rtc: max77686: add Maxim 77686 driver

Add a driver to support max77686 rtc.  MAX77686 rtc support smpl and wtsr
mode.  It has two alarm register which can be used for alarming to wake
system up.  This drvier uses regmap to access its register.

[akpm@linux-foundation.org: remove inline, __devinit annotations]
[jg1.han@samsung.com: fix build warnings]
[akpm@linux-foundation.org: simplify code]
Signed-off-by: Chiwoong Byun <woong.byun@samsung.com>
Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Myugnjoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 641 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
new file mode 100644
index 000000000000..8ab56b00e693
--- /dev/null
+++ b/drivers/rtc/rtc-max77686.c
@@ -0,0 +1,641 @@
+/*
+ * RTC driver for Maxim MAX77686
+ *
+ * Copyright (C) 2012 Samsung Electronics Co.Ltd
+ *
+ *  based on rtc-max8997.c
+ *
+ *  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/slab.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max77686-private.h>
+#include <linux/irqdomain.h>
+#include <linux/regmap.h>
+
+/* RTC Control Register */
+#define BCD_EN_SHIFT			0
+#define BCD_EN_MASK				(1 << BCD_EN_SHIFT)
+#define MODEL24_SHIFT			1
+#define MODEL24_MASK			(1 << MODEL24_SHIFT)
+/* RTC Update Register1 */
+#define RTC_UDR_SHIFT			0
+#define RTC_UDR_MASK			(1 << RTC_UDR_SHIFT)
+#define RTC_RBUDR_SHIFT			4
+#define RTC_RBUDR_MASK			(1 << RTC_RBUDR_SHIFT)
+/* WTSR and SMPL Register */
+#define WTSRT_SHIFT				0
+#define SMPLT_SHIFT				2
+#define WTSR_EN_SHIFT			6
+#define SMPL_EN_SHIFT			7
+#define WTSRT_MASK				(3 << WTSRT_SHIFT)
+#define SMPLT_MASK				(3 << SMPLT_SHIFT)
+#define WTSR_EN_MASK			(1 << WTSR_EN_SHIFT)
+#define SMPL_EN_MASK			(1 << SMPL_EN_SHIFT)
+/* RTC Hour register */
+#define HOUR_PM_SHIFT			6
+#define HOUR_PM_MASK			(1 << HOUR_PM_SHIFT)
+/* RTC Alarm Enable */
+#define ALARM_ENABLE_SHIFT		7
+#define ALARM_ENABLE_MASK		(1 << ALARM_ENABLE_SHIFT)
+
+#define MAX77686_RTC_UPDATE_DELAY	16
+#undef MAX77686_RTC_WTSR_SMPL
+
+enum {
+	RTC_SEC = 0,
+	RTC_MIN,
+	RTC_HOUR,
+	RTC_WEEKDAY,
+	RTC_MONTH,
+	RTC_YEAR,
+	RTC_DATE,
+	RTC_NR_TIME
+};
+
+struct max77686_rtc_info {
+	struct device		*dev;
+	struct max77686_dev	*max77686;
+	struct i2c_client	*rtc;
+	struct rtc_device	*rtc_dev;
+	struct mutex		lock;
+
+	struct regmap		*regmap;
+
+	int virq;
+	int rtc_24hr_mode;
+};
+
+enum MAX77686_RTC_OP {
+	MAX77686_RTC_WRITE,
+	MAX77686_RTC_READ,
+};
+
+static inline int max77686_rtc_calculate_wday(u8 shifted)
+{
+	int counter = -1;
+	while (shifted) {
+		shifted >>= 1;
+		counter++;
+	}
+	return counter;
+}
+
+static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
+				   int rtc_24hr_mode)
+{
+	tm->tm_sec = data[RTC_SEC] & 0x7f;
+	tm->tm_min = data[RTC_MIN] & 0x7f;
+	if (rtc_24hr_mode)
+		tm->tm_hour = data[RTC_HOUR] & 0x1f;
+	else {
+		tm->tm_hour = data[RTC_HOUR] & 0x0f;
+		if (data[RTC_HOUR] & HOUR_PM_MASK)
+			tm->tm_hour += 12;
+	}
+
+	tm->tm_wday = max77686_rtc_calculate_wday(data[RTC_WEEKDAY] & 0x7f);
+	tm->tm_mday = data[RTC_DATE] & 0x1f;
+	tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
+	tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
+	tm->tm_yday = 0;
+	tm->tm_isdst = 0;
+}
+
+static int max77686_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
+{
+	data[RTC_SEC] = tm->tm_sec;
+	data[RTC_MIN] = tm->tm_min;
+	data[RTC_HOUR] = tm->tm_hour;
+	data[RTC_WEEKDAY] = 1 << tm->tm_wday;
+	data[RTC_DATE] = tm->tm_mday;
+	data[RTC_MONTH] = tm->tm_mon + 1;
+	data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0 ;
+
+	if (tm->tm_year < 100) {
+		pr_warn("%s: MAX77686 RTC cannot handle the year %d."
