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457 lines
10 KiB
457 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Roccat driver for Linux |
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* |
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* Copyright (c) 2010 Stefan Achatz <[email protected]> |
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*/ |
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/* |
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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/signal.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 __poll_t 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 EPOLLIN | EPOLLRDNORM; |
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if (!reader->device->exist) |
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return EPOLLERR | EPOLLHUP; |
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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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if (retval < 0) { |
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pr_warn("can't get major number\n"); |
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goto error; |
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} |
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roccat_major = MAJOR(dev_id); |
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cdev_init(&roccat_cdev, &roccat_ops); |
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retval = cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); |
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if (retval < 0) { |
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pr_warn("cannot add cdev\n"); |
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goto cleanup_alloc_chrdev_region; |
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} |
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return 0; |
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cleanup_alloc_chrdev_region: |
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unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); |
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error: |
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return retval; |
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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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