1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (C) STMicroelectronics 2018
  3// Author: Pascal Paillet <p.paillet@st.com> for STMicroelectronics.
  4
  5#include <linux/kernel.h>
  6#include <linux/mfd/stpmic1.h>
  7#include <linux/module.h>
  8#include <linux/platform_device.h>
  9#include <linux/of.h>
 10#include <linux/regmap.h>
 11#include <linux/slab.h>
 12#include <linux/watchdog.h>
 13
 14/* WATCHDOG CONTROL REGISTER bit */
 15#define WDT_START		BIT(0)
 16#define WDT_PING		BIT(1)
 17#define WDT_START_MASK		BIT(0)
 18#define WDT_PING_MASK		BIT(1)
 19#define WDT_STOP		0
 20
 21#define PMIC_WDT_MIN_TIMEOUT 1
 22#define PMIC_WDT_MAX_TIMEOUT 256
 23#define PMIC_WDT_DEFAULT_TIMEOUT 30
 24
 25static bool nowayout = WATCHDOG_NOWAYOUT;
 26module_param(nowayout, bool, 0);
 27MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 28		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 29
 30struct stpmic1_wdt {
 31	struct stpmic1 *pmic;
 32	struct watchdog_device wdtdev;
 33};
 34
 35static int pmic_wdt_start(struct watchdog_device *wdd)
 36{
 37	struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
 38
 39	return regmap_update_bits(wdt->pmic->regmap,
 40				  WCHDG_CR, WDT_START_MASK, WDT_START);
 41}
 42
 43static int pmic_wdt_stop(struct watchdog_device *wdd)
 44{
 45	struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
 46
 47	return regmap_update_bits(wdt->pmic->regmap,
 48				  WCHDG_CR, WDT_START_MASK, WDT_STOP);
 49}
 50
 51static int pmic_wdt_ping(struct watchdog_device *wdd)
 52{
 53	struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
 54
 55	return regmap_update_bits(wdt->pmic->regmap,
 56				  WCHDG_CR, WDT_PING_MASK, WDT_PING);
 57}
 58
 59static int pmic_wdt_set_timeout(struct watchdog_device *wdd,
 60				unsigned int timeout)
 61{
 62	struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
 63
 64	wdd->timeout = timeout;
 65	/* timeout is equal to register value + 1 */
 66	return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
 67}
 68
 69static const struct watchdog_info pmic_watchdog_info = {
 70	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 71	.identity = "STPMIC1 PMIC Watchdog",
 72};
 73
 74static const struct watchdog_ops pmic_watchdog_ops = {
 75	.owner = THIS_MODULE,
 76	.start = pmic_wdt_start,
 77	.stop = pmic_wdt_stop,
 78	.ping = pmic_wdt_ping,
 79	.set_timeout = pmic_wdt_set_timeout,
 80};
 81
 82static int pmic_wdt_probe(struct platform_device *pdev)
 83{
 84	struct device *dev = &pdev->dev;
 85	int ret;
 86	struct stpmic1 *pmic;
 87	struct stpmic1_wdt *wdt;
 88
 89	if (!dev->parent)
 90		return -EINVAL;
 91
 92	pmic = dev_get_drvdata(dev->parent);
 93	if (!pmic)
 94		return -EINVAL;
 95
 96	wdt = devm_kzalloc(dev, sizeof(struct stpmic1_wdt), GFP_KERNEL);
 97	if (!wdt)
 98		return -ENOMEM;
 99
100	wdt->pmic = pmic;
101
102	wdt->wdtdev.info = &pmic_watchdog_info;
103	wdt->wdtdev.ops = &pmic_watchdog_ops;
104	wdt->wdtdev.min_timeout = PMIC_WDT_MIN_TIMEOUT;
105	wdt->wdtdev.max_timeout = PMIC_WDT_MAX_TIMEOUT;
106	wdt->wdtdev.parent = dev;
107
108	wdt->wdtdev.timeout = PMIC_WDT_DEFAULT_TIMEOUT;
109	watchdog_init_timeout(&wdt->wdtdev, 0, dev);
110
111	watchdog_set_nowayout(&wdt->wdtdev, nowayout);
112	watchdog_set_drvdata(&wdt->wdtdev, wdt);
113
114	ret = devm_watchdog_register_device(dev, &wdt->wdtdev);
115	if (ret)
116		return ret;
117
118	dev_dbg(wdt->pmic->dev, "PMIC Watchdog driver probed\n");
119	return 0;
120}
121
122static const struct of_device_id of_pmic_wdt_match[] = {
123	{ .compatible = "st,stpmic1-wdt" },
124	{ },
125};
126
127MODULE_DEVICE_TABLE(of, of_pmic_wdt_match);
128
129static struct platform_driver stpmic1_wdt_driver = {
130	.probe = pmic_wdt_probe,
131	.driver = {
132		.name = "stpmic1-wdt",
133		.of_match_table = of_pmic_wdt_match,
134	},
135};
136module_platform_driver(stpmic1_wdt_driver);
137
138MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
139MODULE_AUTHOR("Pascal Paillet <p.paillet@st.com>");
140MODULE_LICENSE("GPL v2");