1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Watchdog driver for the wm831x PMICs |
4 | * |
5 | * Copyright (C) 2009 Wolfson Microelectronics |
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 | |
17 | #include <linux/mfd/wm831x/core.h> |
18 | #include <linux/mfd/wm831x/pdata.h> |
19 | #include <linux/mfd/wm831x/watchdog.h> |
20 | |
21 | static bool nowayout = WATCHDOG_NOWAYOUT; |
22 | module_param(nowayout, bool, 0); |
23 | MODULE_PARM_DESC(nowayout, |
24 | "Watchdog cannot be stopped once started (default=" |
25 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
26 | |
27 | struct wm831x_wdt_drvdata { |
28 | struct watchdog_device wdt; |
29 | struct wm831x *wm831x; |
30 | struct mutex lock; |
31 | int update_state; |
32 | }; |
33 | |
34 | /* We can't use the sub-second values here but they're included |
35 | * for completeness. */ |
36 | static struct { |
37 | unsigned int time; /* Seconds */ |
38 | u16 val; /* WDOG_TO value */ |
39 | } wm831x_wdt_cfgs[] = { |
40 | { 1, 2 }, |
41 | { 2, 3 }, |
42 | { 4, 4 }, |
43 | { 8, 5 }, |
44 | { 16, 6 }, |
45 | { 32, 7 }, |
46 | { 33, 7 }, /* Actually 32.768s so include both, others round down */ |
47 | }; |
48 | |
49 | static int wm831x_wdt_start(struct watchdog_device *wdt_dev) |
50 | { |
51 | struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdd: wdt_dev); |
52 | struct wm831x *wm831x = driver_data->wm831x; |
53 | int ret; |
54 | |
55 | mutex_lock(&driver_data->lock); |
56 | |
57 | ret = wm831x_reg_unlock(wm831x); |
58 | if (ret == 0) { |
59 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
60 | WM831X_WDOG_ENA, WM831X_WDOG_ENA); |
61 | wm831x_reg_lock(wm831x); |
62 | } else { |
63 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n" , |
64 | ret); |
65 | } |
66 | |
67 | mutex_unlock(lock: &driver_data->lock); |
68 | |
69 | return ret; |
70 | } |
71 | |
72 | static int wm831x_wdt_stop(struct watchdog_device *wdt_dev) |
73 | { |
74 | struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdd: wdt_dev); |
75 | struct wm831x *wm831x = driver_data->wm831x; |
76 | int ret; |
77 | |
78 | mutex_lock(&driver_data->lock); |
79 | |
80 | ret = wm831x_reg_unlock(wm831x); |
81 | if (ret == 0) { |
82 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
83 | WM831X_WDOG_ENA, val: 0); |
84 | wm831x_reg_lock(wm831x); |
85 | } else { |
86 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n" , |
87 | ret); |
88 | } |
89 | |
90 | mutex_unlock(lock: &driver_data->lock); |
91 | |
92 | return ret; |
93 | } |
94 | |
95 | static int wm831x_wdt_ping(struct watchdog_device *wdt_dev) |
96 | { |
97 | struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdd: wdt_dev); |
98 | struct wm831x *wm831x = driver_data->wm831x; |
99 | int ret; |
100 | u16 reg; |
101 | |
102 | mutex_lock(&driver_data->lock); |
103 | |
104 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
105 | |
106 | if (!(reg & WM831X_WDOG_RST_SRC)) { |
107 | dev_err(wm831x->dev, "Hardware watchdog update unsupported\n" ); |
108 | ret = -EINVAL; |
109 | goto out; |
110 | } |
111 | |
112 | reg |= WM831X_WDOG_RESET; |
113 | |
114 | ret = wm831x_reg_unlock(wm831x); |
115 | if (ret == 0) { |
116 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, val: reg); |
117 | wm831x_reg_lock(wm831x); |
118 | } else { |
119 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n" , |
120 | ret); |
121 | } |
122 | |
123 | out: |
124 | mutex_unlock(lock: &driver_data->lock); |
125 | |
126 | return ret; |
127 | } |
128 | |
129 | static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev, |
130 | unsigned int timeout) |
131 | { |
132 | struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdd: wdt_dev); |
133 | struct wm831x *wm831x = driver_data->wm831x; |
134 | int ret, i; |
135 | |
136 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) |
137 | if (wm831x_wdt_cfgs[i].time == timeout) |
138 | break; |
139 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) |
