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Commit 49ae7790 authored by Lee Jones's avatar Lee Jones
Browse files

watchdog: st_wdt: Add new driver for ST's LPC Watchdog 



Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarDavid Paris <david.paris@st.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent b0e68674

drivers/watchdog/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -470,6 +470,18 @@ config SIRFSOC_WATCHDOG 
	  Support for CSR SiRFprimaII and SiRFatlasVI watchdog. When

	  the watchdog triggers the system will be reset.



config ST_LPC_WATCHDOG

	tristate "STMicroelectronics LPC Watchdog"

	depends on ARCH_STI

	depends on OF

	select WATCHDOG_CORE

	help

	  Say Y here to include STMicroelectronics Low Power Controller

	  (LPC) based Watchdog timer support.



	  To compile this driver as a module, choose M here: the

	  module will be called st_lpc_wdt.



config TEGRA_WATCHDOG

	tristate "Tegra watchdog"

	depends on (ARCH_TEGRA || COMPILE_TEST) && HAS_IOMEM

drivers/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o 
obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o

obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o

obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o

obj-$(CONFIG_ST_LPC_WATCHDOG) += st_lpc_wdt.o

obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o

obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o

obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o

drivers/watchdog/st_lpc_wdt.c

0 → 100644
+344 −0
Original line number Diff line number Diff line 
/*

 * ST's LPC Watchdog

 *

 * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved

 *

 * Author: David Paris <david.paris@st.com> for STMicroelectronics

 *         Lee Jones <lee.jones@linaro.org> for STMicroelectronics

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public Licence

 * as published by the Free Software Foundation; either version

 * 2 of the Licence, or (at your option) any later version.

 */



#include <linux/clk.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/mfd/syscon.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_platform.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/watchdog.h>



#include <dt-bindings/mfd/st-lpc.h>



/* Low Power Alarm */

#define LPC_LPA_LSB_OFF			0x410

#define LPC_LPA_START_OFF		0x418



/* LPC as WDT */

#define LPC_WDT_OFF			0x510



static struct watchdog_device st_wdog_dev;



struct st_wdog_syscfg {

	unsigned int reset_type_reg;

	unsigned int reset_type_mask;

	unsigned int enable_reg;

	unsigned int enable_mask;

};



struct st_wdog {

	void __iomem *base;

	struct device *dev;

	struct regmap *regmap;

	struct st_wdog_syscfg *syscfg;

	struct clk *clk;

	unsigned long clkrate;

	bool warm_reset;

};



static struct st_wdog_syscfg stid127_syscfg = {

	.reset_type_reg		= 0x004,

	.reset_type_mask	= BIT(2),

	.enable_reg		= 0x000,

	.enable_mask		= BIT(2),

};



static struct st_wdog_syscfg stih415_syscfg = {

	.reset_type_reg		= 0x0B8,

	.reset_type_mask	= BIT(6),

	.enable_reg		= 0x0B4,

	.enable_mask		= BIT(7),

};



static struct st_wdog_syscfg stih416_syscfg = {

	.reset_type_reg		= 0x88C,

	.reset_type_mask	= BIT(6),

	.enable_reg		= 0x888,

	.enable_mask		= BIT(7),

};



static struct st_wdog_syscfg stih407_syscfg = {

	.enable_reg		= 0x204,

	.enable_mask		= BIT(19),

};



static const struct of_device_id st_wdog_match[] = {

	{

		.compatible = "st,stih407-lpc",

		.data = &stih407_syscfg,

	},

	{

		.compatible = "st,stih416-lpc",

		.data = &stih416_syscfg,

	},

	{

		.compatible = "st,stih415-lpc",

		.data = &stih415_syscfg,

	},

	{

		.compatible = "st,stid127-lpc",

		.data = &stid127_syscfg,

	},

	{},

};

MODULE_DEVICE_TABLE(of, st_wdog_match);



static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)

{

	/* Type of watchdog reset - 0: Cold 1: Warm */

	if (st_wdog->syscfg->reset_type_reg)

		regmap_update_bits(st_wdog->regmap,

				   st_wdog->syscfg->reset_type_reg,

				   st_wdog->syscfg->reset_type_mask,

				   st_wdog->warm_reset);



	/* Mask/unmask watchdog reset */

	regmap_update_bits(st_wdog->regmap,

			   st_wdog->syscfg->enable_reg,

			   st_wdog->syscfg->enable_mask,

			   enable ? 0 : st_wdog->syscfg->enable_mask);

}



static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)

{

	unsigned long clkrate = st_wdog->clkrate;



	writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);

	writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);

}



static int st_wdog_start(struct watchdog_device *wdd)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);



	writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);



	return 0;

}



static int st_wdog_stop(struct watchdog_device *wdd)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);



	writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);



	return 0;

}



static int st_wdog_set_timeout(struct watchdog_device *wdd,

			       unsigned int timeout)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);



	wdd->timeout = timeout;

	st_wdog_load_timer(st_wdog, timeout);



	return 0;

