![Stefan Achatz](/assets/img/avatar_default.png)
Fixed parameter documentation. Signed-off-by: Stefan Achatz <erazor_de@users.sourceforge.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
452 lines
10 KiB
C
452 lines
10 KiB
C
/*
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* Roccat driver for Linux
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*
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* Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net>
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*/
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/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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/*
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* Module roccat is a char device used to report special events of roccat
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* hardware to userland. These events include requests for on-screen-display of
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* profile or dpi settings or requests for execution of macro sequences that are
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* not stored in device. The information in these events depends on hid device
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* implementation and contains data that is not available in a single hid event
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* or else hidraw could have been used.
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* It is inspired by hidraw, but uses only one circular buffer for all readers.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cdev.h>
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#include <linux/poll.h>
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#include <linux/sched.h>
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#include <linux/hid-roccat.h>
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#include <linux/module.h>
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#define ROCCAT_FIRST_MINOR 0
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#define ROCCAT_MAX_DEVICES 8
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/* should be a power of 2 for performance reason */
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#define ROCCAT_CBUF_SIZE 16
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struct roccat_report {
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uint8_t *value;
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};
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struct roccat_device {
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unsigned int minor;
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int report_size;
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int open;
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int exist;
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wait_queue_head_t wait;
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struct device *dev;
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struct hid_device *hid;
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struct list_head readers;
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/* protects modifications of readers list */
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struct mutex readers_lock;
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/*
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* circular_buffer has one writer and multiple readers with their own
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* read pointers
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*/
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struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
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int cbuf_end;
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struct mutex cbuf_lock;
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};
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struct roccat_reader {
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struct list_head node;
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struct roccat_device *device;
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int cbuf_start;
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};
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static int roccat_major;
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static struct cdev roccat_cdev;
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static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
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/* protects modifications of devices array */
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static DEFINE_MUTEX(devices_lock);
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static ssize_t roccat_read(struct file *file, char __user *buffer,
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size_t count, loff_t *ppos)
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{
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struct roccat_reader *reader = file->private_data;
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struct roccat_device *device = reader->device;
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struct roccat_report *report;
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ssize_t retval = 0, len;
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DECLARE_WAITQUEUE(wait, current);
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mutex_lock(&device->cbuf_lock);
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/* no data? */
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if (reader->cbuf_start == device->cbuf_end) {
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add_wait_queue(&device->wait, &wait);
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set_current_state(TASK_INTERRUPTIBLE);
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/* wait for data */
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while (reader->cbuf_start == device->cbuf_end) {
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if (file->f_flags & O_NONBLOCK) {
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retval = -EAGAIN;
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break;
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}
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if (signal_pending(current)) {
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retval = -ERESTARTSYS;
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break;
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}
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if (!device->exist) {
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retval = -EIO;
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break;
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}
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mutex_unlock(&device->cbuf_lock);
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schedule();
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mutex_lock(&device->cbuf_lock);
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set_current_state(TASK_INTERRUPTIBLE);
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}
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&device->wait, &wait);
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}
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/* here we either have data or a reason to return if retval is set */
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if (retval)
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goto exit_unlock;
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report = &device->cbuf[reader->cbuf_start];
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/*
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* If report is larger than requested amount of data, rest of report
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* is lost!
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*/
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len = device->report_size > count ? count : device->report_size;
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if (copy_to_user(buffer, report->value, len)) {
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retval = -EFAULT;
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goto exit_unlock;
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}
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retval += len;
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reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
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exit_unlock:
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mutex_unlock(&device->cbuf_lock);
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return retval;
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}
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static unsigned int roccat_poll(struct file *file, poll_table *wait)
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{
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struct roccat_reader *reader = file->private_data;
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poll_wait(file, &reader->device->wait, wait);
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if (reader->cbuf_start != reader->device->cbuf_end)
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return POLLIN | POLLRDNORM;
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if (!reader->device->exist)
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return POLLERR | POLLHUP;
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return 0;
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}
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static int roccat_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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struct roccat_reader *reader;
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struct roccat_device *device;
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int error = 0;
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reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
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if (!reader)
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return -ENOMEM;
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mutex_lock(&devices_lock);
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device = devices[minor];
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if (!device) {
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pr_emerg("roccat device with minor %d doesn't exist\n", minor);
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error = -ENODEV;
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goto exit_err_devices;
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}
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mutex_lock(&device->readers_lock);
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if (!device->open++) {
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/* power on device on adding first reader */
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error = hid_hw_power(device->hid, PM_HINT_FULLON);
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if (error < 0) {
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--device->open;
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goto exit_err_readers;
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}
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error = hid_hw_open(device->hid);
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if (error < 0) {
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hid_hw_power(device->hid, PM_HINT_NORMAL);
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--device->open;
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goto exit_err_readers;
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}
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}
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reader->device = device;
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/* new reader doesn't get old events */
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reader->cbuf_start = device->cbuf_end;
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list_add_tail(&reader->node, &device->readers);
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file->private_data = reader;
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exit_err_readers:
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mutex_unlock(&device->readers_lock);
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exit_err_devices:
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mutex_unlock(&devices_lock);
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if (error)
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kfree(reader);
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return error;
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}
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static int roccat_release(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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struct roccat_reader *reader = file->private_data;
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struct roccat_device *device;
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mutex_lock(&devices_lock);
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device = devices[minor];
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if (!device) {
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mutex_unlock(&devices_lock);
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pr_emerg("roccat device with minor %d doesn't exist\n", minor);
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return -ENODEV;
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}
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mutex_lock(&device->readers_lock);
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list_del(&reader->node);
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mutex_unlock(&device->readers_lock);
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kfree(reader);
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if (!--device->open) {
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/* removing last reader */
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if (device->exist) {
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hid_hw_power(device->hid, PM_HINT_NORMAL);
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hid_hw_close(device->hid);
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} else {
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kfree(device);
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}
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}
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mutex_unlock(&devices_lock);
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return 0;
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}
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/*
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* roccat_report_event() - output data to readers
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* @minor: minor device number returned by roccat_connect()
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* @data: pointer to data
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*
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* Return value is zero on success, a negative error code on failure.
