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a0d261cc | 1 | // SPDX-License-Identifier: GPL-2.0-only |
bf900639 DR |
2 | /* |
3 | * Watchdog driver for TS-4800 based boards | |
4 | * | |
5 | * Copyright (c) 2015 - Savoir-faire Linux | |
6 | * | |
bf900639 DR |
7 | */ |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/mfd/syscon.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/of.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/regmap.h> | |
15 | #include <linux/watchdog.h> | |
16 | ||
17 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
18 | module_param(nowayout, bool, 0); | |
19 | MODULE_PARM_DESC(nowayout, | |
20 | "Watchdog cannot be stopped once started (default=" | |
21 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
22 | ||
23 | /* possible feed values */ | |
24 | #define TS4800_WDT_FEED_2S 0x1 | |
25 | #define TS4800_WDT_FEED_10S 0x2 | |
26 | #define TS4800_WDT_DISABLE 0x3 | |
27 | ||
28 | struct ts4800_wdt { | |
29 | struct watchdog_device wdd; | |
30 | struct regmap *regmap; | |
31 | u32 feed_offset; | |
32 | u32 feed_val; | |
33 | }; | |
34 | ||
35 | /* | |
36 | * TS-4800 supports the following timeout values: | |
37 | * | |
38 | * value desc | |
39 | * --------------------- | |
40 | * 0 feed for 338ms | |
41 | * 1 feed for 2.706s | |
42 | * 2 feed for 10.824s | |
43 | * 3 disable watchdog | |
44 | * | |
45 | * Keep the regmap/timeout map ordered by timeout | |
46 | */ | |
47 | static const struct { | |
48 | const int timeout; | |
49 | const int regval; | |
50 | } ts4800_wdt_map[] = { | |
51 | { 2, TS4800_WDT_FEED_2S }, | |
52 | { 10, TS4800_WDT_FEED_10S }, | |
53 | }; | |
54 | ||
55 | #define MAX_TIMEOUT_INDEX (ARRAY_SIZE(ts4800_wdt_map) - 1) | |
56 | ||
57 | static void ts4800_write_feed(struct ts4800_wdt *wdt, u32 val) | |
58 | { | |
59 | regmap_write(wdt->regmap, wdt->feed_offset, val); | |
60 | } | |
61 | ||
62 | static int ts4800_wdt_start(struct watchdog_device *wdd) | |
63 | { | |
64 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
65 | ||
66 | ts4800_write_feed(wdt, wdt->feed_val); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | static int ts4800_wdt_stop(struct watchdog_device *wdd) | |
71 | { | |
72 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
73 | ||
74 | ts4800_write_feed(wdt, TS4800_WDT_DISABLE); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | static int ts4800_wdt_set_timeout(struct watchdog_device *wdd, | |
79 | unsigned int timeout) | |
80 | { | |
81 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
82 | int i; | |
83 | ||
84 | for (i = 0; i < MAX_TIMEOUT_INDEX; i++) { | |
85 | if (ts4800_wdt_map[i].timeout >= timeout) | |
86 | break; | |
87 | } | |
88 | ||
89 | wdd->timeout = ts4800_wdt_map[i].timeout; | |
90 | wdt->feed_val = ts4800_wdt_map[i].regval; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static const struct watchdog_ops ts4800_wdt_ops = { | |
96 | .owner = THIS_MODULE, | |
97 | .start = ts4800_wdt_start, | |
98 | .stop = ts4800_wdt_stop, | |
99 | .set_timeout = ts4800_wdt_set_timeout, | |
100 | }; | |
101 | ||
102 | static const struct watchdog_info ts4800_wdt_info = { | |
103 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, | |
104 | .identity = "TS-4800 Watchdog", | |
105 | }; | |
106 | ||
107 | static int ts4800_wdt_probe(struct platform_device *pdev) | |
108 | { | |
44affc08 GR |
109 | struct device *dev = &pdev->dev; |
110 | struct device_node *np = dev->of_node; | |
bf900639 DR |
