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 | |
42 | static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv) |
43 | { |
44 | int reset = 0; |
45 | |
46 | reset |= gpiod_get_value(desc: drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0; |
47 | reset |= gpiod_get_value(desc: drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0; |
48 | reset |= gpiod_get_value(desc: drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0; |
49 | |
50 | return reset; |
51 | } |
52 | |
53 | static int a21_wdt_start(struct watchdog_device *wdt) |
54 | { |
55 | struct a21_wdt_drv *drv = watchdog_get_drvdata(wdd: wdt); |
56 | |
57 | gpiod_set_value(desc: drv->gpios[GPIO_WD_ENAB], value: 1); |
58 | |
59 | return 0; |
60 | } |
61 | |
62 | static int a21_wdt_stop(struct watchdog_device *wdt) |
63 | { |
64 | struct a21_wdt_drv *drv = watchdog_get_drvdata(wdd: wdt); |
65 | |
66 | gpiod_set_value(desc: drv->gpios[GPIO_WD_ENAB], value: 0); |
67 | |
68 | return 0; |
69 | } |
70 | |
71 | static int a21_wdt_ping(struct watchdog_device *wdt) |
72 | { |
73 | struct a21_wdt_drv *drv = watchdog_get_drvdata(wdd: wdt); |
74 | |
75 | gpiod_set_value(desc: drv->gpios[GPIO_WD_TRIG], value: 0); |
76 | ndelay(10); |
77 | gpiod_set_value(desc: drv->gpios[GPIO_WD_TRIG], value: 1); |
78 | |
79 | return 0; |
80 | } |
81 | |
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(wdd: 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(desc: drv->gpios[GPIO_WD_FAST], value: 1); |
100 | else |
101 | gpiod_set_value(desc: drv->gpios[GPIO_WD_FAST], value: 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 | |
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, size: 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, idx: i, flags: gflags); |
157 | if (IS_ERR(ptr: drv->gpios[i])) |
158 | return PTR_ERR(ptr: drv->gpios[i]); |
159 | |
160 | gpiod_set_consumer_name(desc: drv->gpios[i], name: "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(desc: drv->gpios[i]); |
170 | gpiod_direction_output(desc: drv->gpios[i], value: val); |
171 | } |
172 | } |
173 | |
174 | watchdog_init_timeout(wdd: &a21_wdt, timeout_parm: 30, dev); |
175 | watchdog_set_nowayout(wdd: &a21_wdt, nowayout); |
176 | watchdog_set_drvdata(wdd: &a21_wdt, data: 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, data: 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 | |
201 | static void a21_wdt_shutdown(struct platform_device *pdev) |
202 | { |
203 | struct a21_wdt_drv *drv = dev_get_drvdata(dev: &pdev->dev); |
204 | |
205 | gpiod_set_value(desc: drv->gpios[GPIO_WD_ENAB], value: 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 | |