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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog driver for the wm831x PMICs
*
* Copyright (C) 2009 Wolfson Microelectronics
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/gpio.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/watchdog.h>
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 wm831x_wdt_drvdata {
struct watchdog_device wdt;
struct wm831x *wm831x;
struct mutex lock;
int update_gpio;
int update_state;
};
/* We can't use the sub-second values here but they're included
* for completeness. */
static struct {
unsigned int time; /* Seconds */
u16 val; /* WDOG_TO value */
} wm831x_wdt_cfgs[] = {
{ 1, 2 },
{ 2, 3 },
{ 4, 4 },
{ 8, 5 },
{ 16, 6 },
{ 32, 7 },
{ 33, 7 }, /* Actually 32.768s so include both, others round down */
};
static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
{
struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
struct wm831x *wm831x = driver_data->wm831x;
int ret;
mutex_lock(&driver_data->lock);
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_ENA, WM831X_WDOG_ENA);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
mutex_unlock(&driver_data->lock);
return ret;
}
static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
{
struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
struct wm831x *wm831x = driver_data->wm831x;
int ret;
mutex_lock(&driver_data->lock);
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_ENA, 0);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
mutex_unlock(&driver_data->lock);
return ret;
}
static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
{
struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
struct wm831x *wm831x = driver_data->wm831x;
int ret;
u16 reg;
mutex_lock(&driver_data->lock);
if (driver_data->update_gpio) {
gpio_set_value_cansleep(driver_data->update_gpio,
driver_data->update_state);
driver_data->update_state = !driver_data->update_state;
ret = 0;
goto out;
}
reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
if (!(reg & WM831X_WDOG_RST_SRC)) {
dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
ret = -EINVAL;
goto out;
}
reg |= WM831X_WDOG_RESET;
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
out:
mutex_unlock(&driver_data->lock);
return ret;
}
static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
struct wm831x *wm831x = driver_data->wm831x;
int ret, i;
for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
if (wm831x_wdt_cfgs[i].time == timeout)
break;
if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
return -EINVAL;
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
WM831X_WDOG_TO_MASK,
wm831x_wdt_cfgs[i].val);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
ret);
}
wdt_dev->timeout = timeout;
return ret;
}
static const struct watchdog_info wm831x_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "WM831x Watchdog",
};
static const struct watchdog_ops wm831x_wdt_ops = {
.owner = THIS_MODULE,
.start = wm831x_wdt_start,
.stop = wm831x_wdt_stop,
.ping = wm831x_wdt_ping,
.set_timeout = wm831x_wdt_set_timeout,
};
static int wm831x_wdt_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
struct wm831x_pdata *chip_pdata = dev_get_platdata(pdev->dev.parent);
struct wm831x_watchdog_pdata *pdata;
struct wm831x_wdt_drvdata *driver_data;
struct watchdog_device *wm831x_wdt;
int reg, ret, i;
ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
if (ret < 0) {
dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
ret);
return ret;
}
reg = ret;
if (reg & WM831X_WDOG_DEBUG)
dev_warn(wm831x->dev, "Watchdog is paused\n");
driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
GFP_KERNEL);
if (!driver_data)
return -ENOMEM;
mutex_init(&driver_data->lock);
driver_data->wm831x = wm831x;
wm831x_wdt = &driver_data->wdt;
wm831x_wdt->info = &wm831x_wdt_info;
wm831x_wdt->ops = &wm831x_wdt_ops;
wm831x_wdt->parent = &pdev->dev;
watchdog_set_nowayout(wm831x_wdt, nowayout);
watchdog_set_drvdata(wm831x_wdt, driver_data);
reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
reg &= WM831X_WDOG_TO_MASK;
for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
if (wm831x_wdt_cfgs[i].val == reg)
break;
if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
dev_warn(wm831x->dev,
"Unknown watchdog timeout: %x\n", reg);
else
wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
/* Apply any configuration */
if (chip_pdata)
pdata = chip_pdata->watchdog;
else
pdata = NULL;
if (pdata) {
reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
WM831X_WDOG_RST_SRC);
reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
if (pdata->update_gpio) {
ret = devm_gpio_request_one(&pdev->dev,
pdata->update_gpio,
GPIOF_OUT_INIT_LOW,
"Watchdog update");
if (ret < 0) {
dev_err(wm831x->dev,
"Failed to request update GPIO: %d\n",
ret);
return ret;
}
driver_data->update_gpio = pdata->update_gpio;
/* Make sure the watchdog takes hardware updates */
reg |= WM831X_WDOG_RST_SRC;
}
ret = wm831x_reg_unlock(wm831x);
if (ret == 0) {
ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
wm831x_reg_lock(wm831x);
} else {
dev_err(wm831x->dev,
"Failed to unlock security key: %d\n", ret);
return ret;
}
}
ret = devm_watchdog_register_device(&pdev->dev, &driver_data->wdt);
if (ret != 0) {
dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
ret);
return ret;
}
return 0;
}
static struct platform_driver wm831x_wdt_driver = {
.probe = wm831x_wdt_probe,
.driver = {
.name = "wm831x-watchdog",
},
};
module_platform_driver(wm831x_wdt_driver);
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-watchdog");
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