rtc: add ams as3720 rtc driver

addition of AMS as3720 rtc driver

Change-Id: Ie8737a1d29d02b8e129d888f77210dd3da96c6dc
Signed-off-by: Victor Weinstein <vweinstein@nvidia.com>
Signed-off-by: Syed Rafiuddin <srafiuddin@nvidia.com>
Signed-off-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-on: http://git-master/r/146197
Reviewed-by: Mrutyunjay Sawant <msawant@nvidia.com>
Tested-by: Mrutyunjay Sawant <msawant@nvidia.com>

3 files changed, 335 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2bc82b2cbef8..27396cefbcc0 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -498,6 +498,16 @@ config RTC_DRV_RV3029C2
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-rv3029c2.
 
+config RTC_DRV_AS3720
+	tristate "ams AS3720"
+	depends on MFD_AS3720
+	help
+	  If you say Y here you will get support for the RTC feature
+	  of the AS3720 PMIC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-as3720.
+
 endif # I2C
 
 comment "SPI RTC drivers"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 8fc396239bd2..613ade4b278f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
 obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
 obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
 obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
+obj-$(CONFIG_RTC_DRV_AS3720)	+= rtc-as3720.o
 obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_AT91SAM9)	+= rtc-at91sam9.o
diff --git a/drivers/rtc/rtc-as3720.c b/drivers/rtc/rtc-as3720.c
new file mode 100644
index 000000000000..293c249e3217
--- /dev/null
+++ b/drivers/rtc/rtc-as3720.c
@@ -0,0 +1,324 @@
+/*
+ *  Real Time Clock driver for ams AS3720 PMICs
+ *
+ *  Copyright (C) 2012 ams AG.
+ *
+ *  Author: Bernhard Breinbauer <Bernhard.Breinbauer@ams.com>
+ *
+ *  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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/interrupt.h>
+#include <linux/ioctl.h>
+#include <linux/completion.h>
+#include <linux/mfd/as3720.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+
+#define AS3720_SET_ALM_RETRIES	5
+#define AS3720_SET_TIME_RETRIES	5
+#define AS3720_GET_TIME_RETRIES	5
+
+/*
+ * Read current time and date in RTC
+ */
+static int as3720_rtc_readtime(struct device *dev, struct rtc_time *tm)
+{
+	struct as3720 *as3720 = dev_get_drvdata(dev->parent);
+	struct as3720_platform_data *pdata = as3720->dev->platform_data;
+	u8 as_sec;
+	u8 as_min_array[3];
+	int as_min;
+	long time, start_time;
+	struct rtc_time start_tm;
+	int ret;
+
+	as3720_reg_read(as3720, AS3720_RTC_SECOND_REG, &as_sec);
+	ret = as3720_block_read(as3720, AS3720_RTC_MINUTE1_REG,
+				3, as_min_array);
+	if (ret < 0) {
+		dev_err(dev, "failed to read time with err:%d\n", ret);
+		return ret;
+	}
+	as_min = (as_min_array[2] << 16)
+		| (as_min_array[1] << 8)
+		| (as_min_array[0]);
+	time = as_min*60 + as_sec;
+	start_tm.tm_year = (pdata->rtc_start_year - 1900);
+	start_tm.tm_mon = 0;
+	start_tm.tm_mday = 1;
+	start_tm.tm_hour = 0;
+	start_tm.tm_min = 0;
+	start_tm.tm_sec = 0;
+	rtc_tm_to_time(&start_tm, &start_time);
+	time = time + start_time;
+	rtc_time_to_tm(time, tm);
+	return 0;
+}
+
+/*
+ * Set current time and date in RTC
+ */
+static int as3720_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+	struct as3720 *as3720 = dev_get_drvdata(dev->parent);
