diff options
Diffstat (limited to 'drivers/watchdog/wm831x_wdt.c')
| -rw-r--r-- | drivers/watchdog/wm831x_wdt.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/drivers/watchdog/wm831x_wdt.c b/drivers/watchdog/wm831x_wdt.c new file mode 100644 index 000000000..d96ad8f38 --- /dev/null +++ b/drivers/watchdog/wm831x_wdt.c @@ -0,0 +1,258 @@ +// 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/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_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); + + 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 device *dev = &pdev->dev; + struct wm831x *wm831x = dev_get_drvdata(dev->parent); + struct wm831x_pdata *chip_pdata = dev_get_platdata(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(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 = 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; + + 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; + } + } + + return devm_watchdog_register_device(dev, &driver_data->wdt); +} + +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"); |