Commit | Line | Data |
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25134eaf AS |
1 | /* |
2 | * Driver for watchdog device controlled through GPIO-line | |
3 | * | |
4 | * Author: 2013, Alexander Shiyan <shc_work@mail.ru> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/err.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/module.h> | |
25134eaf AS |
15 | #include <linux/of_gpio.h> |
16 | #include <linux/platform_device.h> | |
25134eaf AS |
17 | #include <linux/watchdog.h> |
18 | ||
19 | #define SOFT_TIMEOUT_MIN 1 | |
20 | #define SOFT_TIMEOUT_DEF 60 | |
21 | #define SOFT_TIMEOUT_MAX 0xffff | |
22 | ||
23 | enum { | |
24 | HW_ALGO_TOGGLE, | |
25 | HW_ALGO_LEVEL, | |
26 | }; | |
27 | ||
28 | struct gpio_wdt_priv { | |
29 | int gpio; | |
30 | bool active_low; | |
31 | bool state; | |
ba804a95 ML |
32 | bool always_running; |
33 | bool armed; | |
25134eaf AS |
34 | unsigned int hw_algo; |
35 | unsigned int hw_margin; | |
36 | unsigned long last_jiffies; | |
25134eaf AS |
37 | struct timer_list timer; |
38 | struct watchdog_device wdd; | |
39 | }; | |
40 | ||
41 | static void gpio_wdt_disable(struct gpio_wdt_priv *priv) | |
42 | { | |
43 | gpio_set_value_cansleep(priv->gpio, !priv->active_low); | |
44 | ||
45 | /* Put GPIO back to tristate */ | |
46 | if (priv->hw_algo == HW_ALGO_TOGGLE) | |
47 | gpio_direction_input(priv->gpio); | |
48 | } | |
49 | ||
4f2d0b2d UKK |
50 | static void gpio_wdt_hwping(unsigned long data) |
51 | { | |
52 | struct watchdog_device *wdd = (struct watchdog_device *)data; | |
53 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
54 | ||
55 | if (priv->armed && time_after(jiffies, priv->last_jiffies + | |
56 | msecs_to_jiffies(wdd->timeout * 1000))) { | |
8a7b76be GR |
57 | dev_crit(wdd->parent, |
58 | "Timer expired. System will reboot soon!\n"); | |
4f2d0b2d UKK |
59 | return; |
60 | } | |
61 | ||
62 | /* Restart timer */ | |
63 | mod_timer(&priv->timer, jiffies + priv->hw_margin); | |
64 | ||
65 | switch (priv->hw_algo) { | |
66 | case HW_ALGO_TOGGLE: | |
67 | /* Toggle output pin */ | |
68 | priv->state = !priv->state; | |
69 | gpio_set_value_cansleep(priv->gpio, priv->state); | |
70 | break; | |
71 | case HW_ALGO_LEVEL: | |
72 | /* Pulse */ | |
73 | gpio_set_value_cansleep(priv->gpio, !priv->active_low); | |
74 | udelay(1); | |
75 | gpio_set_value_cansleep(priv->gpio, priv->active_low); | |
76 | break; | |
77 | } | |
78 | } | |
79 | ||
ba804a95 | 80 | static void gpio_wdt_start_impl(struct gpio_wdt_priv *priv) |
25134eaf | 81 | { |
25134eaf AS |
82 | priv->state = priv->active_low; |
83 | gpio_direction_output(priv->gpio, priv->state); | |
84 | priv->last_jiffies = jiffies; | |
4f2d0b2d | 85 | gpio_wdt_hwping((unsigned long)&priv->wdd); |
ba804a95 ML |
86 | } |
87 | ||
88 | static int gpio_wdt_start(struct watchdog_device *wdd) | |
89 | { | |
90 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
91 | ||
92 | gpio_wdt_start_impl(priv); | |
93 | priv->armed = true; | |
25134eaf AS |
94 | |
95 | return 0; | |
96 | } | |
97 | ||
98 | static int gpio_wdt_stop(struct watchdog_device *wdd) | |
99 | { | |
100 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
101 | ||
ba804a95 ML |
102 | priv->armed = false; |
103 | if (!priv->always_running) { | |
104 | mod_timer(&priv->timer, 0); | |
105 | gpio_wdt_disable(priv); | |
106 | } | |
25134eaf AS |
107 | |
108 | return 0; | |
109 | } | |
110 | ||
111 | static int gpio_wdt_ping(struct watchdog_device *wdd) | |
112 | { | |
113 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
114 | ||
115 | priv->last_jiffies = jiffies; | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) | |
121 | { | |
122 | wdd->timeout = t; | |
123 | ||
124 | return gpio_wdt_ping(wdd); | |
125 | } | |
126 | ||
25134eaf AS |
127 | static const struct watchdog_info gpio_wdt_ident = { |
128 | .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | | |
129 | WDIOF_SETTIMEOUT, | |
130 | .identity = "GPIO Watchdog", | |
131 | }; | |
132 | ||
133 | static const struct watchdog_ops gpio_wdt_ops = { | |
134 | .owner = THIS_MODULE, | |
135 | .start = gpio_wdt_start, | |
136 | .stop = gpio_wdt_stop, | |
