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Commit ba5d0181 authored by Sean Wang's avatar Sean Wang Committed by Alexandre Belloni
Browse files

rtc: mediatek: add driver for RTC on MT7622 SoC 



This patch introduces the driver for the RTC on MT7622 SoC.

Signed-off-by: default avatarSean Wang <sean.wang@mediatek.com>
Reviewed-by: default avatarYingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 1901142b

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -1715,6 +1715,16 @@ config RTC_DRV_MT6397 


	  If you want to use Mediatek(R) RTC interface, select Y or M here.



config RTC_DRV_MT7622

	tristate "MediaTek SoC based RTC"

	depends on ARCH_MEDIATEK || COMPILE_TEST

	help

	  This enables support for the real time clock built in the MediaTek

	  SoCs.



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

	  will be called rtc-mt7622.



config RTC_DRV_XGENE

	tristate "APM X-Gene RTC"

	depends on HAS_IOMEM

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ obj-$(CONFIG_RTC_DRV_MPC5121) += rtc-mpc5121.o 
obj-$(CONFIG_RTC_DRV_VRTC)	+= rtc-mrst.o

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

obj-$(CONFIG_RTC_DRV_MT6397)	+= rtc-mt6397.o

obj-$(CONFIG_RTC_DRV_MT7622)	+= rtc-mt7622.o

obj-$(CONFIG_RTC_DRV_MV)	+= rtc-mv.o

obj-$(CONFIG_RTC_DRV_MXC)	+= rtc-mxc.o

obj-$(CONFIG_RTC_DRV_NUC900)	+= rtc-nuc900.o

drivers/rtc/rtc-mt7622.c

0 → 100644
+422 −0
Original line number Diff line number Diff line 
/*

 * Driver for MediaTek SoC based RTC

 *

 * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.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.

 */



#include <linux/clk.h>

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/of_address.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>



#define MTK_RTC_DEV KBUILD_MODNAME



#define MTK_RTC_PWRCHK1		0x4

#define	RTC_PWRCHK1_MAGIC	0xc6



#define MTK_RTC_PWRCHK2		0x8

#define	RTC_PWRCHK2_MAGIC	0x9a



#define MTK_RTC_KEY		0xc

#define	RTC_KEY_MAGIC		0x59



#define MTK_RTC_PROT1		0x10

#define	RTC_PROT1_MAGIC		0xa3



#define MTK_RTC_PROT2		0x14

#define	RTC_PROT2_MAGIC		0x57



#define MTK_RTC_PROT3		0x18

#define	RTC_PROT3_MAGIC		0x67



#define MTK_RTC_PROT4		0x1c

#define	RTC_PROT4_MAGIC		0xd2



#define MTK_RTC_CTL		0x20

#define	RTC_RC_STOP		BIT(0)



#define MTK_RTC_DEBNCE		0x2c

#define	RTC_DEBNCE_MASK		GENMASK(2, 0)



#define MTK_RTC_INT		0x30

#define RTC_INT_AL_STA		BIT(4)



/*

 * Ranges from 0x40 to 0x78 provide RTC time setup for year, month,

 * day of month, day of week, hour, minute and second.

 */

#define MTK_RTC_TREG(_t, _f)	(0x40 + (0x4 * (_f)) + ((_t) * 0x20))



#define MTK_RTC_AL_CTL		0x7c

#define	RTC_AL_EN		BIT(0)

#define	RTC_AL_ALL		GENMASK(7, 0)



/*

 * The offset is used in the translation for the year between in struct

 * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)

 */

#define MTK_RTC_TM_YR_OFFSET	100



/*

 * The lowest value for the valid tm_year. RTC hardware would take incorrectly

 * tm_year 100 as not a leap year and thus it is also required being excluded

 * from the valid options.

 */

#define MTK_RTC_TM_YR_L		(MTK_RTC_TM_YR_OFFSET + 1)



/*

 * The most year the RTC can hold is 99 and the next to 99 in year register

 * would be wraparound to 0, for MT7622.

 */

#define MTK_RTC_HW_YR_LIMIT	99



/* The highest value for the valid tm_year */

#define MTK_RTC_TM_YR_H		(MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)



/* Simple macro helps to check whether the hardware supports the tm_year */

#define MTK_RTC_TM_YR_VALID(_y)	((_y) >= MTK_RTC_TM_YR_L && \

				 (_y) <= MTK_RTC_TM_YR_H)



/* Types of the function the RTC provides are time counter and alarm. */

enum {

	MTK_TC,

	MTK_AL,

};



/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */

enum {

	MTK_YEA,

	MTK_MON,

	MTK_DOM,

	MTK_DOW,

	MTK_HOU,

	MTK_MIN,

	MTK_SEC

};



struct mtk_rtc {

	struct rtc_device *rtc;

	void __iomem *base;

	int irq;

	struct clk *clk;

};



static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)

{

	writel_relaxed(val, rtc->base + reg);

}



static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)

{

	return readl_relaxed(rtc->base + reg);

}



static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)

{

	u32 val;



	val = mtk_r32(rtc, reg);

	val &= ~mask;

	val |= set;

	mtk_w32(rtc, reg, val);

}



static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)

{

	mtk_rmw(rtc, reg, 0, val);

}



static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)

{

	mtk_rmw(rtc, reg, val, 0);

}



static void mtk_rtc_hw_init(struct mtk_rtc *hw)

{

	/* The setup of the init sequence is for allowing RTC got to work */

	mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);

	mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);

	mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);

	mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);

	mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);

	mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);

	mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);

	mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);

	mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);

}



static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,

				      int time_alarm)

{

	u32 year, mon, mday, wday, hour, min, sec;



	/*

	 * Read again until the field of the second is not changed which

	 * ensures all fields in the consistent state. Note that MTK_SEC must

	 * be read first. In this way, it guarantees the others remain not

	 * changed when the results for two MTK_SEC consecutive reads are same.

