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 | |
46 | static int jz4740_wdt_ping(struct watchdog_device *wdt_dev) |
47 | { |
48 | struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdd: wdt_dev); |
49 | |
50 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCNT, val: 0); |
51 | |
52 | return 0; |
53 | } |
54 | |
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(wdd: wdt_dev); |
59 | u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout); |
60 | unsigned int tcer; |
61 | |
62 | regmap_read(map: drvdata->map, TCU_REG_WDT_TCER, val: &tcer); |
63 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCER, val: 0); |
64 | |
65 | regmap_write(map: drvdata->map, TCU_REG_WDT_TDR, val: timeout_value); |
66 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCNT, val: 0); |
67 | |
68 | if (tcer & TCU_WDT_TCER_TCEN) |
69 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN); |
70 | |
71 | wdt_dev->timeout = new_timeout; |
72 | return 0; |
73 | } |
74 | |
75 | static int jz4740_wdt_start(struct watchdog_device *wdt_dev) |
76 | { |
77 | struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdd: wdt_dev); |
78 | unsigned int tcer; |
79 | int ret; |
80 | |
81 | ret = clk_prepare_enable(clk: drvdata->clk); |
82 | if (ret) |
83 | return ret; |
84 | |
85 | regmap_read(map: drvdata->map, TCU_REG_WDT_TCER, val: &tcer); |
86 | |
87 | jz4740_wdt_set_timeout(wdt_dev, new_timeout: wdt_dev->timeout); |
88 | |
89 | /* Start watchdog if it wasn't started already */ |
90 | if (!(tcer & TCU_WDT_TCER_TCEN)) |
91 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN); |
92 | |
93 | return 0; |
94 | } |
95 | |
96 | static int jz4740_wdt_stop(struct watchdog_device *wdt_dev) |
97 | { |
98 | struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdd: wdt_dev); |
99 | |
100 | regmap_write(map: drvdata->map, TCU_REG_WDT_TCER, val: 0); |
101 | clk_disable_unprepare(clk: drvdata->clk); |
102 | |
103 | return 0; |
104 | } |
105 | |
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 | |
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, size: sizeof(struct jz4740_wdt_drvdata), |
146 | GFP_KERNEL); |
147 | if (!drvdata) |
148 | return -ENOMEM; |
149 | |
150 | drvdata->clk = devm_clk_get(dev: &pdev->dev, id: "wdt" ); |
151 | if (IS_ERR(ptr: drvdata->clk)) { |
152 | dev_err(&pdev->dev, "cannot find WDT clock\n" ); |
153 | return PTR_ERR(ptr: drvdata->clk); |
154 | } |
155 | |
156 | /* Set smallest clock possible */ |
157 | rate = clk_round_rate(clk: drvdata->clk, rate: 1); |
158 | if (rate < 0) |
159 | return rate; |
160 | |
161 | ret = clk_set_rate(clk: 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(wdd: jz4740_wdt, nowayout); |
176 | watchdog_set_drvdata(wdd: jz4740_wdt, data: drvdata); |
177 | |
178 | drvdata->map = device_node_to_regmap(np: dev->parent->of_node); |
179 | if (IS_ERR(ptr: drvdata->map)) { |
180 | dev_err(dev, "regmap not found\n" ); |
181 | return PTR_ERR(ptr: 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 | |