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From:   Mike Looijmans <mike.looijmans@topic.nl>
To:     linux-pm@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, sre@kernel.org,
        Mike Looijmans <mike.looijmans@topic.nl>
Subject: [PATCH v5] power/supply: Add ltc4162-l-charger
Date:   Thu,  7 Jan 2021 15:32:48 +0100
Message-Id: <20210107143248.13413-1-mike.looijmans@topic.nl>
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Precedence: bulk

Add support for the LTC4162-L Li-Ion battery charger. The driver allows
reading back telemetry and to set some charging options like the input
current limit.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---
v2: Use microohm units instead of milliohm
    Add interrupt support using smbalert
    Support obtaining cell-count from devicetree
v3: Fix overflows in calculations involving resistor values
v4: Use attr_grp member to register attributes
    Report input current/voltage for charger and make battery
    voltage and current into sysfs attributes
v5: Remove ltc4162l_remove since core now takes care of attributes
    Add ABI documentation for attributes

 .../ABI/testing/sysfs-class-power-ltc4162l    |  82 ++
 drivers/power/supply/Kconfig                  |   8 +
 drivers/power/supply/Makefile                 |   1 +
 drivers/power/supply/ltc4162-l-charger.c      | 931 ++++++++++++++++++
 4 files changed, 1022 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-power-ltc4162l
 create mode 100644 drivers/power/supply/ltc4162-l-charger.c

diff --git a/Documentation/ABI/testing/sysfs-class-power-ltc4162l b/Documentation/ABI/testing/sysfs-class-power-ltc4162l
new file mode 100644
index 000000000000..ba30db93052b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-power-ltc4162l
@@ -0,0 +1,82 @@
+What:		/sys/class/power_supply/ltc4162-l/charge_status
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		Detailed charge status information as reported by the chip.
+
+		Access: Read
+
+		Valid values:
+			ilim_reg_active
+			thermal_reg_active
+			vin_uvcl_active
+			iin_limit_active
+			constant_current
+			constant_voltage
+			charger_off
+
+What:		/sys/class/power_supply/ltc4162-l/ibat
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		Battery input current as measured by the charger. Negative value
+		means that the battery is discharging.
+
+		Access: Read
+
+		Valid values: Signed value in microamps
+
+What:		/sys/class/power_supply/ltc4162-l/vbat
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		Battery voltage as measured by the charger.
+
+		Access: Read
+
+		Valid values: In microvolts
+
+What:		/sys/class/power_supply/ltc4162-l/vbat_avg
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		Battery voltage, averaged over time, as measured by the charger.
+
+		Access: Read
+
+		Valid values: In microvolts
+
+What:		/sys/class/power_supply/ltc4162-l/force_telemetry
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		To save battery current, the measurement system is disabled if
+		the battery is the only source of power. This affects all
+		voltage, current and temperature measurements.
+		Write a "1" to this to keep performing telemetry once every few
+		seconds, even when running on battery (as reported by the online
+		property, which is "1" when external power is available and "0"
+		when the system runs on battery).
+
+		Access: Read, Write
+
+		Valid values: 0 (disabled) or 1 (enabled)
+
+What:		/sys/class/power_supply/ltc4162-l/arm_ship_mode
+Date:		Januari 2021
+KernelVersion:	5.11
+Description:
+		The charger will normally drain the battery while inactive,
+		typically drawing about 54 microamps. Write a "1" to this
+		property to arm a special "ship" mode that extends shelf life
+		by reducing the leakage to about 2.8 microamps. The chip will
+		remain in this mode (and no longer respond to I2C commands)
+		until some external power-supply is attached raising the input
+		voltage above 1V. It will then automatically revert to "0".
+		Writing a "0" to the property cancels the "ship" mode request.
+		The ship mode, when armed, activates once the input voltage
+		drops below 1V.
+
+		Access: Read, Write
+
+		Valid values: 0 (disable) or 1 (enable)
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index eec646c568b7..23000976cb42 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -513,6 +513,14 @@ config CHARGER_LT3651
 	  Say Y to include support for the Analog Devices (Linear Technology)
 	  LT3651 battery charger which reports its status via GPIO lines.
 
+config CHARGER_LTC4162L
+	tristate "LTC4162-L charger"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y to include support for the Analog Devices (Linear Technology)
+	  LTC4162-L battery charger connected to I2C.
