This is a patch to add support for
NXP rtc pca21125
Signed-off-by: Venkat Prashanth B U <[email protected]>
---
changelog v2:
1. used the registers defined in pca21125_set_time function
2. code cleanup in the function pca21125_read_time function
3. Write the address on the bus with pca21125_write_reg function
4. code clean up on pca21125_probe function
5. Add the alarm feature support feature in the driver code
6. fixed the indentation of entire file
---
---
drivers/rtc/Kconfig | 9 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-pca21125.c | 234 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 244 insertions(+)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e215f50..29f40cb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -739,6 +739,15 @@ config RTC_DRV_PCF2123
This driver can also be built as a module. If so, the module
will be called rtc-pcf2123.
+config RTC_DRV_PCA21125
+ tristate "NXP PCA21125"
+ help
+ If you say yes here you get support for the NXP PCA21125
+ RTC chip.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-pca21125.
+
config RTC_DRV_MCP795
tristate "Microchip MCP795"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 7cf7ad5..41a5807 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -106,6 +106,7 @@ obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o
obj-$(CONFIG_RTC_DRV_OPAL) += rtc-opal.o
obj-$(CONFIG_RTC_DRV_PALMAS) += rtc-palmas.o
obj-$(CONFIG_RTC_DRV_PCAP) += rtc-pcap.o
+obj-$(CONFIG_RTC_DRV_PCA21125) += rtc-pca21125.o
obj-$(CONFIG_RTC_DRV_PCF2123) += rtc-pcf2123.o
obj-$(CONFIG_RTC_DRV_PCF2127) += rtc-pcf2127.o
obj-$(CONFIG_RTC_DRV_PCF50633) += rtc-pcf50633.o
diff --git a/drivers/rtc/rtc-pca21125.c b/drivers/rtc/rtc-pca21125.c
index e69de29..536cf50 100644
--- a/drivers/rtc/rtc-pca21125.c
+++ b/drivers/rtc/rtc-pca21125.c
@@ -0,0 +1,234 @@
+ /* rtc-pca21125.c
+ *
+ * Driver for NXP PCA21125 CMOS, SPI Compatible
+ * Real Time Clock
+ *
+ * Author : Venkat Prashanth B U <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+ #include <linux/init.h>
+ #include <linux/module.h>
+ #include <linux/device.h>
+ #include <linux/platform_device.h>
+ #include <linux/rtc.h>
+ #include <linux/spi/spi.h>
+ #include <linux/bcd.h>
+ #include <linux/interrupt.h>
+ #include <linux/regmap.h>
+ #include <linux/pm.h>
+ #include <linux/pm_wakeirq.h>
+ #include <linux/slab.h>
+
+ /* Registers in pca21125 rtc */
+ #define PCA21125_SECONDS_REG 0x02
+ #define PCA21125_MINUTES_REG 0x03
+ #define PCA21125_HOURS_REG 0x04
+ #define PCA21125_DATE_REG 0x05
+ #define PCA21125_DAY_REG 0x06
+ #define PCA21125_MONTH_REG 0x07
+ #define PCA21125_YEAR_REG 0x08
+ #define PCA21125_CONTROL_REG 0x01
+ #define PCA21125_STATUS_REG 0x00
+ #define PCA21125_CLOCK_BURST 0x0D
+
+ struct pca21125_priv {
+
+ struct spi_device *spi;
+ struct rtc_device *rtc;
+ struct regmap *map;
+ struct mutex mutex;
+ unsigned int irqen;
+ int irq;
+ int alarm_sec;
+ int alarm_min;
+ int alarm_hour;
+ int alarm_mday;
+ };
+
+ static int
+ pca21125_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+ {
+ struct pca21125_priv *priv = dev_get_drvdata(dev);
+ int res = 0;
+ unsigned int stat;
+
+ if (priv->irq <= 0)
+ return -EINVAL;
+
+ mutex_lock(&priv->mutex);
+
+ res = regmap_read(priv->map, PCA21125_STATUS_REG, &stat);
+ if (res)
+ goto out;
+
+ alarm->enabled = !!(priv->irqen & RTC_AF);
+
+ alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
+ alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
+ alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
+ alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;
+
+out:
+ mutex_unlock(&priv->mutex);
+ return res;
+ }
+
+ static int
+ pca21125_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+ {
+ struct pca21125_priv *priv = dev_get_drvdata(dev);
+ int res = 0;
+
+ if (priv->irq <= 0)
+ return -EINVAL;
+
+ mutex_lock(&priv->mutex);
+
