1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) STMicroelectronics 2018
3 // Author: Pascal Paillet <p.paillet@st.com> for STMicroelectronics.
4
5 #include <linux/kernel.h>
6 #include <linux/mfd/stpmic1.h>
7 #include <linux/module.h>
8 #include <linux/platform_device.h>
9 #include <linux/of.h>
10 #include <linux/regmap.h>
11 #include <linux/slab.h>
12 #include <linux/watchdog.h>
13
14 /* WATCHDOG CONTROL REGISTER bit */
15 #define WDT_START BIT(0)
16 #define WDT_PING BIT(1)
17 #define WDT_START_MASK BIT(0)
18 #define WDT_PING_MASK BIT(1)
19 #define WDT_STOP 0
20
21 #define PMIC_WDT_MIN_TIMEOUT 1
22 #define PMIC_WDT_MAX_TIMEOUT 256
23 #define PMIC_WDT_DEFAULT_TIMEOUT 30
24
25 static bool nowayout = WATCHDOG_NOWAYOUT;
26 module_param(nowayout, bool, 0);
27 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
28 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
29
30 struct stpmic1_wdt {
31 struct stpmic1 *pmic;
32 struct watchdog_device wdtdev;
33 };
34
pmic_wdt_start(struct watchdog_device * wdd)35 static int pmic_wdt_start(struct watchdog_device *wdd)
36 {
37 struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
38
39 return regmap_update_bits(wdt->pmic->regmap,
40 WCHDG_CR, WDT_START_MASK, WDT_START);
41 }
42
pmic_wdt_stop(struct watchdog_device * wdd)43 static int pmic_wdt_stop(struct watchdog_device *wdd)
44 {
45 struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
46
47 return regmap_update_bits(wdt->pmic->regmap,
48 WCHDG_CR, WDT_START_MASK, WDT_STOP);
49 }
50
pmic_wdt_ping(struct watchdog_device * wdd)51 static int pmic_wdt_ping(struct watchdog_device *wdd)
52 {
53 struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
54
55 return regmap_update_bits(wdt->pmic->regmap,
56 WCHDG_CR, WDT_PING_MASK, WDT_PING);
57 }
58
pmic_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)59 static int pmic_wdt_set_timeout(struct watchdog_device *wdd,
60 unsigned int timeout)
61 {
62 struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
63
64 wdd->timeout = timeout;
65 /* timeout is equal to register value + 1 */
66 return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
67 }
68
69 static const struct watchdog_info pmic_watchdog_info = {
70 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
71 .identity = "STPMIC1 PMIC Watchdog",
72 };
73
74 static const struct watchdog_ops pmic_watchdog_ops = {
75 .owner = THIS_MODULE,
76 .start = pmic_wdt_start,
77 .stop = pmic_wdt_stop,
78 .ping = pmic_wdt_ping,
79 .set_timeout = pmic_wdt_set_timeout,
80 };
81
pmic_wdt_probe(struct platform_device * pdev)82 static int pmic_wdt_probe(struct platform_device *pdev)
83 {
84 struct device *dev = &pdev->dev;
85 int ret;
86 struct stpmic1 *pmic;
87 struct stpmic1_wdt *wdt;
88
89 if (!dev->parent)
90 return -EINVAL;
91
92 pmic = dev_get_drvdata(dev->parent);
93 if (!pmic)
94 return -EINVAL;
95
96 wdt = devm_kzalloc(dev, sizeof(struct stpmic1_wdt), GFP_KERNEL);
97 if (!wdt)
98 return -ENOMEM;
99
100 wdt->pmic = pmic;
101
102 wdt->wdtdev.info = &pmic_watchdog_info;
103 wdt->wdtdev.ops = &pmic_watchdog_ops;
104 wdt->wdtdev.min_timeout = PMIC_WDT_MIN_TIMEOUT;
105 wdt->wdtdev.max_timeout = PMIC_WDT_MAX_TIMEOUT;
106 wdt->wdtdev.parent = dev;
107
108 wdt->wdtdev.timeout = PMIC_WDT_DEFAULT_TIMEOUT;
109 watchdog_init_timeout(&wdt->wdtdev, 0, dev);
110
111 watchdog_set_nowayout(&wdt->wdtdev, nowayout);
112 watchdog_set_drvdata(&wdt->wdtdev, wdt);
113
114 ret = devm_watchdog_register_device(dev, &wdt->wdtdev);
115 if (ret)
116 return ret;
117
118 dev_dbg(wdt->pmic->dev, "PMIC Watchdog driver probed\n");
119 return 0;
120 }
121
122 static const struct of_device_id of_pmic_wdt_match[] = {
123 { .compatible = "st,stpmic1-wdt" },
124 { },
125 };
126
127 MODULE_DEVICE_TABLE(of, of_pmic_wdt_match);
128
129 static struct platform_driver stpmic1_wdt_driver = {
130 .probe = pmic_wdt_probe,
131 .driver = {
132 .name = "stpmic1-wdt",
133 .of_match_table = of_pmic_wdt_match,
134 },
135 };
136 module_platform_driver(stpmic1_wdt_driver);
137
138 MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
139 MODULE_AUTHOR("Pascal Paillet <p.paillet@st.com>");
140 MODULE_LICENSE("GPL v2");
141