+	struct as3720_platform_data *pdata = as3720->dev->platform_data;
+	long time, start_time;
+	u8 as_sec;
+	u8 as_min_array[3];
+	int as_min;
+	struct rtc_time start_tm;
+	int ret;
+
+	/* Write time to RTC */
+	rtc_tm_to_time(tm, &time);
+	start_tm.tm_year = (pdata->rtc_start_year - 1900);
+	start_tm.tm_mon = 0;
+	start_tm.tm_mday = 1;
+	start_tm.tm_hour = 0;
+	start_tm.tm_min = 0;
+	start_tm.tm_sec = 0;
+	rtc_tm_to_time(&start_tm, &start_time);
+	time = time - start_time;
+	as_min = time / 60;
+	as_sec = time % 60;
+	as_min_array[2] = (as_min & 0xFF0000) >> 16;
+	as_min_array[1] = (as_min & 0xFF00) >> 8;
+	as_min_array[0] = as_min & 0xFF;
+	as3720_reg_write(as3720, AS3720_RTC_SECOND_REG, as_sec);
+	ret = as3720_block_write(as3720, AS3720_RTC_MINUTE1_REG, 3,
+				 as_min_array);
+	if (ret < 0) {
+		dev_err(dev, "failed to set time with err:%d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+/*
+ * Read alarm time and date in RTC
+ */
+static int as3720_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct as3720 *as3720 = dev_get_drvdata(dev->parent);
+	struct as3720_platform_data *pdata = as3720->dev->platform_data;
+	u8 as_sec;
+	u8 as_min_array[3];
+	int as_min;
+	long time, start_time;
+	struct rtc_time start_tm;
+	int ret;
+
+	as3720_reg_read(as3720, AS3720_RTC_ALARM_SECOND_REG, &as_sec);
+	ret = as3720_block_read(as3720, AS3720_RTC_ALARM_MINUTE1_REG,
+				3, as_min_array);
+	if (ret < 0) {
+		dev_err(dev, "failed to read alarm with err:%d\n", ret);
+		return ret;
+	}
+	as_min = (as_min_array[2] << 16)
+		| (as_min_array[1] << 8)
+		| (as_min_array[0]);
+	time = as_min*60 + as_sec;
+	start_tm.tm_year = (pdata->rtc_start_year - 1900);
+	start_tm.tm_mon = 0;
+	start_tm.tm_mday = 1;
+	start_tm.tm_hour = 0;
+	start_tm.tm_min = 0;
+	start_tm.tm_sec = 0;
+	rtc_tm_to_time(&start_tm, &start_time);
+	time = time + start_time;
+	rtc_time_to_tm(time, &alrm->time);
+	return 0;
+}
+
+static int as3720_rtc_stop_alarm(struct as3720 *as3720)
+{
+	/* disable rtc alarm interrupt */
+	return as3720_set_bits(as3720, AS3720_INTERRUPTMASK2_REG,
+			AS3720_IRQ_RTC_ALARM, 1);
+}
+
+static int as3720_rtc_start_alarm(struct as3720 *as3720)
+{
+	/* enable rtc alarm interrupt */
+	return as3720_set_bits(as3720, AS3720_INTERRUPTMASK2_REG,
+			AS3720_IRQ_RTC_ALARM, 0);
+}
+
+static int as3720_rtc_alarm_irq_enable(struct device *dev,
+				       unsigned int enabled)
+{
+	struct as3720 *as3720 = dev_get_drvdata(dev->parent);
+
+	if (enabled)
+		return as3720_rtc_start_alarm(as3720);
+	else
+		return as3720_rtc_stop_alarm(as3720);
+}
+
+static int as3720_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct as3720 *as3720 = dev_get_drvdata(dev->parent);
+	struct as3720_platform_data *pdata = as3720->dev->platform_data;
+	long time, start_time;
+	u8 as_sec;
+	u8 as_min_array[3];
+	int as_min;
+	struct rtc_time start_tm;
+	int ret;
+
+	/* Write time to RTC */
+	rtc_tm_to_time(&alrm->time, &time);
+	start_tm.tm_year = (pdata->rtc_start_year - 1900);
+	start_tm.tm_mon = 0;
+	start_tm.tm_mday = 1;
+	start_tm.tm_hour = 0;
+	start_tm.tm_min = 0;
+	start_tm.tm_sec = 0;
+	rtc_tm_to_time(&start_tm, &start_time);
+	time = time - start_time;
+	as_min = time / 60;
+	as_sec = time % 60;
+	as_min_array[2] = (as_min & 0xFF0000) >> 16;
+	as_min_array[1] = (as_min & 0xFF00) >> 8;
