drivers/watchdog/da9055_wdt.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * System monitoring driver for DA9055 PMICs.
0004  *
0005  * Copyright(c) 2012 Dialog Semiconductor Ltd.
0006  *
0007  * Author: David Dajun Chen <dchen@diasemi.com>
0008  *
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/types.h>
0013 #include <linux/kernel.h>
0014 #include <linux/slab.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/watchdog.h>
0017 #include <linux/delay.h>
0018
0019 #include <linux/mfd/da9055/core.h>
0020 #include <linux/mfd/da9055/reg.h>
0021
0022 static bool nowayout = WATCHDOG_NOWAYOUT;
0023 module_param(nowayout, bool, 0);
0024 MODULE_PARM_DESC(nowayout,
0025          "Watchdog cannot be stopped once started (default="
0026          __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0027
0028 #define DA9055_DEF_TIMEOUT  4
0029 #define DA9055_TWDMIN       256
0030
0031 struct da9055_wdt_data {
0032     struct watchdog_device wdt;
0033     struct da9055 *da9055;
0034 };
0035
0036 static const struct {
0037     u8 reg_val;
0038     int user_time;  /* In seconds */
0039 } da9055_wdt_maps[] = {
0040     { 0, 0 },
0041     { 1, 2 },
0042     { 2, 4 },
0043     { 3, 8 },
0044     { 4, 16 },
0045     { 5, 32 },
0046     { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
0047     { 6, 65 },
0048     { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
0049     { 7, 131 },
0050 };
0051
0052 static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
0053                   unsigned int timeout)
0054 {
0055     struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
0056     struct da9055 *da9055 = driver_data->da9055;
0057     int ret, i;
0058
0059     for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
0060         if (da9055_wdt_maps[i].user_time == timeout)
0061             break;
0062
0063     if (i == ARRAY_SIZE(da9055_wdt_maps))
0064         ret = -EINVAL;
0065     else
0066         ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
0067                     DA9055_TWDSCALE_MASK,
0068                     da9055_wdt_maps[i].reg_val <<
0069                     DA9055_TWDSCALE_SHIFT);
0070     if (ret < 0) {
0071         dev_err(da9055->dev,
0072             "Failed to update timescale bit, %d\n", ret);
0073         return ret;
0074     }
0075
0076     wdt_dev->timeout = timeout;
0077
0078     return 0;
0079 }
0080
0081 static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
0082 {
0083     struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
0084     struct da9055 *da9055 = driver_data->da9055;
0085
0086     /*
0087      * We have a minimum time for watchdog window called TWDMIN. A write
0088      * to the watchdog before this elapsed time will cause an error.
0089      */
0090     mdelay(DA9055_TWDMIN);
0091
0092     /* Reset the watchdog timer */
0093     return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
0094                  DA9055_WATCHDOG_MASK, 1);
0095 }
0096
0097 static int da9055_wdt_start(struct watchdog_device *wdt_dev)
0098 {
0099     return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
0100 }
0101
0102 static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
0103 {
0104     return da9055_wdt_set_timeout(wdt_dev, 0);
0105 }
0106
0107 static const struct watchdog_info da9055_wdt_info = {
0108     .options    = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
0109     .identity   = "DA9055 Watchdog",
0110 };
0111
0112 static const struct watchdog_ops da9055_wdt_ops = {
0113     .owner = THIS_MODULE,
0114     .start = da9055_wdt_start,
0115     .stop = da9055_wdt_stop,
0116     .ping = da9055_wdt_ping,
0117     .set_timeout = da9055_wdt_set_timeout,
0118 };
0119
0120 static int da9055_wdt_probe(struct platform_device *pdev)
0121 {
0122     struct device *dev = &pdev->dev;
0123     struct da9055 *da9055 = dev_get_drvdata(dev->parent);
0124     struct da9055_wdt_data *driver_data;
0125     struct watchdog_device *da9055_wdt;
0126     int ret;
0127
0128     driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
0129     if (!driver_data)
0130         return -ENOMEM;
0131
0132     driver_data->da9055 = da9055;
0133
0134     da9055_wdt = &driver_data->wdt;
0135
0136     da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
0137     da9055_wdt->info = &da9055_wdt_info;
0138     da9055_wdt->ops = &da9055_wdt_ops;
0139     da9055_wdt->parent = dev;
0140     watchdog_set_nowayout(da9055_wdt, nowayout);
0141     watchdog_set_drvdata(da9055_wdt, driver_data);
0142
0143     ret = da9055_wdt_stop(da9055_wdt);
0144     if (ret < 0) {
0145         dev_err(dev, "Failed to stop watchdog, %d\n", ret);
0146         return ret;
0147     }
0148
0149     ret = devm_watchdog_register_device(dev, &driver_data->wdt);
0150     if (ret != 0)
0151         dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
0152             ret);
0153
0154     return ret;
0155 }
0156
0157 static struct platform_driver da9055_wdt_driver = {
0158     .probe = da9055_wdt_probe,
0159     .driver = {
0160         .name   = "da9055-watchdog",
0161     },
0162 };
0163
0164 module_platform_driver(da9055_wdt_driver);
0165
0166 MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
0167 MODULE_DESCRIPTION("DA9055 watchdog");
0168 MODULE_LICENSE("GPL");
0169 MODULE_ALIAS("platform:da9055-watchdog");