Input: export LEDs as class devices in sysfs (f60c8ba7) · Commits · 戴 / test

Documentation/leds/leds-class.txt

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		@@ -2,9 +2,6 @@
		LED handling under Linux
		========================

		If you're reading this and thinking about keyboard leds, these are
		handled by the input subsystem and the led class is not needed.

		In its simplest form, the LED class just allows control of LEDs from
		userspace. LEDs appear in /sys/class/leds/. The maximum brightness of the
		LED is defined in max_brightness file. The brightness file will set the brightness

drivers/input/Kconfig

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		@@ -25,6 +25,19 @@ config INPUT

		if INPUT

		config INPUT_LEDS
		tristate "Export input device LEDs in sysfs"
		depends on LEDS_CLASS
		default INPUT
		help
		Say Y here if you would like to export LEDs on input devices
		as standard LED class devices in sysfs.

		If unsure, say Y.

		To compile this driver as a module, choose M here: the
		module will be called input-leds.

		config INPUT_FF_MEMLESS
		tristate "Support for memoryless force-feedback devices"
		help

drivers/input/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,7 @@ obj-$(CONFIG_INPUT_POLLDEV) += input-polldev.o
		obj-$(CONFIG_INPUT_SPARSEKMAP) += sparse-keymap.o
		obj-$(CONFIG_INPUT_MATRIXKMAP) += matrix-keymap.o

		obj-$(CONFIG_INPUT_LEDS) += input-leds.o
		obj-$(CONFIG_INPUT_MOUSEDEV) += mousedev.o
		obj-$(CONFIG_INPUT_JOYDEV) += joydev.o
		obj-$(CONFIG_INPUT_EVDEV) += evdev.o

drivers/input/input-leds.c

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Original line number	Diff line number	Diff line
		/*
		* LED support for the input layer
		*
		* Copyright 2010-2015 Samuel Thibault <samuel.thibault@ens-lyon.org>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*/

		#include <linux/kernel.h>
		#include <linux/slab.h>
		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/leds.h>
		#include <linux/input.h>

		#if IS_ENABLED(CONFIG_VT)
		#define VT_TRIGGER(_name) .trigger = _name
		#else
		#define VT_TRIGGER(_name) .trigger = NULL
		#endif

		static const struct {
		const char *name;
		const char *trigger;
		} input_led_info[LED_CNT] = {
		[LED_NUML] = { "numlock", VT_TRIGGER("kbd-numlock") },
		[LED_CAPSL] = { "capslock", VT_TRIGGER("kbd-capslock") },
		[LED_SCROLLL] = { "scrolllock", VT_TRIGGER("kbd-scrolllock") },
		[LED_COMPOSE] = { "compose" },
		[LED_KANA] = { "kana", VT_TRIGGER("kbd-kanalock") },
		[LED_SLEEP] = { "sleep" } ,
		[LED_SUSPEND] = { "suspend" },
		[LED_MUTE] = { "mute" },
		[LED_MISC] = { "misc" },
		[LED_MAIL] = { "mail" },
		[LED_CHARGING] = { "charging" },
		};

		struct input_led {
		struct led_classdev cdev;
		struct input_handle *handle;
		unsigned int code; /* One of LED_* constants */
		};

		struct input_leds {
		struct input_handle handle;
		unsigned int num_leds;
		struct input_led leds[];
		};

		static enum led_brightness input_leds_brightness_get(struct led_classdev *cdev)
		{
		struct input_led *led = container_of(cdev, struct input_led, cdev);
		struct input_dev *input = led->handle->dev;

		return test_bit(led->code, input->led) ? cdev->max_brightness : 0;
		}

		static void input_leds_brightness_set(struct led_classdev *cdev,
		enum led_brightness brightness)
		{
		struct input_led *led = container_of(cdev, struct input_led, cdev);

		input_inject_event(led->handle, EV_LED, led->code, !!brightness);
		}

		static void input_leds_event(struct input_handle *handle, unsigned int type,
		unsigned int code, int value)
		{
		}