+
 config CHARGER_MAX14577
 	tristate "Maxim MAX14577/77836 battery charger driver"
 	depends on MFD_MAX14577
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index dd4b86318cd9..17b1cf921c44 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
 obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
 obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
+obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
 obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
 obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
 obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
new file mode 100644
index 000000000000..cded6484febb
--- /dev/null
+++ b/drivers/power/supply/ltc4162-l-charger.c
@@ -0,0 +1,931 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Driver for Analog Devices (Linear Technology) LTC4162-L charger IC.
+ *  Copyright (C) 2020, Topic Embedded Products
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/power_supply.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+
+/* Registers (names based on what datasheet uses) */
+#define LTC4162L_EN_LIMIT_ALERTS_REG		0x0D
+#define LTC4162L_EN_CHARGER_STATE_ALERTS_REG	0x0E
+#define LTC4162L_EN_CHARGE_STATUS_ALERTS_REG	0x0F
+#define LTC4162L_CONFIG_BITS_REG		0x14
+#define LTC4162L_IIN_LIMIT_TARGET		0x15
+#define LTC4162L_ARM_SHIP_MODE			0x19
+#define LTC4162L_CHARGE_CURRENT_SETTING		0X1A
+#define LTC4162L_VCHARGE_SETTING		0X1B
+#define LTC4162L_C_OVER_X_THRESHOLD		0x1C
+#define LTC4162L_MAX_CV_TIME			0X1D
+#define LTC4162L_MAX_CHARGE_TIME		0X1E
+#define LTC4162L_CHARGER_CONFIG_BITS		0x29
+#define LTC4162L_CHARGER_STATE			0x34
+#define LTC4162L_CHARGE_STATUS			0x35
+#define LTC4162L_LIMIT_ALERTS_REG		0x36
+#define LTC4162L_CHARGER_STATE_ALERTS_REG	0x37
+#define LTC4162L_CHARGE_STATUS_ALERTS_REG	0x38
+#define LTC4162L_SYSTEM_STATUS_REG		0x39
+#define LTC4162L_VBAT				0x3A
+#define LTC4162L_VIN				0x3B
+#define LTC4162L_VOUT				0x3C
+#define LTC4162L_IBAT				0x3D
+#define LTC4162L_IIN				0x3E
+#define LTC4162L_DIE_TEMPERATURE		0x3F
+#define LTC4162L_THERMISTOR_VOLTAGE		0x40
+#define LTC4162L_BSR				0x41
+#define LTC4162L_JEITA_REGION			0x42
+#define LTC4162L_CHEM_CELLS_REG			0x43
+#define LTC4162L_ICHARGE_DAC			0x44
+#define LTC4162L_VCHARGE_DAC			0x45
+#define LTC4162L_IIN_LIMIT_DAC			0x46
+#define LTC4162L_VBAT_FILT			0x47
+#define LTC4162L_INPUT_UNDERVOLTAGE_DAC		0x4B
+
+/* Enumeration as in datasheet. Individual bits are mutually exclusive. */
+enum ltc4162l_state {
+	battery_detection = 2048,
+	charger_suspended = 256,
+	precharge = 128,   /* trickle on low bat voltage */
+	cc_cv_charge = 64, /* normal charge */
+	ntc_pause = 32,
+	timer_term = 16,
+	c_over_x_term = 8, /* battery is full */
+	max_charge_time_fault = 4,
+	bat_missing_fault = 2,
+	bat_short_fault = 1
+};
+
+/* Individual bits are mutually exclusive. Only active in charging states.*/
+enum ltc4162l_charge_status {
+	ilim_reg_active = 32,
+	thermal_reg_active = 16,
+	vin_uvcl_active = 8,
+	iin_limit_active = 4,
+	constant_current = 2,
+	constant_voltage = 1,
+	charger_off = 0
+};
+
+/* Magic number to write to ARM_SHIP_MODE register */
+#define LTC4162L_ARM_SHIP_MODE_MAGIC 21325
+
+struct ltc4162l_info {
+	struct i2c_client	*client;
+	struct regmap		*regmap;
+	struct power_supply	*charger;
+	u32 rsnsb;	/* Series resistor that sets charge current, microOhm */
+	u32 rsnsi;	/* Series resistor to measure input current, microOhm */
+	u8 cell_count;	/* Number of connected cells, 0 while unknown */
+};
+
+static u8 ltc4162l_get_cell_count(struct ltc4162l_info *info)
+{
+	int ret;
+	unsigned int val;
+
+	/* Once read successfully */
+	if (info->cell_count)
+		return info->cell_count;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHEM_CELLS_REG, &val);
+	if (ret)
