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1 | /* | |
2 | * System monitoring driver for DA9055 PMICs. | |
3 | * | |
4 | * Copyright(c) 2012 Dialog Semiconductor Ltd. | |
5 | * | |
6 | * Author: David Dajun Chen <dchen@diasemi.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | */ | |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/watchdog.h> | |
21 | #include <linux/delay.h> | |
22 | ||
23 | #include <linux/mfd/da9055/core.h> | |
24 | #include <linux/mfd/da9055/reg.h> | |
25 | ||
26 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
27 | module_param(nowayout, bool, 0); | |
28 | MODULE_PARM_DESC(nowayout, | |
29 | "Watchdog cannot be stopped once started (default=" | |
30 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
31 | ||
32 | #define DA9055_DEF_TIMEOUT 4 | |
33 | #define DA9055_TWDMIN 256 | |
34 | ||
35 | struct da9055_wdt_data { | |
36 | struct watchdog_device wdt; | |
37 | struct da9055 *da9055; | |
38 | struct kref kref; | |
39 | }; | |
40 | ||
41 | static const struct { | |
42 | u8 reg_val; | |
43 | int user_time; /* In seconds */ | |
44 | } da9055_wdt_maps[] = { | |
45 | { 0, 0 }, | |
46 | { 1, 2 }, | |
47 | { 2, 4 }, | |
48 | { 3, 8 }, | |
49 | { 4, 16 }, | |
50 | { 5, 32 }, | |
51 | { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ | |
52 | { 6, 65 }, | |
53 | { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ | |
54 | { 7, 131 }, | |
55 | }; | |
56 | ||
57 | static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
58 | unsigned int timeout) | |
59 | { | |
60 | struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); | |
61 | struct da9055 *da9055 = driver_data->da9055; | |
62 | int ret, i; | |
63 | ||
64 | for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++) | |
65 | if (da9055_wdt_maps[i].user_time == timeout) | |
66 | break; | |
67 | ||
68 | if (i == ARRAY_SIZE(da9055_wdt_maps)) | |
69 | ret = -EINVAL; | |
70 | else | |
71 | ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, | |
72 | DA9055_TWDSCALE_MASK, | |
73 | da9055_wdt_maps[i].reg_val << | |
74 | DA9055_TWDSCALE_SHIFT); | |
75 | if (ret < 0) | |
76 | dev_err(da9055->dev, | |
77 | "Failed to update timescale bit, %d\n", ret); | |
78 | ||
79 | wdt_dev->timeout = timeout; | |
80 | ||
81 | return ret; | |
82 | } | |
83 | ||
84 | static int da9055_wdt_ping(struct watchdog_device *wdt_dev) | |
85 | { | |
86 | struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); | |
87 | struct da9055 *da9055 = driver_data->da9055; | |
88 | int ret; | |
89 | ||
90 | /* | |
91 | * We have a minimum time for watchdog window called TWDMIN. A write | |
92 | * to the watchdog before this elapsed time will cause an error. | |
93 | */ | |
94 | mdelay(DA9055_TWDMIN); | |
95 | ||
96 | /* Reset the watchdog timer */ | |
97 | ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_E, | |
98 | DA9055_WATCHDOG_MASK, 1); | |
99 | ||
100 | return ret; | |
101 | } | |
102 | ||
103 | static void da9055_wdt_release_resources(struct kref *r) | |
104 | { | |
105 | } | |
106 | ||
107 | static void da9055_wdt_ref(struct watchdog_device *wdt_dev) | |
108 | { | |
109 | struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); | |
110 | ||
111 | kref_get(&driver_data->kref); | |
112 | } | |
113 | ||
114 | static void da9055_wdt_unref(struct watchdog_device *wdt_dev) | |
115 | { | |
116 | struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); | |
117 | ||
118 | kref_put(&driver_data->kref, da9055_wdt_release_resources); | |
119 | } | |
120 | ||
121 | static int da9055_wdt_start(struct watchdog_device *wdt_dev) | |
122 | { | |
123 | return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout); | |
124 | } | |
125 | ||
126 | static int da9055_wdt_stop(struct watchdog_device *wdt_dev) | |
127 | { | |
128 | return da9055_wdt_set_timeout(wdt_dev, 0); | |
129 | } | |
130 | ||
131 | static struct watchdog_info da9055_wdt_info = { | |
132 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
133 | .identity = "DA9055 Watchdog", | |
134 | }; | |
135 | ||
136 | static const struct watchdog_ops da9055_wdt_ops = { | |
137 | .owner = THIS_MODULE, | |
138 | .start = da9055_wdt_start, | |
139 | .stop = da9055_wdt_stop, | |
140 | .ping = da9055_wdt_ping, | |
141 | .set_timeout = da9055_wdt_set_timeout, | |
142 | .ref = da9055_wdt_ref, | |
143 | .unref = da9055_wdt_unref, | |
144 | }; | |
145 | ||
146 | static int da9055_wdt_probe(struct platform_device *pdev) | |
147 | { | |
148 | struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent); | |
149 | struct da9055_wdt_data *driver_data; | |
150 | struct watchdog_device *da9055_wdt; | |
151 | int ret; | |
152 | ||
153 | driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), | |
154 | GFP_KERNEL); | |
155 | if (!driver_data) { | |
156 | dev_err(da9055->dev, "Failed to allocate watchdog device\n"); | |
157 | return -ENOMEM; | |
158 | } | |
159 | ||
160 | driver_data->da9055 = da9055; | |
161 | ||
162 | da9055_wdt = &driver_data->wdt; | |
163 | ||
164 | da9055_wdt->timeout = DA9055_DEF_TIMEOUT; | |
165 | da9055_wdt->info = &da9055_wdt_info; | |
166 | da9055_wdt->ops = &da9055_wdt_ops; | |
167 | watchdog_set_nowayout(da9055_wdt, nowayout); | |
168 | watchdog_set_drvdata(da9055_wdt, driver_data); | |
169 | ||
170 | kref_init(&driver_data->kref); | |
171 | ||
172 | ret = da9055_wdt_stop(da9055_wdt); | |
173 | if (ret < 0) { | |
174 | dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret); | |
175 | goto err; | |
176 | } | |
177 | ||
178 | dev_set_drvdata(&pdev->dev, driver_data); | |
179 | ||
180 | ret = watchdog_register_device(&driver_data->wdt); | |
181 | if (ret != 0) | |
182 | dev_err(da9055->dev, "watchdog_register_device() failed: %d\n", | |
183 | ret); | |
184 | ||
185 | err: | |
186 | return ret; | |
187 | } | |
188 | ||
189 | static int da9055_wdt_remove(struct platform_device *pdev) | |
190 | { | |
191 | struct da9055_wdt_data *driver_data = dev_get_drvdata(&pdev->dev); | |
192 | ||
193 | watchdog_unregister_device(&driver_data->wdt); | |
194 | kref_put(&driver_data->kref, da9055_wdt_release_resources); | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | static struct platform_driver da9055_wdt_driver = { | |
200 | .probe = da9055_wdt_probe, | |
201 | .remove = da9055_wdt_remove, | |
202 | .driver = { | |
203 | .name = "da9055-watchdog", | |
204 | }, | |
205 | }; | |
206 | ||
207 | module_platform_driver(da9055_wdt_driver); | |
208 | ||
209 | MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>"); | |
210 | MODULE_DESCRIPTION("DA9055 watchdog"); | |
211 | MODULE_LICENSE("GPL"); | |
212 | MODULE_ALIAS("platform:da9055-watchdog"); |