1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Force-disables a regulator to power down a device
 4 *
 5 * Michael Klein <michael@fossekall.de>
 6 *
 7 * Copyright (C) 2020 Michael Klein
 8 *
 9 * Based on the gpio-poweroff driver.
10 */
11#include <linux/delay.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/pm.h>
16#include <linux/regulator/consumer.h>
17
18#define TIMEOUT_MS 3000
19
20/*
21 * Hold configuration here, cannot be more than one instance of the driver
22 * since pm_power_off itself is global.
23 */
24static struct regulator *cpu_regulator;
25
26static void regulator_poweroff_do_poweroff(void)
27{
28	if (cpu_regulator && regulator_is_enabled(cpu_regulator))
29		regulator_force_disable(cpu_regulator);
30
31	/* give it some time */
32	mdelay(TIMEOUT_MS);
33
34	WARN_ON(1);
35}
36
37static int regulator_poweroff_probe(struct platform_device *pdev)
38{
39	/* If a pm_power_off function has already been added, leave it alone */
40	if (pm_power_off != NULL) {
41		dev_err(&pdev->dev,
42			"%s: pm_power_off function already registered\n",
43			__func__);
44		return -EBUSY;
45	}
46
47	cpu_regulator = devm_regulator_get(&pdev->dev, "cpu");
48	if (IS_ERR(cpu_regulator))
49		return PTR_ERR(cpu_regulator);
50
51	pm_power_off = &regulator_poweroff_do_poweroff;
52	return 0;
53}
54
55static void regulator_poweroff_remove(struct platform_device *pdev)
56{
57	if (pm_power_off == &regulator_poweroff_do_poweroff)
58		pm_power_off = NULL;
 
 
59}
60
61static const struct of_device_id of_regulator_poweroff_match[] = {
62	{ .compatible = "regulator-poweroff", },
63	{},
64};
65MODULE_DEVICE_TABLE(of, of_regulator_poweroff_match);
66
67static struct platform_driver regulator_poweroff_driver = {
68	.probe = regulator_poweroff_probe,
69	.remove_new = regulator_poweroff_remove,
70	.driver = {
71		.name = "poweroff-regulator",
72		.of_match_table = of_regulator_poweroff_match,
73	},
74};
75
76module_platform_driver(regulator_poweroff_driver);
77
78MODULE_AUTHOR("Michael Klein <michael@fossekall.de>");
79MODULE_DESCRIPTION("Regulator poweroff driver");
 
80MODULE_ALIAS("platform:poweroff-regulator");

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Force-disables a regulator to power down a device
 4 *
 5 * Michael Klein <michael@fossekall.de>
 6 *
 7 * Copyright (C) 2020 Michael Klein
 8 *
 9 * Based on the gpio-poweroff driver.
10 */
11#include <linux/delay.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/pm.h>
16#include <linux/regulator/consumer.h>
17
18#define TIMEOUT_MS 3000
19
20/*
21 * Hold configuration here, cannot be more than one instance of the driver
22 * since pm_power_off itself is global.
23 */
24static struct regulator *cpu_regulator;
25
26static void regulator_poweroff_do_poweroff(void)
27{
28	if (cpu_regulator && regulator_is_enabled(cpu_regulator))
29		regulator_force_disable(cpu_regulator);
30
31	/* give it some time */
32	mdelay(TIMEOUT_MS);
33
34	WARN_ON(1);
35}
36
37static int regulator_poweroff_probe(struct platform_device *pdev)
38{
39	/* If a pm_power_off function has already been added, leave it alone */
40	if (pm_power_off != NULL) {
41		dev_err(&pdev->dev,
42			"%s: pm_power_off function already registered\n",
43			__func__);
44		return -EBUSY;
45	}
46
47	cpu_regulator = devm_regulator_get(&pdev->dev, "cpu");
48	if (IS_ERR(cpu_regulator))
49		return PTR_ERR(cpu_regulator);
50
51	pm_power_off = &regulator_poweroff_do_poweroff;
52	return 0;
53}
54
55static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev)
56{
57	if (pm_power_off == &regulator_poweroff_do_poweroff)
58		pm_power_off = NULL;
59
60	return 0;
61}
62
63static const struct of_device_id of_regulator_poweroff_match[] = {
64	{ .compatible = "regulator-poweroff", },
65	{},
66};
67MODULE_DEVICE_TABLE(of, of_regulator_poweroff_match);
68
69static struct platform_driver regulator_poweroff_driver = {
70	.probe = regulator_poweroff_probe,
71	.remove = regulator_poweroff_remove,
72	.driver = {
73		.name = "poweroff-regulator",
74		.of_match_table = of_regulator_poweroff_match,
75	},
76};
77
78module_platform_driver(regulator_poweroff_driver);
79
80MODULE_AUTHOR("Michael Klein <michael@fossekall.de>");
81MODULE_DESCRIPTION("Regulator poweroff driver");
82MODULE_LICENSE("GPL v2");
83MODULE_ALIAS("platform:poweroff-regulator");