/* * 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; }; 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); return ret; } wdt_dev->timeout = timeout; return 0; } 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; /* * 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 */ return da9055_reg_update(da9055, DA9055_REG_CONTROL_E, DA9055_WATCHDOG_MASK, 1); } 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 const 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, }; 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) 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; da9055_wdt->parent = &pdev->dev; watchdog_set_nowayout(da9055_wdt, nowayout); watchdog_set_drvdata(da9055_wdt, driver_data); ret = da9055_wdt_stop(da9055_wdt); if (ret < 0) { dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret); return ret; } ret = devm_watchdog_register_device(&pdev->dev, &driver_data->wdt); if (ret != 0) dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", ret); return ret; } static struct platform_driver da9055_wdt_driver = { .probe = da9055_wdt_probe, .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");