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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>4 * JZ4740 Watchdog driver5 */6 7#include <linux/mfd/ingenic-tcu.h>8#include <linux/mfd/syscon.h>9#include <linux/module.h>10#include <linux/moduleparam.h>11#include <linux/types.h>12#include <linux/kernel.h>13#include <linux/watchdog.h>14#include <linux/platform_device.h>15#include <linux/io.h>16#include <linux/device.h>17#include <linux/clk.h>18#include <linux/slab.h>19#include <linux/err.h>20#include <linux/of.h>21#include <linux/regmap.h>22 23#define DEFAULT_HEARTBEAT 524#define MAX_HEARTBEAT 204825 26static bool nowayout = WATCHDOG_NOWAYOUT;27module_param(nowayout, bool, 0);28MODULE_PARM_DESC(nowayout,29 "Watchdog cannot be stopped once started (default="30 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");31 32static unsigned int heartbeat = DEFAULT_HEARTBEAT;33module_param(heartbeat, uint, 0);34MODULE_PARM_DESC(heartbeat,35 "Watchdog heartbeat period in seconds from 1 to "36 __MODULE_STRING(MAX_HEARTBEAT) ", default "37 __MODULE_STRING(DEFAULT_HEARTBEAT));38 39struct jz4740_wdt_drvdata {40 struct watchdog_device wdt;41 struct regmap *map;42 struct clk *clk;43 unsigned long clk_rate;44};45 46static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)47{48 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);49 50 regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);51 52 return 0;53}54 55static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,56 unsigned int new_timeout)57{58 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);59 u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);60 unsigned int tcer;61 62 regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);63 regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);64 65 regmap_write(drvdata->map, TCU_REG_WDT_TDR, timeout_value);66 regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);67 68 if (tcer & TCU_WDT_TCER_TCEN)69 regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);70 71 wdt_dev->timeout = new_timeout;72 return 0;73}74 75static int jz4740_wdt_start(struct watchdog_device *wdt_dev)76{77 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);78 unsigned int tcer;79 int ret;80 81 ret = clk_prepare_enable(drvdata->clk);82 if (ret)83 return ret;84 85 regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);86 87 jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);88 89 /* Start watchdog if it wasn't started already */90 if (!(tcer & TCU_WDT_TCER_TCEN))91 regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);92 93 return 0;94}95 96static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)97{98 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);99 100 regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);101 clk_disable_unprepare(drvdata->clk);102 103 return 0;104}105 106static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,107 unsigned long action, void *data)108{109 wdt_dev->timeout = 0;110 jz4740_wdt_start(wdt_dev);111 return 0;112}113 114static const struct watchdog_info jz4740_wdt_info = {115 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,116 .identity = "jz4740 Watchdog",117};118 119static const struct watchdog_ops jz4740_wdt_ops = {120 .owner = THIS_MODULE,121 .start = jz4740_wdt_start,122 .stop = jz4740_wdt_stop,123 .ping = jz4740_wdt_ping,124 .set_timeout = jz4740_wdt_set_timeout,125 .restart = jz4740_wdt_restart,126};127 128#ifdef CONFIG_OF129static const struct of_device_id jz4740_wdt_of_matches[] = {130 { .compatible = "ingenic,jz4740-watchdog", },131 { .compatible = "ingenic,jz4780-watchdog", },132 { /* sentinel */ }133};134MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);135#endif136 137static int jz4740_wdt_probe(struct platform_device *pdev)138{139 struct device *dev = &pdev->dev;140 struct jz4740_wdt_drvdata *drvdata;141 struct watchdog_device *jz4740_wdt;142 long rate;143 int ret;144 145 drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),146 GFP_KERNEL);147 if (!drvdata)148 return -ENOMEM;149 150 drvdata->clk = devm_clk_get(&pdev->dev, "wdt");151 if (IS_ERR(drvdata->clk)) {152 dev_err(&pdev->dev, "cannot find WDT clock\n");153 return PTR_ERR(drvdata->clk);154 }155 156 /* Set smallest clock possible */157 rate = clk_round_rate(drvdata->clk, 1);158 if (rate < 0)159 return rate;160 161 ret = clk_set_rate(drvdata->clk, rate);162 if (ret)163 return ret;164 165 drvdata->clk_rate = rate;166 jz4740_wdt = &drvdata->wdt;167 jz4740_wdt->info = &jz4740_wdt_info;168 jz4740_wdt->ops = &jz4740_wdt_ops;169 jz4740_wdt->min_timeout = 1;170 jz4740_wdt->max_timeout = 0xffff / rate;171 jz4740_wdt->timeout = clamp(heartbeat,172 jz4740_wdt->min_timeout,173 jz4740_wdt->max_timeout);174 jz4740_wdt->parent = dev;175 watchdog_set_nowayout(jz4740_wdt, nowayout);176 watchdog_set_drvdata(jz4740_wdt, drvdata);177 178 drvdata->map = device_node_to_regmap(dev->parent->of_node);179 if (IS_ERR(drvdata->map)) {180 dev_err(dev, "regmap not found\n");181 return PTR_ERR(drvdata->map);182 }183 184 return devm_watchdog_register_device(dev, &drvdata->wdt);185}186 187static struct platform_driver jz4740_wdt_driver = {188 .probe = jz4740_wdt_probe,189 .driver = {190 .name = "jz4740-wdt",191 .of_match_table = of_match_ptr(jz4740_wdt_of_matches),192 },193};194 195module_platform_driver(jz4740_wdt_driver);196 197MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");198MODULE_DESCRIPTION("jz4740 Watchdog Driver");199MODULE_LICENSE("GPL");200MODULE_ALIAS("platform:jz4740-wdt");201