		static int input_leds_connect(struct input_handler *handler,
		struct input_dev *dev,
		const struct input_device_id *id)
		{
		struct input_leds *leds;
		unsigned int num_leds;
		unsigned int led_code;
		int led_no;
		int error;

		num_leds = bitmap_weight(dev->ledbit, LED_CNT);
		if (!num_leds)
		return -ENXIO;

		leds = kzalloc(sizeof(leds) + num_leds sizeof(*leds->leds),
		GFP_KERNEL);
		if (!leds)
		return -ENOMEM;

		leds->num_leds = num_leds;

		leds->handle.dev = dev;
		leds->handle.handler = handler;
		leds->handle.name = "leds";
		leds->handle.private = leds;

		error = input_register_handle(&leds->handle);
		if (error)
		goto err_free_mem;

		error = input_open_device(&leds->handle);
		if (error)
		goto err_unregister_handle;

		led_no = 0;
		for_each_set_bit(led_code, dev->ledbit, LED_CNT) {
		struct input_led *led = &leds->leds[led_no];

		led->handle = &leds->handle;
		led->code = led_code;

		if (WARN_ON(!input_led_info[led_code].name))
		continue;

		led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
		dev_name(&dev->dev),
		input_led_info[led_code].name);
		if (!led->cdev.name) {
		error = -ENOMEM;
		goto err_unregister_leds;
		}

		led->cdev.max_brightness = 1;
		led->cdev.brightness_get = input_leds_brightness_get;
		led->cdev.brightness_set = input_leds_brightness_set;
		led->cdev.default_trigger = input_led_info[led_code].trigger;

		error = led_classdev_register(&dev->dev, &led->cdev);
		if (error) {
		dev_err(&dev->dev, "failed to register LED %s: %d\n",
		led->cdev.name, error);
		kfree(led->cdev.name);
		goto err_unregister_leds;
		}

		led_no++;
		}

		return 0;

		err_unregister_leds:
		while (--led_no >= 0) {
		struct input_led *led = &leds->leds[led_no];

		led_classdev_unregister(&led->cdev);
		kfree(led->cdev.name);
		}

		input_close_device(&leds->handle);

		err_unregister_handle:
		input_unregister_handle(&leds->handle);

		err_free_mem:
		kfree(leds);
		return error;
		}

		static void input_leds_disconnect(struct input_handle *handle)
		{
		struct input_leds *leds = handle->private;
		int i;

		for (i = 0; i < leds->num_leds; i++) {
		struct input_led *led = &leds->leds[i];

		led_classdev_unregister(&led->cdev);
		kfree(led->cdev.name);
		}

		input_close_device(handle);
		input_unregister_handle(handle);

		kfree(leds);
		}

		static const struct input_device_id input_leds_ids[] = {
		{
		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
		.evbit = { BIT_MASK(EV_LED) },
		},
		{ },
		};
		MODULE_DEVICE_TABLE(input, input_leds_ids);

		static struct input_handler input_leds_handler = {
		.event = input_leds_event,
		.connect = input_leds_connect,
		.disconnect = input_leds_disconnect,
		.name = "leds",
		.id_table = input_leds_ids,
		};

		static int __init input_leds_init(void)
		{
		return input_register_handler(&input_leds_handler);
		}
		module_init(input_leds_init);

		static void __exit input_leds_exit(void)
		{
		input_unregister_handler(&input_leds_handler);
		}
		module_exit(input_leds_exit);

		MODULE_AUTHOR("Samuel Thibault <samuel.thibault@ens-lyon.org>");
		MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>");
		MODULE_DESCRIPTION("Input -> LEDs Bridge");
		MODULE_LICENSE("GPL v2");

drivers/leds/Kconfig

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Original line number	Diff line number	Diff line
		@@ -11,9 +11,6 @@ menuconfig NEW_LEDS
		Say Y to enable Linux LED support. This allows control of supported
		LEDs from both userspace and optionally, by kernel events (triggers).

		This is not related to standard keyboard LEDs which are controlled
		via the input system.

		if NEW_LEDS

		config LEDS_CLASS

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