2 * System monitoring driver for DA9055 PMICs.
4 * Copyright(c) 2012 Dialog Semiconductor Ltd.
6 * Author: David Dajun Chen <dchen@diasemi.com>
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.
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>
23 #include <linux/mfd/da9055/core.h>
24 #include <linux/mfd/da9055/reg.h>
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) ")");
32 #define DA9055_DEF_TIMEOUT 4
33 #define DA9055_TWDMIN 256
35 struct da9055_wdt_data {
36 struct watchdog_device wdt;
37 struct da9055 *da9055;
43 int user_time; /* In seconds */
44 } da9055_wdt_maps[] = {
51 { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */
53 { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */
57 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
60 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
61 struct da9055 *da9055 = driver_data->da9055;
64 for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
65 if (da9055_wdt_maps[i].user_time == timeout)
68 if (i == ARRAY_SIZE(da9055_wdt_maps))
71 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
73 da9055_wdt_maps[i].reg_val <<
74 DA9055_TWDSCALE_SHIFT);
77 "Failed to update timescale bit, %d\n", ret);
79 wdt_dev->timeout = timeout;
84 static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
86 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
87 struct da9055 *da9055 = driver_data->da9055;
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.
94 mdelay(DA9055_TWDMIN);
96 /* Reset the watchdog timer */
97 ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
98 DA9055_WATCHDOG_MASK, 1);
103 static void da9055_wdt_release_resources(struct kref *r)
105 struct da9055_wdt_data *driver_data =
106 container_of(r, struct da9055_wdt_data, kref);
111 static void da9055_wdt_ref(struct watchdog_device *wdt_dev)
113 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
115 kref_get(&driver_data->kref);
118 static void da9055_wdt_unref(struct watchdog_device *wdt_dev)
120 struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
122 kref_put(&driver_data->kref, da9055_wdt_release_resources);
125 static int da9055_wdt_start(struct watchdog_device *wdt_dev)
127 return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
130 static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
132 return da9055_wdt_set_timeout(wdt_dev, 0);
135 static struct watchdog_info da9055_wdt_info = {
136 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
137 .identity = "DA9055 Watchdog",
140 static const struct watchdog_ops da9055_wdt_ops = {
141 .owner = THIS_MODULE,
142 .start = da9055_wdt_start,
143 .stop = da9055_wdt_stop,
144 .ping = da9055_wdt_ping,
145 .set_timeout = da9055_wdt_set_timeout,
146 .ref = da9055_wdt_ref,
147 .unref = da9055_wdt_unref,
150 static int da9055_wdt_probe(struct platform_device *pdev)
152 struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent);
153 struct da9055_wdt_data *driver_data;
154 struct watchdog_device *da9055_wdt;
157 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
160 dev_err(da9055->dev, "Failed to allocate watchdog device\n");
164 driver_data->da9055 = da9055;
166 da9055_wdt = &driver_data->wdt;
168 da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
169 da9055_wdt->info = &da9055_wdt_info;
170 da9055_wdt->ops = &da9055_wdt_ops;
171 watchdog_set_nowayout(da9055_wdt, nowayout);
172 watchdog_set_drvdata(da9055_wdt, driver_data);
174 kref_init(&driver_data->kref);
176 ret = da9055_wdt_stop(da9055_wdt);
178 dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret);
182 dev_set_drvdata(&pdev->dev, driver_data);
184 ret = watchdog_register_device(&driver_data->wdt);
186 dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
193 static int da9055_wdt_remove(struct platform_device *pdev)
195 struct da9055_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
197 watchdog_unregister_device(&driver_data->wdt);
198 kref_put(&driver_data->kref, da9055_wdt_release_resources);
203 static struct platform_driver da9055_wdt_driver = {
204 .probe = da9055_wdt_probe,
205 .remove = da9055_wdt_remove,
207 .name = "da9055-watchdog",
211 module_platform_driver(da9055_wdt_driver);
213 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
214 MODULE_DESCRIPTION("DA9055 watchdog");
215 MODULE_LICENSE("GPL");
216 MODULE_ALIAS("platform:da9055-watchdog");