1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2021 Emil Renner Berthing
4  */
5 
6 #include <linux/mfd/tps65086.h>
7 #include <linux/mod_devicetable.h>
8 #include <linux/module.h>
9 #include <linux/platform_device.h>
10 #include <linux/reboot.h>
11 
12 struct tps65086_restart {
13 	struct notifier_block handler;
14 	struct device *dev;
15 };
16 
17 static int tps65086_restart_notify(struct notifier_block *this,
18 				   unsigned long mode, void *cmd)
19 {
20 	struct tps65086_restart *tps65086_restart =
21 		container_of(this, struct tps65086_restart, handler);
22 	struct tps65086 *tps65086 = dev_get_drvdata(tps65086_restart->dev->parent);
23 	int ret;
24 
25 	ret = regmap_write(tps65086->regmap, TPS65086_FORCESHUTDN, 1);
26 	if (ret) {
27 		dev_err(tps65086_restart->dev, "%s: error writing to tps65086 pmic: %d\n",
28 			__func__, ret);
29 		return NOTIFY_DONE;
30 	}
31 
32 	/* give it a little time */
33 	mdelay(200);
34 
35 	WARN_ON(1);
36 
37 	return NOTIFY_DONE;
38 }
39 
40 static int tps65086_restart_probe(struct platform_device *pdev)
41 {
42 	struct tps65086_restart *tps65086_restart;
43 	int ret;
44 
45 	tps65086_restart = devm_kzalloc(&pdev->dev, sizeof(*tps65086_restart), GFP_KERNEL);
46 	if (!tps65086_restart)
47 		return -ENOMEM;
48 
49 	platform_set_drvdata(pdev, tps65086_restart);
50 
51 	tps65086_restart->handler.notifier_call = tps65086_restart_notify;
52 	tps65086_restart->handler.priority = 192;
53 	tps65086_restart->dev = &pdev->dev;
54 
55 	ret = register_restart_handler(&tps65086_restart->handler);
56 	if (ret) {
57 		dev_err(&pdev->dev, "%s: cannot register restart handler: %d\n",
58 			__func__, ret);
59 		return -ENODEV;
60 	}
61 
62 	return 0;
63 }
64 
65 static int tps65086_restart_remove(struct platform_device *pdev)
66 {
67 	struct tps65086_restart *tps65086_restart = platform_get_drvdata(pdev);
68 	int ret;
69 
70 	ret = unregister_restart_handler(&tps65086_restart->handler);
71 	if (ret) {
72 		dev_err(&pdev->dev, "%s: cannot unregister restart handler: %d\n",
73 			__func__, ret);
74 		return -ENODEV;
75 	}
76 
77 	return 0;
78 }
79 
80 static const struct platform_device_id tps65086_restart_id_table[] = {
81 	{ "tps65086-reset", },
82 	{ /* sentinel */ }
83 };
84 MODULE_DEVICE_TABLE(platform, tps65086_restart_id_table);
85 
86 static struct platform_driver tps65086_restart_driver = {
87 	.driver = {
88 		.name = "tps65086-restart",
89 	},
90 	.probe = tps65086_restart_probe,
91 	.remove = tps65086_restart_remove,
92 	.id_table = tps65086_restart_id_table,
93 };
94 module_platform_driver(tps65086_restart_driver);
95 
96 MODULE_AUTHOR("Emil Renner Berthing <kernel@esmil.dk>");
97 MODULE_DESCRIPTION("TPS65086 restart driver");
98 MODULE_LICENSE("GPL v2");
99