Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
25134eaf AS |
2 | /* |
3 | * Driver for watchdog device controlled through GPIO-line | |
4 | * | |
5 | * Author: 2013, Alexander Shiyan <shc_work@mail.ru> | |
25134eaf AS |
6 | */ |
7 | ||
8 | #include <linux/err.h> | |
9 | #include <linux/delay.h> | |
10 | #include <linux/module.h> | |
a2363f9d LW |
11 | #include <linux/gpio/consumer.h> |
12 | #include <linux/of.h> | |
25134eaf | 13 | #include <linux/platform_device.h> |
25134eaf AS |
14 | #include <linux/watchdog.h> |
15 | ||
1a4aaf9f MR |
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 | ||
25134eaf AS |
22 | #define SOFT_TIMEOUT_MIN 1 |
23 | #define SOFT_TIMEOUT_DEF 60 | |
25134eaf AS |
24 | |
25 | enum { | |
26 | HW_ALGO_TOGGLE, | |
27 | HW_ALGO_LEVEL, | |
28 | }; | |
29 | ||
30 | struct gpio_wdt_priv { | |
a2363f9d | 31 | struct gpio_desc *gpiod; |
25134eaf | 32 | bool state; |
ba804a95 | 33 | bool always_running; |
25134eaf | 34 | unsigned int hw_algo; |
25134eaf AS |
35 | struct watchdog_device wdd; |
36 | }; | |
37 | ||
38 | static void gpio_wdt_disable(struct gpio_wdt_priv *priv) | |
39 | { | |
a2363f9d LW |
40 | /* Eternal ping */ |
41 | gpiod_set_value_cansleep(priv->gpiod, 1); | |
25134eaf AS |
42 | |
43 | /* Put GPIO back to tristate */ | |
44 | if (priv->hw_algo == HW_ALGO_TOGGLE) | |
a2363f9d | 45 | gpiod_direction_input(priv->gpiod); |
25134eaf AS |
46 | } |
47 | ||
03bca158 | 48 | static int gpio_wdt_ping(struct watchdog_device *wdd) |
4f2d0b2d | 49 | { |
4f2d0b2d UKK |
50 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); |
51 | ||
4f2d0b2d UKK |
52 | switch (priv->hw_algo) { |
53 | case HW_ALGO_TOGGLE: | |
54 | /* Toggle output pin */ | |
55 | priv->state = !priv->state; | |
a2363f9d | 56 | gpiod_set_value_cansleep(priv->gpiod, priv->state); |
4f2d0b2d UKK |
57 | break; |
58 | case HW_ALGO_LEVEL: | |
59 | /* Pulse */ | |
a2363f9d | 60 | gpiod_set_value_cansleep(priv->gpiod, 1); |
4f2d0b2d | 61 | udelay(1); |
a2363f9d | 62 | gpiod_set_value_cansleep(priv->gpiod, 0); |
4f2d0b2d UKK |
63 | break; |
64 | } | |
03bca158 | 65 | return 0; |
ba804a95 ML |
66 | } |
67 | ||
68 | static int gpio_wdt_start(struct watchdog_device *wdd) | |
69 | { | |
70 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
71 | ||
a2363f9d LW |
72 | priv->state = 0; |
73 | gpiod_direction_output(priv->gpiod, priv->state); | |
25134eaf | 74 | |
03bca158 GR |
75 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
76 | ||
77 | return gpio_wdt_ping(wdd); | |
25134eaf AS |
78 | } |
79 | ||
80 | static int gpio_wdt_stop(struct watchdog_device *wdd) | |
81 | { | |
82 | struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
83 | ||
ba804a95 | 84 | if (!priv->always_running) { |
ba804a95 | 85 | gpio_wdt_disable(priv); |
bc137dfd RV |
86 | } else { |
87 | set_bit(WDOG_HW_RUNNING, &wdd->status); | |
ba804a95 | 88 | } |
25134eaf AS |
89 | |
90 | return 0; | |
91 | } | |
92 | ||