	 */

	do {

		sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));

		min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));

		hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));

		wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));

		mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));

		mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));

		year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));

	} while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));



	tm->tm_sec  = sec;

	tm->tm_min  = min;

	tm->tm_hour = hour;

	tm->tm_wday = wday;

	tm->tm_mday = mday;

	tm->tm_mon  = mon - 1;



	/* Rebase to the absolute year which userspace queries */

	tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;

}



static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,

				      int time_alarm)

{

	u32 year;



	/* Rebase to the relative year which RTC hardware requires */

	year = tm->tm_year - MTK_RTC_TM_YR_OFFSET;



	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);

	mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);

}



static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)

{

	struct mtk_rtc *hw = (struct mtk_rtc *)id;

	u32 irq_sta;



	irq_sta = mtk_r32(hw, MTK_RTC_INT);

	if (irq_sta & RTC_INT_AL_STA) {

		/* Stop alarm also implicitly disables the alarm interrupt */

		mtk_w32(hw, MTK_RTC_AL_CTL, 0);

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



		/* Ack alarm interrupt status */

		mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);

		return IRQ_HANDLED;

	}



	return IRQ_NONE;

}



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

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);



	mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);



	return rtc_valid_tm(tm);

}



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

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);



	if (!MTK_RTC_TM_YR_VALID(tm->tm_year))

		return -EINVAL;



	/* Stop time counter before setting a new one*/

	mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);



	mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);



	/* Restart the time counter */

	mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);



	return 0;

}



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

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);

	struct rtc_time *alrm_tm = &wkalrm->time;



	mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);



	wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);

	wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);



	return 0;

}



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

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);

	struct rtc_time *alrm_tm = &wkalrm->time;



	if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))

		return -EINVAL;



	/*

	 * Stop the alarm also implicitly including disables interrupt before

	 * setting a new one.

	 */

	mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);



	/*

	 * Avoid contention between mtk_rtc_setalarm and IRQ handler so that

	 * disabling the interrupt and awaiting for pending IRQ handler to

	 * complete.

	 */

	synchronize_irq(hw->irq);



	mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);



	/* Restart the alarm with the new setup */

	mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);



	return 0;

}



static const struct rtc_class_ops mtk_rtc_ops = {

	.read_time		= mtk_rtc_gettime,

	.set_time		= mtk_rtc_settime,

	.read_alarm		= mtk_rtc_getalarm,

	.set_alarm		= mtk_rtc_setalarm,

};



static const struct of_device_id mtk_rtc_match[] = {

	{ .compatible = "mediatek,mt7622-rtc" },

	{ .compatible = "mediatek,soc-rtc" },

	{},

};



static int mtk_rtc_probe(struct platform_device *pdev)

{

	struct mtk_rtc *hw;

	struct resource *res;

	int ret;



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

	if (!hw)

		return -ENOMEM;



	platform_set_drvdata(pdev, hw);



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

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

	if (IS_ERR(hw->base))

		return PTR_ERR(hw->base);



	hw->clk = devm_clk_get(&pdev->dev, "rtc");

	if (IS_ERR(hw->clk)) {

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

		return PTR_ERR(hw->clk);

	}



	ret = clk_prepare_enable(hw->clk);

	if (ret)

		return ret;



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

	if (hw->irq < 0) {

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

		ret = hw->irq;

		goto err;

	}



	ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,

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

	if (ret) {

		dev_err(&pdev->dev, "Can't request IRQ\n");

		goto err;

	}



	mtk_rtc_hw_init(hw);



	device_init_wakeup(&pdev->dev, true);



	hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,

					   &mtk_rtc_ops, THIS_MODULE);

	if (IS_ERR(hw->rtc)) {

		ret = PTR_ERR(hw->rtc);

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

		goto err;

	}



	return 0;

err:

	clk_disable_unprepare(hw->clk);



	return ret;

}



static int mtk_rtc_remove(struct platform_device *pdev)

{

	struct mtk_rtc *hw = platform_get_drvdata(pdev);



	clk_disable_unprepare(hw->clk);



	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int mtk_rtc_suspend(struct device *dev)

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);



	if (device_may_wakeup(dev))

		enable_irq_wake(hw->irq);



	return 0;

}



static int mtk_rtc_resume(struct device *dev)

{

	struct mtk_rtc *hw = dev_get_drvdata(dev);



	if (device_may_wakeup(dev))

		disable_irq_wake(hw->irq);



	return 0;

}



static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);



#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)

#else	/* CONFIG_PM */

#define MTK_RTC_PM_OPS NULL

#endif	/* CONFIG_PM */



static struct platform_driver mtk_rtc_driver = {

	.probe	= mtk_rtc_probe,

	.remove	= mtk_rtc_remove,

	.driver = {

		.name = MTK_RTC_DEV,

		.of_match_table = mtk_rtc_match,

		.pm = MTK_RTC_PM_OPS,

	},

};



module_platform_driver(mtk_rtc_driver);



MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");

MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");

MODULE_LICENSE("GPL");