/* * Maxim MAX77620 Watchdog Driver * * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved. * * Author: Laxman Dewangan <ldewangan@nvidia.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/mfd/max77620.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/slab.h> #include <linux/watchdog.h> static bool nowayout = WATCHDOG_NOWAYOUT; struct max77620_wdt { struct device *dev; struct regmap *rmap; struct watchdog_device wdt_dev; }; static int max77620_wdt_start(struct watchdog_device *wdt_dev) { struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev); return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2, MAX77620_WDTEN, MAX77620_WDTEN); } static int max77620_wdt_stop(struct watchdog_device *wdt_dev) { struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev); return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2, MAX77620_WDTEN, 0); } static int max77620_wdt_ping(struct watchdog_device *wdt_dev) { struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev); return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3, MAX77620_WDTC_MASK, 0x1); } static int max77620_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev); unsigned int wdt_timeout; u8 regval; int ret; switch (timeout) { case 0 ... 2: regval = MAX77620_TWD_2s; wdt_timeout = 2; break; case 3 ... 16: regval = MAX77620_TWD_16s; wdt_timeout = 16; break; case 17 ... 64: regval = MAX77620_TWD_64s; wdt_timeout = 64; break; default: regval = MAX77620_TWD_128s; wdt_timeout = 128; break; } ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3, MAX77620_WDTC_MASK, 0x1); if (ret < 0) return ret; ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2, MAX77620_TWD_MASK, regval); if (ret < 0) return ret; wdt_dev->timeout = wdt_timeout; return 0; } static const struct watchdog_info max77620_wdt_info = { .identity = "max77620-watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops max77620_wdt_ops = { .start = max77620_wdt_start, .stop = max77620_wdt_stop, .ping = max77620_wdt_ping, .set_timeout = max77620_wdt_set_timeout, }; static int max77620_wdt_probe(struct platform_device *pdev) { struct max77620_wdt *wdt; struct watchdog_device *wdt_dev; unsigned int regval; int ret; wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; wdt->dev = &pdev->dev; wdt->rmap = dev_get_regmap(pdev->dev.parent, NULL); if (!wdt->rmap) { dev_err(wdt->dev, "Failed to get parent regmap\n"); return -ENODEV; } wdt_dev = &wdt->wdt_dev; wdt_dev->info = &max77620_wdt_info; wdt_dev->ops = &max77620_wdt_ops; wdt_dev->min_timeout = 2; wdt_dev->max_timeout = 128; wdt_dev->max_hw_heartbeat_ms = 128 * 1000; platform_set_drvdata(pdev, wdt); /* Enable WD_RST_WK - WDT expire results in a restart */ ret = regmap_update_bits(wdt->rmap, MAX77620_REG_ONOFFCNFG2, MAX77620_ONOFFCNFG2_WD_RST_WK, MAX77620_ONOFFCNFG2_WD_RST_WK); if (ret < 0) { dev_err(wdt->dev, "Failed to set WD_RST_WK: %d\n", ret); return ret; } /* Set WDT clear in OFF and sleep mode */ ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2, MAX77620_WDTOFFC | MAX77620_WDTSLPC, MAX77620_WDTOFFC | MAX77620_WDTSLPC); if (ret < 0) { dev_err(wdt->dev, "Failed to set WDT OFF mode: %d\n", ret); return ret; } /* Check if WDT running and if yes then set flags properly */ ret = regmap_read(wdt->rmap, MAX77620_REG_CNFGGLBL2, ®val); if (ret < 0) { dev_err(wdt->dev, "Failed to read WDT CFG register: %d\n", ret); return ret; } switch (regval & MAX77620_TWD_MASK) { case MAX77620_TWD_2s: wdt_dev->timeout = 2; break; case MAX77620_TWD_16s: wdt_dev->timeout = 16; break; case MAX77620_TWD_64s: wdt_dev->timeout = 64; break; default: wdt_dev->timeout = 128; break; } if (regval & MAX77620_WDTEN) set_bit(WDOG_HW_RUNNING, &wdt_dev->status); watchdog_set_nowayout(wdt_dev, nowayout); watchdog_set_drvdata(wdt_dev, wdt); ret = watchdog_register_device(wdt_dev); if (ret < 0) { dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret); return ret; } return 0; } static int max77620_wdt_remove(struct platform_device *pdev) { struct max77620_wdt *wdt = platform_get_drvdata(pdev); max77620_wdt_stop(&wdt->wdt_dev); watchdog_unregister_device(&wdt->wdt_dev); return 0; } static struct platform_device_id max77620_wdt_devtype[] = { { .name = "max77620-watchdog", }, { }, }; static struct platform_driver max77620_wdt_driver = { .driver = { .name = "max77620-watchdog", }, .probe = max77620_wdt_probe, .remove = max77620_wdt_remove, .id_table = max77620_wdt_devtype, }; module_platform_driver(max77620_wdt_driver); MODULE_DESCRIPTION("Max77620 watchdog timer driver"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); MODULE_LICENSE("GPL v2");