rtc: tps80031: Adding driver for TI PMU RTC 80031

With this change, RTC driver for TI PMU 80031 is being checked in.

bug 833336

Original-Change-Id: If4789a5dd49163d2391ab016845ff5807c061f12
Reviewed-on: http://git-master/r/34453
Tested-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Reviewed-by: Thomas Cherry <tcherry@nvidia.com>
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>

Rebase-Id: R98c49f456537e65d02460e738029673e7eea1bc0

3 files changed, 453 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index adb0edf827eb..7b07871aa408 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1086,6 +1086,16 @@ config RTC_DRV_TPS6591x
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-tps6591x.
 
+config RTC_DRV_TPS80031
+	tristate "TPS80031 RTC driver"
+	depends on MFD_TPS80031
+	default n
+	help
+	  If you say yes here you get support for the TPS80031 RTC module.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-tps6591x.
+
 config RTC_DRV_PUV3
 	tristate "PKUnity v3 RTC support"
 	depends on ARCH_PUV3
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 04c616be2c0e..99d0e775af4c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -104,6 +104,7 @@ obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o
 obj-$(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_TWL4030)	+= rtc-twl.o
 obj-$(CONFIG_RTC_DRV_TX4939)	+= rtc-tx4939.o
 obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o
diff --git a/drivers/rtc/rtc-tps80031.c b/drivers/rtc/rtc-tps80031.c
new file mode 100644
index 000000000000..1ee3cdeb23a0
--- /dev/null
+++ b/drivers/rtc/rtc-tps80031.c
@@ -0,0 +1,442 @@
+/*
+ * drivers/rtc/rtc_tps80031.c
+ *
+ * RTC driver for TI TPS80031
+ *
+ * Copyright (c) 2011, NVIDIA 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.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+/* #define DEBUG		1 */
+/* #define VERBOSE_DEBUG	1 */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mfd/tps80031.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+#define RTC_CTRL		0x10
+#define RTC_STATUS		0x11
+#define RTC_SECONDS_REG		0x0
+#define RTC_ALARM		0x8
+#define RTC_INT			0x12
+#define RTC_RESET_STATUS	0x16
+
+#define ENABLE_ALARM_INT 0x8
+#define ALARM_INT_STATUS 0x40
+#define STOP_RTC 1
+
+/* Power on reset Values of RTC registers */
+#define RTC_POR_YEAR 0
+#define RTC_POR_MONTH 1
+#define RTC_POR_DAY 1
+
+/*
+Linux RTC driver refers 19th centaury as base year in many
+calculations. (e.g. refer drivers/rtc/rtc-lib.c)
+*/
+#define OS_REF_YEAR 1900
+
+/*
+	PMU RTC have only 2 nibbles to store year information, so using an
+	offset of 100 to set the base year as 2000 for our driver.
+*/
+#define RTC_YEAR_OFFSET 100
+
+struct tps80031_rtc {
+	unsigned long		epoch_start;
+	int			irq;
+	struct rtc_device	*rtc;
+	bool			irq_en;
+};
+
+static int tps80031_read_regs(struct device *dev, int reg, int len,
+	uint8_t *val)
+{
+	int ret;
+
+	/* dummy read of STATUS_REG as per data sheet */
+	ret = tps80031_reads(dev->parent, 1, RTC_STATUS, 1, val);
+	if (ret < 0) {
+		dev_err(dev->parent, "failed reading RTC_STATUS\n");
+		WARN_ON(1);
+		return ret;
+	}
+
+	ret = tps80031_reads(dev->parent, 1, reg, len, val);
+	if (ret < 0) {
+		dev_err(dev->parent, "failed reading from reg %d\n", reg);
+		WARN_ON(1);
+		return ret;
+	}
+	return 0;
+}
+
+static int tps80031_write_regs(struct device *dev, int reg, int len,
+	uint8_t *val)
+{
+	int ret;
+	ret = tps80031_writes(dev->parent, 1, reg, len, val);
+	if (ret < 0) {
+		dev_err(dev->parent, "failed writing reg: %d\n", reg);
+		WARN_ON(1);
+		return ret;
+	}
+
+	return 0;
+}
+
+static u8 dec2bcd(u8 dec)
+{
+	return ((dec/10)<<4)+(dec%10);
+}
+
+static u8 bcd2dec(u8 bcd)
+{
+	return (bcd >> 4)*10+(bcd & 0xF);
+}
+
+static void convert_bcd_to_decimal(u8 *buf, u8 len)
+{
+	int i = 0;
+	for (i = 0; i < len; i++)
+		buf[i] = bcd2dec(buf[i]);
+}
+
+static void convert_decimal_to_bcd(u8 *buf, u8 len)
+{
