max8907c RTC driver

Initial checkin for Maxim max8907c RTC driver

Change-Id: I764440cc1b0410e54f480a6e0ce424103052df14
Reviewed-on: http://git-master/r/16615
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>

3 files changed, 300 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2532d54eb111..35129efad3e8 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -213,6 +213,16 @@ config RTC_DRV_MAX8925
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-max8925.
 
+config RTC_DRV_MAX8907C
+	tristate "Maxim MAX8907C"
+	depends on MFD_MAX8907C
+	help
+	  If you say yes here you will get support for the
+	  RTC of Maxim MAX8907C PMIC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-max8907c.
+
 config RTC_DRV_RS5C372
 	tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index cc4a28918637..be1f703026a0 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
 obj-$(CONFIG_RTC_MXC)		+= rtc-mxc.o
 obj-$(CONFIG_RTC_DRV_MAX6900)	+= rtc-max6900.o
 obj-$(CONFIG_RTC_DRV_MAX8925)	+= rtc-max8925.o
+obj-$(CONFIG_RTC_DRV_MAX8907C)	+= rtc-max8907c.o
 obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o
 obj-$(CONFIG_RTC_DRV_MC13783)	+= rtc-mc13783.o
 obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o
diff --git a/drivers/rtc/rtc-max8907c.c b/drivers/rtc/rtc-max8907c.c
new file mode 100644
index 000000000000..aa48f4bb2497
--- /dev/null
+++ b/drivers/rtc/rtc-max8907c.c
@@ -0,0 +1,289 @@
+/*
+ * RTC driver for Maxim MAX8907c
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ * Based on drivers/rtc/rtc-max8925.c, Copyright (C) 2009-2010 Marvell International Ltd.
+ *
+ * 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/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max8907c.h>
+
+enum {
+	RTC_SEC = 0,
+	RTC_MIN,
+	RTC_HOUR,
+	RTC_WEEKDAY,
+	RTC_DATE,
+	RTC_MONTH,
+	RTC_YEAR1,
+	RTC_YEAR2,
+};
+
+#define TIME_NUM			8
+#define ALARM_1SEC			(1 << 7)
+#define HOUR_12				(1 << 7)
+#define HOUR_AM_PM			(1 << 5)
+#define ALARM0_IRQ			(1 << 3)
+#define ALARM1_IRQ			(1 << 2)
+#define ALARM0_STATUS			(1 << 2)
+#define ALARM1_STATUS			(1 << 1)
+
+struct max8907c_rtc_info {
+	struct rtc_device	*rtc_dev;
+	struct i2c_client	*i2c;
+	struct max8907c		*chip;
+};
+
+static irqreturn_t rtc_update_handler(int irq, void *data)
+{
+	struct max8907c_rtc_info *info = (struct max8907c_rtc_info *)data;
+
+	/* disable ALARM0 except for 1SEC alarm */
+	max8907c_set_bits(info->i2c, MAX8907C_REG_ALARM0_CNTL, 0x7f, 0);
+	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
+	return IRQ_HANDLED;
+}
+
+static int tm_calc(struct rtc_time *tm, u8 *buf, int len)
+{
+	if (len < TIME_NUM)
+		return -EINVAL;
+	tm->tm_year = (buf[RTC_YEAR2] >> 4) * 1000
+			+ (buf[RTC_YEAR2] & 0xf) * 100
+			+ (buf[RTC_YEAR1] >> 4) * 10
+			+ (buf[RTC_YEAR1] & 0xf);
+	tm->tm_year -= 1900;
+	tm->tm_mon = ((buf[RTC_MONTH] >> 4) & 0x01) * 10
+			+ (buf[RTC_MONTH] & 0x0f);
+	tm->tm_mday = ((buf[RTC_DATE] >> 4) & 0x03) * 10
+			+ (buf[RTC_DATE] & 0x0f);
+	tm->tm_wday = buf[RTC_WEEKDAY] & 0x07;
+	if (buf[RTC_HOUR] & HOUR_12) {
+		tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x1) * 10
+				+ (buf[RTC_HOUR] & 0x0f);
+		if (buf[RTC_HOUR] & HOUR_AM_PM)
+			tm->tm_hour += 12;
+	} else {
+		tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x03) * 10
+				+ (buf[RTC_HOUR] & 0x0f);
+	}
+	tm->tm_min = ((buf[RTC_MIN] >> 4) & 0x7) * 10
+			+ (buf[RTC_MIN] & 0x0f);
+	tm->tm_sec = ((buf[RTC_SEC] >> 4) & 0x7) * 10
+			+ (buf[RTC_SEC] & 0x0f);
+	return 0;
+}
+
+static int data_calc(u8 *buf, struct rtc_time *tm, int len)
+{
+	u8 high, low;
+
+	if (len < TIME_NUM)
+		return -EINVAL;
+
+	high = (tm->tm_year + 1900) / 1000;
+	low = (tm->tm_year + 1900) / 100;
+	low = low - high * 10;
+	buf[RTC_YEAR2] = (high << 4) + low;
+	high = (tm->tm_year + 1900) / 10;
+	low = tm->tm_year + 1900;
+	low = low - high * 10;
+	high = high - (high / 10) * 10;
+	buf[RTC_YEAR1] = (high << 4) + low;
+	high = tm->tm_mon / 10;
+	low = tm->tm_mon;
+	low = low - high * 10;
+	buf[RTC_MONTH] = (high << 4) + low;
+	high = tm->tm_mday / 10;
+	low = tm->tm_mday;
+	low = low - high * 10;
+	buf[RTC_DATE] = (high << 4) + low;
+	buf[RTC_WEEKDAY] = tm->tm_wday;
+	high = tm->tm_hour / 10;
+	low = tm->tm_hour;
+	low = low - high * 10;
