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/*
* MEN 14F021P00 Board Management Controller (BMC) Watchdog Driver.
*
* Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#define DEVNAME "menf21bmc_wdt"
#define BMC_CMD_WD_ON 0x11
#define BMC_CMD_WD_OFF 0x12
#define BMC_CMD_WD_TRIG 0x13
#define BMC_CMD_WD_TIME 0x14
#define BMC_CMD_WD_STATE 0x17
#define BMC_WD_OFF_VAL 0x69
#define BMC_CMD_RST_RSN 0x92
#define BMC_WD_TIMEOUT_MIN 1 /* in sec */
#define BMC_WD_TIMEOUT_MAX 6553 /* in sec */
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct menf21bmc_wdt {
struct watchdog_device wdt;
struct i2c_client *i2c_client;
};
static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data)
{
int rst_rsn;
rst_rsn = i2c_smbus_read_byte_data(data->i2c_client, BMC_CMD_RST_RSN);
if (rst_rsn < 0)
return rst_rsn;
if (rst_rsn == 0x02)
data->wdt.bootstatus |= WDIOF_CARDRESET;
else if (rst_rsn == 0x05)
data->wdt.bootstatus |= WDIOF_EXTERN1;
else if (rst_rsn == 0x06)
data->wdt.bootstatus |= WDIOF_EXTERN2;
else if (rst_rsn == 0x0A)
data->wdt.bootstatus |= WDIOF_POWERUNDER;
return 0;
}
static int menf21bmc_wdt_start(struct watchdog_device *wdt)
{
struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_ON);
}
static int menf21bmc_wdt_stop(struct watchdog_device *wdt)
{
struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
return i2c_smbus_write_byte_data(drv_data->i2c_client,
BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
}
static int
menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
{
int ret;
struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
/*
* BMC Watchdog does have a resolution of 100ms.
* Watchdog API defines the timeout in seconds, so we have to
* multiply the value.
*/
ret = i2c_smbus_write_word_data(drv_data->i2c_client,
BMC_CMD_WD_TIME, timeout * 10);
if (ret < 0)
return ret;
wdt->timeout = timeout;
return 0;
}
static int menf21bmc_wdt_ping(struct watchdog_device *wdt)
{
struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_TRIG);
}
static const struct watchdog_info menf21bmc_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = DEVNAME,
};
static const struct watchdog_ops menf21bmc_wdt_ops = {
.owner = THIS_MODULE,
.start = menf21bmc_wdt_start,
.stop = menf21bmc_wdt_stop,
.ping = menf21bmc_wdt_ping,
.set_timeout = menf21bmc_wdt_settimeout,
};
static int menf21bmc_wdt_probe(struct platform_device *pdev)
{
int ret, bmc_timeout;
struct menf21bmc_wdt *drv_data;
struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
drv_data = devm_kzalloc(&pdev->dev,
sizeof(struct menf21bmc_wdt), GFP_KERNEL);
if (!drv_data)
return -ENOMEM;
drv_data->wdt.ops = &menf21bmc_wdt_ops;
drv_data->wdt.info = &menf21bmc_wdt_info;
drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN;
drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX;
drv_data->wdt.parent = &pdev->dev;
drv_data->i2c_client = i2c_client;
/*
* Get the current wdt timeout value from the BMC because
* the BMC will save the value set before if the system restarts.
*/
bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client,
BMC_CMD_WD_TIME);
if (bmc_timeout < 0) {
dev_err(&pdev->dev, "failed to get current WDT timeout\n");
return bmc_timeout;
}
watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, &pdev->dev);
watchdog_set_nowayout(&drv_data->wdt, nowayout);
watchdog_set_drvdata(&drv_data->wdt, drv_data);
platform_set_drvdata(pdev, drv_data);
ret = menf21bmc_wdt_set_bootstatus(drv_data);
if (ret < 0) {
dev_err(&pdev->dev, "failed to set Watchdog bootstatus\n");
return ret;
}
ret = watchdog_register_device(&drv_data->wdt);
if (ret) {
dev_err(&pdev->dev, "failed to register Watchdog device\n");
return ret;
}
dev_info(&pdev->dev, "MEN 14F021P00 BMC Watchdog device enabled\n");
return 0;
}
static int menf21bmc_wdt_remove(struct platform_device *pdev)
{
struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
dev_warn(&pdev->dev,
"Unregister MEN 14F021P00 BMC Watchdog device, board may reset\n");
watchdog_unregister_device(&drv_data->wdt);
return 0;
}
static void menf21bmc_wdt_shutdown(struct platform_device *pdev)
{
struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
i2c_smbus_write_word_data(drv_data->i2c_client,
BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
}
static struct platform_driver menf21bmc_wdt = {
.driver = {
.name = DEVNAME,
},
.probe = menf21bmc_wdt_probe,
.remove = menf21bmc_wdt_remove,
.shutdown = menf21bmc_wdt_shutdown,
};
module_platform_driver(menf21bmc_wdt);
MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:menf21bmc_wdt");
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