1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
4 * JZ4740 Watchdog driver
5 */
6
7 #include <linux/mfd/ingenic-tcu.h>
8 #include <linux/mfd/syscon.h>
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/watchdog.h>
14 #include <linux/platform_device.h>
15 #include <linux/io.h>
16 #include <linux/device.h>
17 #include <linux/clk.h>
18 #include <linux/slab.h>
19 #include <linux/err.h>
20 #include <linux/of.h>
21 #include <linux/regmap.h>
22
23 #define DEFAULT_HEARTBEAT 5
24 #define MAX_HEARTBEAT 2048
25
26 static bool nowayout = WATCHDOG_NOWAYOUT;
27 module_param(nowayout, bool, 0);
28 MODULE_PARM_DESC(nowayout,
29 "Watchdog cannot be stopped once started (default="
30 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
31
32 static unsigned int heartbeat = DEFAULT_HEARTBEAT;
33 module_param(heartbeat, uint, 0);
34 MODULE_PARM_DESC(heartbeat,
35 "Watchdog heartbeat period in seconds from 1 to "
36 __MODULE_STRING(MAX_HEARTBEAT) ", default "
37 __MODULE_STRING(DEFAULT_HEARTBEAT));
38
39 struct jz4740_wdt_drvdata {
40 struct watchdog_device wdt;
41 struct regmap *map;
42 struct clk *clk;
43 unsigned long clk_rate;
44 };
45
jz4740_wdt_ping(struct watchdog_device * wdt_dev)46 static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
47 {
48 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
49
50 regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
51
52 return 0;
53 }
54
jz4740_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int new_timeout)55 static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
56 unsigned int new_timeout)
57 {
58 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
59 u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);
60 unsigned int tcer;
61
62 regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
63 regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
64
65 regmap_write(drvdata->map, TCU_REG_WDT_TDR, timeout_value);
66 regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
67
68 if (tcer & TCU_WDT_TCER_TCEN)
69 regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
70
71 wdt_dev->timeout = new_timeout;
72 return 0;
73 }
74
jz4740_wdt_start(struct watchdog_device * wdt_dev)75 static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
76 {
77 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
78 unsigned int tcer;
79 int ret;
80
81 ret = clk_prepare_enable(drvdata->clk);
82 if (ret)
83 return ret;
84
85 regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
86
87 jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
88
89 /* Start watchdog if it wasn't started already */
90 if (!(tcer & TCU_WDT_TCER_TCEN))
91 regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
92
93 return 0;
94 }
95
jz4740_wdt_stop(struct watchdog_device * wdt_dev)96 static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
97 {
98 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
99
100 regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
101 clk_disable_unprepare(drvdata->clk);
102
103 return 0;
104 }
105
jz4740_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)106 static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
107 unsigned long action, void *data)
108 {
109 wdt_dev->timeout = 0;
110 jz4740_wdt_start(wdt_dev);
111 return 0;
112 }
113
114 static const struct watchdog_info jz4740_wdt_info = {
115 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
116 .identity = "jz4740 Watchdog",
117 };
118
119 static const struct watchdog_ops jz4740_wdt_ops = {
120 .owner = THIS_MODULE,
121 .start = jz4740_wdt_start,
122 .stop = jz4740_wdt_stop,
123 .ping = jz4740_wdt_ping,
124 .set_timeout = jz4740_wdt_set_timeout,
125 .restart = jz4740_wdt_restart,
126 };
127
128 #ifdef CONFIG_OF
129 static const struct of_device_id jz4740_wdt_of_matches[] = {
130 { .compatible = "ingenic,jz4740-watchdog", },
131 { .compatible = "ingenic,jz4780-watchdog", },
132 { /* sentinel */ }
133 };
134 MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
135 #endif
136
jz4740_wdt_probe(struct platform_device * pdev)137 static int jz4740_wdt_probe(struct platform_device *pdev)
138 {
139 struct device *dev = &pdev->dev;
140 struct jz4740_wdt_drvdata *drvdata;
141 struct watchdog_device *jz4740_wdt;
142 long rate;
143 int ret;
144
145 drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
146 GFP_KERNEL);
147 if (!drvdata)
148 return -ENOMEM;
149
150 drvdata->clk = devm_clk_get(&pdev->dev, "wdt");
151 if (IS_ERR(drvdata->clk)) {
152 dev_err(&pdev->dev, "cannot find WDT clock\n");
153 return PTR_ERR(drvdata->clk);
154 }
155
156 /* Set smallest clock possible */
157 rate = clk_round_rate(drvdata->clk, 1);
158 if (rate < 0)
159 return rate;
160
161 ret = clk_set_rate(drvdata->clk, rate);
162 if (ret)
163 return ret;
164
165 drvdata->clk_rate = rate;
166 jz4740_wdt = &drvdata->wdt;
167 jz4740_wdt->info = &jz4740_wdt_info;
168 jz4740_wdt->ops = &jz4740_wdt_ops;
169 jz4740_wdt->min_timeout = 1;
170 jz4740_wdt->max_timeout = 0xffff / rate;
171 jz4740_wdt->timeout = clamp(heartbeat,
172 jz4740_wdt->min_timeout,
173 jz4740_wdt->max_timeout);
174 jz4740_wdt->parent = dev;
175 watchdog_set_nowayout(jz4740_wdt, nowayout);
176 watchdog_set_drvdata(jz4740_wdt, drvdata);
177
178 drvdata->map = device_node_to_regmap(dev->parent->of_node);
179 if (IS_ERR(drvdata->map)) {
180 dev_err(dev, "regmap not found\n");
181 return PTR_ERR(drvdata->map);
182 }
183
184 return devm_watchdog_register_device(dev, &drvdata->wdt);
185 }
186
187 static struct platform_driver jz4740_wdt_driver = {
188 .probe = jz4740_wdt_probe,
189 .driver = {
190 .name = "jz4740-wdt",
191 .of_match_table = of_match_ptr(jz4740_wdt_of_matches),
192 },
193 };
194
195 module_platform_driver(jz4740_wdt_driver);
196
197 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
198 MODULE_DESCRIPTION("jz4740 Watchdog Driver");
199 MODULE_LICENSE("GPL");
200 MODULE_ALIAS("platform:jz4740-wdt");
201