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7a7cb009 T |
1 | /* |
2 | * da9062_wdt.c - WDT device driver for DA9062 | |
3 | * Copyright (C) 2015 Dialog Semiconductor Ltd. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version 2 | |
8 | * of the License, or (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/watchdog.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/uaccess.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/jiffies.h> | |
24 | #include <linux/mfd/da9062/registers.h> | |
25 | #include <linux/mfd/da9062/core.h> | |
26 | #include <linux/regmap.h> | |
27 | #include <linux/of.h> | |
28 | ||
29 | static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 }; | |
30 | #define DA9062_TWDSCALE_DISABLE 0 | |
31 | #define DA9062_TWDSCALE_MIN 1 | |
32 | #define DA9062_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) | |
33 | #define DA9062_WDT_MIN_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MIN] | |
34 | #define DA9062_WDT_MAX_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX] | |
35 | #define DA9062_WDG_DEFAULT_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX-1] | |
36 | #define DA9062_RESET_PROTECTION_MS 300 | |
37 | ||
38 | struct da9062_watchdog { | |
39 | struct da9062 *hw; | |
40 | struct watchdog_device wdtdev; | |
41 | unsigned long j_time_stamp; | |
42 | }; | |
43 | ||
44 | static void da9062_set_window_start(struct da9062_watchdog *wdt) | |
45 | { | |
46 | wdt->j_time_stamp = jiffies; | |
47 | } | |
48 | ||
49 | static void da9062_apply_window_protection(struct da9062_watchdog *wdt) | |
50 | { | |
51 | unsigned long delay = msecs_to_jiffies(DA9062_RESET_PROTECTION_MS); | |
52 | unsigned long timeout = wdt->j_time_stamp + delay; | |
53 | unsigned long now = jiffies; | |
54 | unsigned int diff_ms; | |
55 | ||
56 | /* if time-limit has not elapsed then wait for remainder */ | |
57 | if (time_before(now, timeout)) { | |
58 | diff_ms = jiffies_to_msecs(timeout-now); | |
59 | dev_dbg(wdt->hw->dev, | |
60 | "Kicked too quickly. Delaying %u msecs\n", diff_ms); | |
61 | msleep(diff_ms); | |
62 | } | |
63 | } | |
64 | ||
65 | static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs) | |
66 | { | |
67 | unsigned int i; | |
68 | ||
69 | for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) { | |
70 | if (wdt_timeout[i] >= secs) | |
71 | return i; | |
72 | } | |
73 | ||
74 | return DA9062_TWDSCALE_MAX; | |
75 | } | |
76 | ||
77 | static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt) | |
78 | { | |
79 | int ret; | |
80 | ||
81 | da9062_apply_window_protection(wdt); | |
82 | ||
83 | ret = regmap_update_bits(wdt->hw->regmap, | |
84 | DA9062AA_CONTROL_F, | |
85 | DA9062AA_WATCHDOG_MASK, | |
86 | DA9062AA_WATCHDOG_MASK); | |
87 | ||
88 | da9062_set_window_start(wdt); | |
89 | ||
90 | return ret; | |
91 | } | |
92 | ||
93 | static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt, | |
94 | unsigned int regval) | |
95 | { | |
96 | struct da9062 *chip = wdt->hw; | |
97 | int ret; | |
98 | ||
99 | ret = da9062_reset_watchdog_timer(wdt); | |
100 | if (ret) | |
101 | return ret; | |
102 | ||
103 | return regmap_update_bits(chip->regmap, | |
104 | DA9062AA_CONTROL_D, | |
105 | DA9062AA_TWDSCALE_MASK, | |
106 | regval); | |
107 | } | |
108 | ||
109 | static int da9062_wdt_start(struct watchdog_device *wdd) | |
110 | { | |
111 | struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); | |
112 | unsigned int selector; | |
113 | int ret; | |
114 | ||
115 | selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout); | |
116 | ret = da9062_wdt_update_timeout_register(wdt, selector); | |
117 | if (ret) | |
118 | dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n", | |
119 | ret); | |
120 | ||
121 | return ret; | |
122 | } | |
123 | ||
124 | static int da9062_wdt_stop(struct watchdog_device *wdd) | |
125 | { | |
126 | struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); | |
127 | int ret; | |
128 | ||
129 | ret = da9062_reset_watchdog_timer(wdt); | |
130 | if (ret) { | |