+		return 0;
+
+	/* Lower 4 bits is the cell count, or 0 if the chip doesn't know yet */
+	val &= 0x0f;
+	if (!val)
+		return 0;
+
+	/* Once determined, keep the value */
+	info->cell_count = val;
+
+	return val;
+};
+
+/* Convert enum value to POWER_SUPPLY_STATUS value */
+static int ltc4162l_state_decode(enum ltc4162l_state value)
+{
+	switch (value) {
+	case precharge:
+	case cc_cv_charge:
+		return POWER_SUPPLY_STATUS_CHARGING;
+	case c_over_x_term:
+		return POWER_SUPPLY_STATUS_FULL;
+	case bat_missing_fault:
+	case bat_short_fault:
+		return POWER_SUPPLY_STATUS_UNKNOWN;
+	default:
+		return POWER_SUPPLY_STATUS_NOT_CHARGING;
+	}
+};
+
+static int ltc4162l_get_status(struct ltc4162l_info *info,
+			       union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHARGER_STATE, &regval);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read CHARGER_STATE\n");
+		return ret;
+	}
+
+	val->intval = ltc4162l_state_decode(regval);
+
+	return 0;
+}
+
+static int ltc4162l_charge_status_decode(enum ltc4162l_charge_status value)
+{
+	if (!value)
+		return POWER_SUPPLY_CHARGE_TYPE_NONE;
+
+	/* constant voltage/current and input_current limit are "fast" modes */
+	if (value <= iin_limit_active)
+		return POWER_SUPPLY_CHARGE_TYPE_FAST;
+
+	/* Anything that's not fast we'll return as trickle */
+	return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
+}
+
+static int ltc4162l_get_charge_type(struct ltc4162l_info *info,
+				    union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHARGE_STATUS, &regval);
+	if (ret)
+		return ret;
+
+	val->intval = ltc4162l_charge_status_decode(regval);
+
+	return 0;
+}
+
+static int ltc4162l_state_to_health(enum ltc4162l_state value)
+{
+	switch (value) {
+	case ntc_pause:
+		return POWER_SUPPLY_HEALTH_OVERHEAT;
+	case timer_term:
+		return POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+	case max_charge_time_fault:
+		return POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE;
+	case bat_missing_fault:
+		return POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+	case bat_short_fault:
+		return POWER_SUPPLY_HEALTH_DEAD;
+	default:
+		return POWER_SUPPLY_HEALTH_GOOD;
+	}
+}
+
+static int ltc4162l_get_health(struct ltc4162l_info *info,
+			       union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHARGER_STATE, &regval);
+	if (ret)
+		return ret;
+
+	val->intval = ltc4162l_state_to_health(regval);
+
+	return 0;
+}
+
+static int ltc4162l_get_online(struct ltc4162l_info *info,
+			       union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_SYSTEM_STATUS_REG, &regval);
+	if (ret)
+		return ret;
+
+	/* BIT(2) indicates if input voltage is sufficient to charge */
+	val->intval = !!(regval & BIT(2));
+
+	return 0;
+}
+
+static int ltc4162l_get_vbat(struct ltc4162l_info *info,
+				  unsigned int reg,
+				  union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, reg, &regval);
+	if (ret)
+		return ret;
+
+	/* cell_count × 192.4μV/LSB */
+	regval *= 1924;
+	regval *= ltc4162l_get_cell_count(info);
+	regval /= 10;
+	val->intval = regval;
+
+	return 0;
+}
+
+static int ltc4162l_get_ibat(struct ltc4162l_info *info,
+			     union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_IBAT, &regval);
+	if (ret)
+		return ret;
+
+	/* Signed 16-bit number, 1.466μV / RSNSB amperes/LSB. */
+	ret = (s16)(regval & 0xFFFF);
+	val->intval = 100 * mult_frac(ret, 14660, (int)info->rsnsb);
+
+	return 0;
+}
+
+
+static int ltc4162l_get_input_voltage(struct ltc4162l_info *info,
+				      union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_VIN, &regval);
+	if (ret)
+		return ret;
+
+	/* 1.649mV/LSB */
+	val->intval =  regval * 1694;
+
+	return 0;
+}
+
+static int ltc4162l_get_input_current(struct ltc4162l_info *info,
