171 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * MStar WDT driver4 *5 * Copyright (C) 2019 - 2021 Daniel Palmer6 * Copyright (C) 2021 Romain Perier7 *8 */9 10#include <linux/clk.h>11#include <linux/io.h>12#include <linux/mod_devicetable.h>13#include <linux/module.h>14#include <linux/platform_device.h>15#include <linux/watchdog.h>16 17#define REG_WDT_CLR 0x018#define REG_WDT_MAX_PRD_L 0x1019#define REG_WDT_MAX_PRD_H 0x1420 21#define MSC313E_WDT_MIN_TIMEOUT 122#define MSC313E_WDT_DEFAULT_TIMEOUT 3023 24static unsigned int timeout;25 26module_param(timeout, int, 0);27MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");28 29struct msc313e_wdt_priv {30 void __iomem *base;31 struct watchdog_device wdev;32 struct clk *clk;33};34 35static int msc313e_wdt_start(struct watchdog_device *wdev)36{37 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);38 u32 timeout;39 int err;40 41 err = clk_prepare_enable(priv->clk);42 if (err)43 return err;44 45 timeout = wdev->timeout * clk_get_rate(priv->clk);46 writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);47 writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);48 writew(1, priv->base + REG_WDT_CLR);49 return 0;50}51 52static int msc313e_wdt_ping(struct watchdog_device *wdev)53{54 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);55 56 writew(1, priv->base + REG_WDT_CLR);57 return 0;58}59 60static int msc313e_wdt_stop(struct watchdog_device *wdev)61{62 struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);63 64 writew(0, priv->base + REG_WDT_MAX_PRD_L);65 writew(0, priv->base + REG_WDT_MAX_PRD_H);66 writew(0, priv->base + REG_WDT_CLR);67 clk_disable_unprepare(priv->clk);68 return 0;69}70 71static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)72{73 wdev->timeout = new_time;74 75 return msc313e_wdt_start(wdev);76}77 78static const struct watchdog_info msc313e_wdt_ident = {79 .identity = "MSC313e watchdog",80 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,81};82 83static const struct watchdog_ops msc313e_wdt_ops = {84 .owner = THIS_MODULE,85 .start = msc313e_wdt_start,86 .stop = msc313e_wdt_stop,87 .ping = msc313e_wdt_ping,88 .set_timeout = msc313e_wdt_settimeout,89};90 91static const struct of_device_id msc313e_wdt_of_match[] = {92 { .compatible = "mstar,msc313e-wdt", },93 { /* sentinel */ }94};95MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match);96 97static int msc313e_wdt_probe(struct platform_device *pdev)98{99 struct device *dev = &pdev->dev;100 struct msc313e_wdt_priv *priv;101 102 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);103 if (!priv)104 return -ENOMEM;105 106 priv->base = devm_platform_ioremap_resource(pdev, 0);107 if (IS_ERR(priv->base))108 return PTR_ERR(priv->base);109 110 priv->clk = devm_clk_get(dev, NULL);111 if (IS_ERR(priv->clk)) {112 dev_err(dev, "No input clock\n");113 return PTR_ERR(priv->clk);114 }115 116 priv->wdev.info = &msc313e_wdt_ident,117 priv->wdev.ops = &msc313e_wdt_ops,118 priv->wdev.parent = dev;119 priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT;120 priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk);121 priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;122 123 /* If the period is non-zero the WDT is running */124 if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16))125 set_bit(WDOG_HW_RUNNING, &priv->wdev.status);126 127 watchdog_set_drvdata(&priv->wdev, priv);128 129 watchdog_init_timeout(&priv->wdev, timeout, dev);130 watchdog_stop_on_reboot(&priv->wdev);131 watchdog_stop_on_unregister(&priv->wdev);132 133 return devm_watchdog_register_device(dev, &priv->wdev);134}135 136static int __maybe_unused msc313e_wdt_suspend(struct device *dev)137{138 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);139 140 if (watchdog_active(&priv->wdev))141 msc313e_wdt_stop(&priv->wdev);142 143 return 0;144}145 146static int __maybe_unused msc313e_wdt_resume(struct device *dev)147{148 struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);149 150 if (watchdog_active(&priv->wdev))151 msc313e_wdt_start(&priv->wdev);152 153 return 0;154}155 156static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);157 158static struct platform_driver msc313e_wdt_driver = {159 .driver = {160 .name = "msc313e-wdt",161 .of_match_table = msc313e_wdt_of_match,162 .pm = &msc313e_wdt_pm_ops,163 },164 .probe = msc313e_wdt_probe,165};166module_platform_driver(msc313e_wdt_driver);167 168MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");169MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");170MODULE_LICENSE("GPL v2");171