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Commit 594c6fb9 authored by Carlo Caione's avatar Carlo Caione Committed by Maxime Ripard
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ARM: sun4i/sun7i: RTC driver 



This patch introduces the driver for the RTC in the Allwinner A10 and
A20 SoCs.

Signed-off-by: default avatarCarlo Caione <carlo.caione@gmail.com>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
parent 182f14d3

drivers/rtc/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -1104,6 +1104,13 @@ config RTC_DRV_SUN4V 
	  If you say Y here you will get support for the Hypervisor

	  based RTC on SUN4V systems.



config RTC_DRV_SUNXI

	tristate "Allwinner sun4i/sun7i RTC"

	depends on ARCH_SUNXI

	help

	  If you say Y here you will get support for the RTC found on

	  Allwinner A10/A20.



config RTC_DRV_STARFIRE

	bool "Starfire RTC"

	depends on SPARC64

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o 
obj-$(CONFIG_RTC_DRV_STK17TA8)	+= rtc-stk17ta8.o

obj-$(CONFIG_RTC_DRV_STMP)	+= rtc-stmp3xxx.o

obj-$(CONFIG_RTC_DRV_SUN4V)	+= rtc-sun4v.o

obj-$(CONFIG_RTC_DRV_SUNXI)	+= rtc-sunxi.o

obj-$(CONFIG_RTC_DRV_TEGRA)	+= rtc-tegra.o

obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o

obj-$(CONFIG_RTC_DRV_TILE)	+= rtc-tile.o

drivers/rtc/rtc-sunxi.c

0 → 100644
+523 −0
Original line number Diff line number Diff line 
/*

 * An RTC driver for Allwinner A10/A20

 *

 * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>

 *

 * 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.

 */



#include <linux/delay.h>

#include <linux/err.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/types.h>



#define SUNXI_LOSC_CTRL				0x0000

#define SUNXI_LOSC_CTRL_RTC_HMS_ACC		BIT(8)

#define SUNXI_LOSC_CTRL_RTC_YMD_ACC		BIT(7)



#define SUNXI_RTC_YMD				0x0004



#define SUNXI_RTC_HMS				0x0008



#define SUNXI_ALRM_DHMS				0x000c



#define SUNXI_ALRM_EN				0x0014

#define SUNXI_ALRM_EN_CNT_EN			BIT(8)



#define SUNXI_ALRM_IRQ_EN			0x0018

#define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)



#define SUNXI_ALRM_IRQ_STA			0x001c

#define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)



#define SUNXI_MASK_DH				0x0000001f

#define SUNXI_MASK_SM				0x0000003f

#define SUNXI_MASK_M				0x0000000f

#define SUNXI_MASK_LY				0x00000001

#define SUNXI_MASK_D				0x00000ffe

#define SUNXI_MASK_M				0x0000000f



#define SUNXI_GET(x, mask, shift)		(((x) & ((mask) << (shift))) \

							>> (shift))



#define SUNXI_SET(x, mask, shift)		(((x) & (mask)) << (shift))



/*

 * Get date values

 */

#define SUNXI_DATE_GET_DAY_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 0)

#define SUNXI_DATE_GET_MON_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_M, 8)

#define SUNXI_DATE_GET_YEAR_VALUE(x, mask)	SUNXI_GET(x, mask, 16)



/*

 * Get time values

 */

#define SUNXI_TIME_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)

#define SUNXI_TIME_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)

#define SUNXI_TIME_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)



/*

 * Get alarm values

 */

#define SUNXI_ALRM_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)

#define SUNXI_ALRM_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)

#define SUNXI_ALRM_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)



/*

 * Set date values

 */

#define SUNXI_DATE_SET_DAY_VALUE(x)		SUNXI_DATE_GET_DAY_VALUE(x)

#define SUNXI_DATE_SET_MON_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_M, 8)

#define SUNXI_DATE_SET_YEAR_VALUE(x, mask)	SUNXI_SET(x, mask, 16)

#define SUNXI_LEAP_SET_VALUE(x, shift)		SUNXI_SET(x, SUNXI_MASK_LY, shift)



/*

 * Set time values

 */

#define SUNXI_TIME_SET_SEC_VALUE(x)		SUNXI_TIME_GET_SEC_VALUE(x)

#define SUNXI_TIME_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)

#define SUNXI_TIME_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)



/*

 * Set alarm values

 */

#define SUNXI_ALRM_SET_SEC_VALUE(x)		SUNXI_ALRM_GET_SEC_VALUE(x)

#define SUNXI_ALRM_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)

#define SUNXI_ALRM_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)

#define SUNXI_ALRM_SET_DAY_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_D, 21)



/*

 * Time unit conversions

 */

#define SEC_IN_MIN				60

#define SEC_IN_HOUR				(60 * SEC_IN_MIN)

#define SEC_IN_DAY				(24 * SEC_IN_HOUR)



/*

 * 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.