+			"Assume it's 2000.\n", __func__, 1900 + tm->tm_year);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int max77686_rtc_update(struct max77686_rtc_info *info,
+	enum MAX77686_RTC_OP op)
+{
+	int ret;
+	unsigned int data;
+
+	if (op == MAX77686_RTC_WRITE)
+		data = 1 << RTC_UDR_SHIFT;
+	else
+		data = 1 << RTC_RBUDR_SHIFT;
+
+	ret = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_RTC_UPDATE0, data, data);
+	if (ret < 0)
+		dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
+				__func__, ret, data);
+	else {
+		/* Minimum 16ms delay required before RTC update. */
+		msleep(MAX77686_RTC_UPDATE_DELAY);
+	}
+
+	return ret;
+}
+
+static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				MAX77686_RTC_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,	ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
+
+	ret = rtc_valid_tm(tm);
+
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	ret = max77686_rtc_tm_to_data(tm, data);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&info->lock);
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_RTC_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
+				ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	unsigned int val;
+	int i, ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
+				__func__, __LINE__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
+
+	alrm->enabled = 0;
+	for (i = 0; i < RTC_NR_TIME; i++) {
+		if (data[i] & ALARM_ENABLE_MASK) {
+			alrm->enabled = 1;
+			break;
+		}
+	}
+
+	alrm->pending = 0;
+	ret = regmap_read(info->max77686->regmap, MAX77686_REG_STATUS1, &val);
+	if (ret < 0) {
+		dev_err(info->dev, "%s:%d fail to read status1 reg(%d)\n",
+				__func__, __LINE__, ret);
+		goto out;
+	}
+
+	if (val & (1 << 4)) /* RTCA1 */
+		alrm->pending = 1;
+
+out:
+	mutex_unlock(&info->lock);
+	return 0;
+}
+
+static int max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
+{
+	u8 data[RTC_NR_TIME];
+	int ret, i;
+	struct rtc_time tm;
+
+	if (!mutex_is_locked(&info->lock))
+		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
+
+	for (i = 0; i < RTC_NR_TIME; i++)
+		data[i] &= ~ALARM_ENABLE_MASK;
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+out:
+	return ret;
+}
+
+static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
+{
+	u8 data[RTC_NR_TIME];
+	int ret;
+	struct rtc_time tm;
+
+	if (!mutex_is_locked(&info->lock))
+		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
+
+	data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
+	data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
+	data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
+	data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
+	if (data[RTC_MONTH] & 0xf)
+		data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
+	if (data[RTC_YEAR] & 0x7f)
+		data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
+	if (data[RTC_DATE] & 0x1f)
+		data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+out:
+	return ret;
+}
+
+static int max77686_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	ret = max77686_rtc_tm_to_data(&alrm->time, data);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_stop_alarm(info);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+	if (ret < 0)
+		goto out;
+
+	if (alrm->enabled)
+		ret = max77686_rtc_start_alarm(info);
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_alarm_irq_enable(struct device *dev,
+					unsigned int enabled)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&info->lock);
+	if (enabled)
+		ret = max77686_rtc_start_alarm(info);
+	else
+		ret = max77686_rtc_stop_alarm(info);
+	mutex_unlock(&info->lock);
+
+	return ret;
+}
+
+static irqreturn_t max77686_rtc_alarm_irq(int irq, void *data)
+{
+	struct max77686_rtc_info *info = data;
+
+	dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);
+
+	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops max77686_rtc_ops = {
+	.read_time = max77686_rtc_read_time,
+	.set_time = max77686_rtc_set_time,
+	.read_alarm = max77686_rtc_read_alarm,
+	.set_alarm = max77686_rtc_set_alarm,
+	.alarm_irq_enable = max77686_rtc_alarm_irq_enable,
+};
+
+#ifdef MAX77686_RTC_WTSR_SMPL
+static void max77686_rtc_enable_wtsr(struct max77686_rtc_info *info, bool enable)
+{
+	int ret;
+	unsigned int val, mask;
+
+	if (enable)
+		val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
+	else
+		val = 0;
+
+	mask = WTSR_EN_MASK | WTSRT_MASK;
+
+	dev_info(info->dev, "%s: %s WTSR\n", __func__,
+			enable ? "enable" : "disable");
+
+	ret = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_WTSR_SMPL_CNTL, mask, val);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
+				__func__, ret);
+		return;
+	}
+
+	max77686_rtc_update(info, MAX77686_RTC_WRITE);
+}
+
+static void max77686_rtc_enable_smpl(struct max77686_rtc_info *info, bool enable)
+{
