1/*
2 * Watchdog driver for Technologic Systems TS-72xx based SBCs
3 * (TS-7200, TS-7250 and TS-7260). These boards have external
4 * glue logic CPLD chip, which includes programmable watchdog
5 * timer.
6 *
7 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
8 *
9 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
10 *
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 */
15
16#include <linux/platform_device.h>
17#include <linux/module.h>
18#include <linux/watchdog.h>
19#include <linux/io.h>
20
21#define TS72XX_WDT_DEFAULT_TIMEOUT	30
22
23static int timeout;
24module_param(timeout, int, 0);
25MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
26
27static bool nowayout = WATCHDOG_NOWAYOUT;
28module_param(nowayout, bool, 0);
29MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
30
31/* priv->control_reg */
32#define TS72XX_WDT_CTRL_DISABLE		0x00
33#define TS72XX_WDT_CTRL_250MS		0x01
34#define TS72XX_WDT_CTRL_500MS		0x02
35#define TS72XX_WDT_CTRL_1SEC		0x03
36#define TS72XX_WDT_CTRL_RESERVED	0x04
37#define TS72XX_WDT_CTRL_2SEC		0x05
38#define TS72XX_WDT_CTRL_4SEC		0x06
39#define TS72XX_WDT_CTRL_8SEC		0x07
40
41/* priv->feed_reg */
42#define TS72XX_WDT_FEED_VAL		0x05
43
44struct ts72xx_wdt_priv {
45	void __iomem	*control_reg;
46	void __iomem	*feed_reg;
47	struct watchdog_device wdd;
48	unsigned char regval;
49};
50
51static int ts72xx_wdt_start(struct watchdog_device *wdd)
52{
53	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
54
55	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
56	writeb(priv->regval, priv->control_reg);
57
58	return 0;
59}
60
61static int ts72xx_wdt_stop(struct watchdog_device *wdd)
62{
63	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
64
65	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
66	writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
67
68	return 0;
69}
70
71static int ts72xx_wdt_ping(struct watchdog_device *wdd)
72{
73	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
74
75	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
76
77	return 0;
78}
79
80static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
81{
82	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
83
84	if (to == 1) {
85		priv->regval = TS72XX_WDT_CTRL_1SEC;
86	} else if (to == 2) {
87		priv->regval = TS72XX_WDT_CTRL_2SEC;
88	} else if (to <= 4) {
89		priv->regval = TS72XX_WDT_CTRL_4SEC;
90		to = 4;
91	} else {
92		priv->regval = TS72XX_WDT_CTRL_8SEC;
93		if (to <= 8)
94			to = 8;
95	}
96
97	wdd->timeout = to;
98
99	if (watchdog_active(wdd)) {
100		ts72xx_wdt_stop(wdd);
101		ts72xx_wdt_start(wdd);
102	}
103
104	return 0;
105}
106
107static const struct watchdog_info ts72xx_wdt_ident = {
108	.options		= WDIOF_KEEPALIVEPING |
109				  WDIOF_SETTIMEOUT |
110				  WDIOF_MAGICCLOSE,
111	.firmware_version	= 1,
112	.identity		= "TS-72XX WDT",
113};
114
115static const struct watchdog_ops ts72xx_wdt_ops = {
116	.owner		= THIS_MODULE,
117	.start		= ts72xx_wdt_start,
118	.stop		= ts72xx_wdt_stop,
119	.ping		= ts72xx_wdt_ping,
120	.set_timeout	= ts72xx_wdt_settimeout,
121};
122
123static int ts72xx_wdt_probe(struct platform_device *pdev)
124{
125	struct device *dev = &pdev->dev;
126	struct ts72xx_wdt_priv *priv;
127	struct watchdog_device *wdd;
128	int ret;
129
130	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
131	if (!priv)
132		return -ENOMEM;
133
134	priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
135	if (IS_ERR(priv->control_reg))
136		return PTR_ERR(priv->control_reg);
137
138	priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
139	if (IS_ERR(priv->feed_reg))
140		return PTR_ERR(priv->feed_reg);
141
142	wdd = &priv->wdd;
143	wdd->info = &ts72xx_wdt_ident;
144	wdd->ops = &ts72xx_wdt_ops;
145	wdd->min_timeout = 1;
146	wdd->max_hw_heartbeat_ms = 8000;
147	wdd->parent = dev;
148
149	watchdog_set_nowayout(wdd, nowayout);
150
151	wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
152	watchdog_init_timeout(wdd, timeout, dev);
153
154	watchdog_set_drvdata(wdd, priv);
155
156	ret = devm_watchdog_register_device(dev, wdd);
157	if (ret)
158		return ret;
159
160	dev_info(dev, "TS-72xx Watchdog driver\n");
161
162	return 0;
163}
164
165static struct platform_driver ts72xx_wdt_driver = {
166	.probe		= ts72xx_wdt_probe,
167	.driver		= {
168		.name	= "ts72xx-wdt",
169	},
170};
171
172module_platform_driver(ts72xx_wdt_driver);
173
174MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
175MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
176MODULE_LICENSE("GPL");
177MODULE_ALIAS("platform:ts72xx-wdt");
178