 */

#define SUNXI_YEAR_OFF(x)			((x)->min - 1900)



/*

 * min and max year are arbitrary set considering the limited range of the

 * hardware register field

 */

struct sunxi_rtc_data_year {

	unsigned int min;		/* min year allowed */

	unsigned int max;		/* max year allowed */

	unsigned int mask;		/* mask for the year field */

	unsigned char leap_shift;	/* bit shift to get the leap year */

};



static struct sunxi_rtc_data_year data_year_param[] = {

	[0] = {

		.min		= 2010,

		.max		= 2073,

		.mask		= 0x3f,

		.leap_shift	= 22,

	},

	[1] = {

		.min		= 1970,

		.max		= 2225,

		.mask		= 0xff,

		.leap_shift	= 24,

	},

};



struct sunxi_rtc_dev {

	struct rtc_device *rtc;

	struct device *dev;

	struct sunxi_rtc_data_year *data_year;

	void __iomem *base;

	int irq;

};



static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)

{

	struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;

	u32 val;



	val = readl(chip->base + SUNXI_ALRM_IRQ_STA);



	if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {

		val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;

		writel(val, chip->base + SUNXI_ALRM_IRQ_STA);



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



		return IRQ_HANDLED;

	}



	return IRQ_NONE;

}



static void sunxi_rtc_setaie(int to, struct sunxi_rtc_dev *chip)

{

	u32 alrm_val = 0;

	u32 alrm_irq_val = 0;



	if (to) {

		alrm_val = readl(chip->base + SUNXI_ALRM_EN);

		alrm_val |= SUNXI_ALRM_EN_CNT_EN;



		alrm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);

		alrm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;

	} else {

		writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,

				chip->base + SUNXI_ALRM_IRQ_STA);

	}



	writel(alrm_val, chip->base + SUNXI_ALRM_EN);

	writel(alrm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);

}



static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)

{

	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);

	struct rtc_time *alrm_tm = &wkalrm->time;

	u32 alrm;

	u32 alrm_en;

	u32 date;



	alrm = readl(chip->base + SUNXI_ALRM_DHMS);

	date = readl(chip->base + SUNXI_RTC_YMD);



	alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alrm);

	alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alrm);

	alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alrm);



	alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);

	alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);

	alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,

			chip->data_year->mask);



	alrm_tm->tm_mon -= 1;



	/*

	 * switch from (data_year->min)-relative offset to

	 * a (1900)-relative one

	 */

	alrm_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);



	alrm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);

	if (alrm_en & SUNXI_ALRM_EN_CNT_EN)

		wkalrm->enabled = 1;



	return 0;

}



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

{

	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);

	u32 date, time;



	/*

	 * read again in case it changes

	 */

	do {

		date = readl(chip->base + SUNXI_RTC_YMD);

		time = readl(chip->base + SUNXI_RTC_HMS);

	} while ((date != readl(chip->base + SUNXI_RTC_YMD)) ||

		 (time != readl(chip->base + SUNXI_RTC_HMS)));



	rtc_tm->tm_sec  = SUNXI_TIME_GET_SEC_VALUE(time);

	rtc_tm->tm_min  = SUNXI_TIME_GET_MIN_VALUE(time);

	rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);



	rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);

	rtc_tm->tm_mon  = SUNXI_DATE_GET_MON_VALUE(date);

	rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,

					chip->data_year->mask);



	rtc_tm->tm_mon  -= 1;



	/*

	 * switch from (data_year->min)-relative offset to

	 * a (1900)-relative one

	 */

	rtc_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);



	return rtc_valid_tm(rtc_tm);

}



static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)

{

	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);

	struct rtc_time *alrm_tm = &wkalrm->time;

	struct rtc_time tm_now;

	u32 alrm = 0;

	unsigned long time_now = 0;

	unsigned long time_set = 0;

	unsigned long time_gap = 0;

	unsigned long time_gap_day = 0;

	unsigned long time_gap_hour = 0;

	unsigned long time_gap_min = 0;

	int ret = 0;



	ret = sunxi_rtc_gettime(dev, &tm_now);

	if (ret < 0) {

		dev_err(dev, "Error in getting time\n");

		return -EINVAL;

	}



	rtc_tm_to_time(alrm_tm, &time_set);

	rtc_tm_to_time(&tm_now, &time_now);

	if (time_set <= time_now) {

		dev_err(dev, "Date to set in the past\n");

		return -EINVAL;

	}



	time_gap = time_set - time_now;

	time_gap_day = time_gap / SEC_IN_DAY;

	time_gap -= time_gap_day * SEC_IN_DAY;

	time_gap_hour = time_gap / SEC_IN_HOUR;

	time_gap -= time_gap_hour * SEC_IN_HOUR;

	time_gap_min = time_gap / SEC_IN_MIN;

	time_gap -= time_gap_min * SEC_IN_MIN;



	if (time_gap_day > 255) {

		dev_err(dev, "Day must be in the range 0 - 255\n");

		return -EINVAL;

	}



	sunxi_rtc_setaie(0, chip);

	writel(0, chip->base + SUNXI_ALRM_DHMS);

	usleep_range(100, 300);



	alrm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |

		SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |

		SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |

		SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);

	writel(alrm, chip->base + SUNXI_ALRM_DHMS);



