This source file includes following definitions.
- gpio_wdt_disable
- gpio_wdt_ping
- gpio_wdt_start
- gpio_wdt_stop
- gpio_wdt_probe
- gpio_wdt_init
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8 #include <linux/err.h>
9 #include <linux/delay.h>
10 #include <linux/module.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/watchdog.h>
15
16 static bool nowayout = WATCHDOG_NOWAYOUT;
17 module_param(nowayout, bool, 0);
18 MODULE_PARM_DESC(nowayout,
19 "Watchdog cannot be stopped once started (default="
20 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
21
22 #define SOFT_TIMEOUT_MIN 1
23 #define SOFT_TIMEOUT_DEF 60
24
25 enum {
26 HW_ALGO_TOGGLE,
27 HW_ALGO_LEVEL,
28 };
29
30 struct gpio_wdt_priv {
31 struct gpio_desc *gpiod;
32 bool state;
33 bool always_running;
34 unsigned int hw_algo;
35 struct watchdog_device wdd;
36 };
37
38 static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
39 {
40
41 gpiod_set_value_cansleep(priv->gpiod, 1);
42
43
44 if (priv->hw_algo == HW_ALGO_TOGGLE)
45 gpiod_direction_input(priv->gpiod);
46 }
47
48 static int gpio_wdt_ping(struct watchdog_device *wdd)
49 {
50 struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
51
52 switch (priv->hw_algo) {
53 case HW_ALGO_TOGGLE:
54
55 priv->state = !priv->state;
56 gpiod_set_value_cansleep(priv->gpiod, priv->state);
57 break;
58 case HW_ALGO_LEVEL:
59
60 gpiod_set_value_cansleep(priv->gpiod, 1);
61 udelay(1);
62 gpiod_set_value_cansleep(priv->gpiod, 0);
63 break;
64 }
65 return 0;
66 }
67
68 static int gpio_wdt_start(struct watchdog_device *wdd)
69 {
70 struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
71
72 priv->state = 0;
73 gpiod_direction_output(priv->gpiod, priv->state);
74
75 set_bit(WDOG_HW_RUNNING, &wdd->status);
76
77 return gpio_wdt_ping(wdd);
78 }
79
80 static int gpio_wdt_stop(struct watchdog_device *wdd)
81 {
82 struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
83
84 if (!priv->always_running) {
85 gpio_wdt_disable(priv);
86 } else {
87 set_bit(WDOG_HW_RUNNING, &wdd->status);
88 }
89
90 return 0;
91 }
92
93 static const struct watchdog_info gpio_wdt_ident = {
94 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
95 WDIOF_SETTIMEOUT,
96 .identity = "GPIO Watchdog",
97 };
98
99 static const struct watchdog_ops gpio_wdt_ops = {
100 .owner = THIS_MODULE,
101 .start = gpio_wdt_start,
102 .stop = gpio_wdt_stop,
103 .ping = gpio_wdt_ping,
104 };
105
106 static int gpio_wdt_probe(struct platform_device *pdev)
107 {
108 struct device *dev = &pdev->dev;
109 struct device_node *np = dev->of_node;
110 struct gpio_wdt_priv *priv;
111 enum gpiod_flags gflags;
112 unsigned int hw_margin;
113 const char *algo;
114 int ret;
115
116 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
117 if (!priv)
118 return -ENOMEM;
119
120 platform_set_drvdata(pdev, priv);
121
122 ret = of_property_read_string(np, "hw_algo", &algo);
123 if (ret)
124 return ret;
125 if (!strcmp(algo, "toggle")) {
126 priv->hw_algo = HW_ALGO_TOGGLE;
127 gflags = GPIOD_IN;
128 } else if (!strcmp(algo, "level")) {
129 priv->hw_algo = HW_ALGO_LEVEL;
130 gflags = GPIOD_OUT_LOW;
131 } else {
132 return -EINVAL;
133 }
134
135 priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
136 if (IS_ERR(priv->gpiod))
137 return PTR_ERR(priv->gpiod);
138
139 ret = of_property_read_u32(np,
140 "hw_margin_ms", &hw_margin);
141 if (ret)
142 return ret;
143
144 if (hw_margin < 2 || hw_margin > 65535)
145 return -EINVAL;
146
147 priv->always_running = of_property_read_bool(np,
148 "always-running");
149
150 watchdog_set_drvdata(&priv->wdd, priv);
151
152 priv->wdd.info = &gpio_wdt_ident;
153 priv->wdd.ops = &gpio_wdt_ops;
154 priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
155 priv->wdd.max_hw_heartbeat_ms = hw_margin;
156 priv->wdd.parent = dev;
157 priv->wdd.timeout = SOFT_TIMEOUT_DEF;
158
159 watchdog_init_timeout(&priv->wdd, 0, dev);
160 watchdog_set_nowayout(&priv->wdd, nowayout);
161
162 watchdog_stop_on_reboot(&priv->wdd);
163
164 if (priv->always_running)
165 gpio_wdt_start(&priv->wdd);
166
167 return devm_watchdog_register_device(dev, &priv->wdd);
168 }
169
170 static const struct of_device_id gpio_wdt_dt_ids[] = {
171 { .compatible = "linux,wdt-gpio", },
172 { }
173 };
174 MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
175
176 static struct platform_driver gpio_wdt_driver = {
177 .driver = {
178 .name = "gpio-wdt",
179 .of_match_table = gpio_wdt_dt_ids,
180 },
181 .probe = gpio_wdt_probe,
182 };
183
184 #ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
185 static int __init gpio_wdt_init(void)
186 {
187 return platform_driver_register(&gpio_wdt_driver);
188 }
189 arch_initcall(gpio_wdt_init);
190 #else
191 module_platform_driver(gpio_wdt_driver);
192 #endif
193
194 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
195 MODULE_DESCRIPTION("GPIO Watchdog");
196 MODULE_LICENSE("GPL");