linux/drivers/hid/hid-roccat.c
<<
>>
Prefs
   1/*
   2 * Roccat driver for Linux
   3 *
   4 * Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net>
   5 */
   6
   7/*
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License as published by the Free
  10 * Software Foundation; either version 2 of the License, or (at your option)
  11 * any later version.
  12 */
  13
  14/*
  15 * Module roccat is a char device used to report special events of roccat
  16 * hardware to userland. These events include requests for on-screen-display of
  17 * profile or dpi settings or requests for execution of macro sequences that are
  18 * not stored in device. The information in these events depends on hid device
  19 * implementation and contains data that is not available in a single hid event
  20 * or else hidraw could have been used.
  21 * It is inspired by hidraw, but uses only one circular buffer for all readers.
  22 */
  23
  24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  25
  26#include <linux/cdev.h>
  27#include <linux/poll.h>
  28#include <linux/sched.h>
  29#include <linux/hid-roccat.h>
  30#include <linux/module.h>
  31
  32#define ROCCAT_FIRST_MINOR 0
  33#define ROCCAT_MAX_DEVICES 8
  34
  35/* should be a power of 2 for performance reason */
  36#define ROCCAT_CBUF_SIZE 16
  37
  38struct roccat_report {
  39        uint8_t *value;
  40};
  41
  42struct roccat_device {
  43        unsigned int minor;
  44        int report_size;
  45        int open;
  46        int exist;
  47        wait_queue_head_t wait;
  48        struct device *dev;
  49        struct hid_device *hid;
  50        struct list_head readers;
  51        /* protects modifications of readers list */
  52        struct mutex readers_lock;
  53
  54        /*
  55         * circular_buffer has one writer and multiple readers with their own
  56         * read pointers
  57         */
  58        struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
  59        int cbuf_end;
  60        struct mutex cbuf_lock;
  61};
  62
  63struct roccat_reader {
  64        struct list_head node;
  65        struct roccat_device *device;
  66        int cbuf_start;
  67};
  68
  69static int roccat_major;
  70static struct cdev roccat_cdev;
  71
  72static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
  73/* protects modifications of devices array */
  74static DEFINE_MUTEX(devices_lock);
  75
  76static ssize_t roccat_read(struct file *file, char __user *buffer,
  77                size_t count, loff_t *ppos)
  78{
  79        struct roccat_reader *reader = file->private_data;
  80        struct roccat_device *device = reader->device;
  81        struct roccat_report *report;
  82        ssize_t retval = 0, len;
  83        DECLARE_WAITQUEUE(wait, current);
  84
  85        mutex_lock(&device->cbuf_lock);
  86
  87        /* no data? */
  88        if (reader->cbuf_start == device->cbuf_end) {
  89                add_wait_queue(&device->wait, &wait);
  90                set_current_state(TASK_INTERRUPTIBLE);
  91
  92                /* wait for data */
  93                while (reader->cbuf_start == device->cbuf_end) {
  94                        if (file->f_flags & O_NONBLOCK) {
  95                                retval = -EAGAIN;
  96                                break;
  97                        }
  98                        if (signal_pending(current)) {
  99                                retval = -ERESTARTSYS;
 100                                break;
 101                        }
 102                        if (!device->exist) {
 103                                retval = -EIO;
 104                                break;
 105                        }
 106
 107                        mutex_unlock(&device->cbuf_lock);
 108                        schedule();
 109                        mutex_lock(&device->cbuf_lock);
 110                        set_current_state(TASK_INTERRUPTIBLE);
 111                }
 112
 113                set_current_state(TASK_RUNNING);
 114                remove_wait_queue(&device->wait, &wait);
 115        }
 116
 117        /* here we either have data or a reason to return if retval is set */
 118        if (retval)
 119                goto exit_unlock;
 120
 121        report = &device->cbuf[reader->cbuf_start];
 122        /*
 123         * If report is larger than requested amount of data, rest of report
 124         * is lost!
