rtc: RTC driver for palmas

Add RTC driver for palmas

Bug 978821

Change-Id: I6cdc1f491f97db0edc1c57d2429de565e407d799
Signed-off-by: Mallikarjun Kasoju <mkasoju@nvidia.com>
Reviewed-on: http://git-master/r/122126
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>

3 files changed, 438 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 29eb6d101556..a868ebcbbdff 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1113,6 +1113,13 @@ config RTC_DRV_TPS80031
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-tps6591x.
 
+config RTC_DRV_PALMAS
+	tristate "PALMAS RTC driver"
+	depends on MFD_PALMAS
+	default n
+	help
+	  If you say yes here you get support for the PALMAS RTC module.
+
 config RTC_DRV_PUV3
 	tristate "PKUnity v3 RTC support"
 	depends on ARCH_PUV3
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 3abf7bd2bddd..de49660776c0 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -109,6 +109,7 @@ obj-$(CONFIG_RTC_DRV_TILE)	+= rtc-tile.o
 obj-$(CONFIG_RTC_DRV_TPS6586X)	+= rtc-tps6586x.o
 obj-$(CONFIG_RTC_DRV_TPS6591x)	+= rtc-tps6591x.o
 obj-$(CONFIG_RTC_DRV_TPS80031)	+= rtc-tps80031.o
+obj-$(CONFIG_RTC_DRV_PALMAS)	+= rtc-palmas.o
 obj-$(CONFIG_RTC_DRV_RC5T583)	+= rtc-ricoh583.o
 obj-$(CONFIG_RTC_DRV_TWL4030)	+= rtc-twl.o
 obj-$(CONFIG_RTC_DRV_TX4939)	+= rtc-tx4939.o
diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c
new file mode 100644
index 000000000000..d5c963e35f6b
--- /dev/null
+++ b/drivers/rtc/rtc-palmas.c
@@ -0,0 +1,430 @@
+/*
+ * rtc-palmas.c -- Palmas Real Time Clock interface
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Author: Kasoju Mallikarjun <mkasoju@nvidia.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/palmas.h>
+
+struct palmas_rtc {
+	struct rtc_device	*rtc;
+	/* To store the list of enabled interrupts */
+	unsigned int irqstat;
+	unsigned int irq;
+};
+
+/* Total number of RTC registers needed to set time*/
+#define NUM_TIME_REGS	(PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
+
+int palmas_rtc_read(struct palmas *palmas, unsigned int reg,
+				unsigned int *dest)
+{
+	unsigned int addr;
+	addr = PALMAS_BASE_TO_REG(PALMAS_RTC_BASE, reg);
+
+	return regmap_read(palmas->regmap[RTC_SLAVE], addr, dest);
+}
+
+int palmas_rtc_write(struct palmas *palmas, unsigned int reg,
+				unsigned int value)
+{
+	unsigned int addr;
+	addr = PALMAS_BASE_TO_REG(PALMAS_RTC_BASE, reg);
+
+	return regmap_write(palmas->regmap[RTC_SLAVE], addr, value);
+}
+
+int palmas_rtc_bulk_read(struct palmas *palmas, unsigned int reg,
+				void *val, size_t val_count)
+{
+	unsigned int addr;
+	addr = PALMAS_BASE_TO_REG(PALMAS_RTC_BASE, reg);
+
+	return regmap_bulk_read(palmas->regmap[RTC_SLAVE], addr,
+		val, val_count);
+}
+
+int palmas_rtc_bulk_write(struct palmas *palmas, unsigned int reg,
+	const void *val, size_t val_count)
+{
+	unsigned int addr;
+	addr = PALMAS_BASE_TO_REG(PALMAS_RTC_BASE, reg);
+
+	return regmap_bulk_write(palmas->regmap[RTC_SLAVE], addr,
+		val, val_count);
+}
+
+int palmas_rtc_update_bits(struct palmas *palmas, unsigned int reg,
+				unsigned int mask, unsigned int val)
+{
+	unsigned int addr;
+	addr = PALMAS_BASE_TO_REG(PALMAS_RTC_BASE, reg);
+
+	return regmap_update_bits(palmas->regmap[RTC_SLAVE], addr, mask, val);
+}
+
+static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
+{
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	u8 val = 0;
+
+	if (enabled)
+		val = PALMAS_RTC_INTERRUPTS_REG_IT_ALARM;
+
+	return palmas_rtc_write(palmas,
+		PALMAS_RTC_INTERRUPTS_REG, val);
+}
+
+/*
+ * Gets current palmas RTC time and date parameters.
+ *
+ * The RTC's time/alarm representation is not what gmtime(3) requires
+ * Linux to use:
+ *
+ *  - Months are 1..12 vs Linux 0-11
+ *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
+ */
+static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char rtc_data[NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	/* Copy RTC counting registers to static registers or latches */
