1 // SPDX-License-Identifier: GPL-2.0+
3 * Watchdog driver for the A21 VME CPU Boards
5 * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/platform_device.h>
14 #include <linux/watchdog.h>
15 #include <linux/uaccess.h>
16 #include <linux/gpio.h>
17 #include <linux/of_gpio.h>
18 #include <linux/delay.h>
19 #include <linux/bitops.h>
33 struct watchdog_device wdt;
35 unsigned gpios[NUM_GPIOS];
38 static bool nowayout = WATCHDOG_NOWAYOUT;
39 module_param(nowayout, bool, 0);
40 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
43 static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
47 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
48 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
49 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
54 static int a21_wdt_start(struct watchdog_device *wdt)
56 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
58 mutex_lock(&drv->lock);
60 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1);
62 mutex_unlock(&drv->lock);
67 static int a21_wdt_stop(struct watchdog_device *wdt)
69 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
71 mutex_lock(&drv->lock);
73 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
75 mutex_unlock(&drv->lock);
80 static int a21_wdt_ping(struct watchdog_device *wdt)
82 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
84 mutex_lock(&drv->lock);
86 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0);
88 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1);
90 mutex_unlock(&drv->lock);
95 static int a21_wdt_set_timeout(struct watchdog_device *wdt,
98 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
100 if (timeout != 1 && timeout != 30) {
101 dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
105 if (timeout == 30 && wdt->timeout == 1) {
107 "Transition from fast to slow mode not allowed\n");
111 mutex_lock(&drv->lock);
114 gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
116 gpio_set_value(drv->gpios[GPIO_WD_FAST], 0);
118 wdt->timeout = timeout;
120 mutex_unlock(&drv->lock);
125 static const struct watchdog_info a21_wdt_info = {
126 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
127 .identity = "MEN A21 Watchdog",
130 static const struct watchdog_ops a21_wdt_ops = {
131 .owner = THIS_MODULE,
132 .start = a21_wdt_start,
133 .stop = a21_wdt_stop,
134 .ping = a21_wdt_ping,
135 .set_timeout = a21_wdt_set_timeout,
138 static struct watchdog_device a21_wdt = {
139 .info = &a21_wdt_info,
145 static int a21_wdt_probe(struct platform_device *pdev)
147 struct device_node *node;
148 struct a21_wdt_drv *drv;
149 unsigned int reset = 0;
154 drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
158 /* Fill GPIO pin array */
159 node = pdev->dev.of_node;
161 num_gpios = of_gpio_count(node);
162 if (num_gpios != NUM_GPIOS) {
163 dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
164 num_gpios, NUM_GPIOS);
168 for (i = 0; i < num_gpios; i++) {
171 val = of_get_gpio(node, i);
178 /* Request the used GPIOs */
179 for (i = 0; i < num_gpios; i++) {
180 ret = devm_gpio_request(&pdev->dev, drv->gpios[i],
185 if (i < GPIO_WD_RST0)
186 ret = gpio_direction_output(drv->gpios[i],
187 gpio_get_value(drv->gpios[i]));
188 else /* GPIO_WD_RST[0..2] are inputs */
189 ret = gpio_direction_input(drv->gpios[i]);
194 mutex_init(&drv->lock);
195 watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
196 watchdog_set_nowayout(&a21_wdt, nowayout);
197 watchdog_set_drvdata(&a21_wdt, drv);
198 a21_wdt.parent = &pdev->dev;
200 reset = a21_wdt_get_bootstatus(drv);
202 a21_wdt.bootstatus |= WDIOF_EXTERN1;
204 a21_wdt.bootstatus |= WDIOF_CARDRESET;
206 a21_wdt.bootstatus |= WDIOF_POWERUNDER;
208 a21_wdt.bootstatus |= WDIOF_EXTERN2;
211 dev_set_drvdata(&pdev->dev, drv);
213 ret = devm_watchdog_register_device(&pdev->dev, &a21_wdt);
215 dev_err(&pdev->dev, "Cannot register watchdog device\n");
219 dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
224 static void a21_wdt_shutdown(struct platform_device *pdev)
226 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
228 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
231 static const struct of_device_id a21_wdt_ids[] = {
232 { .compatible = "men,a021-wdt" },
235 MODULE_DEVICE_TABLE(of, a21_wdt_ids);
237 static struct platform_driver a21_wdt_driver = {
238 .probe = a21_wdt_probe,
239 .shutdown = a21_wdt_shutdown,
241 .name = "a21-watchdog",
242 .of_match_table = a21_wdt_ids,
246 module_platform_driver(a21_wdt_driver);
248 MODULE_AUTHOR("MEN Mikro Elektronik");
249 MODULE_DESCRIPTION("MEN A21 Watchdog");
250 MODULE_LICENSE("GPL");
251 MODULE_ALIAS("platform:a21-watchdog");