 125         */
 126        len = device->report_size > count ? count : device->report_size;
 127
 128        if (copy_to_user(buffer, report->value, len)) {
 129                retval = -EFAULT;
 130                goto exit_unlock;
 131        }
 132        retval += len;
 133        reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
 134
 135exit_unlock:
 136        mutex_unlock(&device->cbuf_lock);
 137        return retval;
 138}
 139
 140static unsigned int roccat_poll(struct file *file, poll_table *wait)
 141{
 142        struct roccat_reader *reader = file->private_data;
 143        poll_wait(file, &reader->device->wait, wait);
 144        if (reader->cbuf_start != reader->device->cbuf_end)
 145                return POLLIN | POLLRDNORM;
 146        if (!reader->device->exist)
 147                return POLLERR | POLLHUP;
 148        return 0;
 149}
 150
 151static int roccat_open(struct inode *inode, struct file *file)
 152{
 153        unsigned int minor = iminor(inode);
 154        struct roccat_reader *reader;
 155        struct roccat_device *device;
 156        int error = 0;
 157
 158        reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
 159        if (!reader)
 160                return -ENOMEM;
 161
 162        mutex_lock(&devices_lock);
 163
 164        device = devices[minor];
 165
 166        if (!device) {
 167                pr_emerg("roccat device with minor %d doesn't exist\n", minor);
 168                error = -ENODEV;
 169                goto exit_err_devices;
 170        }
 171
 172        mutex_lock(&device->readers_lock);
 173
 174        if (!device->open++) {
 175                /* power on device on adding first reader */
 176                error = hid_hw_power(device->hid, PM_HINT_FULLON);
 177                if (error < 0) {
 178                        --device->open;
 179                        goto exit_err_readers;
 180                }
 181
 182                error = hid_hw_open(device->hid);
 183                if (error < 0) {
 184                        hid_hw_power(device->hid, PM_HINT_NORMAL);
 185                        --device->open;
 186                        goto exit_err_readers;
 187                }
 188        }
 189
 190        reader->device = device;
 191        /* new reader doesn't get old events */
 192        reader->cbuf_start = device->cbuf_end;
 193
 194        list_add_tail(&reader->node, &device->readers);
 195        file->private_data = reader;
 196
 197exit_err_readers:
 198        mutex_unlock(&device->readers_lock);
 199exit_err_devices:
 200        mutex_unlock(&devices_lock);
 201        if (error)
 202                kfree(reader);
 203        return error;
 204}
 205
 206static int roccat_release(struct inode *inode, struct file *file)
 207{
 208        unsigned int minor = iminor(inode);
 209        struct roccat_reader *reader = file->private_data;
 210        struct roccat_device *device;
 211
 212        mutex_lock(&devices_lock);
 213
 214        device = devices[minor];
 215        if (!device) {
 216                mutex_unlock(&devices_lock);
 217                pr_emerg("roccat device with minor %d doesn't exist\n", minor);
 218                return -ENODEV;
 219        }
 220
 221        mutex_lock(&device->readers_lock);
 222        list_del(&reader->node);
 223        mutex_unlock(&device->readers_lock);
 224        kfree(reader);
 225
 226        if (!--device->open) {
 227                /* removing last reader */
 228                if (device->exist) {
 229                        hid_hw_power(device->hid, PM_HINT_NORMAL);
 230                        hid_hw_close(device->hid);
 231                } else {
 232                        kfree(device);
 233                }
 234        }
 235
 236        mutex_unlock(&devices_lock);
 237
 238        return 0;
 239}
 240
 241/*
 242 * roccat_report_event() - output data to readers
 243 * @minor: minor device number returned by roccat_connect()
 244 * @data: pointer to data
 245 * @len: size of data
 246 *
 247 * Return value is zero on success, a negative error code on failure.
 248 *
 249 * This is called from interrupt handler.
 250 */
 251int roccat_report_event(int minor, u8 const *data)
 252{
 253        struct roccat_device *device;
 254        struct roccat_reader *reader;
 255        struct roccat_report *report;
 256        uint8_t *new_value;
 257
 258        device = devices[minor];
 259
 260        new_value = kmemdup(data, device->report_size, GFP_ATOMIC);
 261        if (!new_value)
 262                return -ENOMEM;
 263
 264        report = &device->cbuf[device->cbuf_end];
 265
 266        /* passing NULL is safe */
 267        kfree(report->value);
 268
 269        report->value = new_value;
 270        device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;
 271
 272        list_for_each_entry(reader, &device->readers, node) {
 273                /*
 274                 * As we already inserted one element, the buffer can't be
 275                 * empty. If start and end are equal, buffer is full and we
 276                 * increase start, so that slow reader misses one event, but
 277                 * gets the newer ones in the right order.
 278                 */
 279                if (reader->cbuf_start == device->cbuf_end)
 280                        reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
 281        }
 282
 283        wake_up_interruptible(&device->wait);
 284        return 0;
 285}
 286EXPORT_SYMBOL_GPL(roccat_report_event);
 287
 288/*
 289 * roccat_connect() - create a char device for special event output
 290 * @class: the class thats used to create the device. Meant to hold device
 291 * specific sysfs attributes.
 292 * @hid: the hid device the char device should be connected to.
 293 *
 294 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
 295 * success, a negative error code on failure.
