From: Simon Que <sque@xxxxxxxxxxxx>
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 <sque@xxxxxxxxxxxx>
Signed-off-by: Duncan Laurie <dlaurie@xxxxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
---
drivers/leds/Kconfig | 11 ++++
drivers/leds/Makefile | 1 +
drivers/leds/leds-chromeos-keyboard.c | 106 ++++++++++++++++++++++++++++++++++
3 files changed, 118 insertions(+)
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index f86527cf..02aaaf1 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -581,6 +581,17 @@ config LEDS_SN3218
This driver can also be built as a module. If so the module
will be called leds-sn3218.
+config LEDS_CHROMEOS_KEYBOARD
+ tristate "LED backlight support for Chrome OS keyboards"
+ depends on LEDS_CLASS && ACPI
+ depends on CHROME_PLATFORMS || COMPILE_TEST
+ help
+ This option enables support for the keyboard backlight LEDs on
+ select Chrome OS systems.
+
+ This driver can also be built as a module. If so the module
+ will be called leds-chromeos-keyboard.
+
comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 89c9b6f..5b96d15 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_LEDS_KTD2692) += leds-ktd2692.o
obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
obj-$(CONFIG_LEDS_SEAD3) += leds-sead3.o
obj-$(CONFIG_LEDS_SN3218) += leds-sn3218.o
+obj-$(CONFIG_LEDS_CHROMEOS_KEYBOARD) += leds-chromeos-keyboard.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-chromeos-keyboard.c b/drivers/leds/leds-chromeos-keyboard.c
new file mode 100644
index 0000000..3592f09
--- /dev/null
+++ b/drivers/leds/leds-chromeos-keyboard.c
@@ -0,0 +1,106 @@
+/*
+ * 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 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->brightness_set = keyboard_led_set_brightness;
+ cdev->max_brightness = ACPI_KEYBOARD_BACKLIGHT_MAX;
+ cdev->brightness = cdev->max_brightness;
+ cdev->flags |= LED_CORE_SUSPENDRESUME;
+
+ error = devm_led_classdev_register(&pdev->dev, cdev);
+ if (error)
+ return error;
+
+ platform_set_drvdata(pdev, cdev);
+ 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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("ChromeOS Keyboard backlight LED Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:chromeos-keyboard-leds");
--
2.7.0.rc3.207.g0ac5344
--
Dmitry
--
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