+				      union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_IIN, &regval);
+	if (ret)
+		return ret;
+
+	/* Signed 16-bit number, 1.466μV / RSNSI amperes/LSB. */
+	ret = (s16)(regval & 0xFFFF);
+	ret *= 14660;
+	ret /= info->rsnsi;
+	ret *= 100;
+
+	val->intval = ret;
+
+	return 0;
+}
+
+static int ltc4162l_get_icharge(struct ltc4162l_info *info,
+				unsigned int reg,
+				union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, reg, &regval);
+	if (ret)
+		return ret;
+
+	regval &= BIT(6) - 1; /* Only the lower 5 bits */
+
+	/* The charge current servo level: (icharge_dac + 1) × 1mV/RSNSB */
+	++regval;
+	val->intval = 10000u * mult_frac(regval, 100000u, info->rsnsb);
+
+	return 0;
+}
+
+static int ltc4162l_set_icharge(struct ltc4162l_info *info,
+				unsigned int reg,
+				unsigned int value)
+{
+	value = mult_frac(value, info->rsnsb, 100000u);
+	value /= 10000u;
+
+	/* Round to lowest possible */
+	if (value)
+		--value;
+
+	if (value > 31)
+		return -EINVAL;
+
+	return regmap_write(info->regmap, reg, value);
+}
+
+
+static int ltc4162l_get_vcharge(struct ltc4162l_info *info,
+				unsigned int reg,
+				union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+	u32 voltage;
+
+	ret = regmap_read(info->regmap, reg, &regval);
+	if (ret)
+		return ret;
+
+	regval &= BIT(6) - 1; /* Only the lower 5 bits */
+
+	/*
+	 * charge voltage setting can be computed from
+	 * cell_count × (vcharge_setting × 12.5mV + 3.8125V)
+	 * where vcharge_setting ranges from 0 to 31 (4.2V max).
+	 */
+	voltage = 3812500 + (regval * 12500);
+	voltage *= ltc4162l_get_cell_count(info);
+	val->intval = voltage;
+
+	return 0;
+}
+
+static int ltc4162l_set_vcharge(struct ltc4162l_info *info,
+				unsigned int reg,
+				unsigned int value)
+{
+	u8 cell_count = ltc4162l_get_cell_count(info);
+
+	if (!cell_count)
+		return -EBUSY; /* Not available yet, try again later */
+
+	value /= cell_count;
+
+	if (value < 3812500)
+		return -EINVAL;
+
+	value -= 3812500;
+	value /= 12500;
+
+	if (value > 31)
+		return -EINVAL;
+
+	return regmap_write(info->regmap, reg, value);
+}
+
+static int ltc4162l_get_iin_limit_dac(struct ltc4162l_info *info,
+				     union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_IIN_LIMIT_DAC, &regval);
+	if (ret)
+		return ret;
+
+	regval &= BIT(6) - 1; /* Only 6 bits */
+
+	/* (iin_limit_dac + 1) × 500μV / RSNSI */
+	++regval;
+	regval *= 5000000u;
+	regval /= info->rsnsi;
+	val->intval = 100u * regval;
+
+	return 0;
+}
+
+static int ltc4162l_set_iin_limit(struct ltc4162l_info *info,
+				  unsigned int value)
+{
+	unsigned int regval;
+
+	regval = mult_frac(value, info->rsnsi, 50000u);
+	regval /= 10000u;
+	if (regval)
+		--regval;
+	if (regval > 63)
+		regval = 63;
+
+	return regmap_write(info->regmap, LTC4162L_IIN_LIMIT_TARGET, regval);
+}
+
+static int ltc4162l_get_die_temp(struct ltc4162l_info *info,
+				 union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_DIE_TEMPERATURE, &regval);
+	if (ret)
+		return ret;
+
+	/* die_temp × 0.0215°C/LSB - 264.4°C */
+	ret = (s16)(regval & 0xFFFF);
+	ret *= 215;
+	ret /= 100; /* Centidegrees scale */
+	ret -= 26440;
+	val->intval = ret;
+
+	return 0;
+}
+
+static int ltc4162l_get_term_current(struct ltc4162l_info *info,
+				     union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHARGER_CONFIG_BITS, &regval);
+	if (ret)
+		return ret;
+
+	/* Check if C_OVER_X_THRESHOLD is enabled */
+	if (!(regval & BIT(2))) {
+		val->intval = 0;
+		return 0;
+	}
+
+	ret = regmap_read(info->regmap, LTC4162L_C_OVER_X_THRESHOLD, &regval);
+	if (ret)
+		return ret;
+
+	/* 1.466μV / RSNSB amperes/LSB */
+	regval *= 14660u;
+	regval /= info->rsnsb;
+	val->intval = 100 * regval;
+
+	return 0;
+}
+
+static int ltc4162l_set_term_current(struct ltc4162l_info *info,