+	int i = 0;
+	for (i = 0; i < len; i++)
+		buf[i] = dec2bcd(buf[i]);
+}
+
+static int tps80031_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	u8 buff[7];
+	int err;
+	err = tps80031_read_regs(dev, RTC_SECONDS_REG, sizeof(buff), buff);
+	if (err < 0) {
+		dev_err(dev->parent, "failed reading time\n");
+		return err;
+	}
+	convert_bcd_to_decimal(buff, sizeof(buff));
+	tm->tm_sec = buff[0];
+	tm->tm_min = buff[1];
+	tm->tm_hour = buff[2];
+	tm->tm_mday = buff[3];
+	tm->tm_mon = buff[4];
+	tm->tm_year = buff[5] + RTC_YEAR_OFFSET;
+	tm->tm_wday = buff[6];
+	return 0;
+}
+
+static int tps80031_rtc_stop(struct device *dev)
+{
+	int err;
+	err = tps80031_clr_bits(dev->parent, 1, RTC_CTRL, STOP_RTC);
+	if (err < 0)
+		dev_err(dev->parent, "failed to stop RTC. err: %d\n", err);
+	return err;
+}
+
+static int tps80031_rtc_start(struct device *dev)
+{
+	int err;
+	err = tps80031_set_bits(dev->parent, 1, RTC_CTRL, STOP_RTC);
+	if (err < 0)
+		dev_err(dev->parent, "failed to start RTC. err: %d\n", err);
+	return err;
+}
+
+
+static int tps80031_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	u8 buff[7];
+	int err;
+
+	buff[0] = tm->tm_sec;
+	buff[1] = tm->tm_min;
+	buff[2] = tm->tm_hour;
+	buff[3] = tm->tm_mday;
+	buff[4] = tm->tm_mon;
+	buff[5] = tm->tm_year % RTC_YEAR_OFFSET;
+	buff[6] = tm->tm_wday;
+
+	convert_decimal_to_bcd(buff, sizeof(buff));
+	err = tps80031_rtc_stop(dev);
+	if (err < 0)
+		return err;
+
+	err = tps80031_write_regs(dev, RTC_SECONDS_REG, sizeof(buff), buff);
+	if (err < 0) {
+		dev_err(dev->parent, "failed to program new time\n");
+		return err;
+	}
+
+	err = tps80031_rtc_start(dev);
+	return err;
+}
+
+static int tps80031_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long seconds;
+	u8 buff[6];
+	int err;
+	struct rtc_time tm;
+
+	if (rtc->irq == -1)
+		return -EIO;
+
+	rtc_tm_to_time(&alrm->time, &seconds);
+	tps80031_rtc_read_time(dev, &tm);
+	rtc_tm_to_time(&tm, &rtc->epoch_start);
+
+	if (WARN_ON(alrm->enabled && (seconds < rtc->epoch_start))) {
+		dev_err(dev->parent, "can't set alarm to requested time\n");
+		return -EINVAL;
+	}
+
+	if (alrm->enabled && !rtc->irq_en)
+		rtc->irq_en = true;
+	else if (!alrm->enabled && rtc->irq_en)
+		rtc->irq_en = false;
+
+	buff[0] = alrm->time.tm_sec;
+	buff[1] = alrm->time.tm_min;
+	buff[2] = alrm->time.tm_hour;
+	buff[3] = alrm->time.tm_mday;
+	buff[4] = alrm->time.tm_mon;
+	buff[5] = alrm->time.tm_year % RTC_YEAR_OFFSET;
+	convert_decimal_to_bcd(buff, sizeof(buff));
+	err = tps80031_write_regs(dev, RTC_ALARM, sizeof(buff), buff);
+	if (err)
+		dev_err(dev->parent, "unable to program alarm\n");
+
+	return err;
+}
+
+static int tps80031_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	u8 buff[6];
+	int err;
+
+	err = tps80031_read_regs(dev, RTC_ALARM, sizeof(buff), buff);
+	if (err)
+		return err;
+	convert_bcd_to_decimal(buff, sizeof(buff));
+
+	alrm->time.tm_sec = buff[0];
+	alrm->time.tm_min = buff[1];
+	alrm->time.tm_hour = buff[2];
+	alrm->time.tm_mday = buff[3];
+	alrm->time.tm_mon = buff[4];
+	alrm->time.tm_year = buff[5] + RTC_YEAR_OFFSET;
+
+	return 0;
+}
+
+static int tps80031_rtc_alarm_irq_enable(struct device *dev,
+					 unsigned int enable)
+{
+	struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+	int err;
+	struct device *p = dev->parent;
+
+	if (rtc->irq == -1)
+		return -EIO;
+
+	if (enable) {
+		if (rtc->irq_en == true)
+			return 0;
+
+		err = tps80031_set_bits(p, 1, RTC_INT, ENABLE_ALARM_INT);
+		if (err < 0)
+			dev_err(p, "failed to set ALRM int. err: %d\n", err);
+		return err;
+		rtc->irq_en = true;
+	} else {
+		if (rtc->irq_en == false)
+			return 0;
+		err = tps80031_clr_bits(p, 1, RTC_INT, ENABLE_ALARM_INT);
+		if (err < 0)
+			dev_err(p, "failed to clear ALRM int. err: %d\n", err);
+		return err;
+		rtc->irq_en = false;
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops tps80031_rtc_ops = {
+	.read_time = tps80031_rtc_read_time,