+	int ret;
+	unsigned int val, mask;
+
+	if (enable)
+		val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
+	else
+		val = 0;
+
+	mask = SMPL_EN_MASK | SMPLT_MASK;
+
+	dev_info(info->dev, "%s: %s SMPL\n", __func__,
+			enable ? "enable" : "disable");
+
+	ret = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_WTSR_SMPL_CNTL, mask, val);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
+				__func__, ret);
+		return;
+	}
+
+	max77686_rtc_update(info, MAX77686_RTC_WRITE);
+
+	val = 0;
+	regmap_read(info->max77686->rtc_regmap, MAX77686_WTSR_SMPL_CNTL, &val);
+	pr_info("%s: WTSR_SMPL(0x%02x)\n", __func__, val);
+}
+#endif /* MAX77686_RTC_WTSR_SMPL */
+
+static int max77686_rtc_init_reg(struct max77686_rtc_info *info)
+{
+	u8 data[2];
+	int ret;
+
+	/* Set RTC control register : Binary mode, 24hour mdoe */
+	data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
+	data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
+
+	info->rtc_24hr_mode = 1;
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap, MAX77686_RTC_CONTROLM, data, 2);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
+				__func__, ret);
+		return ret;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+	return ret;
+}
+
+static struct regmap_config max77686_rtc_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int max77686_rtc_probe(struct platform_device *pdev)
+{
+	struct max77686_dev *max77686 = dev_get_drvdata(pdev->dev.parent);
+	struct max77686_rtc_info *info;
+	int ret, virq;
+
+	printk(KERN_INFO "%s\n", __func__);
+
+	info = kzalloc(sizeof(struct max77686_rtc_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	mutex_init(&info->lock);
+	info->dev = &pdev->dev;
+	info->max77686 = max77686;
+	info->rtc = max77686->rtc;
+	info->max77686->rtc_regmap = regmap_init_i2c(info->max77686->rtc,
+					 &max77686_rtc_regmap_config);
+	if (IS_ERR(info->max77686->rtc_regmap)) {
+		ret = PTR_ERR(info->max77686->rtc_regmap);
+		dev_err(info->max77686->dev, "Failed to allocate register map: %d\n",
+				ret);
+		kfree(info);
+		return ret;
+	}
+	platform_set_drvdata(pdev, info);
+
+	ret = max77686_rtc_init_reg(info);
+
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
+		goto err_rtc;
+	}
+
+#ifdef MAX77686_RTC_WTSR_SMPL
+	max77686_rtc_enable_wtsr(info, true);
+	max77686_rtc_enable_smpl(info, true);
+#endif
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	info->rtc_dev = rtc_device_register("max77686-rtc", &pdev->dev,
+			&max77686_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(info->rtc_dev)) {
+		printk(KERN_INFO "%s: fail\n", __func__);
+
+		ret = PTR_ERR(info->rtc_dev);
+		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+		if (ret == 0)
+			ret = -EINVAL;
+		goto err_rtc;
+	}
+	virq = irq_create_mapping(max77686->irq_domain, MAX77686_RTCIRQ_RTCA1);
+	if (!virq)
+		goto err_rtc;
+	info->virq = virq;
+
+	ret = request_threaded_irq(virq, NULL, max77686_rtc_alarm_irq, 0,
+			"rtc-alarm0", info);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
+			info->virq, ret);
+		goto err_rtc;
+	}
+
+	goto out;
+err_rtc:
+	kfree(info);
+	return ret;
+out:
+	return ret;
+}
+
+static int max77686_rtc_remove(struct platform_device *pdev)
+{
+	struct max77686_rtc_info *info = platform_get_drvdata(pdev);
+
+	if (info) {
+		free_irq(info->virq, info);
+		rtc_device_unregister(info->rtc_dev);
+		kfree(info);
+	}
+
+	return 0;
+}
+
+static void max77686_rtc_shutdown(struct platform_device *pdev)
+{
+#ifdef MAX77686_RTC_WTSR_SMPL
+	struct max77686_rtc_info *info = platform_get_drvdata(pdev);
+	int i;
+	u8 val = 0;
+
+	for (i = 0; i < 3; i++) {
+		max77686_rtc_enable_wtsr(info, false);
+		regmap_read(info->max77686->rtc_regmap, MAX77686_WTSR_SMPL_CNTL, &val);
+		pr_info("%s: WTSR_SMPL reg(0x%02x)\n", __func__, val);
+		if (val & WTSR_EN_MASK)
+			pr_emerg("%s: fail to disable WTSR\n", __func__);
+		else {
+			pr_info("%s: success to disable WTSR\n", __func__);
+			break;
+		}
+	}
+
+	/* Disable SMPL when power off */
+	max77686_rtc_enable_smpl(info, false);
+#endif /* MAX77686_RTC_WTSR_SMPL */
+}
+
+static const struct platform_device_id rtc_id[] = {
+	{ "max77686-rtc", 0 },
+	{},
+};
+
+static struct platform_driver max77686_rtc_driver = {
+	.driver		= {
+		.name	= "max77686-rtc",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max77686_rtc_probe,
+	.remove		= max77686_rtc_remove,
+	.shutdown	= max77686_rtc_shutdown,
+	.id_table	= rtc_id,
+};
+
+static int __init max77686_rtc_init(void)
+{
+	return platform_driver_register(&max77686_rtc_driver);
+}
+module_init(max77686_rtc_init);
+
+static void __exit max77686_rtc_exit(void)
+{
+	platform_driver_unregister(&max77686_rtc_driver);
+}
+module_exit(max77686_rtc_exit);
+
+MODULE_DESCRIPTION("Maxim MAX77686 RTC driver");
+MODULE_AUTHOR("<woong.byun@samsung.com>");
+MODULE_LICENSE("GPL");