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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 3 normalized pattern(s): 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 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 [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] 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 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 [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
226 lines
4.7 KiB
C
226 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Userspace driver for the LED subsystem
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*
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* Copyright (C) 2016 David Lechner <david@lechnology.com>
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*
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* Based on uinput.c: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/leds.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <uapi/linux/uleds.h>
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#define ULEDS_NAME "uleds"
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enum uleds_state {
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ULEDS_STATE_UNKNOWN,
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ULEDS_STATE_REGISTERED,
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};
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struct uleds_device {
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struct uleds_user_dev user_dev;
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struct led_classdev led_cdev;
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struct mutex mutex;
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enum uleds_state state;
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wait_queue_head_t waitq;
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int brightness;
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bool new_data;
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};
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static struct miscdevice uleds_misc;
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static void uleds_brightness_set(struct led_classdev *led_cdev,
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enum led_brightness brightness)
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{
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struct uleds_device *udev = container_of(led_cdev, struct uleds_device,
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led_cdev);
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if (udev->brightness != brightness) {
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udev->brightness = brightness;
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udev->new_data = true;
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wake_up_interruptible(&udev->waitq);
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}
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}
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static int uleds_open(struct inode *inode, struct file *file)
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{
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struct uleds_device *udev;
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udev = kzalloc(sizeof(*udev), GFP_KERNEL);
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if (!udev)
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return -ENOMEM;
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udev->led_cdev.name = udev->user_dev.name;
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udev->led_cdev.brightness_set = uleds_brightness_set;
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mutex_init(&udev->mutex);
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init_waitqueue_head(&udev->waitq);
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udev->state = ULEDS_STATE_UNKNOWN;
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file->private_data = udev;
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stream_open(inode, file);
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return 0;
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}
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static ssize_t uleds_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos)
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{
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struct uleds_device *udev = file->private_data;
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const char *name;
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int ret;
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if (count == 0)
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return 0;
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ret = mutex_lock_interruptible(&udev->mutex);
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if (ret)
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return ret;
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if (udev->state == ULEDS_STATE_REGISTERED) {
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ret = -EBUSY;
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goto out;
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}
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if (count != sizeof(struct uleds_user_dev)) {
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ret = -EINVAL;
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goto out;
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}
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if (copy_from_user(&udev->user_dev, buffer,
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sizeof(struct uleds_user_dev))) {
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ret = -EFAULT;
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goto out;
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}
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name = udev->user_dev.name;
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if (!name[0] || !strcmp(name, ".") || !strcmp(name, "..") ||
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strchr(name, '/')) {
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ret = -EINVAL;
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goto out;
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}
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if (udev->user_dev.max_brightness <= 0) {
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ret = -EINVAL;
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goto out;
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}
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udev->led_cdev.max_brightness = udev->user_dev.max_brightness;
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ret = devm_led_classdev_register(uleds_misc.this_device,
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&udev->led_cdev);
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if (ret < 0)
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goto out;
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udev->new_data = true;
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udev->state = ULEDS_STATE_REGISTERED;
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ret = count;
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out:
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mutex_unlock(&udev->mutex);
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return ret;
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}
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static ssize_t uleds_read(struct file *file, char __user *buffer, size_t count,
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loff_t *ppos)
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{
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struct uleds_device *udev = file->private_data;
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ssize_t retval;
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if (count < sizeof(udev->brightness))
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return 0;
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do {
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retval = mutex_lock_interruptible(&udev->mutex);
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if (retval)
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return retval;
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if (udev->state != ULEDS_STATE_REGISTERED) {
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retval = -ENODEV;
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} else if (!udev->new_data && (file->f_flags & O_NONBLOCK)) {
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retval = -EAGAIN;
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} else if (udev->new_data) {
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retval = copy_to_user(buffer, &udev->brightness,
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sizeof(udev->brightness));
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udev->new_data = false;
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retval = sizeof(udev->brightness);
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}
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mutex_unlock(&udev->mutex);
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if (retval)
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break;
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if (!(file->f_flags & O_NONBLOCK))
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retval = wait_event_interruptible(udev->waitq,
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udev->new_data ||
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udev->state != ULEDS_STATE_REGISTERED);
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} while (retval == 0);
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return retval;
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}
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static __poll_t uleds_poll(struct file *file, poll_table *wait)
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{
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struct uleds_device *udev = file->private_data;
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poll_wait(file, &udev->waitq, wait);
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if (udev->new_data)
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return EPOLLIN | EPOLLRDNORM;
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return 0;
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}
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static int uleds_release(struct inode *inode, struct file *file)
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{
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struct uleds_device *udev = file->private_data;
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if (udev->state == ULEDS_STATE_REGISTERED) {
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udev->state = ULEDS_STATE_UNKNOWN;
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devm_led_classdev_unregister(uleds_misc.this_device,
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&udev->led_cdev);
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}
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kfree(udev);
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return 0;
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}
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static const struct file_operations uleds_fops = {
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.owner = THIS_MODULE,
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.open = uleds_open,
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.release = uleds_release,
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.read = uleds_read,
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.write = uleds_write,
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.poll = uleds_poll,
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.llseek = no_llseek,
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};
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static struct miscdevice uleds_misc = {
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.fops = &uleds_fops,
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.minor = MISC_DYNAMIC_MINOR,
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.name = ULEDS_NAME,
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};
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static int __init uleds_init(void)
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{
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return misc_register(&uleds_misc);
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}
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module_init(uleds_init);
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static void __exit uleds_exit(void)
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{
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misc_deregister(&uleds_misc);
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}
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module_exit(uleds_exit);
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MODULE_AUTHOR("David Lechner <david@lechnology.com>");
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MODULE_DESCRIPTION("Userspace driver for the LED subsystem");
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MODULE_LICENSE("GPL");
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