+	as_min_array[0] = as_min & 0xFF;
+
+	/* Write time to RTC */
+	as3720_reg_write(as3720, AS3720_RTC_ALARM_SECOND_REG, as_sec);
+	ret = as3720_block_write(as3720, AS3720_RTC_ALARM_MINUTE1_REG, 3,
+				 as_min_array);
+	if (ret < 0) {
+		dev_err(dev, "failed to set alarm with err:%d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops as3720_rtc_ops = {
+	.read_time = as3720_rtc_readtime,
+	.set_time = as3720_rtc_settime,
+	.read_alarm = as3720_rtc_readalarm,
+	.set_alarm = as3720_rtc_setalarm,
+	.alarm_irq_enable = as3720_rtc_alarm_irq_enable,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int as3720_rtc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct as3720 *as3720 = dev_get_drvdata(pdev->dev.parent);
+	int ret = 0;
+	u32 reg;
+
+	as3720_reg_read(as3720, AS3720_INTERRUPTMASK3_REG, &reg);
+
+	if (device_may_wakeup(dev) &&
+	    reg & AS3720_IRQ_MASK_RTC_ALARM) {
+		ret = as3720_rtc_stop_alarm(as3720);
+		if (ret != 0)
+			dev_err(dev, "Failed to stop RTC alarm: %d\n",
+				ret);
+	}
+
+	return ret;
+}
+
+static int as3720_rtc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct as3720 *as3720 = dev_get_drvdata(pdev->dev.parent);
+	int ret;
+
+	if (as3720->rtc.alarm_enabled) {
+		ret = as3720_rtc_start_alarm(as3720);
+		if (ret != 0)
+			dev_err(dev,
+				"Failed to restart RTC alarm: %d\n", ret);
+	}
+
+	return 0;
+}
+
+#define DEV_PM_OPS	(&as3720_rtc_pm_ops)
+#else
+#define DEV_PM_OPS	NULL
+#endif
+
+static int as3720_rtc_probe(struct platform_device *pdev)
+{
+	struct as3720 *as3720 = dev_get_drvdata(pdev->dev.parent);
+	struct as3720_platform_data *pdata = dev_get_platdata(pdev->dev.parent);
+	struct as3720_rtc *rtc = &as3720->rtc;
+	int ret = 0;
+	u8 ctrl;
+
+	/* enable the RTC if it's not already enabled */
+	as3720_reg_read(as3720, AS3720_RTC_CONTROL_REG, &ctrl);
+	if (!(ctrl &  AS3720_RTC_ON_MASK)) {
+		dev_info(&pdev->dev, "Starting RTC\n");
+
+		ret = as3720_set_bits(as3720, AS3720_RTC_CONTROL_REG,
+				      AS3720_RTC_ON_MASK, AS3720_RTC_ON_MASK);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
+			return ret;
+		}
+	}
+	/* enable alarm wakeup */
+	as3720_set_bits(as3720, AS3720_RTC_CONTROL_REG,
+			AS3720_RTC_ALARM_WAKEUP_EN_MASK,
+			AS3720_RTC_ALARM_WAKEUP_EN_MASK);
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	rtc->rtc = rtc_device_register("as3720", &pdev->dev,
+					  &as3720_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc)) {
+		ret = PTR_ERR(rtc->rtc);
+		dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __devexit as3720_rtc_remove(struct platform_device *pdev)
+{
+	struct as3720 *as3720 = platform_get_drvdata(pdev);
+	struct as3720_rtc *rtc = &as3720->rtc;
+
+	rtc_device_unregister(rtc->rtc);
+
+	return 0;
+}
+
+static const struct dev_pm_ops as3720_rtc_pm_ops = {
+	.suspend	= as3720_rtc_suspend,
+	.resume		= as3720_rtc_resume,
+};
+
+static struct platform_driver as3720_rtc_driver = {
+	.probe = as3720_rtc_probe,
+	.remove = __devexit_p(as3720_rtc_remove),
+	.driver = {
+		.name = "as3720-rtc",
+		.pm = DEV_PM_OPS,
+	},
+};
+
+module_platform_driver(as3720_rtc_driver);
+
+MODULE_AUTHOR("Bernhard Breinbauer <bernhard.breinbauer@ams.com>");
+MODULE_DESCRIPTION("RTC driver for AS3720 PMICs");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:as3720-rtc");