool alert_userspace = false;
+ bool is_battery_absent = false;
+ u8 status;
+ int ret;
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL1,
+ RT9455_REG_CTRL1_STAT_MASK,
+ RT9455_REG_CTRL1_STAT_SHIFT,
+ &status);
+ if (ret) {
+ dev_err(dev, "Failed to read STAT bits\n");
+ return IRQ_HANDLED;
+ }
+ dev_dbg(dev, "Charger status is %d\n", status);
+
+ /* Each function that processes an IRQ register receives as output
+ * parameter alert_userspace pointer. alert_userspace is set to true
+ * in such a function only if an interrupt has occurred in the
+ * respective interrupt register. This way, we avoid the following
+ * case: interrupt occurs only in IRQ1 register,
+ * rt9455_irq_handler_check_irq1_register() function sets to true
+ * alert_userspace, but rt9455_irq_handler_check_irq2_register()
+ * and rt9455_irq_handler_check_irq3_register() functions set to false
+ * alert_userspace and power_supply_changed() is never called.
+ */
+ ret = rt9455_irq_handler_check_irq1_register(info, &is_battery_absent,
+ &alert_userspace);
+ if (ret) {
+ dev_err(dev, "Failed to handle IRQ1 register\n");
+ return IRQ_HANDLED;
+ }
+
+ ret = rt9455_irq_handler_check_irq2_register(info, is_battery_absent,
+ &alert_userspace);
+ if (ret) {
+ dev_err(dev, "Failed to handle IRQ2 register\n");
+ return IRQ_HANDLED;
+ }
+
+ ret = rt9455_irq_handler_check_irq3_register(info, &alert_userspace);
+ if (ret) {
+ dev_err(dev, "Failed to handle IRQ3 register\n");
+ return IRQ_HANDLED;
+ }
+
+ if (alert_userspace) {
+ /* Sometimes, an interrupt occurs while probe() function is
+ * executing and power_supply_register() is not yet called.
+ * Do not call power_supply_charged() in this case.
+ */
+ if (!IS_ERR_OR_NULL(info->charger))
+ power_supply_changed(info->charger);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int rt9455_setup_irq(struct rt9455_info *info)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ /* Obtain IRQ GPIO */
+ info->gpiod_irq = devm_gpiod_get_index(dev, RT9455_IRQ_NAME, 0);
+ if (IS_ERR(info->gpiod_irq)) {
+ dev_err(dev, "Failed to get IRQ GPIO\n");
+ return PTR_ERR(info->gpiod_irq);
+ }
+
+ /* Configure IRQ GPIO */
+ ret = gpiod_direction_input(info->gpiod_irq);
+ if (ret) {
+ dev_err(dev, "Failed to set IRQ GPIO direction err = %d\n",
+ ret);
+ return ret;
+ }
+
+ /* Map the pin to an IRQ */
+ ret = gpiod_to_irq(info->gpiod_irq);
+ if (ret < 0) {
+ dev_err(dev, "Failed to associate GPIO with an IRQ err = %d\n",
+ ret);
+ return ret;
+ }
+
+ dev_dbg(dev, "GPIO resource, no:%d irq:%d\n",
+ desc_to_gpio(info->gpiod_irq), ret);
+ info->client->irq = ret;
+ info->gpio_irq = desc_to_gpio(info->gpiod_irq);
+
+ return 0;
+}
+
+static int rt9455_discover_charger(struct rt9455_info *info, u32 *ichrg,
+ u32 *ieoc_percentage, u32 *voreg,
+ u32 *vmivr, u32 *iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ if (!dev->of_node && !ACPI_HANDLE(dev)) {
+ dev_err(dev, "No support for either device tree or ACPI\n");
+ return -EINVAL;
+ }
+ /* ICHRG, IEOC_PERCENTAGE and VOREG are mandatory parameters. */
+ ret = device_property_read_u32(dev, "rt,ICHRG", ichrg);
+ if (ret) {
+ dev_err(dev, "Error: missing \"ICHRG\" property\n");
+ return ret;
+ }
+
+ ret = device_property_read_u32(dev, "rt,IEOC_PERCENTAGE",
+ ieoc_percentage);
+ if (ret) {
+ dev_err(dev, "Error: missing \"IEOC_PERCENTAGE\" property\n");
+ return ret;
+ }
+
+ ret = device_property_read_u32(dev, "rt,VOREG", voreg);
+ if (ret) {
+ dev_err(dev, "Error: missing \"VOREG\" property\n");
+ return ret;
+ }
+
+ /* MIVR and IAICR are optional parameters. Do not return error if one
+ * of them is not present in ACPI table or device tree specification,
+ */
+ device_property_read_u32(dev, "rt,VMIVR", vmivr);
+ device_property_read_u32(dev, "rt,IAICR", iaicr);
+
+ ret = rt9455_setup_irq(info);
+ if (ret) {
+ dev_err(dev, "Failed to allocate IRQ resource\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rt9455_usb_event_none(struct rt9455_info *info,
+ u8 opa_mode, u8 iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ if (opa_mode == RT9455_BOOST_MODE) {
+ /* If the charger is in boost mode, and it has received
+ * USB_EVENT_NONE, this means the device powered by the
+ * charger is not connected anymore.
+ * In this case, the charger goes into charge mode.
+ */
+ dev_dbg(dev, "USB_EVENT_NONE received, therefore the charger goes into charge mode\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ RT9455_CHARGE_MODE);
+ if (ret) {
+ dev_err(dev, "Failed to set charger in charge mode\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ dev_dbg(dev, "USB_EVENT_NONE received, therefore IAICR is set to its minimum value\n");
+ if (iaicr != RT9455_IAICR_100MA) {
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ RT9455_IAICR_100MA);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR value\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_vbus(struct rt9455_info *info,
+ u8 opa_mode, u8 iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ if (opa_mode == RT9455_BOOST_MODE) {
+ /* If the charger is in boost mode, and it has received
+ * USB_EVENT_VBUS, this means the device powered by the
+ * charger is not connected anymore.
+ * In this case, the charger goes into charge mode.
+ */
+ dev_dbg(dev, "USB_EVENT_VBUS received, therefore the charger goes into charge mode\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ RT9455_CHARGE_MODE);
+ if (ret) {
+ dev_err(dev, "Failed to set charger in charge mode\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ dev_dbg(dev, "USB_EVENT_VBUS received, therefore IAICR is set to 500 mA\n");
+ if (iaicr != RT9455_IAICR_500MA) {
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ RT9455_IAICR_500MA);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR value\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_id(struct rt9455_info *info,
+ u8 opa_mode, u8 iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ if (opa_mode == RT9455_CHARGE_MODE) {
+ /* If the charger is in charge mode, and it has received
+ * USB_EVENT_ID, this means the device powered by the
+ * charger is not connected anymore.
+ * In this case, the charger goes into charge mode.
+ */
+ dev_dbg(dev, "USB_EVENT_ID received, therefore the charger goes into boost mode\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ RT9455_BOOST_MODE);
+ if (ret) {
+ dev_err(dev, "Failed to set charger in boost mode\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ dev_dbg(dev, "USB_EVENT_ID received, therefore IAICR is set to its minimum value\n");
+ if (iaicr != RT9455_IAICR_100MA) {
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ RT9455_IAICR_100MA);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR value\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_charger(struct rt9455_info *info,
+ u8 opa_mode, u8 iaicr)
+{
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ if (opa_mode == RT9455_BOOST_MODE) {
+ /* If the charger is in boost mode, and it has received
+ * USB_EVENT_CHARGER, this means the device powered by the
+ * charger is not connected anymore.
