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![Linus Torvalds](/assets/img/avatar_default.png)
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
235 lines
5.1 KiB
C
235 lines
5.1 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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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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nonseekable_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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