+ priv->alarm_sec = alarm->time.tm_sec;
+ priv->alarm_min = alarm->time.tm_min;
+ priv->alarm_hour = alarm->time.tm_hour;
+ priv->alarm_mday = alarm->time.tm_mday;
+
+ if (alarm->enabled)
+ priv->irqen |= RTC_AF;
+
+ mutex_unlock(&priv->mutex);
+
+ return res;
+ }
+
+ static int
+ pca21125_read_reg(struct device *dev, unsigned char address,
+ unsigned char *data)
+ {
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ /* Set MSB to indicate read */
+ *data = address | 0x80;
+
+ return spi_write_then_read(spi, buf, 1, data, 1);
+ }
+
+ static int
+ pca21125_write_reg(struct device *dev, unsigned char address,
+ unsigned char data)
+ {
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ /* MSB must be '0' to write */
+ buf[0] = address & 0x7F;
+ buf[1] = data;
+
+ return spi_write_then_read(spi, buf, 2, NULL, 0);
+ }
+
+ static int
+ pca21125_read_time(struct device *dev, struct rtc_time *dt)
+ {
+ struct spi_device *spi = to_spi_device(dev);
+ int err;
+ unsigned char buf[8];
+
+ buf[0] = 0xbf; /* Burst read */
+
+ err = spi_write_then_read(spi, buf, 1, buf, 8);
+
+ if (err)
+ return err;
+
+ /* The chip sends data in the order mentioned below*/
+
+ dt->tm_sec = bcd2bin(buf[0]);
+ dt->tm_min = bcd2bin(buf[1]);
+ dt->tm_hour = bcd2bin(buf[2]);
+ dt->tm_mday = bcd2bin(buf[3]);
+ dt->tm_mon = bcd2bin(buf[4]);
+ dt->tm_wday = bcd2bin(buf[5]);
+ dt->tm_year = bcd2bin(buf[6]);
+
+ return rtc_valid_tm(dt);
+ }
+
+ static int
+ pca21125_set_time(struct device *dev, struct rtc_time *dt)
+ {
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[9];
+
+ dt->tm_year = dt->tm_year + 1900;
+
+ if (dt->tm_year < 100 || dt->tm_year > 199) {
+
+ dev_err(&spi->dev, "Year must be between 2000 and 2099. It's %d.\n",
+ dt->tm_year + 1900);
+ return -EINVAL;
+ }
+
+ /* Remove write protection */
+ pca21125_write_reg(dev, PCA21125_CONTROL_REG, 0);
+
+ pca21125_write_reg(dev, PCA21125_SECONDS_REG, bin2bcd(dt->tm_sec));
+ pca21125_write_reg(dev, PCA21125_MINUTES_REG, bin2bcd(dt->tm_min));
+ pca21125_write_reg(dev, PCA21125_HOURS_REG, bin2bcd(dt->tm_hour));
+ pca21125_write_reg(dev, PCA21125_DATE_REG, bin2bcd(dt->tm_mday));
+ pca21125_write_reg(dev, PCA21125_MONTH_REG, bin2bcd(dt->tm_mon + 1));
+ pca21125_write_reg(dev, PCA21125_DAY_REG, bin2bcd(dt->tm_wday));
+ pca21125_write_reg(dev, PCA21125_YEAR_REG, bin2bcd(dt->tm_year % 100));
+
+ /* Write protect */
+ pca21125_write_reg(dev, PCA21125_CONTROL_REG, 0x80);
+
+ /* write the rtc settings */
+ return spi_write_then_read(spi, buf, 9, NULL, 0);
+ }
+
+ static const struct rtc_class_ops pca21125_rtc_ops = {
+ .read_time = pca21125_read_time,
+ .set_time = pca21125_set_time,
+ .read_alarm = pca21125_read_alarm,
+ .set_alarm = pca21125_set_alarm,
+ };
+
+ static int
+ pca21125_probe(struct spi_device *spi)
+ {
+ struct rtc_device *rtc;
+ unsigned char tmp;
+ int res;
+
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ res = pca21125_read_reg(&spi->dev, PCA21125_SECONDS_REG, &tmp);
+ if (res != 0)
+ return res;
+
+ rtc = devm_rtc_device_register(&spi->dev, "pca21125",
+ &pca21125_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ spi_set_drvdata(spi, rtc);
+ return 0;
+ }
+
+ static struct spi_driver pca21125_driver = {
+ .driver = {
+ .name = "pca21125",
+ },
+ .probe = pca21125_probe,
+ };
+
+ module_spi_driver(pca21125_driver);
+
+ MODULE_DESCRIPTION("PCA21125 SPI RTC DRIVER");
+ MODULE_AUTHOR("Venkat Prashanth B U <[email protected]>");
+ MODULE_LICENSE("GPL v2");
--
1.9.2
Hi Venkat,
On 19 October 2016 at 19:41, VENKAT PRASHANTH B U
<[email protected]> wrote:
> This is a patch to add support for
> NXP rtc pca21125
The register layout PCA21125 looks similar to PCF8563 which already
has a driver.
Would it be possible to support the PCA21125 device with the rtc-pcf8563 driver?
You will need to add a regmap layer since the PCA21125 is SPI while
the PCF8563 is I2C.
regards,
Joachim Eastwood