}



static int st_wdog_keepalive(struct watchdog_device *wdd)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);



	st_wdog_load_timer(st_wdog, wdd->timeout);



	return 0;

}



static const struct watchdog_info st_wdog_info = {

	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

	.identity = "ST LPC WDT",

};



static const struct watchdog_ops st_wdog_ops = {

	.owner		= THIS_MODULE,

	.start		= st_wdog_start,

	.stop		= st_wdog_stop,

	.ping		= st_wdog_keepalive,

	.set_timeout	= st_wdog_set_timeout,

};



static struct watchdog_device st_wdog_dev = {

	.info		= &st_wdog_info,

	.ops		= &st_wdog_ops,

};



static int st_wdog_probe(struct platform_device *pdev)

{

	const struct of_device_id *match;

	struct device_node *np = pdev->dev.of_node;

	struct st_wdog *st_wdog;

	struct regmap *regmap;

	struct resource *res;

	struct clk *clk;

	void __iomem *base;

	uint32_t mode;

	int ret;



	ret = of_property_read_u32(np, "st,lpc-mode", &mode);

	if (ret) {

		dev_err(&pdev->dev, "An LPC mode must be provided\n");

		return -EINVAL;

	}



	/* LPC can either run in RTC or WDT mode */

	if (mode != ST_LPC_MODE_WDT)

		return -ENODEV;



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

	if (!st_wdog)

		return -ENOMEM;



	match = of_match_device(st_wdog_match, &pdev->dev);

	if (!match) {

		dev_err(&pdev->dev, "Couldn't match device\n");

		return -ENODEV;

	}

	st_wdog->syscfg	= (struct st_wdog_syscfg *)match->data;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

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

	if (IS_ERR(base))

		return PTR_ERR(base);



	regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");

	if (IS_ERR(regmap)) {

		dev_err(&pdev->dev, "No syscfg phandle specified\n");

		return PTR_ERR(regmap);

	}



	clk = devm_clk_get(&pdev->dev, NULL);

	if (IS_ERR(clk)) {

		dev_err(&pdev->dev, "Unable to request clock\n");

		return PTR_ERR(clk);

	}



	st_wdog->dev		= &pdev->dev;

	st_wdog->base		= base;

	st_wdog->clk		= clk;

	st_wdog->regmap		= regmap;

	st_wdog->warm_reset	= of_property_read_bool(np, "st,warm_reset");

	st_wdog->clkrate	= clk_get_rate(st_wdog->clk);



	if (!st_wdog->clkrate) {

		dev_err(&pdev->dev, "Unable to fetch clock rate\n");

		return -EINVAL;

	}

	st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;



	ret = clk_prepare_enable(clk);

	if (ret) {

		dev_err(&pdev->dev, "Unable to enable clock\n");

		return ret;

	}



	watchdog_set_drvdata(&st_wdog_dev, st_wdog);

	watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);



	/* Init Watchdog timeout with value in DT */

	ret = watchdog_init_timeout(&st_wdog_dev, 0, &pdev->dev);

	if (ret) {

		dev_err(&pdev->dev, "Unable to initialise watchdog timeout\n");

		clk_disable_unprepare(clk);

		return ret;

	}



	ret = watchdog_register_device(&st_wdog_dev);

	if (ret) {

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

		clk_disable_unprepare(clk);

		return ret;

	}



	st_wdog_setup(st_wdog, true);



	dev_info(&pdev->dev, "LPC Watchdog driver registered, reset type is %s",

		 st_wdog->warm_reset ? "warm" : "cold");



	return ret;

}



static int st_wdog_remove(struct platform_device *pdev)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);



	st_wdog_setup(st_wdog, false);

	watchdog_unregister_device(&st_wdog_dev);

	clk_disable_unprepare(st_wdog->clk);



	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int st_wdog_suspend(struct device *dev)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);



	if (watchdog_active(&st_wdog_dev))

		st_wdog_stop(&st_wdog_dev);



	st_wdog_setup(st_wdog, false);



	clk_disable(st_wdog->clk);



	return 0;

}



static int st_wdog_resume(struct device *dev)

{

	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);

	int ret;



	ret = clk_enable(st_wdog->clk);

	if (ret) {

		dev_err(dev, "Unable to re-enable clock\n");

		watchdog_unregister_device(&st_wdog_dev);

		clk_unprepare(st_wdog->clk);

		return ret;

	}



	st_wdog_setup(st_wdog, true);



	if (watchdog_active(&st_wdog_dev)) {

		st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);

		st_wdog_start(&st_wdog_dev);

	}



	return 0;

}

#endif



static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,

			 st_wdog_suspend,

			 st_wdog_resume);



static struct platform_driver st_wdog_driver = {

	.driver	= {

		.name = "st-lpc-wdt",

		.pm = &st_wdog_pm_ops,

		.of_match_table = st_wdog_match,

	},

	.probe = st_wdog_probe,

	.remove = st_wdog_remove,

};

module_platform_driver(st_wdog_driver);



MODULE_AUTHOR("David Paris <david.paris@st.com>");

MODULE_DESCRIPTION("ST LPC Watchdog Driver");

MODULE_LICENSE("GPL");