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/consumer.h>
17 #include <linux/delay.h>
18 #include <linux/bitops.h>
33 struct watchdog_device wdt;
34 struct gpio_desc *gpios[NUM_GPIOS];
37 static bool nowayout = WATCHDOG_NOWAYOUT;
38 module_param(nowayout, bool, 0);
39 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42 static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
46 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
47 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
48 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
53 static int a21_wdt_start(struct watchdog_device *wdt)
55 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
57 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);
62 static int a21_wdt_stop(struct watchdog_device *wdt)
64 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
66 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
71 static int a21_wdt_ping(struct watchdog_device *wdt)
73 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
75 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);
77 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);
82 static int a21_wdt_set_timeout(struct watchdog_device *wdt,
85 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
87 if (timeout != 1 && timeout != 30) {
88 dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
92 if (timeout == 30 && wdt->timeout == 1) {
94 "Transition from fast to slow mode not allowed\n");
99 gpiod_set_value(drv->gpios[GPIO_WD_FAST], 1);
101 gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);
103 wdt->timeout = timeout;
108 static const struct watchdog_info a21_wdt_info = {
109 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
110 .identity = "MEN A21 Watchdog",
113 static const struct watchdog_ops a21_wdt_ops = {
114 .owner = THIS_MODULE,
115 .start = a21_wdt_start,
116 .stop = a21_wdt_stop,
117 .ping = a21_wdt_ping,
118 .set_timeout = a21_wdt_set_timeout,
121 static struct watchdog_device a21_wdt = {
122 .info = &a21_wdt_info,
128 static int a21_wdt_probe(struct platform_device *pdev)
130 struct a21_wdt_drv *drv;
131 unsigned int reset = 0;
136 drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
140 num_gpios = gpiod_count(&pdev->dev, NULL);
141 if (num_gpios != NUM_GPIOS) {
142 dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
143 num_gpios, NUM_GPIOS);
147 /* Request the used GPIOs */
148 for (i = 0; i < num_gpios; i++) {
149 enum gpiod_flags gflags;
151 if (i < GPIO_WD_RST0)
155 drv->gpios[i] = devm_gpiod_get_index(&pdev->dev, NULL, i,
157 if (IS_ERR(drv->gpios[i])) {
158 ret = PTR_ERR(drv->gpios[i]);
162 gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");
165 * Retrieve the initial value from the GPIOs that should be
166 * output, then set up the line as output with that value.
168 if (i < GPIO_WD_RST0) {
171 val = gpiod_get_value(drv->gpios[i]);
172 gpiod_direction_output(drv->gpios[i], val);
176 watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
177 watchdog_set_nowayout(&a21_wdt, nowayout);
178 watchdog_set_drvdata(&a21_wdt, drv);
179 a21_wdt.parent = &pdev->dev;
181 reset = a21_wdt_get_bootstatus(drv);
183 a21_wdt.bootstatus |= WDIOF_EXTERN1;
185 a21_wdt.bootstatus |= WDIOF_CARDRESET;
187 a21_wdt.bootstatus |= WDIOF_POWERUNDER;
189 a21_wdt.bootstatus |= WDIOF_EXTERN2;
192 dev_set_drvdata(&pdev->dev, drv);
194 ret = devm_watchdog_register_device(&pdev->dev, &a21_wdt);
196 dev_err(&pdev->dev, "Cannot register watchdog device\n");
200 dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
205 static void a21_wdt_shutdown(struct platform_device *pdev)
207 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
209 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
212 static const struct of_device_id a21_wdt_ids[] = {
213 { .compatible = "men,a021-wdt" },
216 MODULE_DEVICE_TABLE(of, a21_wdt_ids);
218 static struct platform_driver a21_wdt_driver = {
219 .probe = a21_wdt_probe,
220 .shutdown = a21_wdt_shutdown,
222 .name = "a21-watchdog",
223 .of_match_table = a21_wdt_ids,
227 module_platform_driver(a21_wdt_driver);
229 MODULE_AUTHOR("MEN Mikro Elektronik");
230 MODULE_DESCRIPTION("MEN A21 Watchdog");
231 MODULE_LICENSE("GPL");
232 MODULE_ALIAS("platform:a21-watchdog");