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*
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* This is called from interrupt handler.
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*/
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int roccat_report_event(int minor, u8 const *data)
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{
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struct roccat_device *device;
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struct roccat_reader *reader;
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struct roccat_report *report;
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uint8_t *new_value;
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device = devices[minor];
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new_value = kmemdup(data, device->report_size, GFP_ATOMIC);
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if (!new_value)
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return -ENOMEM;
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report = &device->cbuf[device->cbuf_end];
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/* passing NULL is safe */
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kfree(report->value);
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report->value = new_value;
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device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;
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list_for_each_entry(reader, &device->readers, node) {
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/*
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* As we already inserted one element, the buffer can't be
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* empty. If start and end are equal, buffer is full and we
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* increase start, so that slow reader misses one event, but
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* gets the newer ones in the right order.
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*/
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if (reader->cbuf_start == device->cbuf_end)
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reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
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}
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wake_up_interruptible(&device->wait);
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return 0;
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}
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EXPORT_SYMBOL_GPL(roccat_report_event);
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/*
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* roccat_connect() - create a char device for special event output
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* @class: the class thats used to create the device. Meant to hold device
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* specific sysfs attributes.
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* @hid: the hid device the char device should be connected to.
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* @report_size: size of reports
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*
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* Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
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* success, a negative error code on failure.
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*/
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int roccat_connect(struct class *klass, struct hid_device *hid, int report_size)
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{
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unsigned int minor;
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struct roccat_device *device;
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int temp;
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device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
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if (!device)
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return -ENOMEM;
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mutex_lock(&devices_lock);
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for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
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if (devices[minor])
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continue;
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break;
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}
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if (minor < ROCCAT_MAX_DEVICES) {
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devices[minor] = device;
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} else {
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mutex_unlock(&devices_lock);
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kfree(device);
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return -EINVAL;
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}
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device->dev = device_create(klass, &hid->dev,
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MKDEV(roccat_major, minor), NULL,
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"%s%s%d", "roccat", hid->driver->name, minor);
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if (IS_ERR(device->dev)) {
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devices[minor] = NULL;
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mutex_unlock(&devices_lock);
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temp = PTR_ERR(device->dev);
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kfree(device);
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return temp;
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}
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mutex_unlock(&devices_lock);
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init_waitqueue_head(&device->wait);
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INIT_LIST_HEAD(&device->readers);
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mutex_init(&device->readers_lock);
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mutex_init(&device->cbuf_lock);
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device->minor = minor;
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device->hid = hid;
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device->exist = 1;
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device->cbuf_end = 0;
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device->report_size = report_size;
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return minor;
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}
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EXPORT_SYMBOL_GPL(roccat_connect);
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/* roccat_disconnect() - remove char device from hid device
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* @minor: the minor device number returned by roccat_connect()
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*/
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void roccat_disconnect(int minor)
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{
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struct roccat_device *device;
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mutex_lock(&devices_lock);
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device = devices[minor];
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mutex_unlock(&devices_lock);
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device->exist = 0; /* TODO exist maybe not needed */
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device_destroy(device->dev->class, MKDEV(roccat_major, minor));
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mutex_lock(&devices_lock);
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devices[minor] = NULL;
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mutex_unlock(&devices_lock);
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if (device->open) {
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hid_hw_close(device->hid);
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wake_up_interruptible(&device->wait);
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} else {
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kfree(device);
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}
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}
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EXPORT_SYMBOL_GPL(roccat_disconnect);
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static long roccat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct inode *inode = file_inode(file);
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struct roccat_device *device;
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unsigned int minor = iminor(inode);
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long retval = 0;
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mutex_lock(&devices_lock);
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device = devices[minor];
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if (!device) {
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retval = -ENODEV;
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goto out;
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}
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switch (cmd) {
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case ROCCATIOCGREPSIZE:
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if (put_user(device->report_size, (int __user *)arg))
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retval = -EFAULT;
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break;
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default:
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retval = -ENOTTY;
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}
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out:
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mutex_unlock(&devices_lock);
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return retval;
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}
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static const struct file_operations roccat_ops = {
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.owner = THIS_MODULE,
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.read = roccat_read,
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.poll = roccat_poll,
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.open = roccat_open,
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.release = roccat_release,
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.llseek = noop_llseek,
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.unlocked_ioctl = roccat_ioctl,
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};
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static int __init roccat_init(void)
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{
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int retval;
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dev_t dev_id;
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retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
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ROCCAT_MAX_DEVICES, "roccat");
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roccat_major = MAJOR(dev_id);
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if (retval < 0) {
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pr_warn("can't get major number\n");
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return retval;
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}
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cdev_init(&roccat_cdev, &roccat_ops);
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cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);
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return 0;
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}
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static void __exit roccat_exit(void)
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{
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dev_t dev_id = MKDEV(roccat_major, 0);
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cdev_del(&roccat_cdev);
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unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
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}
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module_init(roccat_init);
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module_exit(roccat_exit);
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MODULE_AUTHOR("Stefan Achatz");
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MODULE_DESCRIPTION("USB Roccat char device");
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MODULE_LICENSE("GPL v2");
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