+	.set_time = tps80031_rtc_set_time,
+	.set_alarm = tps80031_rtc_set_alarm,
+	.read_alarm = tps80031_rtc_read_alarm,
+	.alarm_irq_enable = tps80031_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t tps80031_rtc_irq(int irq, void *data)
+{
+	struct device *dev = data;
+	struct tps80031_rtc *rtc = dev_get_drvdata(dev);
+	u8 reg;
+	int err;
+
+	/* clear Alarm status bits.*/
+	err = tps80031_read_regs(dev, RTC_STATUS, 1, &reg);
+	if (err) {
+		dev_err(dev->parent, "unable to read RTC_STATUS reg\n");
+		return -EBUSY;
+	}
+
+	err = tps80031_set_bits(dev->parent, 1, RTC_STATUS, ALARM_INT_STATUS);
+	if (err) {
+		dev_err(dev->parent, "unable to set Alarm INT\n");
+		return -EBUSY;
+	}
+
+	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
+	return IRQ_HANDLED;
+}
+
+static int __devinit tps80031_rtc_probe(struct platform_device *pdev)
+{
+	struct tps80031_rtc_platform_data *pdata = pdev->dev.platform_data;
+	struct tps80031_rtc *rtc;
+	struct rtc_time tm;
+	int err;
+	u8 reg;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform_data specified\n");
+		return -EINVAL;
+	}
+
+	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->irq = -1;
+	if (pdata->irq < 0)
+		dev_err(&pdev->dev, "no IRQ specified, wakeup is disabled\n");
+
+	rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+				       &tps80031_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rtc->rtc)) {
+		err = PTR_ERR(rtc->rtc);
+		goto fail;
+	}
+
+	if ((int)pdev && (int)&pdev->dev)
+		err = tps80031_read_regs(&pdev->dev, RTC_STATUS, 1, &reg);
+	else {
+		dev_err(&pdev->dev, "%s Input params incorrect\n", __func__);
+		err = -EBUSY;
+		goto fail;
+	}
+
+	if (err) {
+		dev_err(&pdev->dev, "%s unable to read status\n", __func__);
+		err = -EBUSY;
+		goto fail;
+	}
+
+	err = tps80031_set_bits(pdev->dev.parent, 1, RTC_INT, ENABLE_ALARM_INT);
+	if (err) {
+		dev_err(&pdev->dev, "unable to program Interrupt Mask reg\n");
+		err = -EBUSY;
+		goto fail;
+	}
+
+	/* If RTC have POR values, set time using platform data*/
+	tps80031_rtc_read_time(&pdev->dev, &tm);
+	if ((tm.tm_year == RTC_YEAR_OFFSET + RTC_POR_YEAR) &&
+		(tm.tm_mon == RTC_POR_MONTH) &&
+		(tm.tm_mday == RTC_POR_DAY)) {
+		if (pdata->time.tm_year < 2000 ||
+			pdata->time.tm_year > 2100) {
+			dev_err(&pdev->dev, "Invalid platform data\n");
+			memset(&pdata->time, 0, sizeof(pdata->time));
+			pdata->time.tm_year = 2011;
+			pdata->time.tm_mday = 1;
+		}
+		tps80031_rtc_set_time(&pdev->dev, &pdata->time);
+	}
+
+	dev_set_drvdata(&pdev->dev, rtc);
+	if (pdata && (pdata->irq >= 0)) {
+		rtc->irq = pdata->irq;
+		err = request_threaded_irq(pdata->irq, NULL, tps80031_rtc_irq,
+					IRQF_ONESHOT, "rtc_tps80031",
+					&pdev->dev);
+		if (err) {
+			dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
+			rtc->irq = -1;
+		} else {
+			device_init_wakeup(&pdev->dev, 1);
+			enable_irq_wake(rtc->irq);
+		}
+	}
+	return 0;
+
+fail:
+	if (!IS_ERR_OR_NULL(rtc->rtc))
+		rtc_device_unregister(rtc->rtc);
+	kfree(rtc);
+	return err;
+}
+
+static int __devexit tps80031_rtc_remove(struct platform_device *pdev)
+{
+	struct tps80031_rtc *rtc = dev_get_drvdata(&pdev->dev);
+
+	if (rtc->irq != -1)
+		free_irq(rtc->irq, rtc);
+	rtc_device_unregister(rtc->rtc);
+	kfree(rtc);
+	return 0;
+}
+
+static struct platform_driver tps80031_rtc_driver = {
+	.driver	= {
+		.name	= "rtc_tps80031",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= tps80031_rtc_probe,
+	.remove	= __devexit_p(tps80031_rtc_remove),
+};
+
+static int __init tps80031_rtc_init(void)
+{
+	return platform_driver_register(&tps80031_rtc_driver);
+}
+module_init(tps80031_rtc_init);
+
+static void __exit tps80031_rtc_exit(void)
+{
+	platform_driver_unregister(&tps80031_rtc_driver);
+}
+module_exit(tps80031_rtc_exit);
+
+MODULE_DESCRIPTION("TI TPS80031 RTC driver");
+MODULE_AUTHOR("NVIDIA Corporation");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc_tps80031");