+ * In this case, the charger goes into charge mode.
+ */
+ dev_dbg(dev, "USB_EVENT_CHARGER received, therefore the charger goes into charge mode\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ RT9455_CHARGE_MODE);
+ if (ret) {
+ dev_err(dev, "Failed to set charger in charge mode\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ dev_dbg(dev, "USB_EVENT_CHARGER received, therefore IAICR is set to no current limit\n");
+ if (iaicr != RT9455_IAICR_NO_LIMIT) {
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ RT9455_IAICR_NO_LIMIT);
+ if (ret) {
+ dev_err(dev, "Failed to set IAICR value\n");
+ return NOTIFY_DONE;
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static int rt9455_usb_event(struct notifier_block *nb,
+ unsigned long event, void *power)
+{
+ struct rt9455_info *info = container_of(nb, struct rt9455_info, nb);
+ struct device *dev = &info->client->dev;
+ u8 opa_mode, iaicr;
+ int ret;
+
+ if (!info)
+ return NOTIFY_DONE;
+
+ /* Determine whether the charger is in charge mode
+ * or in boost mode.
+ */
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_OPA_MODE_MASK,
+ RT9455_REG_CTRL2_OPA_MODE_SHIFT,
+ &opa_mode);
+ if (ret) {
+ dev_err(dev, "Failed to read operation mode value\n");
+ return NOTIFY_DONE;
+ }
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL2,
+ RT9455_REG_CTRL2_IAICR_MASK,
+ RT9455_REG_CTRL2_IAICR_SHIFT,
+ &iaicr);
+ if (ret) {
+ dev_err(dev, "Failed to read IAICR value\n");
+ return NOTIFY_DONE;
+ }
+
+ dev_dbg(dev, "Received USB event %lu\n", event);
+ switch (event) {
+ case USB_EVENT_NONE:
+ return rt9455_usb_event_none(info, opa_mode, iaicr);
+ case USB_EVENT_VBUS:
+ return rt9455_usb_event_vbus(info, opa_mode, iaicr);
+ case USB_EVENT_ID:
+ return rt9455_usb_event_id(info, opa_mode, iaicr);
+ case USB_EVENT_CHARGER:
+ return rt9455_usb_event_charger(info, opa_mode, iaicr);
+ default:
+ dev_err(dev, "Unknown USB event\n");
+ }
+ return NOTIFY_DONE;
+}
+
+static void rt9455_pwr_rdy_work_callback(struct work_struct *work)
+{
+ struct rt9455_info *info = container_of(work, struct rt9455_info,
+ pwr_rdy_work.work);
+ struct device *dev = &info->client->dev;
+ u8 pwr_rdy;
+ int ret;
+
+ ret = rt9455_read_mask(info, RT9455_REG_CTRL1,
+ RT9455_REG_CTRL1_PWR_RDY_MASK,
+ RT9455_REG_CTRL1_PWR_RDY_SHIFT,
+ &pwr_rdy);
+ if (ret) {
+ dev_err(dev, "Failed to read Power Ready bit\n");
+ return;
+ }
+ switch (pwr_rdy) {
+ case RT9455_PWR_FAULT:
+ dev_dbg(dev, "Charger disconnected from power source\n");
+ cancel_delayed_work_sync(&info->max_charging_time_work);
+ break;
+ case RT9455_PWR_GOOD:
+ dev_dbg(dev, "Charger connected to power source\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_CHG_EN_MASK,
+ RT9455_REG_CTRL7_CHG_EN_SHIFT,
+ RT9455_CHARGE_ENABLE);
+ if (ret) {
+ dev_err(dev, "Failed to enable charging\n");
+ return;
+ }
+ schedule_delayed_work(&info->max_charging_time_work,
+ RT9455_MAX_CHARGING_TIME * HZ);
+ break;
+ }
+}
+
+static void rt9455_max_charging_time_work_callback(struct work_struct *work)
+{
+ struct rt9455_info *info = container_of(work, struct rt9455_info,
+ max_charging_time_work.work);
+ struct device *dev = &info->client->dev;
+ int ret;
+
+ dev_err(dev, "Battery has been charging for at least 6 hours and is not yet fully charged. Battery is dead, therefore charging is disabled.\n");
+ ret = rt9455_write_mask(info, RT9455_REG_CTRL7,
+ RT9455_REG_CTRL7_CHG_EN_MASK,
+ RT9455_REG_CTRL7_CHG_EN_SHIFT,
+ RT9455_CHARGE_DISABLE);
+ if (ret)
+ dev_err(dev, "Failed to disable charging\n");
+}
+
+static void rt9455_batt_presence_work_callback(struct work_struct *work)
+{
+ struct rt9455_info *info = container_of(work, struct rt9455_info,
+ batt_presence_work.work);
+ struct device *dev = &info->client->dev;
+ u8 irq1;
+ int ret;
+
+ ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
+ if (ret) {
+ dev_err(dev, "Failed to read IRQ1 register\n");
+ return;
+ }
+
+ /* If the battery is still absent, batt_presence_work is rescheduled.
+ Otherwise, max_charging_time is scheduled.
