Commit | Line | Data |
---|---|---|
1094ebe9 JC |
1 | /* Copyright (c) 2014, The Linux Foundation. All rights reserved. |
2 | * | |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License version 2 and | |
5 | * only version 2 as published by the Free Software Foundation. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | */ | |
13 | #include <linux/clk.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/of.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/watchdog.h> | |
20 | ||
21 | #define WDT_RST 0x0 | |
22 | #define WDT_EN 0x8 | |
23 | #define WDT_BITE_TIME 0x24 | |
24 | ||
25 | struct qcom_wdt { | |
26 | struct watchdog_device wdd; | |
27 | struct clk *clk; | |
28 | unsigned long rate; | |
29 | void __iomem *base; | |
30 | }; | |
31 | ||
32 | static inline | |
33 | struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd) | |
34 | { | |
35 | return container_of(wdd, struct qcom_wdt, wdd); | |
36 | } | |
37 | ||
38 | static int qcom_wdt_start(struct watchdog_device *wdd) | |
39 | { | |
40 | struct qcom_wdt *wdt = to_qcom_wdt(wdd); | |
41 | ||
42 | writel(0, wdt->base + WDT_EN); | |
43 | writel(1, wdt->base + WDT_RST); | |
44 | writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME); | |
45 | writel(1, wdt->base + WDT_EN); | |
46 | return 0; | |
47 | } | |
48 | ||
49 | static int qcom_wdt_stop(struct watchdog_device *wdd) | |
50 | { | |
51 | struct qcom_wdt *wdt = to_qcom_wdt(wdd); | |
52 | ||
53 | writel(0, wdt->base + WDT_EN); | |
54 | return 0; | |
55 | } | |
56 | ||
57 | static int qcom_wdt_ping(struct watchdog_device *wdd) | |
58 | { | |
59 | struct qcom_wdt *wdt = to_qcom_wdt(wdd); | |
60 | ||
61 | writel(1, wdt->base + WDT_RST); | |
62 | return 0; | |
63 | } | |
64 | ||
65 | static int qcom_wdt_set_timeout(struct watchdog_device *wdd, | |
66 | unsigned int timeout) | |
67 | { | |
68 | wdd->timeout = timeout; | |
69 | return qcom_wdt_start(wdd); | |
70 | } | |
71 | ||
72 | static const struct watchdog_ops qcom_wdt_ops = { | |
73 | .start = qcom_wdt_start, | |
74 | .stop = qcom_wdt_stop, | |
75 | .ping = qcom_wdt_ping, | |
76 | .set_timeout = qcom_wdt_set_timeout, | |
77 | .owner = THIS_MODULE, | |
78 | }; | |
79 | ||
80 | static const struct watchdog_info qcom_wdt_info = { | |
81 | .options = WDIOF_KEEPALIVEPING | |
82 | | WDIOF_MAGICCLOSE | |
83 | | WDIOF_SETTIMEOUT, | |
84 | .identity = KBUILD_MODNAME, | |
85 | }; | |
86 | ||
87 | static int qcom_wdt_probe(struct platform_device *pdev) | |
88 | { | |
89 | struct qcom_wdt *wdt; | |
90 | struct resource *res; | |
91 | int ret; | |
92 | ||
93 | wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); | |
94 | if (!wdt) | |
95 | return -ENOMEM; | |
96 | ||
97 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
98 | wdt->base = devm_ioremap_resource(&pdev->dev, res); | |
99 | if (IS_ERR(wdt->base)) | |
100 | return PTR_ERR(wdt->base); | |
101 | ||
102 | wdt->clk = devm_clk_get(&pdev->dev, NULL); | |
103 | if (IS_ERR(wdt->clk)) { | |
104 | dev_err(&pdev->dev, "failed to get input clock\n"); | |
105 | return PTR_ERR(wdt->clk); | |
106 | } | |
107 | ||
108 | ret = clk_prepare_enable(wdt->clk); | |
109 | if (ret) { | |
110 | dev_err(&pdev->dev, "failed to setup clock\n"); | |
111 | return ret; | |
112 | } | |
113 | ||
114 | /* | |
115 | * We use the clock rate to calculate the max timeout, so ensure it's | |
116 | * not zero to avoid a divide-by-zero exception. | |
117 | * | |
118 | * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such | |
119 | * that it would bite before a second elapses it's usefulness is | |
120 | * limited. Bail if this is the case. | |
121 | */ | |
122 | wdt->rate = clk_get_rate(wdt->clk); | |
123 | if (wdt->rate == 0 || | |
124 | wdt->rate > 0x10000000U) { | |
125 | dev_err(&pdev->dev, "invalid clock rate\n"); | |
126 | ret = -EINVAL; | |
127 | goto err_clk_unprepare; | |
128 | } | |
129 | ||
130 | wdt->wdd.dev = &pdev->dev; | |
131 | wdt->wdd.info = &qcom_wdt_info; | |
132 | wdt->wdd.ops = &qcom_wdt_ops; | |
133 | wdt->wdd.min_timeout = 1; | |
134 | wdt->wdd.max_timeout = 0x10000000U / wdt->rate; | |
135 | ||
136 | /* | |
137 | * If 'timeout-sec' unspecified in devicetree, assume a 30 second | |
138 | * default, unless the max timeout is less than 30 seconds, then use | |
139 | * the max instead. | |
140 | */ | |
141 | wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U); | |
142 | watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev); | |
143 | ||
144 | ret = watchdog_register_device(&wdt->wdd); | |
145 | if (ret) { | |
146 | dev_err(&pdev->dev, "failed to register watchdog\n"); | |
147 | goto err_clk_unprepare; | |
148 | } | |
149 | ||
150 | platform_set_drvdata(pdev, wdt); | |
151 | return 0; | |
152 | ||
153 | err_clk_unprepare: | |
154 | clk_disable_unprepare(wdt->clk); | |
155 | return ret; | |
156 | } | |
157 | ||
158 | static int qcom_wdt_remove(struct platform_device *pdev) | |
159 | { | |
160 | struct qcom_wdt *wdt = platform_get_drvdata(pdev); | |
161 | ||
162 | watchdog_unregister_device(&wdt->wdd); | |
163 | clk_disable_unprepare(wdt->clk); | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static const struct of_device_id qcom_wdt_of_table[] = { | |
168 | { .compatible = "qcom,kpss-wdt-msm8960", }, | |
169 | { .compatible = "qcom,kpss-wdt-apq8064", }, | |
170 | { .compatible = "qcom,kpss-wdt-ipq8064", }, | |
171 | { }, | |
172 | }; | |
173 | MODULE_DEVICE_TABLE(of, qcom_wdt_of_table); | |
174 | ||
175 | static struct platform_driver qcom_watchdog_driver = { | |
176 | .probe = qcom_wdt_probe, | |
177 | .remove = qcom_wdt_remove, | |
178 | .driver = { | |
179 | .name = KBUILD_MODNAME, | |
180 | .of_match_table = qcom_wdt_of_table, | |
181 | }, | |
182 | }; | |
183 | module_platform_driver(qcom_watchdog_driver); | |
184 | ||
185 | MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver"); | |
186 | MODULE_LICENSE("GPL v2"); |