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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.h>
17#include <linux/of_gpio.h>
18#include <linux/delay.h>
19#include <linux/bitops.h>
20
21#define NUM_GPIOS 6
22
23enum 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
32struct a21_wdt_drv {
33 struct watchdog_device wdt;
34 struct mutex lock;
35 unsigned gpios[NUM_GPIOS];
36};
37
38static bool nowayout = WATCHDOG_NOWAYOUT;
39module_param(nowayout, bool, 0);
40MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42
43static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
44{
45 int reset = 0;
46
47 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
48 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
49 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
50
51 return reset;
52}
53
54static int a21_wdt_start(struct watchdog_device *wdt)
55{
56 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
57
58 mutex_lock(&drv->lock);
59
60 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1);
61
62 mutex_unlock(&drv->lock);
63
64 return 0;
65}
66
67static int a21_wdt_stop(struct watchdog_device *wdt)
68{
69 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
70
71 mutex_lock(&drv->lock);
72
73 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
74
75 mutex_unlock(&drv->lock);
76
77 return 0;
78}
79
80static int a21_wdt_ping(struct watchdog_device *wdt)
81{
82 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
83
84 mutex_lock(&drv->lock);
85
86 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0);
87 ndelay(10);
88 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1);
89
90 mutex_unlock(&drv->lock);
91
92 return 0;
93}
94
95static int a21_wdt_set_timeout(struct watchdog_device *wdt,
96 unsigned int timeout)
97{
98 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
99
100 if (timeout != 1 && timeout != 30) {
101 dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");
102 return -EINVAL;
103 }
104
105 if (timeout == 30 && wdt->timeout == 1) {
106 dev_err(wdt->parent,
107 "Transition from fast to slow mode not allowed\n");
108 return -EINVAL;
109 }
110
111 mutex_lock(&drv->lock);
112
113 if (timeout == 1)
114 gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
115 else
116 gpio_set_value(drv->gpios[GPIO_WD_FAST], 0);
117
118 wdt->timeout = timeout;
119
120 mutex_unlock(&drv->lock);
121
122 return 0;
123}
124
125static const struct watchdog_info a21_wdt_info = {
126 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
127 .identity = "MEN A21 Watchdog",
128};
129
130static const struct watchdog_ops a21_wdt_ops = {
131 .owner = THIS_MODULE,
132 .start = a21_wdt_start,
133 .stop = a21_wdt_stop,
134 .ping = a21_wdt_ping,
135 .set_timeout = a21_wdt_set_timeout,
136};
137
138static struct watchdog_device a21_wdt = {
139 .info = &a21_wdt_info,
140 .ops = &a21_wdt_ops,
141 .min_timeout = 1,
142 .max_timeout = 30,
143};
144
145static int a21_wdt_probe(struct platform_device *pdev)
146{
147 struct device_node *node;
148 struct a21_wdt_drv *drv;
149 unsigned int reset = 0;
150 int num_gpios;
151 int ret;
152 int i;
153
154 drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
155 if (!drv)
156 return -ENOMEM;
157
158
159 node = pdev->dev.of_node;
160
161 num_gpios = of_gpio_count(node);
162 if (num_gpios != NUM_GPIOS) {
163 dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
164 num_gpios, NUM_GPIOS);
165 return -ENODEV;
166 }
167
168 for (i = 0; i < num_gpios; i++) {
169 int val;
170
171 val = of_get_gpio(node, i);
172 if (val < 0)
173 return val;
174
175 drv->gpios[i] = val;
176 }
177
178
179 for (i = 0; i < num_gpios; i++) {
180 ret = devm_gpio_request(&pdev->dev, drv->gpios[i],
181 "MEN A21 Watchdog");
182 if (ret)
183 return ret;
184
185 if (i < GPIO_WD_RST0)
186 ret = gpio_direction_output(drv->gpios[i],
187 gpio_get_value(drv->gpios[i]));
188 else
189 ret = gpio_direction_input(drv->gpios[i]);
190 if (ret)
191 return ret;
192 }
193
194 mutex_init(&drv->lock);
195 watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
196 watchdog_set_nowayout(&a21_wdt, nowayout);
197 watchdog_set_drvdata(&a21_wdt, drv);
198 a21_wdt.parent = &pdev->dev;
199
200 reset = a21_wdt_get_bootstatus(drv);
201 if (reset == 2)
202 a21_wdt.bootstatus |= WDIOF_EXTERN1;
203 else if (reset == 4)
204 a21_wdt.bootstatus |= WDIOF_CARDRESET;
205 else if (reset == 5)
206 a21_wdt.bootstatus |= WDIOF_POWERUNDER;
207 else if (reset == 7)
208 a21_wdt.bootstatus |= WDIOF_EXTERN2;
209
210 drv->wdt = a21_wdt;
211 dev_set_drvdata(&pdev->dev, drv);
212
213 ret = devm_watchdog_register_device(&pdev->dev, &a21_wdt);
214 if (ret) {
215 dev_err(&pdev->dev, "Cannot register watchdog device\n");
216 return ret;
217 }
218
219 dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
220
221 return 0;
222}
223
224static void a21_wdt_shutdown(struct platform_device *pdev)
225{
226 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
227
228 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
229}
230
231static const struct of_device_id a21_wdt_ids[] = {
232 { .compatible = "men,a021-wdt" },
233 { },
234};
235MODULE_DEVICE_TABLE(of, a21_wdt_ids);
236
237static struct platform_driver a21_wdt_driver = {
238 .probe = a21_wdt_probe,
239 .shutdown = a21_wdt_shutdown,
240 .driver = {
241 .name = "a21-watchdog",
242 .of_match_table = a21_wdt_ids,
243 },
244};
245
246module_platform_driver(a21_wdt_driver);
247
248MODULE_AUTHOR("MEN Mikro Elektronik");
249MODULE_DESCRIPTION("MEN A21 Watchdog");
250MODULE_LICENSE("GPL");
251MODULE_ALIAS("platform:a21-watchdog");
252