+ */
+ if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
+ schedule_delayed_work(&info->batt_presence_work,
+ RT9455_BATT_PRESENCE_DELAY * HZ);
+ } else {
+ schedule_delayed_work(&info->max_charging_time_work,
+ RT9455_MAX_CHARGING_TIME * HZ);
+ }
+}
+
+struct power_supply_desc rt9455_charger_desc = {
+ .name = RT9455_DRIVER_NAME,
+ .type = POWER_SUPPLY_TYPE_USB,
+ .properties = rt9455_charger_properties,
+ .num_properties = ARRAY_SIZE(rt9455_charger_properties),
+ .get_property = rt9455_charger_get_property,
+ .set_property = rt9455_charger_set_property,
+ .property_is_writeable = rt9455_charger_property_is_writeable,
+};
+
+static int rt9455_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+ struct device *dev = &client->dev;
+ struct rt9455_info *info;
+ struct power_supply_config rt9455_charger_config = {};
+ /* mandatory device-specific data values */
+ u32 ichrg, ieoc_percentage, voreg;
+ /* optional device-specific data values */
+ u32 vmivr = -1, iaicr = -1;
+ int ret;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+ dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
+ return -ENODEV;
+ }
+ info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->client = client;
+ i2c_set_clientdata(client, info);
+
+ ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
+ &voreg, &vmivr, &iaicr);
+ if (ret) {
+ dev_err(dev, "Failed to discover charger\n");
+ return ret;
+ }
+
+#if IS_ENABLED(CONFIG_USB_PHY)
+ info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
+ if (IS_ERR_OR_NULL(info->usb_phy)) {
+ dev_err(dev, "Failed to get USB transceiver\n");
+ } else {
+ info->nb.notifier_call = rt9455_usb_event;
+ ret = usb_register_notifier(info->usb_phy, &info->nb);
+ if (ret) {
+ dev_err(dev, "Failed to register USB notifier\n");
+ usb_put_phy(info->usb_phy);
+ }
+ }
+#endif
+
+ INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
+ INIT_DELAYED_WORK(&info->max_charging_time_work,
+ rt9455_max_charging_time_work_callback);
+ INIT_DELAYED_WORK(&info->batt_presence_work,
+ rt9455_batt_presence_work_callback);
+
+ rt9455_charger_config.of_node = dev->of_node;
+ rt9455_charger_config.drv_data = info;
+ rt9455_charger_config.supplied_to = rt9455_charger_supplied_to;
+ rt9455_charger_config.num_supplicants =
+ ARRAY_SIZE(rt9455_charger_supplied_to);
+ ret = devm_request_threaded_irq(dev, client->irq, NULL,
+ rt9455_irq_handler_thread,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ RT9455_DRIVER_NAME, info);
+ if (ret < 0) {
+ dev_err(dev, "Failed to register IRQ handler\n");
+ return ret;
+ }
+
+ ret = rt9455_hw_init(info, ichrg, ieoc_percentage, voreg, vmivr, iaicr);
+ if (ret) {
+ dev_err(dev, "Failed to set charger to its default values\n");
+ return ret;
+ }
+
+ info->charger = power_supply_register(dev, &rt9455_charger_desc,
+ &rt9455_charger_config);
+ if (IS_ERR_OR_NULL(info->charger)) {
+ dev_err(dev, "Failed to register charger\n");
+ ret = PTR_ERR(info->charger);
+ goto put_usb_phy;
+ }
+
+ return 0;
+
+put_usb_phy:
+#if IS_ENABLED(CONFIG_USB_PHY)
+ if (!IS_ERR_OR_NULL(info->usb_phy)) {
+ usb_unregister_notifier(info->usb_phy, &info->nb);
+ usb_put_phy(info->usb_phy);
+ }
+#endif
+ return ret;
+}
+
+static int rt9455_remove(struct i2c_client *client)
+{
+ int ret;
+ struct rt9455_info *info = i2c_get_clientdata(client);
+
+ ret = rt9455_register_reset(info);
+ if (ret)
+ dev_err(&info->client->dev, "Failed to set charger to its default values\n");
+
+#if IS_ENABLED(CONFIG_USB_PHY)
+ if (!IS_ERR_OR_NULL(info->usb_phy)) {
+ usb_unregister_notifier(info->usb_phy, &info->nb);
+ usb_put_phy(info->usb_phy);
+ }
+#endif
+
+ cancel_delayed_work_sync(&info->pwr_rdy_work);
+ cancel_delayed_work_sync(&info->max_charging_time_work);
+ cancel_delayed_work_sync(&info->batt_presence_work);
+
+ power_supply_unregister(info->charger);
+
+ return ret;
+}
+
+static const struct i2c_device_id rt9455_i2c_id_table[] = {
+ { RT9455_DRIVER_NAME, 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);
+
+static const struct of_device_id rt9455_of_match[] = {
+ { .compatible = "rt,rt9455", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, rt9455_of_match);
+
+static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
+ {"RTK9455", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);
+
+static struct i2c_driver rt9455_driver = {
+ .probe = rt9455_probe,
+ .remove = rt9455_remove,
+ .id_table = rt9455_i2c_id_table,
+ .driver = {
+ .name = RT9455_DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(rt9455_of_match),
+ .acpi_match_table = ACPI_PTR(rt9455_i2c_acpi_match),
+ },
+};
+module_i2c_driver(rt9455_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Anda-Maria Nicolae <[email protected]>");
+MODULE_ALIAS("i2c:rt9455-charger");
+MODULE_DESCRIPTION("Richtek RT9455 Charger Driver");
--
1.7.9.5
2015-04-24 16:57 GMT+09:00 Anda-Maria Nicolae <[email protected]>:
> Based on the datasheet found here:
> http://www.richtek.com/download_ds.jsp?p=RT9455
Hi,
Some comments below.
> Signed-off-by: Anda-Maria Nicolae <[email protected]>
> ---
> .../devicetree/bindings/power/rt9455_charger.txt | 38 +
> .../devicetree/bindings/vendor-prefixes.txt | 1 +
> drivers/power/Kconfig | 6 +
> drivers/power/Makefile | 1 +
> drivers/power/rt9455_charger.c | 1770 ++++++++++++++++++++
> 5 files changed, 1816 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/power/rt9455_charger.txt
> create mode 100644 drivers/power/rt9455_charger.c
>
> diff --git a/Documentation/devicetree/bindings/power/rt9455_charger.txt b/Documentation/devicetree/bindings/power/rt9455_charger.txt
> new file mode 100644
> index 0000000..f716cf6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/rt9455_charger.txt
> @@ -0,0 +1,38 @@
> +Binding for RT rt9455 battery charger
> +
> +Required properties:
> +- compatible: Should contain one of the following:
> + * "rt,rt9455"
> +
> +- reg: integer, i2c address of the device.
> +- rt,ICHRG: integer, output charge current in uA.
> +- rt,IEOC_PERCENTAGE: integer, the percent of the output charge current (ICHRG).
> + When the current in constant-voltage phase drops below
> + ICHRG x IEOC_PERCENTAGE, charge is terminated.
> +- rt,VOREG: integer, battery regulation voltage in uV.
> +
> +Optional properties:
> +- rt,VMIVR: integer, minimum input voltage regulation in uV.
> + Prevents input voltage drop due to insufficient current
> + provided by the power source.
> +- rt,IAICR: integer, input current regulation in uA.
These should be lowercase separated with dash '-'.
> +
> +Example:
> +
> +rt9455@22 {
> + compatible = "rt,rt9455";
> + reg = <0x22>;
> +
> + interrupt-parent = <&gpio1>;
> + interrupts = <0 1>;
> +
> + interrupt-gpio = <&gpio1 0 1>;
> + reset-gpio = <&gpio1 1 1>;
> +
> + rt,ICHRG = <500000>;
> + rt,IEOC_PERCENTAGE = <10>;
> + rt,VOREG = <4200000>;
> +
> + rt,VMIVR = <4500000>;
> + rt,IAICR = <500000>;
> +};
> diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
> index 389ca13..dc868ed 100644
> --- a/Documentation/devicetree/bindings/vendor-prefixes.txt
> +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
> @@ -148,6 +148,7 @@ raidsonic RaidSonic Technology GmbH
> ralink Mediatek/Ralink Technology Corp.
> ramtron Ramtron International
> realtek Realtek Semiconductor Corp.
> +rt Richtek Technology Corporation
Actually I would prefer sticking to "richtek" prefix, sent some time
ago by Beomho Seo:
http://lwn.net/Articles/625133/
"rt" could be easily taken as "Realtek".
(...)
> +/*
> + * Each array initialised below shows the possible real-world values for a
> + * group of bits belonging to RT9455 registers. The arrays are sorted in
> + * ascending order. The index of each real-world value represents the value
> + * that is encoded in the group of bits belonging to RT9455 registers.