+				     unsigned int value)
+{
+	int ret;
+	unsigned int regval;
+
+	if (!value) {
+		/* Disable en_c_over_x_term when set to zero */
+		return regmap_update_bits(info->regmap,
+					  LTC4162L_CHARGER_CONFIG_BITS,
+					  BIT(2), 0);
+	}
+
+	regval = mult_frac(value, info->rsnsb, 14660u);
+	regval /= 100u;
+
+	ret =  regmap_write(info->regmap, LTC4162L_C_OVER_X_THRESHOLD, regval);
+	if (ret)
+		return ret;
+
+	/* Set en_c_over_x_term after changing the threshold value */
+	return regmap_update_bits(info->regmap, LTC4162L_CHARGER_CONFIG_BITS,
+				  BIT(2), BIT(2));
+}
+
+/* Custom properties */
+static const char * const ltc4162l_charge_status_name[] = {
+	"ilim_reg_active", /* 32 */
+	"thermal_reg_active",
+	"vin_uvcl_active",
+	"iin_limit_active",
+	"constant_current",
+	"constant_voltage",
+	"charger_off" /* 0 */
+};
+
+static ssize_t charge_status_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	const char *result = ltc4162l_charge_status_name[
+				ARRAY_SIZE(ltc4162l_charge_status_name) - 1];
+	unsigned int regval;
+	unsigned int mask;
+	unsigned int index;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CHARGE_STATUS, &regval);
+	if (ret)
+		return ret;
+
+	/* Only one bit is set according to datasheet, let's be safe here */
+	for (mask = 32, index = 0; mask != 0; mask >>= 1, ++index) {
+		if (regval & mask) {
+			result = ltc4162l_charge_status_name[index];
+			break;
+		}
+	}
+
+	return sprintf(buf, "%s\n", result);
+}
+static DEVICE_ATTR_RO(charge_status);
+
+static ssize_t vbat_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	union power_supply_propval val;
+	int ret;
+
+	ret = ltc4162l_get_vbat(info, LTC4162L_VBAT, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%d\n", val.intval);
+}
+static DEVICE_ATTR_RO(vbat);
+
+static ssize_t vbat_avg_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	union power_supply_propval val;
+	int ret;
+
+	ret = ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%d\n", val.intval);
+}
+static DEVICE_ATTR_RO(vbat_avg);
+
+static ssize_t ibat_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	union power_supply_propval val;
+	int ret;
+
+	ret = ltc4162l_get_ibat(info, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%d\n", val.intval);
+}
+static DEVICE_ATTR_RO(ibat);
+
+static ssize_t force_telemetry_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_CONFIG_BITS_REG, &regval);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n", regval & BIT(2) ? 1 : 0);
+}
+
+static ssize_t force_telemetry_store(struct device *dev,
+	struct device_attribute *attr,
+	const char *buf,
+	size_t count)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	int ret;
+	unsigned int value;
+
+	ret = kstrtouint(buf, 0, &value);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(info->regmap, LTC4162L_CONFIG_BITS_REG,
+				 BIT(2), value ? BIT(2) : 0);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(force_telemetry);
+
+static ssize_t arm_ship_mode_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->regmap, LTC4162L_ARM_SHIP_MODE, &regval);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n",
+		regval == LTC4162L_ARM_SHIP_MODE_MAGIC ? 1 : 0);
+}
+
+static ssize_t arm_ship_mode_store(struct device *dev,
+	struct device_attribute *attr,
+	const char *buf,
+	size_t count)
+{
+	struct power_supply *psy = to_power_supply(dev);
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+	int ret;
+	unsigned int value;
+
+	ret = kstrtouint(buf, 0, &value);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(info->regmap, LTC4162L_ARM_SHIP_MODE,
+				value ? LTC4162L_ARM_SHIP_MODE_MAGIC : 0);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(arm_ship_mode);
+
+static struct attribute *ltc4162l_sysfs_entries[] = {
+	&dev_attr_charge_status.attr,
