From: Simon Que Date: Tue, 8 Mar 2016 19:12:46 +0000 (-0800) Subject: platform/chrome: Add Chrome OS keyboard backlight LEDs support X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=492ef7829d2d09428803bffb187d5781bbc12ca5;p=linux-beck.git platform/chrome: Add Chrome OS keyboard backlight LEDs support This is a driver for ACPI-based keyboard backlight LEDs found on Chromebooks. The driver locates \\_SB.KBLT ACPI device and exports backlight as "chromeos::kbd_backlight" LED class device in sysfs. Signed-off-by: Simon Que Signed-off-by: Duncan Laurie Tested-by: Evan McClain Signed-off-by: Dmitry Torokhov Signed-off-by: Olof Johansson --- diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index d03df4a60d05..76bdae1a93bb 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -64,4 +64,14 @@ config CROS_EC_PROTO help ChromeOS EC communication protocol helpers. +config CROS_KBD_LED_BACKLIGHT + tristate "Backlight LED support for Chrome OS keyboards" + depends on LEDS_CLASS && ACPI + help + This option enables support for the keyboard backlight LEDs on + select Chrome OS systems. + + To compile this driver as a module, choose M here: the + module will be called cros_kbd_led_backlight. + endif # CHROMEOS_PLATFORMS diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index bc498bda8211..4f3462783a3c 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -1,8 +1,9 @@ -obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o -obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o -cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o \ - cros_ec_lightbar.o cros_ec_vbc.o -obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o -obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o -obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o +obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o +obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o +cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o \ + cros_ec_lightbar.o cros_ec_vbc.o +obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o +obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o +obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o +obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o 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 000000000000..ca3e4da852b4 --- /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 +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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 "); +MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:chromeos-keyboard-leds");