> + */
> +/* REG06[6:4] (ICHRG) in uAh */
> +static const int rt9455_ichrg_values[] = {
> + 500000, 650000, 800000, 950000, 1100000, 1250000, 1400000, 1550000
> +};
> +
> +/* REG02[7:2] (VOREG) in uV */
> +static const int rt9455_voreg_values[] = {
> + 3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
> + 3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
> + 3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
> + 3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
> + 4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
> + 4300000, 4330000, 4350000, 4370000, 4390000, 4410000, 4430000, 4450000,
> + 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000,
> + 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000
> +};
> +
> +/* REG07[3:0] (VMREG) in uV */
> +static const int rt9455_vmreg_values[] = {
> + 4200000, 4220000, 4240000, 4260000, 4280000, 4300000, 4320000, 4340000,
> + 4360000, 4380000, 4400000, 4430000, 4450000, 4450000, 4450000, 4450000
> +};
> +
> +/* REG05[5:4] (IEOC_PERCENTAGE) */
> +static const int rt9455_ieoc_percentage_values[] = {
> + 10, 30, 20, 30
> +};
> +
> +/* REG05[1:0] (VMIVR) in uV */
> +static const int rt9455_vmivr_values[] = {
> + 4000000, 4250000, 4500000, 5000000
> +};
> +
> +/* REG05[1:0] (IAICR) in uA */
> +static const int rt9455_iaicr_values[] = {
> + 100000, 500000, 1000000, 2000000
> +};
> +
> +struct rt9455_info {
> + struct i2c_client *client;
> + struct power_supply *charger;
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + struct usb_phy *usb_phy;
> + struct notifier_block nb;
> +#endif
> + struct gpio_desc *gpiod_irq;
> + unsigned int gpio_irq;
> + struct delayed_work pwr_rdy_work;
> + struct delayed_work max_charging_time_work;
> + struct delayed_work batt_presence_work;
> +};
> +
> +/* I2C read/write API */
> +static int rt9455_read(struct rt9455_info *info, u8 reg, u8 *data)
> +{
> + int ret;
> +
> + ret = i2c_smbus_read_byte_data(info->client, reg);
> + if (ret < 0)
> + return ret;
> +
> + *data = ret;
> + return 0;
> +}
> +
> +static int rt9455_write(struct rt9455_info *info, u8 reg, u8 data)
> +{
> + return i2c_smbus_write_byte_data(info->client, reg, data);
> +}
> +
> +static int rt9455_read_mask(struct rt9455_info *info, u8 reg,
> + u8 mask, u8 shift, u8 *data)
> +{
> + u8 v;
> + int ret;
> +
> + ret = rt9455_read(info, reg, &v);
> + if (ret < 0)
> + return ret;
> +
> + v &= mask;
> + v >>= shift;
> + *data = v;
> +
> + return 0;
> +}
> +
> +static int rt9455_write_mask(struct rt9455_info *info, u8 reg,
> + u8 mask, u8 shift, u8 data)
> +{
> + u8 v;
> + int ret;
> +
> + ret = rt9455_read(info, reg, &v);
> + if (ret < 0)
> + return ret;
> +
> + v &= ~mask;
> + v |= ((data << shift) & mask);
> +
> + return rt9455_write(info, reg, v);
> +}
Maybe just regmap_read(), regmap_write() and regmap_update_bits().
> +
> +/*
> + * Iterate through each element of the 'tbl' array until an element whose value
> + * is greater than v is found. Return the index of the respective element,
> + * or the index of the last element in the array, if no such element is found.
> + */
> +static u8 rt9455_find_idx(const int tbl[], int tbl_size, int v)
> +{
> + int i;
> +
> + /* No need to iterate until the last index in the table because
> + * if no element greater than v is found in the table,
> + * or if only the last element is greater than v,
> + * function returns the index of the last element.
> + */
Here and in other places - please use standard kernel multi-line comment:
/*
* lorem
* ipsum
*/
(...)
> +
> +static void rt9455_batt_presence_work_callback(struct work_struct *work)
> +{
> + struct rt9455_info *info = container_of(work, struct rt9455_info,
> + batt_presence_work.work);
> + struct device *dev = &info->client->dev;
> + u8 irq1;
> + int ret;
> +
> + ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
> + if (ret) {
> + dev_err(dev, "Failed to read IRQ1 register\n");
> + return;
> + }
> +
> + /* If the battery is still absent, batt_presence_work is rescheduled.
> + Otherwise, max_charging_time is scheduled.
> + */
> + if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
> + schedule_delayed_work(&info->batt_presence_work,
> + RT9455_BATT_PRESENCE_DELAY * HZ);
> + } else {
> + schedule_delayed_work(&info->max_charging_time_work,
> + RT9455_MAX_CHARGING_TIME * HZ);
> + }
Do all of these schedules have to be executed on system_wq? Maybe
power efficient workqueue could be used? I don't see any locking so
probably not... but still it is worth investigating.
> +}
> +
> +struct power_supply_desc rt9455_charger_desc = {
> + .name = RT9455_DRIVER_NAME,
> + .type = POWER_SUPPLY_TYPE_USB,
> + .properties = rt9455_charger_properties,
> + .num_properties = ARRAY_SIZE(rt9455_charger_properties),
> + .get_property = rt9455_charger_get_property,
> + .set_property = rt9455_charger_set_property,
> + .property_is_writeable = rt9455_charger_property_is_writeable,
> +};
This can be "static const".
> +
> +static int rt9455_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
> + struct device *dev = &client->dev;
> + struct rt9455_info *info;
> + struct power_supply_config rt9455_charger_config = {};
> + /* mandatory device-specific data values */
> + u32 ichrg, ieoc_percentage, voreg;
> + /* optional device-specific data values */
> + u32 vmivr = -1, iaicr = -1;
> + int ret;
> +
> + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
> + dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
> + return -ENODEV;
> + }
> + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;
> +
> + info->client = client;
> + i2c_set_clientdata(client, info);
> +
> + ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
> + &voreg, &vmivr, &iaicr);
> + if (ret) {
> + dev_err(dev, "Failed to discover charger\n");
> + return ret;
> + }
> +
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
> + if (IS_ERR_OR_NULL(info->usb_phy)) {
> + dev_err(dev, "Failed to get USB transceiver\n");
> + } else {
> + info->nb.notifier_call = rt9455_usb_event;
> + ret = usb_register_notifier(info->usb_phy, &info->nb);
> + if (ret) {
> + dev_err(dev, "Failed to register USB notifier\n");
> + usb_put_phy(info->usb_phy);
> + }
> + }
> +#endif
> +
> + INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
> + INIT_DELAYED_WORK(&info->max_charging_time_work,
> + rt9455_max_charging_time_work_callback);
> + INIT_DELAYED_WORK(&info->batt_presence_work,
> + rt9455_batt_presence_work_callback);
Maybe any of these could be made as DEFERRABLE_WORK? Just thinking out loud...
> +
> + rt9455_charger_config.of_node = dev->of_node;
> + rt9455_charger_config.drv_data = info;
> + rt9455_charger_config.supplied_to = rt9455_charger_supplied_to;
> + rt9455_charger_config.num_supplicants =
> + ARRAY_SIZE(rt9455_charger_supplied_to);
> + ret = devm_request_threaded_irq(dev, client->irq, NULL,
> + rt9455_irq_handler_thread,
> + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> + RT9455_DRIVER_NAME, info);
> + if (ret < 0) {
> + dev_err(dev, "Failed to register IRQ handler\n");
> + return ret;
goto put_usb_phy;
> + }
> +
> + ret = rt9455_hw_init(info, ichrg, ieoc_percentage, voreg, vmivr, iaicr);
> + if (ret) {
> + dev_err(dev, "Failed to set charger to its default values\n");
> + return ret;
Ditto.
> + }
> +
> + info->charger = power_supply_register(dev, &rt9455_charger_desc,
> + &rt9455_charger_config);
> + if (IS_ERR_OR_NULL(info->charger)) {
I think here it cannot be NULL. IS_ERR() is sufficient.