+	&dev_attr_ibat.attr,
+	&dev_attr_vbat.attr,
+	&dev_attr_vbat_avg.attr,
+	&dev_attr_force_telemetry.attr,
+	&dev_attr_arm_ship_mode.attr,
+	NULL,
+};
+
+static struct attribute_group ltc4162l_attr_group = {
+	.name	= NULL,	/* put in device directory */
+	.attrs	= ltc4162l_sysfs_entries,
+};
+
+static const struct attribute_group *ltc4162l_attr_groups[] = {
+	&ltc4162l_attr_group,
+	NULL,
+};
+
+static int ltc4162l_get_property(struct power_supply *psy,
+				 enum power_supply_property psp,
+				 union power_supply_propval *val)
+{
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		return ltc4162l_get_status(info, val);
+	case POWER_SUPPLY_PROP_CHARGE_TYPE:
+		return ltc4162l_get_charge_type(info, val);
+	case POWER_SUPPLY_PROP_HEALTH:
+		return ltc4162l_get_health(info, val);
+	case POWER_SUPPLY_PROP_ONLINE:
+		return ltc4162l_get_online(info, val);
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		return ltc4162l_get_input_voltage(info, val);
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		return ltc4162l_get_input_current(info, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		return ltc4162l_get_icharge(info,
+				LTC4162L_ICHARGE_DAC, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		return ltc4162l_get_icharge(info,
+				LTC4162L_CHARGE_CURRENT_SETTING, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		return ltc4162l_get_vcharge(info,
+				LTC4162L_VCHARGE_DAC, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		return ltc4162l_get_vcharge(info,
+				LTC4162L_VCHARGE_SETTING, val);
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return ltc4162l_get_iin_limit_dac(info, val);
+	case POWER_SUPPLY_PROP_TEMP:
+		return ltc4162l_get_die_temp(info, val);
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		return ltc4162l_get_term_current(info, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ltc4162l_set_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 const union power_supply_propval *val)
+{
+	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		return ltc4162l_set_icharge(info,
+				LTC4162L_CHARGE_CURRENT_SETTING, val->intval);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		return ltc4162l_set_vcharge(info,
+				LTC4162L_VCHARGE_SETTING, val->intval);
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return ltc4162l_set_iin_limit(info, val->intval);
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		return ltc4162l_set_term_current(info, val->intval);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ltc4162l_property_is_writeable(struct power_supply *psy,
+						enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+/* Charger power supply property routines */
+static enum power_supply_property ltc4162l_properties[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_CHARGE_TYPE,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	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_INPUT_CURRENT_LIMIT,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+};
+
+static const struct power_supply_desc ltc4162l_desc = {
+	.name		= "ltc4162-l",
+	.type		= POWER_SUPPLY_TYPE_MAINS,
+	.properties	= ltc4162l_properties,
+	.num_properties	= ARRAY_SIZE(ltc4162l_properties),
+	.get_property	= ltc4162l_get_property,
+	.set_property	= ltc4162l_set_property,
+	.property_is_writeable = ltc4162l_property_is_writeable,
+};
+
+static bool ltc4162l_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	/* all registers up to this one are writeable */
+	if (reg <= LTC4162L_CHARGER_CONFIG_BITS)
+		return true;
+
+	/* The ALERTS registers can be written to clear alerts */
+	if (reg >= LTC4162L_LIMIT_ALERTS_REG &&
+	    reg <= LTC4162L_CHARGE_STATUS_ALERTS_REG)
+		return true;
+
+	return false;
+}
+
