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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/consumer.h>
17#include <linux/delay.h>
18#include <linux/bitops.h>
19#include <linux/of.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 gpio_desc *gpios[NUM_GPIOS];
35};
36
37static bool nowayout = WATCHDOG_NOWAYOUT;
38module_param(nowayout, bool, 0);
39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41
42static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
43{
44 int reset = 0;
45
46 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
47 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
48 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
49
50 return reset;
51}
52
53static int a21_wdt_start(struct watchdog_device *wdt)
54{
55 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
56
57 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);
58
59 return 0;
60}
61
62static int a21_wdt_stop(struct watchdog_device *wdt)
63{
64 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
65
66 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
67
68 return 0;
69}
70
71static int a21_wdt_ping(struct watchdog_device *wdt)
72{
73 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
74
75 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);
76 ndelay(10);
77 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);
78
79 return 0;
80}
81
82static int a21_wdt_set_timeout(struct watchdog_device *wdt,
83 unsigned int timeout)
84{
85 struct a21_wdt_drv *drv = watchdog_get_drvdata(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(drv->gpios[GPIO_WD_FAST], 1);
100 else
101 gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);
102
103 wdt->timeout = timeout;
104
105 return 0;
106}
107
108static const struct watchdog_info a21_wdt_info = {
109 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
110 .identity = "MEN A21 Watchdog",
111};
112
113static 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
121static 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
128static 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, 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
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, i, gflags);
157 if (IS_ERR(drv->gpios[i]))
158 return PTR_ERR(drv->gpios[i]);
159
160 gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");
161
162
163
164
165
166 if (i < GPIO_WD_RST0) {
167 int val;
168
169 val = gpiod_get_value(drv->gpios[i]);
170 gpiod_direction_output(drv->gpios[i], val);
171 }
172 }
173
174 watchdog_init_timeout(&a21_wdt, 30, dev);
175 watchdog_set_nowayout(&a21_wdt, nowayout);
176 watchdog_set_drvdata(&a21_wdt, 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, 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
201static void a21_wdt_shutdown(struct platform_device *pdev)
202{
203 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
204
205 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);
206}
207
208static const struct of_device_id a21_wdt_ids[] = {
209 { .compatible = "men,a021-wdt" },
210 { },
211};
212MODULE_DEVICE_TABLE(of, a21_wdt_ids);
213
214static 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
223module_platform_driver(a21_wdt_driver);
224
225MODULE_AUTHOR("MEN Mikro Elektronik");
226MODULE_DESCRIPTION("MEN A21 Watchdog");
227MODULE_LICENSE("GPL");
228MODULE_ALIAS("platform:a21-watchdog");
229
