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bf900639 DR |
1 | /* |
2 | * Watchdog driver for TS-4800 based boards | |
3 | * | |
4 | * Copyright (c) 2015 - Savoir-faire Linux | |
5 | * | |
6 | * This file is licensed under the terms of the GNU General Public | |
7 | * License version 2. This program is licensed "as is" without any | |
8 | * warranty of any kind, whether express or implied. | |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/mfd/syscon.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/platform_device.h> | |
16 | #include <linux/regmap.h> | |
17 | #include <linux/watchdog.h> | |
18 | ||
19 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
20 | module_param(nowayout, bool, 0); | |
21 | MODULE_PARM_DESC(nowayout, | |
22 | "Watchdog cannot be stopped once started (default=" | |
23 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
24 | ||
25 | /* possible feed values */ | |
26 | #define TS4800_WDT_FEED_2S 0x1 | |
27 | #define TS4800_WDT_FEED_10S 0x2 | |
28 | #define TS4800_WDT_DISABLE 0x3 | |
29 | ||
30 | struct ts4800_wdt { | |
31 | struct watchdog_device wdd; | |
32 | struct regmap *regmap; | |
33 | u32 feed_offset; | |
34 | u32 feed_val; | |
35 | }; | |
36 | ||
37 | /* | |
38 | * TS-4800 supports the following timeout values: | |
39 | * | |
40 | * value desc | |
41 | * --------------------- | |
42 | * 0 feed for 338ms | |
43 | * 1 feed for 2.706s | |
44 | * 2 feed for 10.824s | |
45 | * 3 disable watchdog | |
46 | * | |
47 | * Keep the regmap/timeout map ordered by timeout | |
48 | */ | |
49 | static const struct { | |
50 | const int timeout; | |
51 | const int regval; | |
52 | } ts4800_wdt_map[] = { | |
53 | { 2, TS4800_WDT_FEED_2S }, | |
54 | { 10, TS4800_WDT_FEED_10S }, | |
55 | }; | |
56 | ||
57 | #define MAX_TIMEOUT_INDEX (ARRAY_SIZE(ts4800_wdt_map) - 1) | |
58 | ||
59 | static void ts4800_write_feed(struct ts4800_wdt *wdt, u32 val) | |
60 | { | |
61 | regmap_write(wdt->regmap, wdt->feed_offset, val); | |
62 | } | |
63 | ||
64 | static int ts4800_wdt_start(struct watchdog_device *wdd) | |
65 | { | |
66 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
67 | ||
68 | ts4800_write_feed(wdt, wdt->feed_val); | |
69 | return 0; | |
70 | } | |
71 | ||
72 | static int ts4800_wdt_stop(struct watchdog_device *wdd) | |
73 | { | |
74 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
75 | ||
76 | ts4800_write_feed(wdt, TS4800_WDT_DISABLE); | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static int ts4800_wdt_set_timeout(struct watchdog_device *wdd, | |
81 | unsigned int timeout) | |
82 | { | |
83 | struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd); | |
84 | int i; | |
85 | ||
86 | for (i = 0; i < MAX_TIMEOUT_INDEX; i++) { | |
87 | if (ts4800_wdt_map[i].timeout >= timeout) | |
88 | break; | |
89 | } | |
90 | ||
91 | wdd->timeout = ts4800_wdt_map[i].timeout; | |
92 | wdt->feed_val = ts4800_wdt_map[i].regval; | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | static const struct watchdog_ops ts4800_wdt_ops = { | |
98 | .owner = THIS_MODULE, | |
99 | .start = ts4800_wdt_start, | |
100 | .stop = ts4800_wdt_stop, | |
101 | .set_timeout = ts4800_wdt_set_timeout, | |
102 | }; | |
103 | ||
104 | static const struct watchdog_info ts4800_wdt_info = { | |
105 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, | |
106 | .identity = "TS-4800 Watchdog", | |
107 | }; | |
108 | ||
109 | static int ts4800_wdt_probe(struct platform_device *pdev) | |
110 | { | |
44affc08 GR |