140 | return -EINVAL; |
141 | |
142 | ret = wm831x_reg_unlock(wm831x); |
143 | if (ret == 0) { |
144 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
145 | WM831X_WDOG_TO_MASK, |
146 | val: wm831x_wdt_cfgs[i].val); |
147 | wm831x_reg_lock(wm831x); |
148 | } else { |
149 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n" , |
150 | ret); |
151 | } |
152 | |
153 | wdt_dev->timeout = timeout; |
154 | |
155 | return ret; |
156 | } |
157 | |
158 | static const struct watchdog_info wm831x_wdt_info = { |
159 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
160 | .identity = "WM831x Watchdog" , |
161 | }; |
162 | |
163 | static const struct watchdog_ops wm831x_wdt_ops = { |
164 | .owner = THIS_MODULE, |
165 | .start = wm831x_wdt_start, |
166 | .stop = wm831x_wdt_stop, |
167 | .ping = wm831x_wdt_ping, |
168 | .set_timeout = wm831x_wdt_set_timeout, |
169 | }; |
170 | |
171 | static int wm831x_wdt_probe(struct platform_device *pdev) |
172 | { |
173 | struct device *dev = &pdev->dev; |
174 | struct wm831x *wm831x = dev_get_drvdata(dev: dev->parent); |
175 | struct wm831x_pdata *chip_pdata = dev_get_platdata(dev: dev->parent); |
176 | struct wm831x_watchdog_pdata *pdata; |
177 | struct wm831x_wdt_drvdata *driver_data; |
178 | struct watchdog_device *wm831x_wdt; |
179 | int reg, ret, i; |
180 | |
181 | ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
182 | if (ret < 0) { |
183 | dev_err(wm831x->dev, "Failed to read watchdog status: %d\n" , |
184 | ret); |
185 | return ret; |
186 | } |
187 | reg = ret; |
188 | |
189 | if (reg & WM831X_WDOG_DEBUG) |
190 | dev_warn(wm831x->dev, "Watchdog is paused\n" ); |
191 | |
192 | driver_data = devm_kzalloc(dev, size: sizeof(*driver_data), GFP_KERNEL); |
193 | if (!driver_data) |
194 | return -ENOMEM; |
195 | |
196 | mutex_init(&driver_data->lock); |
197 | driver_data->wm831x = wm831x; |
198 | |
199 | wm831x_wdt = &driver_data->wdt; |
200 | |
201 | wm831x_wdt->info = &wm831x_wdt_info; |
202 | wm831x_wdt->ops = &wm831x_wdt_ops; |
203 | wm831x_wdt->parent = dev; |
204 | watchdog_set_nowayout(wdd: wm831x_wdt, nowayout); |
205 | watchdog_set_drvdata(wdd: wm831x_wdt, data: driver_data); |
206 | |
207 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
208 | reg &= WM831X_WDOG_TO_MASK; |
209 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) |
210 | if (wm831x_wdt_cfgs[i].val == reg) |
211 | break; |
212 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) |
213 | dev_warn(wm831x->dev, |
214 | "Unknown watchdog timeout: %x\n" , reg); |
215 | else |
216 | wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time; |
217 | |
218 | /* Apply any configuration */ |
219 | if (chip_pdata) |
220 | pdata = chip_pdata->watchdog; |
221 | else |
222 | pdata = NULL; |
223 | |
224 | if (pdata) { |
225 | reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK | |
226 | WM831X_WDOG_RST_SRC); |
227 | |
228 | reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT; |
229 | reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT; |
230 | reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT; |
231 | |
232 | ret = wm831x_reg_unlock(wm831x); |
233 | if (ret == 0) { |
234 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, val: reg); |
235 | wm831x_reg_lock(wm831x); |
236 | } else { |
237 | dev_err(wm831x->dev, |
238 | "Failed to unlock security key: %d\n" , ret); |
239 | return ret; |
240 | } |
241 | } |
242 | |
243 | return devm_watchdog_register_device(dev, &driver_data->wdt); |
244 | } |
245 | |
246 | static struct platform_driver wm831x_wdt_driver = { |
247 | .probe = wm831x_wdt_probe, |
248 | .driver = { |
249 | .name = "wm831x-watchdog" , |
250 | }, |
251 | }; |
252 | |
253 | module_platform_driver(wm831x_wdt_driver); |
254 | |
255 | MODULE_AUTHOR("Mark Brown" ); |
256 | MODULE_DESCRIPTION("WM831x Watchdog" ); |
257 | MODULE_LICENSE("GPL" ); |
258 | MODULE_ALIAS("platform:wm831x-watchdog" ); |
259 | |