> + dev_err(dev, "Failed to register charger\n");
> + ret = PTR_ERR(info->charger);
> + goto put_usb_phy;
> + }
> +
> + return 0;
> +
> +put_usb_phy:
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + if (!IS_ERR_OR_NULL(info->usb_phy)) {
> + usb_unregister_notifier(info->usb_phy, &info->nb);
> + usb_put_phy(info->usb_phy);
> + }
> +#endif
> + return ret;
> +}
> +
> +static int rt9455_remove(struct i2c_client *client)
> +{
> + int ret;
> + struct rt9455_info *info = i2c_get_clientdata(client);
> +
> + ret = rt9455_register_reset(info);
> + if (ret)
> + dev_err(&info->client->dev, "Failed to set charger to its default values\n");
> +
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + if (!IS_ERR_OR_NULL(info->usb_phy)) {
> + usb_unregister_notifier(info->usb_phy, &info->nb);
> + usb_put_phy(info->usb_phy);
> + }
> +#endif
> +
> + cancel_delayed_work_sync(&info->pwr_rdy_work);
> + cancel_delayed_work_sync(&info->max_charging_time_work);
> + cancel_delayed_work_sync(&info->batt_presence_work);
> +
> + power_supply_unregister(info->charger);
> +
> + return ret;
> +}
> +
> +static const struct i2c_device_id rt9455_i2c_id_table[] = {
> + { RT9455_DRIVER_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);
> +
> +static const struct of_device_id rt9455_of_match[] = {
> + { .compatible = "rt,rt9455", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, rt9455_of_match);
> +
> +static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
> + {"RTK9455", 0},
To be consistent: spaces after/before brackets.
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);
> +
> +static struct i2c_driver rt9455_driver = {
> + .probe = rt9455_probe,
> + .remove = rt9455_remove,
> + .id_table = rt9455_i2c_id_table,
> + .driver = {
> + .name = RT9455_DRIVER_NAME,
> + .owner = THIS_MODULE,
Owner is now set by core and such initialization was removed from drivers.
Best regards,
Krzysztof
Just a single nit: a license mismatch.
On Fri, 2015-04-24 at 10:57 +0300, Anda-Maria Nicolae wrote:
> --- /dev/null
> +++ b/drivers/power/rt9455_charger.c
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
This states the license is GPL v2 or later.
> +MODULE_LICENSE("GPL v2");
And, according to include/linux/module.h, this states the license is
(only) GPL v2. So I think either the license comment or the ident used
in the MODULE_LICENSE() macro should be changed.
Paul Bolle
Hello Paul,
Thanks for feedback :).
I understand. I will change the license to GPL.
Thanks,
Anda
________________________________________
From: Paul Bolle [[email protected]]
Sent: Saturday, April 25, 2015 12:00 PM
To: Nicolae, Anda-maria
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH] power_supply: Add support for Richtek rt9455 battery charger
Just a single nit: a license mismatch.
On Fri, 2015-04-24 at 10:57 +0300, Anda-Maria Nicolae wrote:
> --- /dev/null
> +++ b/drivers/power/rt9455_charger.c
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
This states the license is GPL v2 or later.
> +MODULE_LICENSE("GPL v2");
And, according to include/linux/module.h, this states the license is
(only) GPL v2. So I think either the license comment or the ident used
in the MODULE_LICENSE() macro should be changed.
Paul Bolle
Hello Krzysztof,
Thanks for feedback :).
More comments inline.
Thanks,
Anda
________________________________________
From: Krzysztof Koz?owski [[email protected]]
Sent: Saturday, April 25, 2015 10:25 AM
To: Nicolae, Anda-maria
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH] power_supply: Add support for Richtek rt9455 battery charger
2015-04-24 16:57 GMT+09:00 Anda-Maria Nicolae <[email protected]>:
> Based on the datasheet found here:
> http://www.richtek.com/download_ds.jsp?p=RT9455
Hi,
Some comments below.
> Signed-off-by: Anda-Maria Nicolae <[email protected]>
> ---
> .../devicetree/bindings/power/rt9455_charger.txt | 38 +
> .../devicetree/bindings/vendor-prefixes.txt | 1 +
> drivers/power/Kconfig | 6 +
> drivers/power/Makefile | 1 +
> drivers/power/rt9455_charger.c | 1770 ++++++++++++++++++++
> 5 files changed, 1816 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/power/rt9455_charger.txt
> create mode 100644 drivers/power/rt9455_charger.c
>
> diff --git a/Documentation/devicetree/bindings/power/rt9455_charger.txt b/Documentation/devicetree/bindings/power/rt9455_charger.txt
> new file mode 100644
> index 0000000..f716cf6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/rt9455_charger.txt
> @@ -0,0 +1,38 @@
> +Binding for RT rt9455 battery charger
> +
> +Required properties:
> +- compatible: Should contain one of the following:
> + * "rt,rt9455"
> +
> +- reg: integer, i2c address of the device.
> +- rt,ICHRG: integer, output charge current in uA.
> +- rt,IEOC_PERCENTAGE: integer, the percent of the output charge current (ICHRG).
> + When the current in constant-voltage phase drops below
> + ICHRG x IEOC_PERCENTAGE, charge is terminated.
> +- rt,VOREG: integer, battery regulation voltage in uV.
> +
> +Optional properties:
> +- rt,VMIVR: integer, minimum input voltage regulation in uV.
> + Prevents input voltage drop due to insufficient current
> + provided by the power source.
> +- rt,IAICR: integer, input current regulation in uA.
These should be lowercase separated with dash '-'.
Will rename the properties to be lowercase separated with dash '-'.
> +
> +Example:
> +
> +rt9455@22 {
> + compatible = "rt,rt9455";
> + reg = <0x22>;
> +
> + interrupt-parent = <&gpio1>;
> + interrupts = <0 1>;
> +
> + interrupt-gpio = <&gpio1 0 1>;
> + reset-gpio = <&gpio1 1 1>;
> +
> + rt,ICHRG = <500000>;
> + rt,IEOC_PERCENTAGE = <10>;
> + rt,VOREG = <4200000>;
> +
> + rt,VMIVR = <4500000>;
> + rt,IAICR = <500000>;
> +};
> diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
> index 389ca13..dc868ed 100644
> --- a/Documentation/devicetree/bindings/vendor-prefixes.txt
> +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
> @@ -148,6 +148,7 @@ raidsonic RaidSonic Technology GmbH
> ralink Mediatek/Ralink Technology Corp.
> ramtron Ramtron International
> realtek Realtek Semiconductor Corp.
> +rt Richtek Technology Corporation
Actually I would prefer sticking to "richtek" prefix, sent some time
ago by Beomho Seo:
http://lwn.net/Articles/625133/
"rt" could be easily taken as "Realtek".
Will use richtek.
(...)
> +/*
> + * Each array initialised below shows the possible real-world values for a
> + * group of bits belonging to RT9455 registers. The arrays are sorted in
> + * ascending order. The index of each real-world value represents the value
> + * that is encoded in the group of bits belonging to RT9455 registers.
