xref: /openbmc/linux/drivers/watchdog/ts72xx_wdt.c (revision a0d261cc)
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 
21 static int timeout;
22 module_param(timeout, int, 0);
23 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
24 
25 static bool nowayout = WATCHDOG_NOWAYOUT;
26 module_param(nowayout, bool, 0);
27 MODULE_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 
42 struct ts72xx_wdt_priv {
43 	void __iomem	*control_reg;
44 	void __iomem	*feed_reg;
45 	struct watchdog_device wdd;
46 	unsigned char regval;
47 };
48 
ts72xx_wdt_start(struct watchdog_device * wdd)49 static 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 
ts72xx_wdt_stop(struct watchdog_device * wdd)59 static 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 
ts72xx_wdt_ping(struct watchdog_device * wdd)69 static 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 
ts72xx_wdt_settimeout(struct watchdog_device * wdd,unsigned int to)78 static 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 
105 static 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 
113 static 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 
ts72xx_wdt_probe(struct platform_device * pdev)121 static 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 
163 static struct platform_driver ts72xx_wdt_driver = {
164 	.probe		= ts72xx_wdt_probe,
165 	.driver		= {
166 		.name	= "ts72xx-wdt",
167 	},
168 };
169 
170 module_platform_driver(ts72xx_wdt_driver);
171 
172 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
173 MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
174 MODULE_LICENSE("GPL");
175 MODULE_ALIAS("platform:ts72xx-wdt");
176