1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * System monitoring driver for DA9055 PMICs.
  4 *
  5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
  6 *
  7 * Author: David Dajun Chen <dchen@diasemi.com>
  8 *
  9 */
 10
 11#include <linux/module.h>
 12#include <linux/types.h>
 13#include <linux/kernel.h>
 14#include <linux/slab.h>
 15#include <linux/platform_device.h>
 16#include <linux/watchdog.h>
 17#include <linux/delay.h>
 18
 19#include <linux/mfd/da9055/core.h>
 20#include <linux/mfd/da9055/reg.h>
 21
 22static bool nowayout = WATCHDOG_NOWAYOUT;
 23module_param(nowayout, bool, 0);
 24MODULE_PARM_DESC(nowayout,
 25		 "Watchdog cannot be stopped once started (default="
 26		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 27
 28#define DA9055_DEF_TIMEOUT	4
 29#define DA9055_TWDMIN		256
 30
 31struct da9055_wdt_data {
 32	struct watchdog_device wdt;
 33	struct da9055 *da9055;
 34};
 35
 36static const struct {
 37	u8 reg_val;
 38	int user_time;  /* In seconds */
 39} da9055_wdt_maps[] = {
 40	{ 0, 0 },
 41	{ 1, 2 },
 42	{ 2, 4 },
 43	{ 3, 8 },
 44	{ 4, 16 },
 45	{ 5, 32 },
 46	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
 47	{ 6, 65 },
 48	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
 49	{ 7, 131 },
 50};
 51
 52static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
 53				  unsigned int timeout)
 54{
 55	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 56	struct da9055 *da9055 = driver_data->da9055;
 57	int ret, i;
 58
 59	for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
 60		if (da9055_wdt_maps[i].user_time == timeout)
 61			break;
 62
 63	if (i == ARRAY_SIZE(da9055_wdt_maps))
 64		ret = -EINVAL;
 65	else
 66		ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
 67					DA9055_TWDSCALE_MASK,
 68					da9055_wdt_maps[i].reg_val <<
 69					DA9055_TWDSCALE_SHIFT);
 70	if (ret < 0) {
 71		dev_err(da9055->dev,
 72			"Failed to update timescale bit, %d\n", ret);
 73		return ret;
 74	}
 75
 76	wdt_dev->timeout = timeout;
 77
 78	return 0;
 79}
 80
 81static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
 82{
 83	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 84	struct da9055 *da9055 = driver_data->da9055;
 85
 86	/*
 87	 * We have a minimum time for watchdog window called TWDMIN. A write
 88	 * to the watchdog before this elapsed time will cause an error.
 89	 */
 90	mdelay(DA9055_TWDMIN);
 91
 92	/* Reset the watchdog timer */
 93	return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
 94				 DA9055_WATCHDOG_MASK, 1);
 95}
 96
 97static int da9055_wdt_start(struct watchdog_device *wdt_dev)
 98{
 99	return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
100}
101
102static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
103{
104	return da9055_wdt_set_timeout(wdt_dev, 0);
105}
106
107static const struct watchdog_info da9055_wdt_info = {
108	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
109	.identity	= "DA9055 Watchdog",
110};
111
112static const struct watchdog_ops da9055_wdt_ops = {
113	.owner = THIS_MODULE,
114	.start = da9055_wdt_start,
115	.stop = da9055_wdt_stop,
116	.ping = da9055_wdt_ping,
117	.set_timeout = da9055_wdt_set_timeout,
118};
119
120static int da9055_wdt_probe(struct platform_device *pdev)
121{
122	struct device *dev = &pdev->dev;
123	struct da9055 *da9055 = dev_get_drvdata(dev->parent);
124	struct da9055_wdt_data *driver_data;
125	struct watchdog_device *da9055_wdt;
126	int ret;
127
128	driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
129	if (!driver_data)
130		return -ENOMEM;
131
132	driver_data->da9055 = da9055;
133
134	da9055_wdt = &driver_data->wdt;
135
136	da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
137	da9055_wdt->info = &da9055_wdt_info;
138	da9055_wdt->ops = &da9055_wdt_ops;
139	da9055_wdt->parent = dev;
140	watchdog_set_nowayout(da9055_wdt, nowayout);
141	watchdog_set_drvdata(da9055_wdt, driver_data);
142
143	ret = da9055_wdt_stop(da9055_wdt);
144	if (ret < 0) {
145		dev_err(dev, "Failed to stop watchdog, %d\n", ret);
146		return ret;
147	}
148
149	ret = devm_watchdog_register_device(dev, &driver_data->wdt);
150	if (ret != 0)
151		dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
152			ret);
153
154	return ret;
155}
156
157static struct platform_driver da9055_wdt_driver = {
158	.probe = da9055_wdt_probe,
159	.driver = {
160		.name	= "da9055-watchdog",
161	},
162};
163
164module_platform_driver(da9055_wdt_driver);
165
166MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
167MODULE_DESCRIPTION("DA9055 watchdog");
168MODULE_LICENSE("GPL");
169MODULE_ALIAS("platform:da9055-watchdog");