watchdog: Add Mstar MSC313e WDT driver (e9800b79) · Commits · EulixOS / Software / Kernel

MAINTAINERS

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		@@ -2175,6 +2175,7 @@ F: arch/arm/boot/dts/mstar-*
		F: arch/arm/mach-mstar/
		F: drivers/clk/mstar/
		F: drivers/gpio/gpio-msc313.c
		F: drivers/watchdog/msc313e_wdt.c
		F: include/dt-bindings/clock/mstar-*
		F: include/dt-bindings/gpio/msc313-gpio.h

drivers/watchdog/Kconfig

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		@@ -989,6 +989,18 @@ config VISCONTI_WATCHDOG
		Say Y here to include support for the watchdog timer in Toshiba
		Visconti SoCs.

		config MSC313E_WATCHDOG
		tristate "MStar MSC313e watchdog"
		depends on ARCH_MSTARV7 \|\| COMPILE_TEST
		select WATCHDOG_CORE
		help
		Say Y here to include support for the Watchdog timer embedded
		into MStar MSC313e chips. This will reboot your system when the
		timeout is reached.

		To compile this driver as a module, choose M here: the
		module will be called msc313e_wdt.

		# X86 (i386 + ia64 + x86_64) Architecture

		config ACQUIRE_WDT

drivers/watchdog/Makefile

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		@@ -93,6 +93,7 @@ obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
		obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
		obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
		obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
		obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o

		# X86 (i386 + ia64 + x86_64) Architecture
		obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o

drivers/watchdog/msc313e_wdt.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* MStar WDT driver
		*
		* Copyright (C) 2019 - 2021 Daniel Palmer
		* Copyright (C) 2021 Romain Perier
		*
		*/

		#include <linux/clk.h>
		#include <linux/io.h>
		#include <linux/mod_devicetable.h>
		#include <linux/module.h>
		#include <linux/platform_device.h>
		#include <linux/watchdog.h>

		#define REG_WDT_CLR 0x0
		#define REG_WDT_MAX_PRD_L 0x10
		#define REG_WDT_MAX_PRD_H 0x14

		#define MSC313E_WDT_MIN_TIMEOUT 1
		#define MSC313E_WDT_DEFAULT_TIMEOUT 30

		static unsigned int timeout;

		module_param(timeout, int, 0);
		MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

		struct msc313e_wdt_priv {
		void __iomem *base;
		struct watchdog_device wdev;
		struct clk *clk;
		};

		static int msc313e_wdt_start(struct watchdog_device *wdev)
		{
		struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
		u32 timeout;
		int err;

		err = clk_prepare_enable(priv->clk);
		if (err)
		return err;

		timeout = wdev->timeout * clk_get_rate(priv->clk);
		writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
		writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
		writew(1, priv->base + REG_WDT_CLR);
		return 0;
		}

		static int msc313e_wdt_ping(struct watchdog_device *wdev)
		{
		struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);

		writew(1, priv->base + REG_WDT_CLR);
		return 0;
		}

		static int msc313e_wdt_stop(struct watchdog_device *wdev)
		{
		struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);

		writew(0, priv->base + REG_WDT_MAX_PRD_L);
		writew(0, priv->base + REG_WDT_MAX_PRD_H);
		writew(0, priv->base + REG_WDT_CLR);
		clk_disable_unprepare(priv->clk);
		return 0;
		}

		static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)
		{
		wdev->timeout = new_time;

		return msc313e_wdt_start(wdev);
		}

		static const struct watchdog_info msc313e_wdt_ident = {
		.identity = "MSC313e watchdog",
		.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT,
		};

		static const struct watchdog_ops msc313e_wdt_ops = {
		.owner = THIS_MODULE,
		.start = msc313e_wdt_start,
		.stop = msc313e_wdt_stop,
		.ping = msc313e_wdt_ping,
		.set_timeout = msc313e_wdt_settimeout,
		};

		static const struct of_device_id msc313e_wdt_of_match[] = {
		{ .compatible = "mstar,msc313e-wdt", },
		{ /* sentinel */ }
		};
		MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match);

		static int msc313e_wdt_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct msc313e_wdt_priv *priv;

		priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
		if (!priv)
		return -ENOMEM;

		priv->base = devm_platform_ioremap_resource(pdev, 0);
		if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

		priv->clk = devm_clk_get(dev, NULL);
		if (IS_ERR(priv->clk)) {
		dev_err(dev, "No input clock\n");
		return PTR_ERR(priv->clk);
		}

		priv->wdev.info = &msc313e_wdt_ident,
		priv->wdev.ops = &msc313e_wdt_ops,
		priv->wdev.parent = dev;
		priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT;
		priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk);
		priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;

		watchdog_set_drvdata(&priv->wdev, priv);

		watchdog_init_timeout(&priv->wdev, timeout, dev);
		watchdog_stop_on_reboot(&priv->wdev);
		watchdog_stop_on_unregister(&priv->wdev);

		return devm_watchdog_register_device(dev, &priv->wdev);
		}

		static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
		{
		struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);

		if (watchdog_active(&priv->wdev))
		msc313e_wdt_stop(&priv->wdev);

		return 0;
		}

		static int __maybe_unused msc313e_wdt_resume(struct device *dev)
		{
		struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);

		if (watchdog_active(&priv->wdev))
		msc313e_wdt_start(&priv->wdev);

		return 0;
		}

		static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);

		static struct platform_driver msc313e_wdt_driver = {
		.driver = {
		.name = "msc313e-wdt",
		.of_match_table = msc313e_wdt_of_match,
		.pm = &msc313e_wdt_pm_ops,
		},
		.probe = msc313e_wdt_probe,
		};
		module_platform_driver(msc313e_wdt_driver);

		MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
		MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");
		MODULE_LICENSE("GPL v2");