/*
|
* 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");
|
