diff options
Diffstat (limited to 'drivers/watchdog/da9055_wdt.c')
| -rw-r--r-- | drivers/watchdog/da9055_wdt.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/watchdog/da9055_wdt.c b/drivers/watchdog/da9055_wdt.c new file mode 100644 index 00000000000..709ea1aefeb --- /dev/null +++ b/drivers/watchdog/da9055_wdt.c @@ -0,0 +1,216 @@ +/* + * System monitoring driver for DA9055 PMICs. + * + * Copyright(c) 2012 Dialog Semiconductor Ltd. + * + * Author: David Dajun Chen <dchen@diasemi.com> + * + * 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/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> +#include <linux/delay.h> + +#include <linux/mfd/da9055/core.h> +#include <linux/mfd/da9055/reg.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) ")"); + +#define DA9055_DEF_TIMEOUT 4 +#define DA9055_TWDMIN 256 + +struct da9055_wdt_data { + struct watchdog_device wdt; + struct da9055 *da9055; + struct kref kref; +}; + +static const struct { + u8 reg_val; + int user_time; /* In seconds */ +} da9055_wdt_maps[] = { + { 0, 0 }, + { 1, 2 }, + { 2, 4 }, + { 3, 8 }, + { 4, 16 }, + { 5, 32 }, + { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ + { 6, 65 }, + { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ + { 7, 131 }, +}; + +static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + struct da9055 *da9055 = driver_data->da9055; + int ret, i; + + for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++) + if (da9055_wdt_maps[i].user_time == timeout) + break; + + if (i == ARRAY_SIZE(da9055_wdt_maps)) + ret = -EINVAL; + else + ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, + DA9055_TWDSCALE_MASK, + da9055_wdt_maps[i].reg_val << + DA9055_TWDSCALE_SHIFT); + if (ret < 0) + dev_err(da9055->dev, + "Failed to update timescale bit, %d\n", ret); + + wdt_dev->timeout = timeout; + + return ret; +} + +static int da9055_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + struct da9055 *da9055 = driver_data->da9055; + int ret; + + /* + * We have a minimum time for watchdog window called TWDMIN. A write + * to the watchdog before this elapsed time will cause an error. + */ + mdelay(DA9055_TWDMIN); + + /* Reset the watchdog timer */ + ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_E, + DA9055_WATCHDOG_MASK, 1); + + return ret; +} + +static void da9055_wdt_release_resources(struct kref *r) +{ + struct da9055_wdt_data *driver_data = + container_of(r, struct da9055_wdt_data, kref); + + kfree(driver_data); +} + +static void da9055_wdt_ref(struct watchdog_device *wdt_dev) +{ + struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + + kref_get(&driver_data->kref); +} + +static void da9055_wdt_unref(struct watchdog_device *wdt_dev) +{ + struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + + kref_put(&driver_data->kref, da9055_wdt_release_resources); +} + +static int da9055_wdt_start(struct watchdog_device *wdt_dev) +{ + return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout); +} + +static int da9055_wdt_stop(struct watchdog_device *wdt_dev) +{ + return da9055_wdt_set_timeout(wdt_dev, 0); +} + +static struct watchdog_info da9055_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = "DA9055 Watchdog", +}; + +static const struct watchdog_ops da9055_wdt_ops = { + .owner = THIS_MODULE, + .start = da9055_wdt_start, + .stop = da9055_wdt_stop, + .ping = da9055_wdt_ping, + .set_timeout = da9055_wdt_set_timeout, + .ref = da9055_wdt_ref, + .unref = da9055_wdt_unref, +}; + +static int da9055_wdt_probe(struct platform_device *pdev) +{ + struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent); + struct da9055_wdt_data *driver_data; + struct watchdog_device *da9055_wdt; + int ret; + + driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), + GFP_KERNEL); + if (!driver_data) { + dev_err(da9055->dev, "Failed to allocate watchdog device\n"); + return -ENOMEM; + } + + driver_data->da9055 = da9055; + + da9055_wdt = &driver_data->wdt; + + da9055_wdt->timeout = DA9055_DEF_TIMEOUT; + da9055_wdt->info = &da9055_wdt_info; + da9055_wdt->ops = &da9055_wdt_ops; + watchdog_set_nowayout(da9055_wdt, nowayout); + watchdog_set_drvdata(da9055_wdt, driver_data); + + kref_init(&driver_data->kref); + + ret = da9055_wdt_stop(da9055_wdt); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret); + goto err; + } + + dev_set_drvdata(&pdev->dev, driver_data); + + ret = watchdog_register_device(&driver_data->wdt); + if (ret != 0) + dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", + ret); + +err: + return ret; +} + +static int da9055_wdt_remove(struct platform_device *pdev) +{ + struct da9055_wdt_data *driver_data = dev_get_drvdata(&pdev->dev); + + watchdog_unregister_device(&driver_data->wdt); + kref_put(&driver_data->kref, da9055_wdt_release_resources); + + return 0; +} + +static struct platform_driver da9055_wdt_driver = { + .probe = da9055_wdt_probe, + .remove = da9055_wdt_remove, + .driver = { + .name = "da9055-watchdog", + }, +}; + +module_platform_driver(da9055_wdt_driver); + +MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>"); +MODULE_DESCRIPTION("DA9055 watchdog"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:da9055-watchdog"); |