+	buf[RTC_HOUR] = (high << 4) + low;
+	high = tm->tm_min / 10;
+	low = tm->tm_min;
+	low = low - high * 10;
+	buf[RTC_MIN] = (high << 4) + low;
+	high = tm->tm_sec / 10;
+	low = tm->tm_sec;
+	low = low - high * 10;
+	buf[RTC_SEC] = (high << 4) + low;
+	return 0;
+}
+
+static int max8907c_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max8907c_rtc_info *info = dev_get_drvdata(dev);
+	u8 buf[TIME_NUM];
+	int ret;
+
+	ret = max8907c_reg_bulk_read(info->i2c, MAX8907C_REG_RTC_SEC, TIME_NUM, buf);
+
+	if (ret < 0)
+		return ret;
+	ret = tm_calc(tm, buf, TIME_NUM);
+
+	return ret;
+}
+
+static int max8907c_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max8907c_rtc_info *info = dev_get_drvdata(dev);
+	u8 buf[TIME_NUM];
+	int ret;
+
+	ret = data_calc(buf, tm, TIME_NUM);
+
+	if (ret < 0)
+		return ret;
+	ret = max8907c_reg_bulk_write(info->i2c, MAX8907C_REG_RTC_SEC, TIME_NUM, buf);
+
+	return ret;
+}
+
+static int max8907c_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max8907c_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[TIME_NUM];
+	int ret;
+
+	ret = max8907c_reg_bulk_read(info->i2c, MAX8907C_REG_ALARM0_SEC, TIME_NUM, buf);
+	if (ret < 0)
+		return ret;
+	ret = tm_calc(&alrm->time, buf, TIME_NUM);
+	if (ret < 0)
+		return ret;
+	ret = max8907c_reg_read(info->i2c, MAX8907C_REG_RTC_IRQ_MASK);
+	if (ret < 0)
+		return ret;
+	if ((ret & ALARM0_IRQ) == 0)
+		alrm->enabled = 1;
+	else
+		alrm->enabled = 0;
+	ret = max8907c_reg_read(info->i2c, MAX8907C_REG_RTC_STATUS);
+	if (ret < 0)
+		return ret;
+	if (ret & ALARM0_STATUS)
+		alrm->pending = 1;
+	else
+		alrm->pending = 0;
+
+	return ret;
+}
+
+static int max8907c_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max8907c_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[TIME_NUM];
+	int ret;
+
+	ret = data_calc(buf, &alrm->time, TIME_NUM);
+	if (ret < 0)
+		return ret;
+	ret = max8907c_reg_bulk_write(info->i2c, MAX8907C_REG_ALARM0_SEC, TIME_NUM, buf);
+	if (ret < 0)
+		return ret;
+	/* only enable alarm on year/month/day/hour/min/sec */
+	ret = max8907c_reg_write(info->i2c, MAX8907C_REG_ALARM0_CNTL, 0x77);
+
+	return ret;
+}
+
+static const struct rtc_class_ops max8907c_rtc_ops = {
+	.read_time	= max8907c_rtc_read_time,
+	.set_time	= max8907c_rtc_set_time,
+	.read_alarm	= max8907c_rtc_read_alarm,
+	.set_alarm	= max8907c_rtc_set_alarm,
+};
+
+static int __devinit max8907c_rtc_probe(struct platform_device *pdev)
+{
+	struct max8907c *chip = dev_get_drvdata(pdev->dev.parent);
+	struct max8907c_rtc_info *info;
+	int irq, ret;
+
+	info = kzalloc(sizeof(struct max8907c_rtc_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->i2c = chip->i2c_rtc;
+	info->chip = chip;
+
+	irq = chip->irq_base + MAX8907C_IRQ_RTC_ALARM0;
+
+	ret = request_threaded_irq(irq, NULL, rtc_update_handler,
+				   IRQF_ONESHOT, "rtc-alarm0", info);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
+			irq, ret);
+		goto out_irq;
+	}
+
+	info->rtc_dev = rtc_device_register("max8907c-rtc", &pdev->dev,
+					&max8907c_rtc_ops, THIS_MODULE);
+	ret = PTR_ERR(info->rtc_dev);
+	if (IS_ERR(info->rtc_dev)) {
+		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+		goto out_rtc;
+	}
+
+	dev_set_drvdata(&pdev->dev, info);
+
+	platform_set_drvdata(pdev, info);
+
+	return 0;
+out_rtc:
+	free_irq(chip->irq_base + MAX8907C_IRQ_RTC_ALARM0, info);
+
+out_irq:
+	kfree(info);
+	return ret;
+}
+
+static int __devexit max8907c_rtc_remove(struct platform_device *pdev)
+{
+	struct max8907c_rtc_info *info = platform_get_drvdata(pdev);
+
+	if (info) {
+		free_irq(info->chip->irq_base + MAX8907C_IRQ_RTC_ALARM0, info);
+
+		rtc_device_unregister(info->rtc_dev);
+		kfree(info);
+	}
+	return 0;
+}
+
+static struct platform_driver max8907c_rtc_driver = {
+	.driver		= {
+		.name	= "max8907c-rtc",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max8907c_rtc_probe,
+	.remove		= __devexit_p(max8907c_rtc_remove),
+};
+
+static int __init max8907c_rtc_init(void)
+{
+	return platform_driver_register(&max8907c_rtc_driver);
+}
+module_init(max8907c_rtc_init);
+
+static void __exit max8907c_rtc_exit(void)
+{
+	platform_driver_unregister(&max8907c_rtc_driver);
+}
+module_exit(max8907c_rtc_exit);
+
+MODULE_DESCRIPTION("Maxim MAX8907C RTC driver");
+MODULE_LICENSE("GPL");
+