Commit | Line | Data |
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492ef782 SQ |
1 | /* |
2 | * Keyboard backlight LED driver for Chrome OS. | |
3 | * | |
4 | * Copyright (C) 2012 Google, Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | */ | |
16 | ||
17 | #include <linux/acpi.h> | |
18 | #include <linux/leds.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/platform_device.h> | |
25 | #include <linux/slab.h> | |
26 | ||
27 | /* Keyboard LED ACPI Device must be defined in firmware */ | |
28 | #define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT" | |
29 | #define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC" | |
30 | #define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM" | |
31 | ||
32 | #define ACPI_KEYBOARD_BACKLIGHT_MAX 100 | |
33 | ||
34 | static void keyboard_led_set_brightness(struct led_classdev *cdev, | |
35 | enum led_brightness brightness) | |
36 | { | |
37 | union acpi_object param; | |
38 | struct acpi_object_list input; | |
39 | acpi_status status; | |
40 | ||
41 | param.type = ACPI_TYPE_INTEGER; | |
42 | param.integer.value = brightness; | |
43 | input.count = 1; | |
44 | input.pointer = ¶m; | |
45 | ||
46 | status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE, | |
47 | &input, NULL); | |
48 | if (ACPI_FAILURE(status)) | |
49 | dev_err(cdev->dev, "Error setting keyboard LED value: %d\n", | |
50 | status); | |
51 | } | |
52 | ||
53 | static enum led_brightness | |
54 | keyboard_led_get_brightness(struct led_classdev *cdev) | |
55 | { | |
56 | unsigned long long brightness; | |
57 | acpi_status status; | |
58 | ||
59 | status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ, | |
60 | NULL, &brightness); | |
61 | if (ACPI_FAILURE(status)) { | |
62 | dev_err(cdev->dev, "Error getting keyboard LED value: %d\n", | |
63 | status); | |
64 | return -EIO; | |
65 | } | |
66 | ||
67 | return brightness; | |
68 | } | |
69 | ||
70 | static int keyboard_led_probe(struct platform_device *pdev) | |
71 | { | |
72 | struct led_classdev *cdev; | |
73 | acpi_handle handle; | |
74 | acpi_status status; | |
75 | int error; | |
76 | ||
77 | /* Look for the keyboard LED ACPI Device */ | |
78 | status = acpi_get_handle(ACPI_ROOT_OBJECT, | |
79 | ACPI_KEYBOARD_BACKLIGHT_DEVICE, | |
80 | &handle); | |
81 | if (ACPI_FAILURE(status)) { | |
82 | dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n", | |
83 | ACPI_KEYBOARD_BACKLIGHT_DEVICE, status); | |
84 | return -ENXIO; | |
85 | } | |
86 | ||
87 | cdev = devm_kzalloc(&pdev->dev, sizeof(*cdev), GFP_KERNEL); | |
88 | if (!cdev) | |
89 | return -ENOMEM; | |
90 | ||
91 | cdev->name = "chromeos::kbd_backlight"; | |
92 | cdev->max_brightness = ACPI_KEYBOARD_BACKLIGHT_MAX; | |
93 | cdev->flags |= LED_CORE_SUSPENDRESUME; | |
94 | cdev->brightness_set = keyboard_led_set_brightness; | |
95 | cdev->brightness_get = keyboard_led_get_brightness; | |
96 | ||
97 | error = devm_led_classdev_register(&pdev->dev, cdev); | |
98 | if (error) | |
99 | return error; | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static const struct acpi_device_id keyboard_led_id[] = { | |
105 | { "GOOG0002", 0 }, | |
106 | { } | |
107 | }; | |
108 | MODULE_DEVICE_TABLE(acpi, keyboard_led_id); | |
109 | ||
110 | static struct platform_driver keyboard_led_driver = { | |
111 | .driver = { | |
112 | .name = "chromeos-keyboard-leds", | |
113 | .acpi_match_table = ACPI_PTR(keyboard_led_id), | |
114 | }, | |
115 | .probe = keyboard_led_probe, | |
116 | }; | |
117 | module_platform_driver(keyboard_led_driver); | |
118 | ||
119 | MODULE_AUTHOR("Simon Que <sque@chromium.org>"); | |
120 | MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); | |
121 | MODULE_LICENSE("GPL"); | |
122 | MODULE_ALIAS("platform:chromeos-keyboard-leds"); |