+	ret = palmas_rtc_update_bits(palmas, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
+	if (ret < 0) {
+		dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
+		return ret;
+	}
+
+	ret = palmas_rtc_bulk_read(palmas, PALMAS_SECONDS_REG,
+		rtc_data, NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
+		return ret;
+	}
+
+	tm->tm_sec = bcd2bin(rtc_data[0]);
+	tm->tm_min = bcd2bin(rtc_data[1]);
+	tm->tm_hour = bcd2bin(rtc_data[2]);
+	tm->tm_mday = bcd2bin(rtc_data[3]);
+	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
+	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
+
+	return ret;
+}
+
+static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char rtc_data[NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	rtc_data[0] = bin2bcd(tm->tm_sec);
+	rtc_data[1] = bin2bcd(tm->tm_min);
+	rtc_data[2] = bin2bcd(tm->tm_hour);
+	rtc_data[3] = bin2bcd(tm->tm_mday);
+	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
+	rtc_data[5] = bin2bcd(tm->tm_year - 100);
+
+	/* Stop RTC while updating the RTC time registers */
+	ret = palmas_rtc_update_bits(palmas, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
+	if (ret < 0) {
+		dev_err(dev, "RTC stop failed with err:%d\n", ret);
+		return ret;
+	}
+
+	/* update all the time registers in one shot */
+	ret = palmas_rtc_bulk_write(palmas, PALMAS_SECONDS_REG,
+		rtc_data, NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "rtc_set_time error %d\n", ret);
+		return ret;
+	}
+
+	/* Start back RTC */
+	ret = palmas_rtc_update_bits(palmas, PALMAS_RTC_CTRL_REG,
+		PALMAS_RTC_CTRL_REG_STOP_RTC, 1);
+	if (ret < 0)
+		dev_err(dev, "RTC start failed with err:%d\n", ret);
+
+	return ret;
+}
+
+/*
+ * Gets current palmas RTC alarm time.
+ */
+static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	unsigned char alarm_data[NUM_TIME_REGS];
+	u32 int_val;
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	ret = palmas_rtc_bulk_read(palmas, PALMAS_SECONDS_REG,
+		alarm_data, NUM_TIME_REGS);
+	if (ret < 0) {
+		dev_err(dev, "rtc_read_alarm error %d\n", ret);
+		return ret;
+	}
+
+	alm->time.tm_sec = bcd2bin(alarm_data[0]);
+	alm->time.tm_min = bcd2bin(alarm_data[1]);
+	alm->time.tm_hour = bcd2bin(alarm_data[2]);
+	alm->time.tm_mday = bcd2bin(alarm_data[3]);
+	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
+	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
+
+	ret = palmas_rtc_read(palmas, PALMAS_RTC_INTERRUPTS_REG,
+		&int_val);
+	if (ret < 0)
+		return ret;
+
+	if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
+		alm->enabled = 1;
+
+	return ret;
+}
+
+static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	unsigned char alarm_data[NUM_TIME_REGS];
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	int ret;
+
+	ret = palmas_rtc_alarm_irq_enable(dev, 0);
+	if (ret)
+		return ret;
+
+	alarm_data[0] = bin2bcd(alm->time.tm_sec);
+	alarm_data[1] = bin2bcd(alm->time.tm_min);
+	alarm_data[2] = bin2bcd(alm->time.tm_hour);
+	alarm_data[3] = bin2bcd(alm->time.tm_mday);
+	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
+	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
+
+	/* update all the alarm registers in one shot */
+	ret = palmas_rtc_bulk_write(palmas,
+		PALMAS_ALARM_SECONDS_REG, alarm_data, NUM_TIME_REGS);
+	if (ret) {
+		dev_err(dev, "rtc_set_alarm error %d\n", ret);
+		return ret;
+	}
+
+	if (alm->enabled)
+		ret = palmas_rtc_alarm_irq_enable(dev, 1);
+
+	return ret;
+}
+
+static irqreturn_t palmas_rtc_interrupt(int irq, void *rtc)
+{
+	struct device *dev = rtc;
+	unsigned long events = 0;
+	struct palmas *palmas = dev_get_drvdata(dev->parent);
+	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
+	int ret;
+	u32 rtc_reg;
+
+	ret = palmas_rtc_read(palmas, PALMAS_RTC_STATUS_REG,
+		&rtc_reg);
+	if (ret)
+		return IRQ_NONE;
+
+	if (rtc_reg & PALMAS_RTC_STATUS_REG_ALARM)
+		events = RTC_IRQF | RTC_AF;
+
+	ret = palmas_rtc_write(palmas, PALMAS_RTC_STATUS_REG,
+		rtc_reg);
+	if (ret)
+		return IRQ_NONE;
+
+	/* Notify RTC core on event */
+	rtc_update_irq(palmas_rtc->rtc, 1, events);