	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);

	writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);



	sunxi_rtc_setaie(wkalrm->enabled, chip);



	return 0;

}



static int sunxi_rtc_wait(struct sunxi_rtc_dev *chip, int offset,

			  unsigned int mask, unsigned int ms_timeout)

{

	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);

	u32 reg;



	do {

		reg = readl(chip->base + offset);

		reg &= mask;



		if (reg == mask)

			return 0;



	} while (time_before(jiffies, timeout));



	return -ETIMEDOUT;

}



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

{

	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);

	u32 date = 0;

	u32 time = 0;

	int year;



	/*

	 * the input rtc_tm->tm_year is the offset relative to 1900. We use

	 * the SUNXI_YEAR_OFF macro to rebase it with respect to the min year

	 * allowed by the hardware

	 */



	year = rtc_tm->tm_year + 1900;

	if (year < chip->data_year->min || year > chip->data_year->max) {

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

				chip->data_year->min, chip->data_year->max);

		return -EINVAL;

	}



	rtc_tm->tm_year -= SUNXI_YEAR_OFF(chip->data_year);

	rtc_tm->tm_mon += 1;



	date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |

		SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |

		SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,

				chip->data_year->mask);



	if (is_leap_year(year))

		date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);



	time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |

		SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |

		SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);



	writel(0, chip->base + SUNXI_RTC_HMS);

	writel(0, chip->base + SUNXI_RTC_YMD);



	writel(time, chip->base + SUNXI_RTC_HMS);



	/*

	 * After writing the RTC HH-MM-SS register, the

	 * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not

	 * be cleared until the real writing operation is finished

	 */



	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,

				SUNXI_LOSC_CTRL_RTC_HMS_ACC, 50)) {

		dev_err(dev, "Failed to set rtc time.\n");

		return -1;

	}



	writel(date, chip->base + SUNXI_RTC_YMD);



	/*

	 * After writing the RTC YY-MM-DD register, the

	 * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not

	 * be cleared until the real writing operation is finished

	 */



	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,

				SUNXI_LOSC_CTRL_RTC_YMD_ACC, 50)) {

		dev_err(dev, "Failed to set rtc time.\n");

		return -1;

	}



	return 0;

}



static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)

{

	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);



	if (!enabled)

		sunxi_rtc_setaie(enabled, chip);



	return 0;

}



static const struct rtc_class_ops sunxi_rtc_ops = {

	.read_time		= sunxi_rtc_gettime,

	.set_time		= sunxi_rtc_settime,

	.read_alarm		= sunxi_rtc_getalarm,

	.set_alarm		= sunxi_rtc_setalarm,

	.alarm_irq_enable	= sunxi_rtc_alarm_irq_enable

};



static const struct of_device_id sunxi_rtc_dt_ids[] = {

	{ .compatible = "allwinner,sun4i-rtc", .data = &data_year_param[0] },

	{ .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },

	{ /* sentinel */ },

};

MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);



static int sunxi_rtc_probe(struct platform_device *pdev)

{

	struct sunxi_rtc_dev *chip;

	struct resource *res;

	const struct of_device_id *of_id;

	int ret;



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

	if (!chip)

		return -ENOMEM;



	platform_set_drvdata(pdev, chip);

	chip->dev = &pdev->dev;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	chip->base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(chip->base))

		return PTR_ERR(chip->base);



	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_irq(&pdev->dev, chip->irq, sunxi_rtc_alarmirq,

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

	if (ret) {

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

		return ret;

	}



	of_id = of_match_device(sunxi_rtc_dt_ids, &pdev->dev);

	if (!of_id) {

		dev_err(&pdev->dev, "Unable to setup RTC data\n");

		return -ENODEV;

	}

	chip->data_year = (struct sunxi_rtc_data_year *) of_id->data;



	/* clear the alarm count value */

	writel(0, chip->base + SUNXI_ALRM_DHMS);



	/* disable alarm, not generate irq pending */

	writel(0, chip->base + SUNXI_ALRM_EN);



	/* disable alarm week/cnt irq, unset to cpu */

	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);



	/* clear alarm week/cnt irq pending */

	writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +

			SUNXI_ALRM_IRQ_STA);



	chip->rtc = rtc_device_register("rtc-sunxi", &pdev->dev,

			&sunxi_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 int sunxi_rtc_remove(struct platform_device *pdev)

{

	struct sunxi_rtc_dev *chip = platform_get_drvdata(pdev);



	rtc_device_unregister(chip->rtc);



	return 0;

}



static struct platform_driver sunxi_rtc_driver = {

	.probe		= sunxi_rtc_probe,

	.remove		= sunxi_rtc_remove,

	.driver		= {

		.name		= "sunxi-rtc",

		.owner		= THIS_MODULE,

		.of_match_table = sunxi_rtc_dt_ids,

	},

};



module_platform_driver(sunxi_rtc_driver);



MODULE_DESCRIPTION("sunxi RTC driver");

MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");

MODULE_LICENSE("GPL");