> + */
> +/* REG06[6:4] (ICHRG) in uAh */
> +static const int rt9455_ichrg_values[] = {
> + 500000, 650000, 800000, 950000, 1100000, 1250000, 1400000, 1550000
> +};
> +
> +/* REG02[7:2] (VOREG) in uV */
> +static const int rt9455_voreg_values[] = {
> + 3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
> + 3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
> + 3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
> + 3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
> + 4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
> + 4300000, 4330000, 4350000, 4370000, 4390000, 4410000, 4430000, 4450000,
> + 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000,
> + 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000
> +};
> +
> +/* REG07[3:0] (VMREG) in uV */
> +static const int rt9455_vmreg_values[] = {
> + 4200000, 4220000, 4240000, 4260000, 4280000, 4300000, 4320000, 4340000,
> + 4360000, 4380000, 4400000, 4430000, 4450000, 4450000, 4450000, 4450000
> +};
> +
> +/* REG05[5:4] (IEOC_PERCENTAGE) */
> +static const int rt9455_ieoc_percentage_values[] = {
> + 10, 30, 20, 30
> +};
> +
> +/* REG05[1:0] (VMIVR) in uV */
> +static const int rt9455_vmivr_values[] = {
> + 4000000, 4250000, 4500000, 5000000
> +};
> +
> +/* REG05[1:0] (IAICR) in uA */
> +static const int rt9455_iaicr_values[] = {
> + 100000, 500000, 1000000, 2000000
> +};
> +
> +struct rt9455_info {
> + struct i2c_client *client;
> + struct power_supply *charger;
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + struct usb_phy *usb_phy;
> + struct notifier_block nb;
> +#endif
> + struct gpio_desc *gpiod_irq;
> + unsigned int gpio_irq;
> + struct delayed_work pwr_rdy_work;
> + struct delayed_work max_charging_time_work;
> + struct delayed_work batt_presence_work;
> +};
> +
> +/* I2C read/write API */
> +static int rt9455_read(struct rt9455_info *info, u8 reg, u8 *data)
> +{
> + int ret;
> +
> + ret = i2c_smbus_read_byte_data(info->client, reg);
> + if (ret < 0)
> + return ret;
> +
> + *data = ret;
> + return 0;
> +}
> +
> +static int rt9455_write(struct rt9455_info *info, u8 reg, u8 data)
> +{
> + return i2c_smbus_write_byte_data(info->client, reg, data);
> +}
> +
> +static int rt9455_read_mask(struct rt9455_info *info, u8 reg,
> + u8 mask, u8 shift, u8 *data)
> +{
> + u8 v;
> + int ret;
> +
> + ret = rt9455_read(info, reg, &v);
> + if (ret < 0)
> + return ret;
> +
> + v &= mask;
> + v >>= shift;
> + *data = v;
> +
> + return 0;
> +}
> +
> +static int rt9455_write_mask(struct rt9455_info *info, u8 reg,
> + u8 mask, u8 shift, u8 data)
> +{
> + u8 v;
> + int ret;
> +
> + ret = rt9455_read(info, reg, &v);
> + if (ret < 0)
> + return ret;
> +
> + v &= ~mask;
> + v |= ((data << shift) & mask);
> +
> + return rt9455_write(info, reg, v);
> +}
Maybe just regmap_read(), regmap_write() and regmap_update_bits().
Ok, I will use regmap.
> +
> +/*
> + * Iterate through each element of the 'tbl' array until an element whose value
> + * is greater than v is found. Return the index of the respective element,
> + * or the index of the last element in the array, if no such element is found.
> + */
> +static u8 rt9455_find_idx(const int tbl[], int tbl_size, int v)
> +{
> + int i;
> +
> + /* No need to iterate until the last index in the table because
> + * if no element greater than v is found in the table,
> + * or if only the last element is greater than v,
> + * function returns the index of the last element.
> + */
Here and in other places - please use standard kernel multi-line comment:
/*
* lorem
* ipsum
*/
Will do.
(...)
> +
> +static void rt9455_batt_presence_work_callback(struct work_struct *work)
> +{
> + struct rt9455_info *info = container_of(work, struct rt9455_info,
> + batt_presence_work.work);
> + struct device *dev = &info->client->dev;
> + u8 irq1;
> + int ret;
> +
> + ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
> + if (ret) {
> + dev_err(dev, "Failed to read IRQ1 register\n");
> + return;
> + }
> +
> + /* If the battery is still absent, batt_presence_work is rescheduled.
> + Otherwise, max_charging_time is scheduled.
> + */
> + if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
> + schedule_delayed_work(&info->batt_presence_work,
> + RT9455_BATT_PRESENCE_DELAY * HZ);
> + } else {
> + schedule_delayed_work(&info->max_charging_time_work,
> + RT9455_MAX_CHARGING_TIME * HZ);
> + }
Do all of these schedules have to be executed on system_wq? Maybe
power efficient workqueue could be used? I don't see any locking so
probably not... but still it is worth investigating.
Ok, I will use queue_delayed_work(system_power_efficient_wq, ...). I'm not sure if I understand exactly what do you mean by "I don't see any locking so probably not". I can see that __queue_work() uses spinlocks. And other drivers that use system_power_efficient_wq also do not use additional locking.
I intend to replace schedule_delayed_work() with queue_delayed_work(system_power_efficient_wq, ...), without adding any locking in the driver. Please let me know if I understood correctly what you meant .
> +}
> +
> +struct power_supply_desc rt9455_charger_desc = {
> + .name = RT9455_DRIVER_NAME,
> + .type = POWER_SUPPLY_TYPE_USB,
> + .properties = rt9455_charger_properties,
> + .num_properties = ARRAY_SIZE(rt9455_charger_properties),
> + .get_property = rt9455_charger_get_property,
> + .set_property = rt9455_charger_set_property,
> + .property_is_writeable = rt9455_charger_property_is_writeable,
> +};
This can be "static const".
Will do.
> +
> +static int rt9455_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
> + struct device *dev = &client->dev;
> + struct rt9455_info *info;
> + struct power_supply_config rt9455_charger_config = {};
> + /* mandatory device-specific data values */
> + u32 ichrg, ieoc_percentage, voreg;
> + /* optional device-specific data values */
> + u32 vmivr = -1, iaicr = -1;
> + int ret;
> +
> + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
> + dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
> + return -ENODEV;
> + }
> + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;
> +
> + info->client = client;
> + i2c_set_clientdata(client, info);
> +
> + ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
> + &voreg, &vmivr, &iaicr);
> + if (ret) {
> + dev_err(dev, "Failed to discover charger\n");
> + return ret;
> + }
> +
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
> + if (IS_ERR_OR_NULL(info->usb_phy)) {
> + dev_err(dev, "Failed to get USB transceiver\n");
> + } else {
> + info->nb.notifier_call = rt9455_usb_event;
> + ret = usb_register_notifier(info->usb_phy, &info->nb);
> + if (ret) {
> + dev_err(dev, "Failed to register USB notifier\n");
> + usb_put_phy(info->usb_phy);
> + }
> + }
> +#endif
> +
> + INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
> + INIT_DELAYED_WORK(&info->max_charging_time_work,
> + rt9455_max_charging_time_work_callback);
> + INIT_DELAYED_WORK(&info->batt_presence_work,
> + rt9455_batt_presence_work_callback);
Maybe any of these could be made as DEFERRABLE_WORK? Just thinking out loud...
I cannot use DEFERRABLE_WORK instead of DELAYED_WORK. DEFERRABLE_WORK runs in interrupt context, while DELAYED_WORK runs in process context. All handlers for DELAYED_WORK from the driver perform read/write operations via I2C, which may sleep. This is the reason why DELAYED_WORK is used.
