ts72xx_wdt.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Watchdog driver for Technologic Systems TS-72xx based SBCs
  4 * (TS-7200, TS-7250 and TS-7260). These boards have external
  5 * glue logic CPLD chip, which includes programmable watchdog
  6 * timer.
  7 *
  8 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
  9 *
 10 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
 11 *
 12 */
 13
 14#include <linux/platform_device.h>
 15#include <linux/mod_devicetable.h>
 16#include <linux/module.h>
 17#include <linux/watchdog.h>
 18#include <linux/io.h>
 19
 20#define TS72XX_WDT_DEFAULT_TIMEOUT	30
 21
 22static int timeout;
 23module_param(timeout, int, 0);
 24MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
 25
 26static bool nowayout = WATCHDOG_NOWAYOUT;
 27module_param(nowayout, bool, 0);
 28MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
 29
 30/* priv->control_reg */
 31#define TS72XX_WDT_CTRL_DISABLE		0x00
 32#define TS72XX_WDT_CTRL_250MS		0x01
 33#define TS72XX_WDT_CTRL_500MS		0x02
 34#define TS72XX_WDT_CTRL_1SEC		0x03
 35#define TS72XX_WDT_CTRL_RESERVED	0x04
 36#define TS72XX_WDT_CTRL_2SEC		0x05
 37#define TS72XX_WDT_CTRL_4SEC		0x06
 38#define TS72XX_WDT_CTRL_8SEC		0x07
 39
 40/* priv->feed_reg */
 41#define TS72XX_WDT_FEED_VAL		0x05
 42
 43struct ts72xx_wdt_priv {
 44	void __iomem	*control_reg;
 45	void __iomem	*feed_reg;
 46	struct watchdog_device wdd;
 47	unsigned char regval;
 48};
 49
 50static int ts72xx_wdt_start(struct watchdog_device *wdd)
 51{
 52	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 53
 54	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 55	writeb(priv->regval, priv->control_reg);
 56
 57	return 0;
 58}
 59
 60static int ts72xx_wdt_stop(struct watchdog_device *wdd)
 61{
 62	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 63
 64	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 65	writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
 66
 67	return 0;
 68}
 69
 70static int ts72xx_wdt_ping(struct watchdog_device *wdd)
 71{
 72	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 73
 74	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 75
 76	return 0;
 77}
 78
 79static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
 80{
 81	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 82
 83	if (to == 1) {
 84		priv->regval = TS72XX_WDT_CTRL_1SEC;
 85	} else if (to == 2) {
 86		priv->regval = TS72XX_WDT_CTRL_2SEC;
 87	} else if (to <= 4) {
 88		priv->regval = TS72XX_WDT_CTRL_4SEC;
 89		to = 4;
 90	} else {
 91		priv->regval = TS72XX_WDT_CTRL_8SEC;
 92		if (to <= 8)
 93			to = 8;
 94	}
 95
 96	wdd->timeout = to;
 97
 98	if (watchdog_active(wdd)) {
 99		ts72xx_wdt_stop(wdd);
100		ts72xx_wdt_start(wdd);
101	}
102
103	return 0;
104}
105
106static const struct watchdog_info ts72xx_wdt_ident = {
107	.options		= WDIOF_KEEPALIVEPING |
108				  WDIOF_SETTIMEOUT |
109				  WDIOF_MAGICCLOSE,
110	.firmware_version	= 1,
111	.identity		= "TS-72XX WDT",
112};
113
114static const struct watchdog_ops ts72xx_wdt_ops = {
115	.owner		= THIS_MODULE,
116	.start		= ts72xx_wdt_start,
117	.stop		= ts72xx_wdt_stop,
118	.ping		= ts72xx_wdt_ping,
119	.set_timeout	= ts72xx_wdt_settimeout,
120};
121
122static int ts72xx_wdt_probe(struct platform_device *pdev)
123{
124	struct device *dev = &pdev->dev;
125	struct ts72xx_wdt_priv *priv;
126	struct watchdog_device *wdd;
127	int ret;
128
129	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
130	if (!priv)
131		return -ENOMEM;
132
133	priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
134	if (IS_ERR(priv->control_reg))
135		return PTR_ERR(priv->control_reg);
136
137	priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
138	if (IS_ERR(priv->feed_reg))
139		return PTR_ERR(priv->feed_reg);
140
141	wdd = &priv->wdd;
142	wdd->info = &ts72xx_wdt_ident;
143	wdd->ops = &ts72xx_wdt_ops;
144	wdd->min_timeout = 1;
145	wdd->max_hw_heartbeat_ms = 8000;
146	wdd->parent = dev;
147
148	watchdog_set_nowayout(wdd, nowayout);
149
150	wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
151	watchdog_init_timeout(wdd, timeout, dev);
152
153	watchdog_set_drvdata(wdd, priv);
154
155	ret = devm_watchdog_register_device(dev, wdd);
156	if (ret)
157		return ret;
158
159	dev_info(dev, "TS-72xx Watchdog driver\n");
160
161	return 0;
162}
163
164static const struct of_device_id ts72xx_wdt_of_ids[] = {
165	{ .compatible = "technologic,ts7200-wdt" },
166	{ /* sentinel */ }
167};
168MODULE_DEVICE_TABLE(of, ts72xx_wdt_of_ids);
169
170static struct platform_driver ts72xx_wdt_driver = {
171	.probe		= ts72xx_wdt_probe,
172	.driver		= {
173		.name	= "ts72xx-wdt",
174		.of_match_table = ts72xx_wdt_of_ids,
175	},
176};
177
178module_platform_driver(ts72xx_wdt_driver);
179
180MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
181MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
182MODULE_LICENSE("GPL");
183MODULE_ALIAS("platform:ts72xx-wdt");