Commit | Line | Data |
---|---|---|
96ff0f5c JL |
1 | /* |
2 | * Toggles a GPIO pin to power down a device | |
3 | * | |
4 | * Jamie Lentin <jm@lentin.co.uk> | |
5 | * Andrew Lunn <andrew@lunn.ch> | |
6 | * | |
7 | * Copyright (C) 2012 Jamie Lentin | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | * | |
13 | */ | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/platform_device.h> | |
86336ba4 | 18 | #include <linux/gpio/consumer.h> |
96ff0f5c | 19 | #include <linux/of_platform.h> |
96ff0f5c JL |
20 | #include <linux/module.h> |
21 | ||
22 | /* | |
23 | * Hold configuration here, cannot be more than one instance of the driver | |
24 | * since pm_power_off itself is global. | |
25 | */ | |
86336ba4 | 26 | static struct gpio_desc *reset_gpio; |
96ff0f5c JL |
27 | |
28 | static void gpio_poweroff_do_poweroff(void) | |
29 | { | |
86336ba4 | 30 | BUG_ON(!reset_gpio); |
96ff0f5c | 31 | |
5343527b | 32 | /* drive it active, also inactive->active edge */ |
86336ba4 | 33 | gpiod_direction_output(reset_gpio, 1); |
96ff0f5c | 34 | mdelay(100); |
5343527b | 35 | /* drive inactive, also active->inactive edge */ |
86336ba4 | 36 | gpiod_set_value(reset_gpio, 0); |
96ff0f5c | 37 | mdelay(100); |
5343527b AL |
38 | |
39 | /* drive it active, also inactive->active edge */ | |
86336ba4 | 40 | gpiod_set_value(reset_gpio, 1); |
96ff0f5c JL |
41 | |
42 | /* give it some time */ | |
43 | mdelay(3000); | |
44 | ||
45 | WARN_ON(1); | |
46 | } | |
47 | ||
6d2cea4f | 48 | static int gpio_poweroff_probe(struct platform_device *pdev) |
96ff0f5c | 49 | { |
96ff0f5c | 50 | bool input = false; |
96ff0f5c JL |
51 | |
52 | /* If a pm_power_off function has already been added, leave it alone */ | |
53 | if (pm_power_off != NULL) { | |
86336ba4 LW |
54 | dev_err(&pdev->dev, |
55 | "%s: pm_power_off function already registered", | |
96ff0f5c JL |
56 | __func__); |
57 | return -EBUSY; | |
58 | } | |
59 | ||
86336ba4 LW |
60 | reset_gpio = devm_gpiod_get(&pdev->dev, NULL); |
61 | if (IS_ERR(reset_gpio)) | |
62 | return PTR_ERR(reset_gpio); | |
96ff0f5c | 63 | |
5343527b | 64 | input = of_property_read_bool(pdev->dev.of_node, "input"); |
96ff0f5c | 65 | |
96ff0f5c | 66 | if (input) { |
86336ba4 LW |
67 | if (gpiod_direction_input(reset_gpio)) { |
68 | dev_err(&pdev->dev, | |
69 | "Could not set direction of reset GPIO to input\n"); | |
70 | return -ENODEV; | |
96ff0f5c JL |
71 | } |
72 | } else { | |
86336ba4 LW |
73 | if (gpiod_direction_output(reset_gpio, 0)) { |
74 | dev_err(&pdev->dev, | |
75 | "Could not set direction of reset GPIO\n"); | |
76 | return -ENODEV; | |
96ff0f5c JL |
77 | } |
78 | } | |
79 | ||
80 | pm_power_off = &gpio_poweroff_do_poweroff; | |
81 | return 0; | |
96ff0f5c JL |
82 | } |
83 | ||
6d2cea4f | 84 | static int gpio_poweroff_remove(struct platform_device *pdev) |
96ff0f5c | 85 | { |
96ff0f5c JL |
86 | if (pm_power_off == &gpio_poweroff_do_poweroff) |
87 | pm_power_off = NULL; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | static const struct of_device_id of_gpio_poweroff_match[] = { | |
93 | { .compatible = "gpio-poweroff", }, | |
94 | {}, | |
95 | }; | |
96 | ||
97 | static struct platform_driver gpio_poweroff_driver = { | |
98 | .probe = gpio_poweroff_probe, | |
6d2cea4f | 99 | .remove = gpio_poweroff_remove, |
96ff0f5c | 100 | .driver = { |
5343527b | 101 | .name = "poweroff-gpio", |
5343527b AL |
102 | .of_match_table = of_gpio_poweroff_match, |
103 | }, | |
96ff0f5c JL |
104 | }; |
105 | ||
106 | module_platform_driver(gpio_poweroff_driver); | |
107 | ||
108 | MODULE_AUTHOR("Jamie Lentin <jm@lentin.co.uk>"); | |
109 | MODULE_DESCRIPTION("GPIO poweroff driver"); | |
5343527b | 110 | MODULE_LICENSE("GPL v2"); |
96ff0f5c | 111 | MODULE_ALIAS("platform:poweroff-gpio"); |