 296 */
 297int roccat_connect(struct class *klass, struct hid_device *hid, int report_size)
 298{
 299        unsigned int minor;
 300        struct roccat_device *device;
 301        int temp;
 302
 303        device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
 304        if (!device)
 305                return -ENOMEM;
 306
 307        mutex_lock(&devices_lock);
 308
 309        for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
 310                if (devices[minor])
 311                        continue;
 312                break;
 313        }
 314
 315        if (minor < ROCCAT_MAX_DEVICES) {
 316                devices[minor] = device;
 317        } else {
 318                mutex_unlock(&devices_lock);
 319                kfree(device);
 320                return -EINVAL;
 321        }
 322
 323        device->dev = device_create(klass, &hid->dev,
 324                        MKDEV(roccat_major, minor), NULL,
 325                        "%s%s%d", "roccat", hid->driver->name, minor);
 326
 327        if (IS_ERR(device->dev)) {
 328                devices[minor] = NULL;
 329                mutex_unlock(&devices_lock);
 330                temp = PTR_ERR(device->dev);
 331                kfree(device);
 332                return temp;
 333        }
 334
 335        mutex_unlock(&devices_lock);
 336
 337        init_waitqueue_head(&device->wait);
 338        INIT_LIST_HEAD(&device->readers);
 339        mutex_init(&device->readers_lock);
 340        mutex_init(&device->cbuf_lock);
 341        device->minor = minor;
 342        device->hid = hid;
 343        device->exist = 1;
 344        device->cbuf_end = 0;
 345        device->report_size = report_size;
 346
 347        return minor;
 348}
 349EXPORT_SYMBOL_GPL(roccat_connect);
 350
 351/* roccat_disconnect() - remove char device from hid device
 352 * @minor: the minor device number returned by roccat_connect()
 353 */
 354void roccat_disconnect(int minor)
 355{
 356        struct roccat_device *device;
 357
 358        mutex_lock(&devices_lock);
 359        device = devices[minor];
 360        mutex_unlock(&devices_lock);
 361
 362        device->exist = 0; /* TODO exist maybe not needed */
 363
 364        device_destroy(device->dev->class, MKDEV(roccat_major, minor));
 365
 366        mutex_lock(&devices_lock);
 367        devices[minor] = NULL;
 368        mutex_unlock(&devices_lock);
 369        
 370        if (device->open) {
 371                hid_hw_close(device->hid);
 372                wake_up_interruptible(&device->wait);
 373        } else {
 374                kfree(device);
 375        }
 376}
 377EXPORT_SYMBOL_GPL(roccat_disconnect);
 378
 379static long roccat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 380{
 381        struct inode *inode = file->f_path.dentry->d_inode;
 382        struct roccat_device *device;
 383        unsigned int minor = iminor(inode);
 384        long retval = 0;
 385
 386        mutex_lock(&devices_lock);
 387
 388        device = devices[minor];
 389        if (!device) {
 390                retval = -ENODEV;
 391                goto out;
 392        }
 393
 394        switch (cmd) {
 395        case ROCCATIOCGREPSIZE:
 396                if (put_user(device->report_size, (int __user *)arg))
 397                        retval = -EFAULT;
 398                break;
 399        default:
 400                retval = -ENOTTY;
 401        }
 402out:
 403        mutex_unlock(&devices_lock);
 404        return retval;
 405}
 406
 407static const struct file_operations roccat_ops = {
 408        .owner = THIS_MODULE,
 409        .read = roccat_read,
 410        .poll = roccat_poll,
 411        .open = roccat_open,
 412        .release = roccat_release,
 413        .llseek = noop_llseek,
 414        .unlocked_ioctl = roccat_ioctl,
 415};
 416
 417static int __init roccat_init(void)
 418{
 419        int retval;
 420        dev_t dev_id;
 421
 422        retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
 423                        ROCCAT_MAX_DEVICES, "roccat");
 424
 425        roccat_major = MAJOR(dev_id);
 426
 427        if (retval < 0) {
 428                pr_warn("can't get major number\n");
 429                return retval;
 430        }
 431
 432        cdev_init(&roccat_cdev, &roccat_ops);
 433        cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);
 434
 435        return 0;
 436}
 437
 438static void __exit roccat_exit(void)
 439{
 440        dev_t dev_id = MKDEV(roccat_major, 0);
 441
 442        cdev_del(&roccat_cdev);
 443        unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
 444}
 445
 446module_init(roccat_init);
 447module_exit(roccat_exit);
 448
 449MODULE_AUTHOR("Stefan Achatz");
 450MODULE_DESCRIPTION("USB Roccat char device");
 451MODULE_LICENSE("GPL v2");
 452
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.