111 | struct device_node *syscon_np; |
112 | struct watchdog_device *wdd; | |
113 | struct ts4800_wdt *wdt; | |
114 | u32 reg; | |
115 | int ret; | |
116 | ||
117 | syscon_np = of_parse_phandle(np, "syscon", 0); | |
118 | if (!syscon_np) { | |
44affc08 | 119 | dev_err(dev, "no syscon property\n"); |
bf900639 DR |
120 | return -ENODEV; |
121 | } | |
122 | ||
123 | ret = of_property_read_u32_index(np, "syscon", 1, ®); | |
124 | if (ret < 0) { | |
44affc08 | 125 | dev_err(dev, "no offset in syscon\n"); |
5d24df3d | 126 | of_node_put(syscon_np); |
bf900639 DR |
127 | return ret; |
128 | } | |
129 | ||
130 | /* allocate memory for watchdog struct */ | |
44affc08 | 131 | wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); |
5d24df3d ML |
132 | if (!wdt) { |
133 | of_node_put(syscon_np); | |
bf900639 | 134 | return -ENOMEM; |
5d24df3d | 135 | } |
bf900639 DR |
136 | |
137 | /* set regmap and offset to know where to write */ | |
138 | wdt->feed_offset = reg; | |
139 | wdt->regmap = syscon_node_to_regmap(syscon_np); | |
cd6ba41c | 140 | of_node_put(syscon_np); |
bf900639 | 141 | if (IS_ERR(wdt->regmap)) { |
44affc08 | 142 | dev_err(dev, "cannot get parent's regmap\n"); |
bf900639 DR |
143 | return PTR_ERR(wdt->regmap); |
144 | } | |
145 | ||
146 | /* Initialize struct watchdog_device */ | |
147 | wdd = &wdt->wdd; | |
44affc08 | 148 | wdd->parent = dev; |
bf900639 DR |
149 | wdd->info = &ts4800_wdt_info; |
150 | wdd->ops = &ts4800_wdt_ops; | |
151 | wdd->min_timeout = ts4800_wdt_map[0].timeout; | |
152 | wdd->max_timeout = ts4800_wdt_map[MAX_TIMEOUT_INDEX].timeout; | |
153 | ||
154 | watchdog_set_drvdata(wdd, wdt); | |
155 | watchdog_set_nowayout(wdd, nowayout); | |
44affc08 | 156 | watchdog_init_timeout(wdd, 0, dev); |
bf900639 DR |
157 | |
158 | /* | |
159 | * As this watchdog supports only a few values, ts4800_wdt_set_timeout | |
160 | * must be called to initialize timeout and feed_val with valid values. | |
161 | * Default to maximum timeout if none, or an invalid one, is provided in | |
162 | * device tree. | |
163 | */ | |
164 | if (!wdd->timeout) | |
165 | wdd->timeout = wdd->max_timeout; | |
166 | ts4800_wdt_set_timeout(wdd, wdd->timeout); | |
167 | ||
168 | /* | |
169 | * The feed register is write-only, so it is not possible to determine | |
170 | * watchdog's state. Disable it to be in a known state. | |
171 | */ | |
172 | ts4800_wdt_stop(wdd); | |
173 | ||
44affc08 | 174 | ret = devm_watchdog_register_device(dev, wdd); |
c8c844f2 | 175 | if (ret) |
bf900639 | 176 | return ret; |
bf900639 DR |
177 | |
178 | platform_set_drvdata(pdev, wdt); | |
179 | ||
44affc08 | 180 | dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n", |
bf900639 DR |
181 | wdd->timeout, nowayout); |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
bf900639 DR |
186 | static const struct of_device_id ts4800_wdt_of_match[] = { |
187 | { .compatible = "technologic,ts4800-wdt", }, | |
188 | { }, | |
189 | }; | |
190 | MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match); | |
191 | ||
192 | static struct platform_driver ts4800_wdt_driver = { | |
193 | .probe = ts4800_wdt_probe, | |
bf900639 DR |
194 | .driver = { |
195 | .name = "ts4800_wdt", | |
196 | .of_match_table = ts4800_wdt_of_match, | |
197 | }, | |
198 | }; | |
199 | ||
200 | module_platform_driver(ts4800_wdt_driver); | |
201 | ||
202 | MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>"); | |
203 | MODULE_LICENSE("GPL v2"); | |
204 | MODULE_ALIAS("platform:ts4800_wdt"); |