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Commit d00a18a4 authored by Chen-Yu Tsai's avatar Chen-Yu Tsai Committed by Lee Jones
Browse files

rtc: ac100: Add RTC driver for X-Powers AC100 



X-Powers AC100 is a codec / RTC combo chip. This driver supports
the RTC sub-device.

The RTC block also has clock outputs and non-volatile storage.
Non-volatile storage wthin the RTC hardware is not supported.
Clock output support is added in the next patch.

Signed-off-by: default avatarChen-Yu Tsai <wens@csie.org>
Acked-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 585083c5

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -187,6 +187,16 @@ config RTC_DRV_ABX80X 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-abx80x.



config RTC_DRV_AC100

	tristate "X-Powers AC100"

	depends on MFD_AC100

	help

	  If you say yes here you get support for the real-time clock found

	  in X-Powers AC100 family peripheral ICs.



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

	  will be called rtc-ac100.



config RTC_DRV_AS3722

	tristate "ams AS3722 RTC driver"

	depends on MFD_AS3722

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ obj-$(CONFIG_RTC_DRV_AB3100) += rtc-ab3100.o 
obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o

obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o

obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o

obj-$(CONFIG_RTC_DRV_AC100)	+= rtc-ac100.o

obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o

obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o

obj-$(CONFIG_RTC_DRV_ASM9260)	+= rtc-asm9260.o

drivers/rtc/rtc-ac100.c

0 → 100644
+325 −0
Original line number Diff line number Diff line 
/*

 * RTC Driver for X-Powers AC100

 *

 * Copyright (c) 2016 Chen-Yu Tsai

 *

 * Chen-Yu Tsai <wens@csie.org>

 *

 * 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.

 *

 * 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.

 */



#include <linux/bcd.h>

#include <linux/device.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/mfd/ac100.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/rtc.h>

#include <linux/types.h>



/* Control register */

#define AC100_RTC_CTRL_24HOUR	BIT(0)



/* RTC */

#define AC100_RTC_SEC_MASK	GENMASK(6, 0)

#define AC100_RTC_MIN_MASK	GENMASK(6, 0)

#define AC100_RTC_HOU_MASK	GENMASK(5, 0)

#define AC100_RTC_WEE_MASK	GENMASK(2, 0)

#define AC100_RTC_DAY_MASK	GENMASK(5, 0)

#define AC100_RTC_MON_MASK	GENMASK(4, 0)

#define AC100_RTC_YEA_MASK	GENMASK(7, 0)

#define AC100_RTC_YEA_LEAP	BIT(15)

#define AC100_RTC_UPD_TRIGGER	BIT(15)



/* Alarm (wall clock) */

#define AC100_ALM_INT_ENABLE	BIT(0)



#define AC100_ALM_SEC_MASK	GENMASK(6, 0)

#define AC100_ALM_MIN_MASK	GENMASK(6, 0)

#define AC100_ALM_HOU_MASK	GENMASK(5, 0)

#define AC100_ALM_WEE_MASK	GENMASK(2, 0)

#define AC100_ALM_DAY_MASK	GENMASK(5, 0)

#define AC100_ALM_MON_MASK	GENMASK(4, 0)

#define AC100_ALM_YEA_MASK	GENMASK(7, 0)

#define AC100_ALM_ENABLE_FLAG	BIT(15)

#define AC100_ALM_UPD_TRIGGER	BIT(15)



/*

 * The year parameter passed to the driver is usually an offset relative to

 * the year 1900. This macro is used to convert this offset to another one

 * relative to the minimum year allowed by the hardware.

 *

 * The year range is 1970 - 2069. This range is selected to match Allwinner's

 * driver.

 */

#define AC100_YEAR_MIN				1970

#define AC100_YEAR_MAX				2069

#define AC100_YEAR_OFF				(AC100_YEAR_MIN - 1900)



struct ac100_rtc_dev {

	struct rtc_device *rtc;

	struct device *dev;

	struct regmap *regmap;

	int irq;

	unsigned long alarm;

};



static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)

{

	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);

	struct regmap *regmap = chip->regmap;

	u16 reg[7];

	int ret;



	ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);

	if (ret)

		return ret;



	rtc_tm->tm_sec  = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);

	rtc_tm->tm_min  = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);

	rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);

	rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);

	rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);

	rtc_tm->tm_mon  = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1;

	rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) +

			  AC100_YEAR_OFF;



	return rtc_valid_tm(rtc_tm);

}



static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)

{

	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);

	struct regmap *regmap = chip->regmap;

	int year;

	u16 reg[8];



	/* our RTC has a limited year range... */

	year = rtc_tm->tm_year - AC100_YEAR_OFF;

	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {

		dev_err(dev, "rtc only supports year in range %d - %d\n",

			AC100_YEAR_MIN, AC100_YEAR_MAX);

		return -EINVAL;

	}



	/* convert to BCD */

	reg[0] = bin2bcd(rtc_tm->tm_sec)     & AC100_RTC_SEC_MASK;

	reg[1] = bin2bcd(rtc_tm->tm_min)     & AC100_RTC_MIN_MASK;

	reg[2] = bin2bcd(rtc_tm->tm_hour)    & AC100_RTC_HOU_MASK;

	reg[3] = bin2bcd(rtc_tm->tm_wday)    & AC100_RTC_WEE_MASK;

	reg[4] = bin2bcd(rtc_tm->tm_mday)    & AC100_RTC_DAY_MASK;

	reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK;

	reg[6] = bin2bcd(year)		     & AC100_RTC_YEA_MASK;

