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 
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 
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 
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 
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 
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