Commit a4d4121b authored by Javier Martinez Canillas's avatar Javier Martinez Canillas Committed by Linus Torvalds
Browse files

rtc: add driver for Maxim 77802 PMIC Real-Time-Clock 



The MAX7802 PMIC has a Real-Time-Clock (RTC) with two alarms.  This
patch adds support for the RTC and is based on a driver added by Simon
Glass to the Chrome OS kernel 3.8 tree.

[akpm@linux-foundation.org: add comment clarifying ffs() use]
Signed-off-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Olof Johansson <olof@lixom.net>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a20cd88e

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -298,6 +298,16 @@ config RTC_DRV_RK808 
	  This driver can also be built as a module. If so, the module

	  will be called rk808-rtc.



config RTC_DRV_MAX77802

	tristate "Maxim 77802 RTC"

	depends on MFD_MAX77686

	help

	  If you say yes here you will get support for the

	  RTC of Maxim MAX77802 PMIC.



	  This driver can also be built as a module. If so, the module

	  will be called rtc-max77802.



config RTC_DRV_RS5C372

	tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"

	help

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ obj-$(CONFIG_RTC_DRV_MAX8998) += rtc-max8998.o 
obj-$(CONFIG_RTC_DRV_MAX8997)	+= rtc-max8997.o

obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o

obj-$(CONFIG_RTC_DRV_MAX77686)	+= rtc-max77686.o

obj-$(CONFIG_RTC_DRV_MAX77802)  += rtc-max77802.o

obj-$(CONFIG_RTC_DRV_MC13XXX)	+= rtc-mc13xxx.o

obj-$(CONFIG_RTC_DRV_MCP795)	+= rtc-mcp795.o

obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o

drivers/rtc/rtc-max77802.c

0 → 100644
+502 −0
Original line number Diff line number Diff line 
/*

 * RTC driver for Maxim MAX77802

 *

 * Copyright (C) 2013 Google, Inc

 *

 * 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)

/* 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)



/* For the RTCAE1 register, we write this value to enable the alarm */

#define ALARM_ENABLE_VALUE		0x77



#define MAX77802_RTC_UPDATE_DELAY_US	200



enum {

	RTC_SEC = 0,

	RTC_MIN,

	RTC_HOUR,

	RTC_WEEKDAY,

	RTC_MONTH,

	RTC_YEAR,

	RTC_DATE,

	RTC_NR_TIME

};



struct max77802_rtc_info {

	struct device		*dev;

	struct max77686_dev	*max77802;

	struct i2c_client	*rtc;

	struct rtc_device	*rtc_dev;

	struct mutex		lock;



	struct regmap		*regmap;



	int virq;

	int rtc_24hr_mode;

};



enum MAX77802_RTC_OP {

	MAX77802_RTC_WRITE,

	MAX77802_RTC_READ,

};



static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,

				   int rtc_24hr_mode)

{

	tm->tm_sec = data[RTC_SEC] & 0xff;

	tm->tm_min = data[RTC_MIN] & 0xff;

	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;

	}



	/* Only a single bit is set in data[], so fls() would be equivalent */

	tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0xff) - 1;

	tm->tm_mday = data[RTC_DATE] & 0x1f;

	tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;



	tm->tm_year = data[RTC_YEAR] & 0xff;

	tm->tm_yday = 0;

	tm->tm_isdst = 0;

}



static int max77802_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;



	return 0;

}



static int max77802_rtc_update(struct max77802_rtc_info *info,

	enum MAX77802_RTC_OP op)

{

	int ret;

	unsigned int data;



	if (op == MAX77802_RTC_WRITE)

		data = 1 << RTC_UDR_SHIFT;

	else

		data = 1 << RTC_RBUDR_SHIFT;



	ret = regmap_update_bits(info->max77802->regmap,

				 MAX77802_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 delay required before RTC update. */

		usleep_range(MAX77802_RTC_UPDATE_DELAY_US,

			     MAX77802_RTC_UPDATE_DELAY_US * 2);

	}



	return ret;

}



static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct max77802_rtc_info *info = dev_get_drvdata(dev);

	u8 data[RTC_NR_TIME];

	int ret;



	mutex_lock(&info->lock);



	ret = max77802_rtc_update(info, MAX77802_RTC_READ);

	if (ret < 0)

		goto out;



	ret = regmap_bulk_read(info->max77802->regmap,

				MAX77802_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;

	}



	max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);



	ret = rtc_valid_tm(tm);



out:

	mutex_unlock(&info->lock);

	return ret;

}



static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct max77802_rtc_info *info = dev_get_drvdata(dev);

	u8 data[RTC_NR_TIME];

	int ret;



	ret = max77802_rtc_tm_to_data(tm, data);

	if (ret < 0)

		return ret;



	mutex_lock(&info->lock);



	ret = regmap_bulk_write(info->max77802->regmap,

				 MAX77802_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 = max77802_rtc_update(info, MAX77802_RTC_WRITE);



out:

	mutex_unlock(&info->lock);

	return ret;

}



static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct max77802_rtc_info *info = dev_get_drvdata(dev);

	u8 data[RTC_NR_TIME];

	unsigned int val;

	int ret;



	mutex_lock(&info->lock);



	ret = max77802_rtc_update(info, MAX77802_RTC_READ);

	if (ret < 0)

		goto out;



	ret = regmap_bulk_read(info->max77802->regmap,

				 MAX77802_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;

	}



	max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);



	alrm->enabled = 0;

	ret = regmap_read(info->max77802->regmap,

			  MAX77802_RTC_AE1, &val);

	if (ret < 0) {

		dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",

			__func__, __LINE__, ret);

		goto out;

	}

	if (val)

		alrm->enabled = 1;



	alrm->pending = 0;

	ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);

	if (ret < 0) {

		dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",

				__func__, __LINE__, ret);

		goto out;

	}



	if (val & (1 << 2)) /* RTCA1 */

		alrm->pending = 1;



out:

	mutex_unlock(&info->lock);

	return 0;

}



static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)

{

	int ret;



	if (!mutex_is_locked(&info->lock))

		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);



	ret = max77802_rtc_update(info, MAX77802_RTC_READ);

	if (ret < 0)

		goto out;



	ret = regmap_write(info->max77802->regmap,

			   MAX77802_RTC_AE1, 0);

	if (ret < 0) {

		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",

			__func__, ret);

		goto out;

	}



	ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);

out:

	return ret;

}



static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)

{

	int ret;



	if (!mutex_is_locked(&info->lock))

		dev_warn(info->dev, "%s: should have mutex locked\n",

			 __func__);



	ret = max77802_rtc_update(info, MAX77802_RTC_READ);

	if (ret < 0)

		goto out;



	ret = regmap_write(info->max77802->regmap,

				   MAX77802_RTC_AE1,

				   ALARM_ENABLE_VALUE);



	if (ret < 0) {

		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",

				__func__, ret);

		goto out;

	}



	ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);

out:

	return ret;

}



static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct max77802_rtc_info *info = dev_get_drvdata(dev);

	u8 data[RTC_NR_TIME];

	int ret;



	ret = max77802_rtc_tm_to_data(&alrm->time, data);

	if (ret < 0)

		return ret;



	mutex_lock(&info->lock);



	ret = max77802_rtc_stop_alarm(info);

	if (ret < 0)

		goto out;



	ret = regmap_bulk_write(info->max77802->regmap,

				 MAX77802_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 = max77802_rtc_update(info, MAX77802_RTC_WRITE);

	if (ret < 0)

		goto out;



	if (alrm->enabled)

		ret = max77802_rtc_start_alarm(info);

out:

	mutex_unlock(&info->lock);

	return ret;

}



static int max77802_rtc_alarm_irq_enable(struct device *dev,

					 unsigned int enabled)

{

	struct max77802_rtc_info *info = dev_get_drvdata(dev);

	int ret;



	mutex_lock(&info->lock);

	if (enabled)

		ret = max77802_rtc_start_alarm(info);

	else

		ret = max77802_rtc_stop_alarm(info);

	mutex_unlock(&info->lock);



	return ret;

}



static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)

{

	struct max77802_rtc_info *info = data;



	dev_dbg(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 max77802_rtc_ops = {

	.read_time = max77802_rtc_read_time,

	.set_time = max77802_rtc_set_time,

	.read_alarm = max77802_rtc_read_alarm,

	.set_alarm = max77802_rtc_set_alarm,

	.alarm_irq_enable = max77802_rtc_alarm_irq_enable,

};



static int max77802_rtc_init_reg(struct max77802_rtc_info *info)

{

	u8 data[2];

	int ret;



	max77802_rtc_update(info, MAX77802_RTC_READ);



	/* 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->max77802->regmap,

				MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));

	if (ret < 0) {

		dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",

				__func__, ret);

		return ret;

	}



	ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);

	return ret;

}



static int max77802_rtc_probe(struct platform_device *pdev)

{

	struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);

	struct max77802_rtc_info *info;

	int ret;



	dev_dbg(&pdev->dev, "%s\n", __func__);



	info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),

			    GFP_KERNEL);

	if (!info)

		return -ENOMEM;



	mutex_init(&info->lock);

	info->dev = &pdev->dev;

	info->max77802 = max77802;

	info->rtc = max77802->i2c;



	platform_set_drvdata(pdev, info);



	ret = max77802_rtc_init_reg(info);



	if (ret < 0) {

		dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);

		return ret;

	}



	device_init_wakeup(&pdev->dev, 1);



	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",

						 &max77802_rtc_ops, THIS_MODULE);



	if (IS_ERR(info->rtc_dev)) {

		ret = PTR_ERR(info->rtc_dev);

		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);

		if (ret == 0)

			ret = -EINVAL;

		return ret;

	}



	if (!max77802->rtc_irq_data) {

		dev_err(&pdev->dev, "No RTC regmap IRQ chip\n");

		return -EINVAL;

	}



	info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,

					 MAX77686_RTCIRQ_RTCA1);



	if (info->virq <= 0) {

		dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",

			MAX77686_RTCIRQ_RTCA1);

		return -EINVAL;

	}



	ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,

					max77802_rtc_alarm_irq, 0, "rtc-alarm1",

					info);

	if (ret < 0)

		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",

			info->virq, ret);



	return ret;

}



#ifdef CONFIG_PM_SLEEP

static int max77802_rtc_suspend(struct device *dev)

{

	if (device_may_wakeup(dev)) {

		struct max77802_rtc_info *info = dev_get_drvdata(dev);



		return enable_irq_wake(info->virq);

	}



	return 0;

}



static int max77802_rtc_resume(struct device *dev)

{

	if (device_may_wakeup(dev)) {

		struct max77802_rtc_info *info = dev_get_drvdata(dev);



		return disable_irq_wake(info->virq);

	}



	return 0;

}

#endif



static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,

			 max77802_rtc_suspend, max77802_rtc_resume);



static const struct platform_device_id rtc_id[] = {

	{ "max77802-rtc", 0 },

	{},

};



static struct platform_driver max77802_rtc_driver = {

	.driver		= {

		.name	= "max77802-rtc",

		.owner	= THIS_MODULE,

		.pm	= &max77802_rtc_pm_ops,

	},

	.probe		= max77802_rtc_probe,

	.id_table	= rtc_id,

};



module_platform_driver(max77802_rtc_driver);



MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");

MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");

MODULE_LICENSE("GPL");

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