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