da9052_wdt.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * System monitoring driver for DA9052 PMICs.
  4 *
  5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
  6 *
  7 * Author: Anthony Olech <Anthony.Olech@diasemi.com>
  8 *
  9 */
 10
 11#include <linux/module.h>
 12#include <linux/delay.h>
 13#include <linux/uaccess.h>
 14#include <linux/platform_device.h>
 15#include <linux/time.h>
 16#include <linux/watchdog.h>
 17#include <linux/types.h>
 18#include <linux/kernel.h>
 19#include <linux/jiffies.h>
 20
 21#include <linux/mfd/da9052/reg.h>
 22#include <linux/mfd/da9052/da9052.h>
 23
 24#define DA9052_DEF_TIMEOUT	4
 25#define DA9052_TWDMIN		256
 26
 27struct da9052_wdt_data {
 28	struct watchdog_device wdt;
 29	struct da9052 *da9052;
 30	unsigned long jpast;
 31};
 32
 33static bool nowayout = WATCHDOG_NOWAYOUT;
 34module_param(nowayout, bool, 0);
 35MODULE_PARM_DESC(nowayout,
 36		 "Watchdog cannot be stopped once started (default="
 37		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 38
 39static int timeout;
 40module_param(timeout, int, 0);
 41MODULE_PARM_DESC(timeout,
 42	"Watchdog timeout in seconds. (default = "
 43	__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
 44
 45static const struct {
 46	u8 reg_val;
 47	int time;  /* Seconds */
 48} da9052_wdt_maps[] = {
 49	{ 1, 2 },
 50	{ 2, 4 },
 51	{ 3, 8 },
 52	{ 4, 16 },
 53	{ 5, 32 },
 54	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
 55	{ 6, 65 },
 56	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
 57	{ 7, 131 },
 58};
 59
 60
 61static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
 62				  unsigned int timeout)
 63{
 64	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
 65	struct da9052 *da9052 = driver_data->da9052;
 66	int ret, i;
 67
 68	/*
 69	 * Disable the Watchdog timer before setting
 70	 * new time out.
 71	 */
 72	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 73				DA9052_CONTROLD_TWDSCALE, 0);
 74	if (ret < 0) {
 75		dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
 76			ret);
 77		return ret;
 78	}
 79	if (timeout) {
 80		/*
 81		 * To change the timeout, da9052 needs to
 82		 * be disabled for at least 150 us.
 83		 */
 84		udelay(150);
 85
 86		/* Set the desired timeout */
 87		for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
 88			if (da9052_wdt_maps[i].time == timeout)
 89				break;
 90
 91		if (i == ARRAY_SIZE(da9052_wdt_maps))
 92			ret = -EINVAL;
 93		else
 94			ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
 95						DA9052_CONTROLD_TWDSCALE,
 96						da9052_wdt_maps[i].reg_val);
 97		if (ret < 0) {
 98			dev_err(da9052->dev,
 99				"Failed to update timescale bit, %d\n", ret);
100			return ret;
101		}
102
103		wdt_dev->timeout = timeout;
104		driver_data->jpast = jiffies;
105	}
106
107	return 0;
108}
109
110static int da9052_wdt_start(struct watchdog_device *wdt_dev)
111{
112	return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
113}
114
115static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
116{
117	return da9052_wdt_set_timeout(wdt_dev, 0);
118}
119
120static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
121{
122	struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
123	struct da9052 *da9052 = driver_data->da9052;
124	unsigned long msec, jnow = jiffies;
125	int ret;
126
127	/*
128	 * We have a minimum time for watchdog window called TWDMIN. A write
129	 * to the watchdog before this elapsed time should cause an error.
130	 */
131	msec = (jnow - driver_data->jpast) * 1000/HZ;
132	if (msec < DA9052_TWDMIN)
133		mdelay(msec);
134
135	/* Reset the watchdog timer */
136	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
137				DA9052_CONTROLD_WATCHDOG, 1 << 7);
138	if (ret < 0)
139		return ret;
140
141	/*
142	 * FIXME: Reset the watchdog core, in general PMIC
143	 * is supposed to do this
144	 */
145	return da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
146				 DA9052_CONTROLD_WATCHDOG, 0 << 7);
147}
148
149static const struct watchdog_info da9052_wdt_info = {
150	.options =	WDIOF_SETTIMEOUT |
151			WDIOF_KEEPALIVEPING |
152			WDIOF_CARDRESET |
153			WDIOF_OVERHEAT |
154			WDIOF_POWERUNDER,
155	.identity	= "DA9052 Watchdog",
156};
157
158static const struct watchdog_ops da9052_wdt_ops = {
159	.owner = THIS_MODULE,
160	.start = da9052_wdt_start,
161	.stop = da9052_wdt_stop,
162	.ping = da9052_wdt_ping,
163	.set_timeout = da9052_wdt_set_timeout,
164};
165
166
167static int da9052_wdt_probe(struct platform_device *pdev)
168{
169	struct device *dev = &pdev->dev;
170	struct da9052 *da9052 = dev_get_drvdata(dev->parent);
171	struct da9052_wdt_data *driver_data;
172	struct watchdog_device *da9052_wdt;
173	int ret;
174
175	driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
176	if (!driver_data)
177		return -ENOMEM;
178	driver_data->da9052 = da9052;
179
180	da9052_wdt = &driver_data->wdt;
181
182	da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
183	da9052_wdt->min_hw_heartbeat_ms = DA9052_TWDMIN;
184	da9052_wdt->info = &da9052_wdt_info;
185	da9052_wdt->ops = &da9052_wdt_ops;
186	da9052_wdt->parent = dev;
187	watchdog_set_drvdata(da9052_wdt, driver_data);
188	watchdog_init_timeout(da9052_wdt, timeout, dev);
189	watchdog_set_nowayout(da9052_wdt, nowayout);
190
191	if (da9052->fault_log & DA9052_FAULTLOG_TWDERROR)
192		da9052_wdt->bootstatus |= WDIOF_CARDRESET;
193	if (da9052->fault_log & DA9052_FAULTLOG_TEMPOVER)
194		da9052_wdt->bootstatus |= WDIOF_OVERHEAT;
195	if (da9052->fault_log & DA9052_FAULTLOG_VDDFAULT)
196		da9052_wdt->bootstatus |= WDIOF_POWERUNDER;
197
198	ret = da9052_reg_read(da9052, DA9052_CONTROL_D_REG);
199	if (ret < 0)
200		return ret;
201
202	/* Check if FW enabled the watchdog */
203	if (ret & DA9052_CONTROLD_TWDSCALE) {
204		/* Ensure proper initialization */
205		da9052_wdt_start(da9052_wdt);
206		set_bit(WDOG_HW_RUNNING, &da9052_wdt->status);
207	}
208
209	return devm_watchdog_register_device(dev, &driver_data->wdt);
210}
211
212static struct platform_driver da9052_wdt_driver = {
213	.probe = da9052_wdt_probe,
214	.driver = {
215		.name	= "da9052-watchdog",
216	},
217};
218
219module_platform_driver(da9052_wdt_driver);
220
221MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
222MODULE_DESCRIPTION("DA9052 SM Device Driver");
223MODULE_LICENSE("GPL");
224MODULE_ALIAS("platform:da9052-watchdog");