+static bool ltc4162l_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	/* all registers after this one are read-only status registers */
+	return reg > LTC4162L_CHARGER_CONFIG_BITS;
+}
+
+static const struct regmap_config ltc4162l_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 16,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+	.writeable_reg	= ltc4162l_is_writeable_reg,
+	.volatile_reg	= ltc4162l_is_volatile_reg,
+	.max_register	= LTC4162L_INPUT_UNDERVOLTAGE_DAC,
+	.cache_type	= REGCACHE_RBTREE,
+};
+
+static void ltc4162l_clear_interrupts(struct ltc4162l_info *info)
+{
+	/* Acknowledge interrupt to chip by clearing all events */
+	regmap_write(info->regmap, LTC4162L_LIMIT_ALERTS_REG, 0);
+	regmap_write(info->regmap, LTC4162L_CHARGER_STATE_ALERTS_REG, 0);
+	regmap_write(info->regmap, LTC4162L_CHARGE_STATUS_ALERTS_REG, 0);
+}
+
+static int ltc4162l_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct device *dev = &client->dev;
+	struct ltc4162l_info *info;
+	struct power_supply_config ltc4162l_config = {};
+	u32 value;
+	int ret;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
+		dev_err(dev, "No support for SMBUS_WORD_DATA\n");
+		return -ENODEV;
+	}
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->client = client;
+	i2c_set_clientdata(client, info);
+
+	info->regmap = devm_regmap_init_i2c(client, &ltc4162l_regmap_config);
+	if (IS_ERR(info->regmap)) {
+		dev_err(dev, "Failed to initialize register map\n");
+		return PTR_ERR(info->regmap);
+	}
+
+	ret = device_property_read_u32(dev, "lltc,rsnsb-micro-ohms",
+				       &info->rsnsb);
+	if (ret) {
+		dev_err(dev, "Missing lltc,rsnsb-micro-ohms property\n");
+		return ret;
+	}
+	if (!info->rsnsb)
+		return -EINVAL;
+
+	ret = device_property_read_u32(dev, "lltc,rsnsi-micro-ohms",
+				       &info->rsnsi);
+	if (ret) {
+		dev_err(dev, "Missing lltc,rsnsi-micro-ohms property\n");
+		return ret;
+	}
+	if (!info->rsnsi)
+		return -EINVAL;
+
+	if (!device_property_read_u32(dev, "lltc,cell-count", &value))
+		info->cell_count = value;
+
+	ltc4162l_config.of_node = dev->of_node;
+	ltc4162l_config.drv_data = info;
+	ltc4162l_config.attr_grp = ltc4162l_attr_groups;
+
+	info->charger = devm_power_supply_register(dev, &ltc4162l_desc,
+						   &ltc4162l_config);
+	if (IS_ERR(info->charger)) {
+		dev_err(dev, "Failed to register charger\n");
+		return PTR_ERR(info->charger);
+	}
+
+	/* Disable the threshold alerts, we're not using them */
+	regmap_write(info->regmap, LTC4162L_EN_LIMIT_ALERTS_REG, 0);
+
+	/* Enable interrupts on all status changes */
+	regmap_write(info->regmap, LTC4162L_EN_CHARGER_STATE_ALERTS_REG,
+		     0x1fff);
+	regmap_write(info->regmap, LTC4162L_EN_CHARGE_STATUS_ALERTS_REG, 0x1f);
+
+	ltc4162l_clear_interrupts(info);
+
+	return 0;
+}
+
+static void ltc4162l_alert(struct i2c_client *client,
+			   enum i2c_alert_protocol type, unsigned int flag)
+{
+	struct ltc4162l_info *info = i2c_get_clientdata(client);
+
+	if (type != I2C_PROTOCOL_SMBUS_ALERT)
+		return;
+
+	ltc4162l_clear_interrupts(info);
+	power_supply_changed(info->charger);
+}
+
+static const struct i2c_device_id ltc4162l_i2c_id_table[] = {
+	{ "ltc4162-l", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, ltc4162l_i2c_id_table);
+
+static const struct of_device_id ltc4162l_of_match[] = {
+	{ .compatible = "lltc,ltc4162-l", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ltc4162l_of_match);
+
+static struct i2c_driver ltc4162l_driver = {
+	.probe		= ltc4162l_probe,
+	.alert		= ltc4162l_alert,
+	.id_table	= ltc4162l_i2c_id_table,
+	.driver = {
+		.name		= "ltc4162-l-charger",
+		.of_match_table	= of_match_ptr(ltc4162l_of_match),
+	},
+};
+module_i2c_driver(ltc4162l_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
+MODULE_DESCRIPTION("LTC4162-L charger driver");
-- 
2.17.1