131 | dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n", | |
132 | ret); | |
133 | return ret; | |
134 | } | |
135 | ||
136 | ret = regmap_update_bits(wdt->hw->regmap, | |
137 | DA9062AA_CONTROL_D, | |
138 | DA9062AA_TWDSCALE_MASK, | |
139 | DA9062_TWDSCALE_DISABLE); | |
140 | if (ret) | |
141 | dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n", | |
142 | ret); | |
143 | ||
144 | return ret; | |
145 | } | |
146 | ||
147 | static int da9062_wdt_ping(struct watchdog_device *wdd) | |
148 | { | |
149 | struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); | |
150 | int ret; | |
151 | ||
152 | ret = da9062_reset_watchdog_timer(wdt); | |
153 | if (ret) | |
154 | dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n", | |
155 | ret); | |
156 | ||
157 | return ret; | |
158 | } | |
159 | ||
160 | static int da9062_wdt_set_timeout(struct watchdog_device *wdd, | |
161 | unsigned int timeout) | |
162 | { | |
163 | struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); | |
164 | unsigned int selector; | |
165 | int ret; | |
166 | ||
167 | selector = da9062_wdt_timeout_to_sel(timeout); | |
168 | ret = da9062_wdt_update_timeout_register(wdt, selector); | |
169 | if (ret) | |
170 | dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n", | |
171 | ret); | |
172 | else | |
173 | wdd->timeout = wdt_timeout[selector]; | |
174 | ||
175 | return ret; | |
176 | } | |
177 | ||
178 | static const struct watchdog_info da9062_watchdog_info = { | |
179 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
180 | .identity = "DA9062 WDT", | |
181 | }; | |
182 | ||
183 | static const struct watchdog_ops da9062_watchdog_ops = { | |
184 | .owner = THIS_MODULE, | |
185 | .start = da9062_wdt_start, | |
186 | .stop = da9062_wdt_stop, | |
187 | .ping = da9062_wdt_ping, | |
188 | .set_timeout = da9062_wdt_set_timeout, | |
189 | }; | |
190 | ||
191 | static int da9062_wdt_probe(struct platform_device *pdev) | |
192 | { | |
193 | int ret; | |
194 | struct da9062 *chip; | |
195 | struct da9062_watchdog *wdt; | |
196 | ||
197 | chip = dev_get_drvdata(pdev->dev.parent); | |
198 | if (!chip) | |
199 | return -EINVAL; | |
200 | ||
201 | wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); | |
202 | if (!wdt) | |
203 | return -ENOMEM; | |
204 | ||
205 | wdt->hw = chip; | |
206 | ||
207 | wdt->wdtdev.info = &da9062_watchdog_info; | |
208 | wdt->wdtdev.ops = &da9062_watchdog_ops; | |
209 | wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT; | |
210 | wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT; | |
211 | wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT; | |
212 | wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS; | |
6551881c | 213 | wdt->wdtdev.parent = &pdev->dev; |
7a7cb009 T |
214 | |
215 | watchdog_set_drvdata(&wdt->wdtdev, wdt); | |
216 | dev_set_drvdata(&pdev->dev, wdt); | |
217 | ||
218 | ret = watchdog_register_device(&wdt->wdtdev); | |
219 | if (ret < 0) { | |
220 | dev_err(wdt->hw->dev, | |
221 | "watchdog registration failed (%d)\n", ret); | |
222 | return ret; | |
223 | } | |
224 | ||
225 | da9062_set_window_start(wdt); | |
226 | ||
227 | ret = da9062_wdt_ping(&wdt->wdtdev); | |
228 | if (ret < 0) | |
229 | watchdog_unregister_device(&wdt->wdtdev); | |
230 | ||
231 | return ret; | |
232 | } | |
233 | ||
234 | static int da9062_wdt_remove(struct platform_device *pdev) | |
235 | { | |
236 | struct da9062_watchdog *wdt = dev_get_drvdata(&pdev->dev); | |
237 | ||
238 | watchdog_unregister_device(&wdt->wdtdev); | |
239 | return 0; | |
240 | } | |
241 | ||
242 | static struct platform_driver da9062_wdt_driver = { | |
243 | .probe = da9062_wdt_probe, | |
244 | .remove = da9062_wdt_remove, | |
245 | .driver = { | |
246 | .name = "da9062-watchdog", | |
247 | }, | |
248 | }; | |
249 | module_platform_driver(da9062_wdt_driver); | |
250 | ||
251 | MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>"); | |
252 | MODULE_DESCRIPTION("WDT device driver for Dialog DA9062"); | |
253 | MODULE_LICENSE("GPL"); | |
254 | MODULE_ALIAS("platform:da9062-watchdog"); |