25134eaf AS |
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, | |
25134eaf AS |
104 | }; |
105 | ||
106 | static int gpio_wdt_probe(struct platform_device *pdev) | |
107 | { | |
d0d0677e LW |
108 | struct device *dev = &pdev->dev; |
109 | struct device_node *np = dev->of_node; | |
25134eaf | 110 | struct gpio_wdt_priv *priv; |
a2363f9d | 111 | enum gpiod_flags gflags; |
25134eaf | 112 | unsigned int hw_margin; |
25134eaf AS |
113 | const char *algo; |
114 | int ret; | |
115 | ||
d0d0677e | 116 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
25134eaf AS |
117 | if (!priv) |
118 | return -ENOMEM; | |
119 | ||
1ac06563 WY |
120 | platform_set_drvdata(pdev, priv); |
121 | ||
d0d0677e | 122 | ret = of_property_read_string(np, "hw_algo", &algo); |
25134eaf AS |
123 | if (ret) |
124 | return ret; | |
0a0a542f | 125 | if (!strcmp(algo, "toggle")) { |
25134eaf | 126 | priv->hw_algo = HW_ALGO_TOGGLE; |
a2363f9d | 127 | gflags = GPIOD_IN; |
0a0a542f | 128 | } else if (!strcmp(algo, "level")) { |
25134eaf | 129 | priv->hw_algo = HW_ALGO_LEVEL; |
a2363f9d | 130 | gflags = GPIOD_OUT_LOW; |
25134eaf AS |
131 | } else { |
132 | return -EINVAL; | |
133 | } | |
134 | ||
a2363f9d LW |
135 | priv->gpiod = devm_gpiod_get(dev, NULL, gflags); |
136 | if (IS_ERR(priv->gpiod)) | |
137 | return PTR_ERR(priv->gpiod); | |
25134eaf | 138 | |
d0d0677e | 139 | ret = of_property_read_u32(np, |
25134eaf AS |
140 | "hw_margin_ms", &hw_margin); |
141 | if (ret) | |
142 | return ret; | |
143 | /* Disallow values lower than 2 and higher than 65535 ms */ | |
144 | if (hw_margin < 2 || hw_margin > 65535) | |
145 | return -EINVAL; | |
146 | ||
d0d0677e | 147 | priv->always_running = of_property_read_bool(np, |
ba804a95 ML |
148 | "always-running"); |
149 | ||
25134eaf AS |
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; | |
03bca158 | 155 | priv->wdd.max_hw_heartbeat_ms = hw_margin; |
d0d0677e | 156 | priv->wdd.parent = dev; |
65adfa22 | 157 | priv->wdd.timeout = SOFT_TIMEOUT_DEF; |
25134eaf | 158 | |
3564fbc5 | 159 | watchdog_init_timeout(&priv->wdd, 0, dev); |
1a4aaf9f | 160 | watchdog_set_nowayout(&priv->wdd, nowayout); |
25134eaf | 161 | |
28e805b4 DR |
162 | watchdog_stop_on_reboot(&priv->wdd); |
163 | ||
ba804a95 | 164 | if (priv->always_running) |
03bca158 | 165 | gpio_wdt_start(&priv->wdd); |
ba804a95 | 166 | |
3564fbc5 | 167 | return devm_watchdog_register_device(dev, &priv->wdd); |
25134eaf AS |
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", | |
25134eaf AS |
179 | .of_match_table = gpio_wdt_dt_ids, |
180 | }, | |
181 | .probe = gpio_wdt_probe, | |
25134eaf | 182 | }; |
5e53c8ed JBT |
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 | |
25134eaf | 191 | module_platform_driver(gpio_wdt_driver); |
5e53c8ed | 192 | #endif |
25134eaf AS |
193 | |
194 | MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); | |
195 | MODULE_DESCRIPTION("GPIO Watchdog"); | |
196 | MODULE_LICENSE("GPL"); |