> +
> + rt9455_charger_config.of_node = dev->of_node;
> + rt9455_charger_config.drv_data = info;
> + rt9455_charger_config.supplied_to = rt9455_charger_supplied_to;
> + rt9455_charger_config.num_supplicants =
> + ARRAY_SIZE(rt9455_charger_supplied_to);
> + ret = devm_request_threaded_irq(dev, client->irq, NULL,
> + rt9455_irq_handler_thread,
> + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> + RT9455_DRIVER_NAME, info);
> + if (ret < 0) {
> + dev_err(dev, "Failed to register IRQ handler\n");
> + return ret;
goto put_usb_phy;
> + }
> +
> + ret = rt9455_hw_init(info, ichrg, ieoc_percentage, voreg, vmivr, iaicr);
> + if (ret) {
> + dev_err(dev, "Failed to set charger to its default values\n");
> + return ret;
Ditto.
> + }
> +
> + info->charger = power_supply_register(dev, &rt9455_charger_desc,
> + &rt9455_charger_config);
> + if (IS_ERR_OR_NULL(info->charger)) {
I think here it cannot be NULL. IS_ERR() is sufficient.
i checked it and you are right. Will do.
> + dev_err(dev, "Failed to register charger\n");
> + ret = PTR_ERR(info->charger);
> + goto put_usb_phy;
> + }
> +
> + return 0;
> +
> +put_usb_phy:
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + if (!IS_ERR_OR_NULL(info->usb_phy)) {
> + usb_unregister_notifier(info->usb_phy, &info->nb);
> + usb_put_phy(info->usb_phy);
> + }
> +#endif
> + return ret;
> +}
> +
> +static int rt9455_remove(struct i2c_client *client)
> +{
> + int ret;
> + struct rt9455_info *info = i2c_get_clientdata(client);
> +
> + ret = rt9455_register_reset(info);
> + if (ret)
> + dev_err(&info->client->dev, "Failed to set charger to its default values\n");
> +
> +#if IS_ENABLED(CONFIG_USB_PHY)
> + if (!IS_ERR_OR_NULL(info->usb_phy)) {
> + usb_unregister_notifier(info->usb_phy, &info->nb);
> + usb_put_phy(info->usb_phy);
> + }
> +#endif
> +
> + cancel_delayed_work_sync(&info->pwr_rdy_work);
> + cancel_delayed_work_sync(&info->max_charging_time_work);
> + cancel_delayed_work_sync(&info->batt_presence_work);
> +
> + power_supply_unregister(info->charger);
> +
> + return ret;
> +}
> +
> +static const struct i2c_device_id rt9455_i2c_id_table[] = {
> + { RT9455_DRIVER_NAME, 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);
> +
> +static const struct of_device_id rt9455_of_match[] = {
> + { .compatible = "rt,rt9455", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, rt9455_of_match);
> +
> +static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
> + {"RTK9455", 0},
To be consistent: spaces after/before brackets.
Will do.
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);
> +
> +static struct i2c_driver rt9455_driver = {
> + .probe = rt9455_probe,
> + .remove = rt9455_remove,
> + .id_table = rt9455_i2c_id_table,
> + .driver = {
> + .name = RT9455_DRIVER_NAME,
> + .owner = THIS_MODULE,
Owner is now set by core and such initialization was removed from drivers.
Will remove it.
Best regards,
Krzysztof
2015-04-27 22:06 GMT+09:00 Nicolae, Anda-maria <[email protected]>:
(...)
>> +
>> +static void rt9455_batt_presence_work_callback(struct work_struct *work)
>> +{
>> + struct rt9455_info *info = container_of(work, struct rt9455_info,
>> + batt_presence_work.work);
>> + struct device *dev = &info->client->dev;
>> + u8 irq1;
>> + int ret;
>> +
>> + ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
>> + if (ret) {
>> + dev_err(dev, "Failed to read IRQ1 register\n");
>> + return;
>> + }
>> +
>> + /* If the battery is still absent, batt_presence_work is rescheduled.
>> + Otherwise, max_charging_time is scheduled.
>> + */
>> + if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
>> + schedule_delayed_work(&info->batt_presence_work,
>> + RT9455_BATT_PRESENCE_DELAY * HZ);
>> + } else {
>> + schedule_delayed_work(&info->max_charging_time_work,
>> + RT9455_MAX_CHARGING_TIME * HZ);
>> + }
>
> Do all of these schedules have to be executed on system_wq? Maybe
> power efficient workqueue could be used? I don't see any locking so
> probably not... but still it is worth investigating.
>
> Ok, I will use queue_delayed_work(system_power_efficient_wq, ...). I'm not sure if I understand exactly what do you mean by "I don't see any locking so probably not". I can see that __queue_work() uses spinlocks. And other drivers that use system_power_efficient_wq also do not use additional locking.
> I intend to replace schedule_delayed_work() with queue_delayed_work(system_power_efficient_wq, ...), without adding any locking in the driver. Please let me know if I understood correctly what you meant .
You understood me correctly. I was thinking about possibility of
concurrent execution of work callbacks... but actually this should not
be impacted by unbound or bound workqueues. So never mind.
However after looking at the code I got different question. You are
reading here and in few other places the RT9455_REG_IRQ1. Isn't the
register auto-cleared?
(...)
>> +
>> +#if IS_ENABLED(CONFIG_USB_PHY)
>> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
>> + if (IS_ERR_OR_NULL(info->usb_phy)) {
>> + dev_err(dev, "Failed to get USB transceiver\n");
>> + } else {
>> + info->nb.notifier_call = rt9455_usb_event;
>> + ret = usb_register_notifier(info->usb_phy, &info->nb);
>> + if (ret) {
>> + dev_err(dev, "Failed to register USB notifier\n");
>> + usb_put_phy(info->usb_phy);
>> + }
>> + }
>> +#endif
>> +
>> + INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
>> + INIT_DELAYED_WORK(&info->max_charging_time_work,
>> + rt9455_max_charging_time_work_callback);
>> + INIT_DELAYED_WORK(&info->batt_presence_work,
>> + rt9455_batt_presence_work_callback);
>
> Maybe any of these could be made as DEFERRABLE_WORK? Just thinking out loud...
>
> I cannot use DEFERRABLE_WORK instead of DELAYED_WORK. DEFERRABLE_WORK runs in interrupt context, while DELAYED_WORK runs in process context. All handlers for DELAYED_WORK from the driver perform read/write operations via I2C, which may sleep. This is the reason why DELAYED_WORK is used.
AFAIK, the context is the same. The only difference is the type of
timer used for scheduling the work. In case of deferrable timer it
won't wake up a sleeping CPU. Which means that it may be executed some
unspecified time in the future. This has energy conserving benefits
but may not be appropriate for your case because you could want to
poll the battery status in exact intervals.
Best regards,
Krzysztof
Hello Krzysztof,
Thank you for your prompt answer :).
More comments inline.
Thanks,
Anda
________________________________________
From: Krzysztof Koz?owski [[email protected]]
Sent: Monday, April 27, 2015 4:37 PM
To: Nicolae, Anda-maria
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH] power_supply: Add support for Richtek rt9455 battery charger
2015-04-27 22:06 GMT+09:00 Nicolae, Anda-maria <[email protected]>:
(...)