111 | struct device *dev = &pdev->dev; |
112 | struct device_node *np = dev->of_node; | |
bf900639 DR |
113 | struct device_node *syscon_np; |
114 | struct watchdog_device *wdd; | |
115 | struct ts4800_wdt *wdt; | |
116 | u32 reg; | |
117 | int ret; | |
118 | ||
119 | syscon_np = of_parse_phandle(np, "syscon", 0); | |
120 | if (!syscon_np) { | |
44affc08 | 121 | dev_err(dev, "no syscon property\n"); |
bf900639 DR |
122 | return -ENODEV; |
123 | } | |
124 | ||
125 | ret = of_property_read_u32_index(np, "syscon", 1, ®); | |
126 | if (ret < 0) { | |
44affc08 | 127 | dev_err(dev, "no offset in syscon\n"); |
bf900639 DR |
128 | return ret; |
129 | } | |
130 | ||
131 | /* allocate memory for watchdog struct */ | |
44affc08 | 132 | wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); |
bf900639 DR |
133 | if (!wdt) |
134 | return -ENOMEM; | |
135 | ||
136 | /* set regmap and offset to know where to write */ | |
137 | wdt->feed_offset = reg; | |
138 | wdt->regmap = syscon_node_to_regmap(syscon_np); | |
cd6ba41c | 139 | of_node_put(syscon_np); |
bf900639 | 140 | if (IS_ERR(wdt->regmap)) { |
44affc08 | 141 | dev_err(dev, "cannot get parent's regmap\n"); |
bf900639 DR |
142 | return PTR_ERR(wdt->regmap); |
143 | } | |
144 | ||
145 | /* Initialize struct watchdog_device */ | |
146 | wdd = &wdt->wdd; | |
44affc08 | 147 | wdd->parent = dev; |
bf900639 DR |
148 | wdd->info = &ts4800_wdt_info; |
149 | wdd->ops = &ts4800_wdt_ops; | |
150 | wdd->min_timeout = ts4800_wdt_map[0].timeout; | |
151 | wdd->max_timeout = ts4800_wdt_map[MAX_TIMEOUT_INDEX].timeout; | |
152 | ||
153 | watchdog_set_drvdata(wdd, wdt); | |
154 | watchdog_set_nowayout(wdd, nowayout); | |
44affc08 | 155 | watchdog_init_timeout(wdd, 0, dev); |
bf900639 DR |
156 | |
157 | /* | |
158 | * As this watchdog supports only a few values, ts4800_wdt_set_timeout | |
159 | * must be called to initialize timeout and feed_val with valid values. | |
160 | * Default to maximum timeout if none, or an invalid one, is provided in | |
161 | * device tree. | |
162 | */ | |
163 | if (!wdd->timeout) | |
164 | wdd->timeout = wdd->max_timeout; | |
165 | ts4800_wdt_set_timeout(wdd, wdd->timeout); | |
166 | ||
167 | /* | |
168 | * The feed register is write-only, so it is not possible to determine | |
169 | * watchdog's state. Disable it to be in a known state. | |
170 | */ | |
171 | ts4800_wdt_stop(wdd); | |
172 | ||
44affc08 | 173 | ret = devm_watchdog_register_device(dev, wdd); |
c8c844f2 | 174 | if (ret) |
bf900639 | 175 | return ret; |
bf900639 DR |
176 | |
177 | platform_set_drvdata(pdev, wdt); | |
178 | ||
44affc08 | 179 | dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n", |
bf900639 DR |
180 | wdd->timeout, nowayout); |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
bf900639 DR |
185 | static const struct of_device_id ts4800_wdt_of_match[] = { |
186 | { .compatible = "technologic,ts4800-wdt", }, | |
187 | { }, | |
188 | }; | |
189 | MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match); | |
190 | ||
191 | static struct platform_driver ts4800_wdt_driver = { | |
192 | .probe = ts4800_wdt_probe, | |
bf900639 DR |
193 | .driver = { |
194 | .name = "ts4800_wdt", | |
195 | .of_match_table = ts4800_wdt_of_match, | |
196 | }, | |
197 | }; | |
198 | ||
199 | module_platform_driver(ts4800_wdt_driver); | |
200 | ||
201 | MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>"); | |
202 | MODULE_LICENSE("GPL v2"); | |
203 | MODULE_ALIAS("platform:ts4800_wdt"); |