diff options
Diffstat (limited to 'drivers/platform/chrome/cros_kbd_led_backlight.c')
| -rw-r--r-- | drivers/platform/chrome/cros_kbd_led_backlight.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c new file mode 100644 index 000000000..ca3e4da85 --- /dev/null +++ b/drivers/platform/chrome/cros_kbd_led_backlight.c @@ -0,0 +1,122 @@ +/* + * Keyboard backlight LED driver for Chrome OS. + * + * Copyright (C) 2012 Google, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/acpi.h> +#include <linux/leds.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +/* Keyboard LED ACPI Device must be defined in firmware */ +#define ACPI_KEYBOARD_BACKLIGHT_DEVICE "\\_SB.KBLT" +#define ACPI_KEYBOARD_BACKLIGHT_READ ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBQC" +#define ACPI_KEYBOARD_BACKLIGHT_WRITE ACPI_KEYBOARD_BACKLIGHT_DEVICE ".KBCM" + +#define ACPI_KEYBOARD_BACKLIGHT_MAX 100 + +static void keyboard_led_set_brightness(struct led_classdev *cdev, + enum led_brightness brightness) +{ + union acpi_object param; + struct acpi_object_list input; + acpi_status status; + + param.type = ACPI_TYPE_INTEGER; + param.integer.value = brightness; + input.count = 1; + input.pointer = ¶m; + + status = acpi_evaluate_object(NULL, ACPI_KEYBOARD_BACKLIGHT_WRITE, + &input, NULL); + if (ACPI_FAILURE(status)) + dev_err(cdev->dev, "Error setting keyboard LED value: %d\n", + status); +} + +static enum led_brightness +keyboard_led_get_brightness(struct led_classdev *cdev) +{ + unsigned long long brightness; + acpi_status status; + + status = acpi_evaluate_integer(NULL, ACPI_KEYBOARD_BACKLIGHT_READ, + NULL, &brightness); + if (ACPI_FAILURE(status)) { + dev_err(cdev->dev, "Error getting keyboard LED value: %d\n", + status); + return -EIO; + } + + return brightness; +} + +static int keyboard_led_probe(struct platform_device *pdev) +{ + struct led_classdev *cdev; + acpi_handle handle; + acpi_status status; + int error; + + /* Look for the keyboard LED ACPI Device */ + status = acpi_get_handle(ACPI_ROOT_OBJECT, + ACPI_KEYBOARD_BACKLIGHT_DEVICE, + &handle); + if (ACPI_FAILURE(status)) { + dev_err(&pdev->dev, "Unable to find ACPI device %s: %d\n", + ACPI_KEYBOARD_BACKLIGHT_DEVICE, status); + return -ENXIO; + } + + cdev = devm_kzalloc(&pdev->dev, sizeof(*cdev), GFP_KERNEL); + if (!cdev) + return -ENOMEM; + + cdev->name = "chromeos::kbd_backlight"; + cdev->max_brightness = ACPI_KEYBOARD_BACKLIGHT_MAX; + cdev->flags |= LED_CORE_SUSPENDRESUME; + cdev->brightness_set = keyboard_led_set_brightness; + cdev->brightness_get = keyboard_led_get_brightness; + + error = devm_led_classdev_register(&pdev->dev, cdev); + if (error) + return error; + + return 0; +} + +static const struct acpi_device_id keyboard_led_id[] = { + { "GOOG0002", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, keyboard_led_id); + +static struct platform_driver keyboard_led_driver = { + .driver = { + .name = "chromeos-keyboard-leds", + .acpi_match_table = ACPI_PTR(keyboard_led_id), + }, + .probe = keyboard_led_probe, +}; +module_platform_driver(keyboard_led_driver); + +MODULE_AUTHOR("Simon Que <sque@chromium.org>"); +MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:chromeos-keyboard-leds"); |