>> +
>> +static void rt9455_batt_presence_work_callback(struct work_struct *work)
>> +{
>> + struct rt9455_info *info = container_of(work, struct rt9455_info,
>> + batt_presence_work.work);
>> + struct device *dev = &info->client->dev;
>> + u8 irq1;
>> + int ret;
>> +
>> + ret = rt9455_read(info, RT9455_REG_IRQ1, &irq1);
>> + if (ret) {
>> + dev_err(dev, "Failed to read IRQ1 register\n");
>> + return;
>> + }
>> +
>> + /* If the battery is still absent, batt_presence_work is rescheduled.
>> + Otherwise, max_charging_time is scheduled.
>> + */
>> + if (irq1 & RT9455_REG_IRQ1_BATAB_MASK) {
>> + schedule_delayed_work(&info->batt_presence_work,
>> + RT9455_BATT_PRESENCE_DELAY * HZ);
>> + } else {
>> + schedule_delayed_work(&info->max_charging_time_work,
>> + RT9455_MAX_CHARGING_TIME * HZ);
>> + }
>
> Do all of these schedules have to be executed on system_wq? Maybe
> power efficient workqueue could be used? I don't see any locking so
> probably not... but still it is worth investigating.
>
> Ok, I will use queue_delayed_work(system_power_efficient_wq, ...). I'm not sure if I understand exactly what do you mean by "I don't see any locking so probably not". I can see that __queue_work() uses spinlocks. And other drivers that use system_power_efficient_wq also do not use additional locking.
> I intend to replace schedule_delayed_work() with queue_delayed_work(system_power_efficient_wq, ...), without adding any locking in the driver. Please let me know if I understood correctly what you meant .
You understood me correctly. I was thinking about possibility of
concurrent execution of work callbacks... but actually this should not
be impacted by unbound or bound workqueues. So never mind.
So, I will stick to replacing schedule_delayed_work() with queue_delayed_work(system_power_efficient_wq, ...), without adding any locking in the driver.
However after looking at the code I got different question. You are
reading here and in few other places the RT9455_REG_IRQ1. Isn't the
register auto-cleared?
No, RT9455_REG_IRQ1 is not cleared after reading. Let me give you an example. Suppose the battery is missing, so BATAB bit is set. This bit remains set until the battery is reconnected to the charger, independent of the number of i2c_reads over RT9455_REG_IRQ1. Unfortunately, no interrupt is triggered when the battery is reconnected (and BATAB bit is cleared).
(...)
>> +
>> +#if IS_ENABLED(CONFIG_USB_PHY)
>> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
>> + if (IS_ERR_OR_NULL(info->usb_phy)) {
>> + dev_err(dev, "Failed to get USB transceiver\n");
>> + } else {
>> + info->nb.notifier_call = rt9455_usb_event;
>> + ret = usb_register_notifier(info->usb_phy, &info->nb);
>> + if (ret) {
>> + dev_err(dev, "Failed to register USB notifier\n");
>> + usb_put_phy(info->usb_phy);
>> + }
>> + }
>> +#endif
>> +
>> + INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
>> + INIT_DELAYED_WORK(&info->max_charging_time_work,
>> + rt9455_max_charging_time_work_callback);
>> + INIT_DELAYED_WORK(&info->batt_presence_work,
>> + rt9455_batt_presence_work_callback);
>
> Maybe any of these could be made as DEFERRABLE_WORK? Just thinking out loud...
>
> I cannot use DEFERRABLE_WORK instead of DELAYED_WORK. DEFERRABLE_WORK runs in interrupt context, while DELAYED_WORK runs in process context. All handlers for DELAYED_WORK from the driver perform read/write operations via I2C, which may sleep. This is the reason why DELAYED_WORK is used.
AFAIK, the context is the same. The only difference is the type of
timer used for scheduling the work. In case of deferrable timer it
won't wake up a sleeping CPU. Which means that it may be executed some
unspecified time in the future. This has energy conserving benefits
but may not be appropriate for your case because you could want to
poll the battery status in exact intervals.
Just to understand correctly, you mean that if I use DEFERRABLE_WORK, I will not get kernel panic with message "scheduling while atomic"? This is what happens if I use timers and I thought that I would get the same result with DEFERRABLE_WORK. Actually, the timers are not critical and status of the charger may be checked some fraction of a second later.
Best regards,
Krzysztof
2015-04-27 23:02 GMT+09:00 Nicolae, Anda-maria <[email protected]>:
> However after looking at the code I got different question. You are
> reading here and in few other places the RT9455_REG_IRQ1. Isn't the
> register auto-cleared?
>
> No, RT9455_REG_IRQ1 is not cleared after reading. Let me give you an example. Suppose the battery is missing, so BATAB bit is set. This bit remains set until the battery is reconnected to the charger, independent of the number of i2c_reads over RT9455_REG_IRQ1. Unfortunately, no interrupt is triggered when the battery is reconnected (and BATAB bit is cleared).
OK, I got it.
>
> (...)
>
>>> +
>>> +#if IS_ENABLED(CONFIG_USB_PHY)
>>> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
>>> + if (IS_ERR_OR_NULL(info->usb_phy)) {
>>> + dev_err(dev, "Failed to get USB transceiver\n");
>>> + } else {
>>> + info->nb.notifier_call = rt9455_usb_event;
>>> + ret = usb_register_notifier(info->usb_phy, &info->nb);
>>> + if (ret) {
>>> + dev_err(dev, "Failed to register USB notifier\n");
>>> + usb_put_phy(info->usb_phy);
>>> + }
>>> + }
>>> +#endif
>>> +
>>> + INIT_DELAYED_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
>>> + INIT_DELAYED_WORK(&info->max_charging_time_work,
>>> + rt9455_max_charging_time_work_callback);
>>> + INIT_DELAYED_WORK(&info->batt_presence_work,
>>> + rt9455_batt_presence_work_callback);
>>
>> Maybe any of these could be made as DEFERRABLE_WORK? Just thinking out loud...
>>
>> I cannot use DEFERRABLE_WORK instead of DELAYED_WORK. DEFERRABLE_WORK runs in interrupt context, while DELAYED_WORK runs in process context. All handlers for DELAYED_WORK from the driver perform read/write operations via I2C, which may sleep. This is the reason why DELAYED_WORK is used.
>
> AFAIK, the context is the same. The only difference is the type of
> timer used for scheduling the work. In case of deferrable timer it
> won't wake up a sleeping CPU. Which means that it may be executed some
> unspecified time in the future. This has energy conserving benefits
> but may not be appropriate for your case because you could want to
> poll the battery status in exact intervals.
>
> Just to understand correctly, you mean that if I use DEFERRABLE_WORK, I will not get kernel panic with message "scheduling while atomic"? This is what happens if I use timers and I thought that I would get the same result with DEFERRABLE_WORK. Actually, the timers are not critical and status of the charger may be checked some fraction of a second later.
You shouldn't get that panic. Deferrable work is used in few other
similar places. As you can check in the include/linux/workqueue.h file
the timers are used in both cases. The INIT_DELAYED_WORK already uses
a flag for timers - TIMER_IRQSAFE. However for deferrable work it uses
additional flag - deferrable timer.
Unfortunately the difference may not be a "fraction of a second
later". Actually the difference may be as much as 1 second later for
the fully non-tickless system. If system is truly idle, the deferrable
timers (and work) may not fire for long time. So this must be
considered.
Best regards,
Krzysztof