+
+	return IRQ_HANDLED;
+}
+
+static struct rtc_class_ops palmas_rtc_ops = {
+	.read_time	= palmas_rtc_read_time,
+	.set_time	= palmas_rtc_set_time,
+	.read_alarm	= palmas_rtc_read_alarm,
+	.set_alarm	= palmas_rtc_set_alarm,
+	.alarm_irq_enable = palmas_rtc_alarm_irq_enable,
+};
+
+static int __devinit palmas_rtc_probe(struct platform_device *pdev)
+{
+	struct palmas *palmas = NULL;
+	struct palmas_rtc *palmas_rtc = NULL;
+	int ret;
+	u32 rtc_reg;
+
+	palmas = dev_get_drvdata(pdev->dev.parent);
+
+	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
+			GFP_KERNEL);
+	if (!palmas_rtc) {
+		dev_err(&pdev->dev, "Memory allocation failed.\n");
+		return -ENOMEM;
+	}
+
+	/* Clear pending interrupts */
+	ret = palmas_rtc_read(palmas, PALMAS_RTC_STATUS_REG,
+		&rtc_reg);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "rtc_read_status error %d\n", ret);
+		return ret;
+	}
+
+	ret = palmas_rtc_write(palmas, PALMAS_RTC_STATUS_REG,
+		rtc_reg);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "rtc_clear_interupt error %d\n", ret);
+		return ret;
+	}
+
+	dev_dbg(&pdev->dev, "Enabling palmas-RTC.\n");
+	rtc_reg = PALMAS_RTC_CTRL_REG_STOP_RTC;
+	ret = palmas_rtc_write(palmas, PALMAS_RTC_CTRL_REG,
+		rtc_reg);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "rtc_enable error %d\n", ret);
+		return ret;
+	}
+
+	if (!regmap_irq_chip_get_base(palmas->irq_data))
+		return -EINVAL;
+
+	palmas_rtc->irq = regmap_irq_chip_get_base(palmas->irq_data);
+	if (palmas_rtc->irq <= 0) {
+		dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
+			palmas_rtc->irq);
+		return ret;
+	}
+
+	palmas_rtc->irq += PALMAS_RTC_ALARM_IRQ;
+
+	ret = request_threaded_irq(palmas_rtc->irq, NULL,
+		palmas_rtc_interrupt, IRQF_TRIGGER_LOW,
+		"palmas-rtc", &pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "IRQ is not free.\n");
+		return ret;
+	}
+	device_init_wakeup(&pdev->dev, 1);
+
+	palmas_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+		&palmas_rtc_ops, THIS_MODULE);
+	if (IS_ERR(palmas_rtc->rtc)) {
+		ret = PTR_ERR(palmas_rtc->rtc);
+		free_irq(palmas_rtc->irq, &pdev->dev);
+		dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, palmas_rtc);
+
+	return 0;
+}
+
+/*
+ * Disable all palmas RTC module interrupts.
+ * Sets status flag to free.
+ */
+static int __devexit palmas_rtc_remove(struct platform_device *pdev)
+{
+	/* leave rtc running, but disable irqs */
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+
+	palmas_rtc_alarm_irq_enable(&palmas->rtc->rtc->dev, 0);
+	free_irq(palmas->irq, &pdev->dev);
+	rtc_device_unregister(palmas->rtc->rtc);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int palmas_rtc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+	u8 alarm = PALMAS_RTC_INTERRUPTS_REG_IT_ALARM;
+	int ret;
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(palmas->rtc->irq);
+
+	/* Store current list of enabled interrupts*/
+	ret = palmas_rtc_read(palmas, PALMAS_RTC_INTERRUPTS_REG,
+		&palmas->rtc->irqstat);
+	if (ret < 0)
+		return ret;
+
+	/* Enable RTC ALARM interrupt only */
+	return palmas_rtc_write(palmas,
+		PALMAS_RTC_INTERRUPTS_REG, alarm);
+}
+
+static int palmas_rtc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(palmas->rtc->irq);
+
+	/* Restore list of enabled interrupts before suspend */
+	return palmas_rtc_write(palmas,
+		PALMAS_RTC_INTERRUPTS_REG, palmas->rtc->irqstat);
+}
+
+static const struct dev_pm_ops palmas_rtc_pm_ops = {
+	.suspend	= palmas_rtc_suspend,
+	.resume		= palmas_rtc_resume,
+};
+
+#define DEV_PM_OPS     (&palmas_rtc_pm_ops)
+#else
+#define DEV_PM_OPS     NULL
+#endif
+
+static struct platform_driver palmas_rtc_driver = {
+	.probe		= palmas_rtc_probe,
+	.remove		= __devexit_p(palmas_rtc_remove),
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "palmas-rtc",
+		.pm	= DEV_PM_OPS,
+	},
+};
+
+module_platform_driver(palmas_rtc_driver);
+MODULE_ALIAS("platform:palmas_rtc");
+MODULE_AUTHOR("Kasoju Mallikarjun <mkasoju@nvidia.com>");
+MODULE_LICENSE("GPL v2");