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Commit 6ef35398 authored by Neil Armstrong's avatar Neil Armstrong Committed by Alexandre Belloni
Browse files

rtc: Add Amlogic Virtual Wake RTC 



The Amlogic Meson GX SoCs uses a special register to store the
time in seconds to wakeup after a system suspend.

In order to be able to reuse the RTC wakealarm feature, this
driver implements a fake RTC device which uses the system time
to deduce a suspend delay.

Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
[khilman: rebase to v5.3-rc, rework and modernization]
Signed-off-by: default avatarKevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20190812232850.8016-3-khilman@kernel.org


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent ed162396

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -1443,6 +1443,7 @@ F: arch/arm64/boot/dts/amlogic/ 
F:	drivers/pinctrl/meson/

F:	drivers/mmc/host/meson*

F:	drivers/soc/amlogic/

F:	drivers/rtc/rtc-meson*

N:	meson



ARM/Amlogic Meson SoC Sound Drivers

drivers/rtc/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -373,6 +373,17 @@ config RTC_DRV_MAX77686 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-max77686.



config RTC_DRV_MESON_VRTC

	tristate "Amlogic Meson Virtual RTC"

	depends on ARCH_MESON || COMPILE_TEST

	default m if ARCH_MESON

	help

	  If you say yes here you will get support for the

	  Virtual RTC of Amlogic SoCs.



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

	  will be called rtc-meson-vrtc.



config RTC_DRV_RK808

	tristate "Rockchip RK805/RK808/RK809/RK817/RK818 RTC"

	depends on MFD_RK808

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ obj-$(CONFIG_RTC_DRV_MAX8907) += rtc-max8907.o 
obj-$(CONFIG_RTC_DRV_MAX8925)	+= rtc-max8925.o

obj-$(CONFIG_RTC_DRV_MAX8997)	+= rtc-max8997.o

obj-$(CONFIG_RTC_DRV_MAX8998)	+= rtc-max8998.o

obj-$(CONFIG_RTC_DRV_MESON_VRTC)+= rtc-meson-vrtc.o

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

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

obj-$(CONFIG_RTC_DRV_MESON)	+= rtc-meson.o

drivers/rtc/rtc-meson-vrtc.c

0 → 100644
+156 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2019 BayLibre, SAS

 * Author: Neil Armstrong <narmstrong@baylibre.com>

 * Copyright (C) 2015 Amlogic, Inc. All rights reserved.

 */

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/time64.h>



struct meson_vrtc_data {

	void __iomem *io_alarm;

	struct rtc_device *rtc;

	unsigned long alarm_time;

	bool enabled;

};



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

{

	struct timespec64 time;



	dev_dbg(dev, "%s\n", __func__);

	ktime_get_raw_ts64(&time);

	rtc_time64_to_tm(time.tv_sec, tm);



	return 0;

}



static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,

				       unsigned long time)

{

	writel_relaxed(time, vrtc->io_alarm);

}



static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)

{

	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);



	dev_dbg(dev, "%s: alarm->enabled=%d\n", __func__, alarm->enabled);

	if (alarm->enabled)

		vrtc->alarm_time = rtc_tm_to_time64(&alarm->time);

	else

		vrtc->alarm_time = 0;



	return 0;

}



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

{

	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);



	vrtc->enabled = enabled;

	return 0;

}



static const struct rtc_class_ops meson_vrtc_ops = {

	.read_time = meson_vrtc_read_time,

	.set_alarm = meson_vrtc_set_alarm,

	.alarm_irq_enable = meson_vrtc_alarm_irq_enable,

};



static int meson_vrtc_probe(struct platform_device *pdev)

{

	struct meson_vrtc_data *vrtc;

	int ret;



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

	if (!vrtc)

		return -ENOMEM;



	vrtc->io_alarm = devm_platform_ioremap_resource(pdev, 0);

	if (IS_ERR(vrtc->io_alarm))

		return PTR_ERR(vrtc->io_alarm);



	device_init_wakeup(&pdev->dev, 1);



	platform_set_drvdata(pdev, vrtc);



	vrtc->rtc = devm_rtc_allocate_device(&pdev->dev);

	if (IS_ERR(vrtc->rtc))

		return PTR_ERR(vrtc->rtc);



	vrtc->rtc->ops = &meson_vrtc_ops;

	ret = rtc_register_device(vrtc->rtc);

	if (ret)

		return ret;



	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int meson_vrtc_suspend(struct device *dev)

{

	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);



	dev_dbg(dev, "%s\n", __func__);

	if (vrtc->alarm_time) {

		unsigned long local_time;

		long alarm_secs;

		struct timespec64 time;



		ktime_get_raw_ts64(&time);

		local_time = time.tv_sec;



		dev_dbg(dev, "alarm_time = %lus, local_time=%lus\n",

			vrtc->alarm_time, local_time);

		alarm_secs = vrtc->alarm_time - local_time;

		if (alarm_secs > 0) {

			meson_vrtc_set_wakeup_time(vrtc, alarm_secs);

			dev_dbg(dev, "system will wakeup in %lds.\n",

				alarm_secs);

		} else {

			dev_err(dev, "alarm time already passed: %lds.\n",

				alarm_secs);

		}

	}



	return 0;

}



static int meson_vrtc_resume(struct device *dev)

{

	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);



	dev_dbg(dev, "%s\n", __func__);



	vrtc->alarm_time = 0;

	meson_vrtc_set_wakeup_time(vrtc, 0);

	return 0;

}

#endif

static SIMPLE_DEV_PM_OPS(meson_vrtc_pm_ops,

			 meson_vrtc_suspend, meson_vrtc_resume);



static const struct of_device_id meson_vrtc_dt_match[] = {

	{ .compatible = "amlogic,meson-vrtc"},

	{},

};

MODULE_DEVICE_TABLE(of, meson_vrtc_dt_match);



static struct platform_driver meson_vrtc_driver = {

	.probe = meson_vrtc_probe,

	.driver = {

		.name = "meson-vrtc",

		.of_match_table = meson_vrtc_dt_match,

		.pm = &meson_vrtc_pm_ops,

	},

};



module_platform_driver(meson_vrtc_driver);



MODULE_DESCRIPTION("Amlogic Virtual Wakeup RTC Timer driver");

MODULE_LICENSE("GPL");