/* * Watchdog driver for the A21 VME CPU Boards * * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH * * 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 */ #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/of_gpio.h> #include <linux/delay.h> #include <linux/bitops.h> #define NUM_GPIOS 6 enum a21_wdt_gpios { GPIO_WD_ENAB, GPIO_WD_FAST, GPIO_WD_TRIG, GPIO_WD_RST0, GPIO_WD_RST1, GPIO_WD_RST2, }; struct a21_wdt_drv { struct watchdog_device wdt; struct mutex lock; unsigned gpios[NUM_GPIOS]; }; 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) ")"); static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv) { int reset = 0; reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0; reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0; reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0; return reset; } static int a21_wdt_start(struct watchdog_device *wdt) { struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); mutex_lock(&drv->lock); gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1); mutex_unlock(&drv->lock); return 0; } static int a21_wdt_stop(struct watchdog_device *wdt) { struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); mutex_lock(&drv->lock); gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); mutex_unlock(&drv->lock); return 0; } static int a21_wdt_ping(struct watchdog_device *wdt) { struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); mutex_lock(&drv->lock); gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0); ndelay(10); gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1); mutex_unlock(&drv->lock); return 0; } static int a21_wdt_set_timeout(struct watchdog_device *wdt, unsigned int timeout) { struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt); if (timeout != 1 && timeout != 30) { dev_err(wdt->dev, "Only 1 and 30 allowed as timeout\n"); return -EINVAL; } if (timeout == 30 && wdt->timeout == 1) { dev_err(wdt->dev, "Transition from fast to slow mode not allowed\n"); return -EINVAL; } mutex_lock(&drv->lock); if (timeout == 1) gpio_set_value(drv->gpios[GPIO_WD_FAST], 1); else gpio_set_value(drv->gpios[GPIO_WD_FAST], 0); wdt->timeout = timeout; mutex_unlock(&drv->lock); return 0; } static const struct watchdog_info a21_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "MEN A21 Watchdog", }; static const struct watchdog_ops a21_wdt_ops = { .owner = THIS_MODULE, .start = a21_wdt_start, .stop = a21_wdt_stop, .ping = a21_wdt_ping, .set_timeout = a21_wdt_set_timeout, }; static struct watchdog_device a21_wdt = { .info = &a21_wdt_info, .ops = &a21_wdt_ops, .min_timeout = 1, .max_timeout = 30, }; static int a21_wdt_probe(struct platform_device *pdev) { struct device_node *node; struct a21_wdt_drv *drv; unsigned int reset = 0; int num_gpios; int ret; int i; drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL); if (!drv) return -ENOMEM; /* Fill GPIO pin array */ node = pdev->dev.of_node; num_gpios = of_gpio_count(node); if (num_gpios != NUM_GPIOS) { dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d", num_gpios, NUM_GPIOS); return -ENODEV; } for (i = 0; i < num_gpios; i++) { int val; val = of_get_gpio(node, i); if (val < 0) return val; drv->gpios[i] = val; } /* Request the used GPIOs */ for (i = 0; i < num_gpios; i++) { ret = devm_gpio_request(&pdev->dev, drv->gpios[i], "MEN A21 Watchdog"); if (ret) return ret; if (i < GPIO_WD_RST0) ret = gpio_direction_output(drv->gpios[i], gpio_get_value(drv->gpios[i])); else /* GPIO_WD_RST[0..2] are inputs */ ret = gpio_direction_input(drv->gpios[i]); if (ret) return ret; } mutex_init(&drv->lock); watchdog_init_timeout(&a21_wdt, 30, &pdev->dev); watchdog_set_nowayout(&a21_wdt, nowayout); watchdog_set_drvdata(&a21_wdt, drv); reset = a21_wdt_get_bootstatus(drv); if (reset == 2) a21_wdt.bootstatus |= WDIOF_EXTERN1; else if (reset == 4) a21_wdt.bootstatus |= WDIOF_CARDRESET; else if (reset == 5) a21_wdt.bootstatus |= WDIOF_POWERUNDER; else if (reset == 7) a21_wdt.bootstatus |= WDIOF_EXTERN2; ret = watchdog_register_device(&a21_wdt); if (ret) { dev_err(&pdev->dev, "Cannot register watchdog device\n"); goto err_register_wd; } dev_set_drvdata(&pdev->dev, drv); dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n"); return 0; err_register_wd: mutex_destroy(&drv->lock); return ret; } static int a21_wdt_remove(struct platform_device *pdev) { struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev); dev_warn(&pdev->dev, "Unregistering A21 watchdog driver, board may reboot\n"); watchdog_unregister_device(&drv->wdt); mutex_destroy(&drv->lock); return 0; } static void a21_wdt_shutdown(struct platform_device *pdev) { struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev); gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0); } static const struct of_device_id a21_wdt_ids[] = { { .compatible = "men,a021-wdt" }, { }, }; static struct platform_driver a21_wdt_driver = { .probe = a21_wdt_probe, .remove = a21_wdt_remove, .shutdown = a21_wdt_shutdown, .driver = { .name = "a21-watchdog", .of_match_table = a21_wdt_ids, }, }; module_platform_driver(a21_wdt_driver); MODULE_AUTHOR("MEN Mikro Elektronik"); MODULE_DESCRIPTION("MEN A21 Watchdog"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:a21-watchdog");