137 | .ping = gpio_wdt_ping, | |
138 | .set_timeout = gpio_wdt_set_timeout, | |
139 | }; | |
140 | ||
141 | static int gpio_wdt_probe(struct platform_device *pdev) | |
142 | { | |
143 | struct gpio_wdt_priv *priv; | |
144 | enum of_gpio_flags flags; | |
145 | unsigned int hw_margin; | |
146 | unsigned long f = 0; | |
147 | const char *algo; | |
148 | int ret; | |
149 | ||
150 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); | |
151 | if (!priv) | |
152 | return -ENOMEM; | |
153 | ||
1ac06563 WY |
154 | platform_set_drvdata(pdev, priv); |
155 | ||
25134eaf AS |
156 | priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags); |
157 | if (!gpio_is_valid(priv->gpio)) | |
158 | return priv->gpio; | |
159 | ||
160 | priv->active_low = flags & OF_GPIO_ACTIVE_LOW; | |
161 | ||
162 | ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo); | |
163 | if (ret) | |
164 | return ret; | |
0a0a542f | 165 | if (!strcmp(algo, "toggle")) { |
25134eaf AS |
166 | priv->hw_algo = HW_ALGO_TOGGLE; |
167 | f = GPIOF_IN; | |
0a0a542f | 168 | } else if (!strcmp(algo, "level")) { |
25134eaf AS |
169 | priv->hw_algo = HW_ALGO_LEVEL; |
170 | f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; | |
171 | } else { | |
172 | return -EINVAL; | |
173 | } | |
174 | ||
175 | ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f, | |
176 | dev_name(&pdev->dev)); | |
177 | if (ret) | |
178 | return ret; | |
179 | ||
180 | ret = of_property_read_u32(pdev->dev.of_node, | |
181 | "hw_margin_ms", &hw_margin); | |
182 | if (ret) | |
183 | return ret; | |
184 | /* Disallow values lower than 2 and higher than 65535 ms */ | |
185 | if (hw_margin < 2 || hw_margin > 65535) | |
186 | return -EINVAL; | |
187 | ||
188 | /* Use safe value (1/2 of real timeout) */ | |
189 | priv->hw_margin = msecs_to_jiffies(hw_margin / 2); | |
190 | ||
ba804a95 ML |
191 | priv->always_running = of_property_read_bool(pdev->dev.of_node, |
192 | "always-running"); | |
193 | ||
25134eaf AS |
194 | watchdog_set_drvdata(&priv->wdd, priv); |
195 | ||
196 | priv->wdd.info = &gpio_wdt_ident; | |
197 | priv->wdd.ops = &gpio_wdt_ops; | |
198 | priv->wdd.min_timeout = SOFT_TIMEOUT_MIN; | |
199 | priv->wdd.max_timeout = SOFT_TIMEOUT_MAX; | |
6551881c | 200 | priv->wdd.parent = &pdev->dev; |
25134eaf AS |
201 | |
202 | if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0) | |
203 | priv->wdd.timeout = SOFT_TIMEOUT_DEF; | |
204 | ||
205 | setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd); | |
206 | ||
28e805b4 DR |
207 | watchdog_stop_on_reboot(&priv->wdd); |
208 | ||
25134eaf AS |
209 | ret = watchdog_register_device(&priv->wdd); |
210 | if (ret) | |
211 | return ret; | |
212 | ||
ba804a95 ML |
213 | if (priv->always_running) |
214 | gpio_wdt_start_impl(priv); | |
215 | ||
216 | return 0; | |
25134eaf AS |
217 | } |
218 | ||
219 | static int gpio_wdt_remove(struct platform_device *pdev) | |
220 | { | |
221 | struct gpio_wdt_priv *priv = platform_get_drvdata(pdev); | |
222 | ||
223 | del_timer_sync(&priv->timer); | |
25134eaf AS |
224 | watchdog_unregister_device(&priv->wdd); |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static const struct of_device_id gpio_wdt_dt_ids[] = { | |
230 | { .compatible = "linux,wdt-gpio", }, | |
231 | { } | |
232 | }; | |
233 | MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids); | |
234 | ||
235 | static struct platform_driver gpio_wdt_driver = { | |
236 | .driver = { | |
237 | .name = "gpio-wdt", | |
25134eaf AS |
238 | .of_match_table = gpio_wdt_dt_ids, |
239 | }, | |
240 | .probe = gpio_wdt_probe, | |
241 | .remove = gpio_wdt_remove, | |
242 | }; | |
5e53c8ed JBT |
243 | |
244 | #ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL | |
245 | static int __init gpio_wdt_init(void) | |
246 | { | |
247 | return platform_driver_register(&gpio_wdt_driver); | |
248 | } | |
249 | arch_initcall(gpio_wdt_init); | |
250 | #else | |
25134eaf | 251 | module_platform_driver(gpio_wdt_driver); |
5e53c8ed | 252 | #endif |
25134eaf AS |
253 | |
254 | MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); | |
255 | MODULE_DESCRIPTION("GPIO Watchdog"); | |
256 | MODULE_LICENSE("GPL"); |