xref: /openbmc/linux/drivers/watchdog/mena21_wdt.c (revision eddeb07b)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Watchdog driver for the A21 VME CPU Boards
4  *
5  * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH
6  *
7  */
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>
19 #include <linux/of.h>
20 
21 #define NUM_GPIOS 6
22 
23 enum a21_wdt_gpios {
24 	GPIO_WD_ENAB,
25 	GPIO_WD_FAST,
26 	GPIO_WD_TRIG,
27 	GPIO_WD_RST0,
28 	GPIO_WD_RST1,
29 	GPIO_WD_RST2,
30 };
31 
32 struct a21_wdt_drv {
33 	struct watchdog_device wdt;
34 	struct gpio_desc *gpios[NUM_GPIOS];
35 };
36 
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) ")");
41 
a21_wdt_get_bootstatus(struct a21_wdt_drv * drv)42 static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
43 {
44 	int reset = 0;
45 
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;
49 
50 	return reset;
51 }
52 
a21_wdt_start(struct watchdog_device * wdt)53 static int a21_wdt_start(struct watchdog_device *wdt)
54 {
55 	struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
56 
57 	gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);
58 
59 	return 0;
60 }
61 
a21_wdt_stop(struct watchdog_device * wdt)62 static int a21_wdt_stop(struct watchdog_device *wdt)
63 {
64 	struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
65 
66 	gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
67 
68 	return 0;
69 }
70 
a21_wdt_ping(struct watchdog_device * wdt)71 static int a21_wdt_ping(struct watchdog_device *wdt)
72 {
73 	struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
74 
75 	gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);
76 	ndelay(10);
77 	gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);
78 
79 	return 0;
80 }
81 
a21_wdt_set_timeout(struct watchdog_device * wdt,unsigned int timeout)82 static int a21_wdt_set_timeout(struct watchdog_device *wdt,
83 			       unsigned int timeout)
84 {
85 	struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
86 
87 	if (timeout != 1 && timeout != 30) {
88 		dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
89 		return -EINVAL;
90 	}
91 
92 	if (timeout == 30 && wdt->timeout == 1) {
93 		dev_err(wdt->parent,
94 			"Transition from fast to slow mode not allowed\n");
95 		return -EINVAL;
96 	}
97 
98 	if (timeout == 1)
99 		gpiod_set_value(drv->gpios[GPIO_WD_FAST], 1);
100 	else
101 		gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);
102 
103 	wdt->timeout = timeout;
104 
105 	return 0;
106 }
107 
108 static const struct watchdog_info a21_wdt_info = {
109 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
110 	.identity = "MEN A21 Watchdog",
111 };
112 
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,
119 };
120 
121 static struct watchdog_device a21_wdt = {
122 	.info = &a21_wdt_info,
123 	.ops = &a21_wdt_ops,
124 	.min_timeout = 1,
125 	.max_timeout = 30,
126 };
127 
a21_wdt_probe(struct platform_device * pdev)128 static int a21_wdt_probe(struct platform_device *pdev)
129 {
130 	struct device *dev = &pdev->dev;
131 	struct a21_wdt_drv *drv;
132 	unsigned int reset = 0;
133 	int num_gpios;
134 	int ret;
135 	int i;
136 
137 	drv = devm_kzalloc(dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
138 	if (!drv)
139 		return -ENOMEM;
140 
141 	num_gpios = gpiod_count(dev, NULL);
142 	if (num_gpios != NUM_GPIOS) {
143 		dev_err(dev, "gpios DT property wrong, got %d want %d",
144 			num_gpios, NUM_GPIOS);
145 		return -ENODEV;
146 	}
147 
148 	/* Request the used GPIOs */
149 	for (i = 0; i < num_gpios; i++) {
150 		enum gpiod_flags gflags;
151 
152 		if (i < GPIO_WD_RST0)
153 			gflags = GPIOD_ASIS;
154 		else
155 			gflags = GPIOD_IN;
156 		drv->gpios[i] = devm_gpiod_get_index(dev, NULL, i, gflags);
157 		if (IS_ERR(drv->gpios[i]))
158 			return PTR_ERR(drv->gpios[i]);
159 
160 		gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");
161 
162 		/*
163 		 * Retrieve the initial value from the GPIOs that should be
164 		 * output, then set up the line as output with that value.
165 		 */
166 		if (i < GPIO_WD_RST0) {
167 			int val;
168 
169 			val = gpiod_get_value(drv->gpios[i]);
170 			gpiod_direction_output(drv->gpios[i], val);
171 		}
172 	}
173 
174 	watchdog_init_timeout(&a21_wdt, 30, dev);
175 	watchdog_set_nowayout(&a21_wdt, nowayout);
176 	watchdog_set_drvdata(&a21_wdt, drv);
177 	a21_wdt.parent = dev;
178 
179 	reset = a21_wdt_get_bootstatus(drv);
180 	if (reset == 2)
181 		a21_wdt.bootstatus |= WDIOF_EXTERN1;
182 	else if (reset == 4)
183 		a21_wdt.bootstatus |= WDIOF_CARDRESET;
184 	else if (reset == 5)
185 		a21_wdt.bootstatus |= WDIOF_POWERUNDER;
186 	else if (reset == 7)
187 		a21_wdt.bootstatus |= WDIOF_EXTERN2;
188 
189 	drv->wdt = a21_wdt;
190 	dev_set_drvdata(dev, drv);
191 
192 	ret = devm_watchdog_register_device(dev, &a21_wdt);
193 	if (ret)
194 		return ret;
195 
196 	dev_info(dev, "MEN A21 watchdog timer driver enabled\n");
197 
198 	return 0;
199 }
200 
a21_wdt_shutdown(struct platform_device * pdev)201 static void a21_wdt_shutdown(struct platform_device *pdev)
202 {
203 	struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
204 
205 	gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
206 }
207 
208 static const struct of_device_id a21_wdt_ids[] = {
209 	{ .compatible = "men,a021-wdt" },
210 	{ },
211 };
212 MODULE_DEVICE_TABLE(of, a21_wdt_ids);
213 
214 static struct platform_driver a21_wdt_driver = {
215 	.probe = a21_wdt_probe,
216 	.shutdown = a21_wdt_shutdown,
217 	.driver = {
218 		.name = "a21-watchdog",
219 		.of_match_table = a21_wdt_ids,
220 	},
221 };
222 
223 module_platform_driver(a21_wdt_driver);
224 
225 MODULE_AUTHOR("MEN Mikro Elektronik");
226 MODULE_DESCRIPTION("MEN A21 Watchdog");
227 MODULE_LICENSE("GPL");
228 MODULE_ALIAS("platform:a21-watchdog");
229