	/* trigger write */

	reg[7] = AC100_RTC_UPD_TRIGGER;



	/* Is it a leap year? */

	if (is_leap_year(year + AC100_YEAR_OFF + 1900))

		reg[6] |= AC100_RTC_YEA_LEAP;



	return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);

}



static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)

{

	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);

	struct regmap *regmap = chip->regmap;

	unsigned int val;



	val = en ? AC100_ALM_INT_ENABLE : 0;



	return regmap_write(regmap, AC100_ALM_INT_ENA, val);

}



static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);

	struct regmap *regmap = chip->regmap;

	struct rtc_time *alrm_tm = &alrm->time;

	u16 reg[7];

	unsigned int val;

	int ret;



	ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);

	if (ret)

		return ret;



	alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);



	ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);

	if (ret)

		return ret;



	alrm_tm->tm_sec  = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);

	alrm_tm->tm_min  = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);

	alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);

	alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);

	alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);

	alrm_tm->tm_mon  = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1;

	alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) +

			   AC100_YEAR_OFF;



	return 0;

}



static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);

	struct regmap *regmap = chip->regmap;

	struct rtc_time *alrm_tm = &alrm->time;

	u16 reg[8];

	int year;

	int ret;



	/* our alarm has a limited year range... */

	year = alrm_tm->tm_year - AC100_YEAR_OFF;

	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {

		dev_err(dev, "alarm only supports year in range %d - %d\n",

			AC100_YEAR_MIN, AC100_YEAR_MAX);

		return -EINVAL;

	}



	/* convert to BCD */

	reg[0] = (bin2bcd(alrm_tm->tm_sec)  & AC100_ALM_SEC_MASK) |

			AC100_ALM_ENABLE_FLAG;

	reg[1] = (bin2bcd(alrm_tm->tm_min)  & AC100_ALM_MIN_MASK) |

			AC100_ALM_ENABLE_FLAG;

	reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |

			AC100_ALM_ENABLE_FLAG;

	/* Do not enable weekday alarm */

	reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;

	reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |

			AC100_ALM_ENABLE_FLAG;

	reg[5] = (bin2bcd(alrm_tm->tm_mon + 1)  & AC100_ALM_MON_MASK) |

			AC100_ALM_ENABLE_FLAG;

	reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) |

			AC100_ALM_ENABLE_FLAG;

	/* trigger write */

	reg[7] = AC100_ALM_UPD_TRIGGER;



	ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);

	if (ret)

		return ret;



	return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);

}



static irqreturn_t ac100_rtc_irq(int irq, void *data)

{

	struct ac100_rtc_dev *chip = data;

	struct regmap *regmap = chip->regmap;

	unsigned int val = 0;

	int ret;



	mutex_lock(&chip->rtc->ops_lock);



	/* read status */

	ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);

	if (ret)

		goto out;



	if (val & AC100_ALM_INT_ENABLE) {

		/* signal rtc framework */

		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);



		/* clear status */

		ret = regmap_write(regmap, AC100_ALM_INT_STA, val);

		if (ret)

			goto out;



		/* disable interrupt */

		ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);

		if (ret)

			goto out;

	}



out:

	mutex_unlock(&chip->rtc->ops_lock);

	return IRQ_HANDLED;

}



static const struct rtc_class_ops ac100_rtc_ops = {

	.read_time	  = ac100_rtc_get_time,

	.set_time	  = ac100_rtc_set_time,

	.read_alarm	  = ac100_rtc_get_alarm,

	.set_alarm	  = ac100_rtc_set_alarm,

	.alarm_irq_enable = ac100_rtc_alarm_irq_enable,

};



static int ac100_rtc_probe(struct platform_device *pdev)

{

	struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);

	struct ac100_rtc_dev *chip;

	int ret;



	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);

	platform_set_drvdata(pdev, chip);

	chip->dev = &pdev->dev;

	chip->regmap = ac100->regmap;



	chip->irq = platform_get_irq(pdev, 0);

	if (chip->irq < 0) {

		dev_err(&pdev->dev, "No IRQ resource\n");

		return chip->irq;

	}



	ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,

					ac100_rtc_irq,

					IRQF_SHARED | IRQF_ONESHOT,

					dev_name(&pdev->dev), chip);

	if (ret) {

		dev_err(&pdev->dev, "Could not request IRQ\n");

		return ret;

	}



	/* always use 24 hour mode */

	regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,

			  AC100_RTC_CTRL_24HOUR);



	/* disable counter alarm interrupt */

	regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);



	/* clear counter alarm pending interrupts */

	regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);



	chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100",

					     &ac100_rtc_ops, THIS_MODULE);

	if (IS_ERR(chip->rtc)) {

		dev_err(&pdev->dev, "unable to register device\n");

		return PTR_ERR(chip->rtc);

	}



	dev_info(&pdev->dev, "RTC enabled\n");



	return 0;

}



static const struct of_device_id ac100_rtc_match[] = {

	{ .compatible = "x-powers,ac100-rtc" },

	{ },

};

MODULE_DEVICE_TABLE(of, ac100_rtc_match);



static struct platform_driver ac100_rtc_driver = {

	.probe		= ac100_rtc_probe,

	.driver		= {

		.name		= "ac100-rtc",

		.of_match_table	= of_match_ptr(ac100_rtc_match),

	},

};

module_platform_driver(ac100_rtc_driver);



MODULE_DESCRIPTION("X-Powers AC100 RTC driver");

MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");

MODULE_LICENSE("GPL v2");