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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * MEN 14F021P00 Board Management Controller (BMC) Watchdog Driver.4 *5 * Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH6 */7 8#include <linux/kernel.h>9#include <linux/device.h>10#include <linux/module.h>11#include <linux/watchdog.h>12#include <linux/platform_device.h>13#include <linux/i2c.h>14 15#define DEVNAME "menf21bmc_wdt"16 17#define BMC_CMD_WD_ON 0x1118#define BMC_CMD_WD_OFF 0x1219#define BMC_CMD_WD_TRIG 0x1320#define BMC_CMD_WD_TIME 0x1421#define BMC_CMD_WD_STATE 0x1722#define BMC_WD_OFF_VAL 0x6923#define BMC_CMD_RST_RSN 0x9224 25#define BMC_WD_TIMEOUT_MIN 1 /* in sec */26#define BMC_WD_TIMEOUT_MAX 6553 /* in sec */27 28static bool nowayout = WATCHDOG_NOWAYOUT;29module_param(nowayout, bool, 0);30MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="31 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");32 33struct menf21bmc_wdt {34 struct watchdog_device wdt;35 struct i2c_client *i2c_client;36};37 38static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data)39{40 int rst_rsn;41 42 rst_rsn = i2c_smbus_read_byte_data(data->i2c_client, BMC_CMD_RST_RSN);43 if (rst_rsn < 0)44 return rst_rsn;45 46 if (rst_rsn == 0x02)47 data->wdt.bootstatus |= WDIOF_CARDRESET;48 else if (rst_rsn == 0x05)49 data->wdt.bootstatus |= WDIOF_EXTERN1;50 else if (rst_rsn == 0x06)51 data->wdt.bootstatus |= WDIOF_EXTERN2;52 else if (rst_rsn == 0x0A)53 data->wdt.bootstatus |= WDIOF_POWERUNDER;54 55 return 0;56}57 58static int menf21bmc_wdt_start(struct watchdog_device *wdt)59{60 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);61 62 return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_ON);63}64 65static int menf21bmc_wdt_stop(struct watchdog_device *wdt)66{67 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);68 69 return i2c_smbus_write_byte_data(drv_data->i2c_client,70 BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);71}72 73static int74menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)75{76 int ret;77 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);78 79 /*80 * BMC Watchdog does have a resolution of 100ms.81 * Watchdog API defines the timeout in seconds, so we have to82 * multiply the value.83 */84 ret = i2c_smbus_write_word_data(drv_data->i2c_client,85 BMC_CMD_WD_TIME, timeout * 10);86 if (ret < 0)87 return ret;88 89 wdt->timeout = timeout;90 91 return 0;92}93 94static int menf21bmc_wdt_ping(struct watchdog_device *wdt)95{96 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);97 98 return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_TRIG);99}100 101static const struct watchdog_info menf21bmc_wdt_info = {102 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,103 .identity = DEVNAME,104};105 106static const struct watchdog_ops menf21bmc_wdt_ops = {107 .owner = THIS_MODULE,108 .start = menf21bmc_wdt_start,109 .stop = menf21bmc_wdt_stop,110 .ping = menf21bmc_wdt_ping,111 .set_timeout = menf21bmc_wdt_settimeout,112};113 114static int menf21bmc_wdt_probe(struct platform_device *pdev)115{116 struct device *dev = &pdev->dev;117 int ret, bmc_timeout;118 struct menf21bmc_wdt *drv_data;119 struct i2c_client *i2c_client = to_i2c_client(dev->parent);120 121 drv_data = devm_kzalloc(dev, sizeof(struct menf21bmc_wdt), GFP_KERNEL);122 if (!drv_data)123 return -ENOMEM;124 125 drv_data->wdt.ops = &menf21bmc_wdt_ops;126 drv_data->wdt.info = &menf21bmc_wdt_info;127 drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN;128 drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX;129 drv_data->wdt.parent = dev;130 drv_data->i2c_client = i2c_client;131 132 /*133 * Get the current wdt timeout value from the BMC because134 * the BMC will save the value set before if the system restarts.135 */136 bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client,137 BMC_CMD_WD_TIME);138 if (bmc_timeout < 0) {139 dev_err(dev, "failed to get current WDT timeout\n");140 return bmc_timeout;141 }142 143 watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, dev);144 watchdog_set_nowayout(&drv_data->wdt, nowayout);145 watchdog_set_drvdata(&drv_data->wdt, drv_data);146 platform_set_drvdata(pdev, drv_data);147 148 ret = menf21bmc_wdt_set_bootstatus(drv_data);149 if (ret < 0) {150 dev_err(dev, "failed to set Watchdog bootstatus\n");151 return ret;152 }153 154 ret = devm_watchdog_register_device(dev, &drv_data->wdt);155 if (ret)156 return ret;157 158 dev_info(dev, "MEN 14F021P00 BMC Watchdog device enabled\n");159 160 return 0;161}162 163static void menf21bmc_wdt_shutdown(struct platform_device *pdev)164{165 struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);166 167 i2c_smbus_write_word_data(drv_data->i2c_client,168 BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);169}170 171static struct platform_driver menf21bmc_wdt = {172 .driver = {173 .name = DEVNAME,174 },175 .probe = menf21bmc_wdt_probe,176 .shutdown = menf21bmc_wdt_shutdown,177};178 179module_platform_driver(menf21bmc_wdt);180 181MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");182MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");183MODULE_LICENSE("GPL v2");184MODULE_ALIAS("platform:menf21bmc_wdt");185