linux-imx

/*

 *  HID driver for Speedlink Vicious and Divine Cezanne (USB mouse).

 *  Fixes "jumpy" cursor and removes nonexistent keyboard LEDS from

 *  the HID descriptor.

 *

 *  Copyright (c) 2011, 2013 Stefan Kriwanek <dev@stefankriwanek.de>

 */

​

/*

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the Free

 * Software Foundation; either version 2 of the License, or (at your option)

 * any later version.

 */

​

#include <linux/device.h>

#include <linux/hid.h>

#include <linux/module.h>

​

#include "hid-ids.h"

​

static const struct hid_device_id speedlink_devices[] = {

    { HID_USB_DEVICE(USB_VENDOR_ID_X_TENSIONS, USB_DEVICE_ID_SPEEDLINK_VAD_CEZANNE)},

    { }

};

​

static int speedlink_input_mapping(struct hid_device *hdev,

        struct hid_input *hi,

        struct hid_field *field, struct hid_usage *usage,

        unsigned long **bit, int *max)

{

    /*

     * The Cezanne mouse has a second "keyboard" USB endpoint for it is

     * able to map keyboard events to the button presses.

     * It sends a standard keyboard report descriptor, though, whose

     * LEDs we ignore.

     */

    switch (usage->hid & HID_USAGE_PAGE) {

    case HID_UP_LED:

        return -1;

    }

    return 0;

}

​

static int speedlink_event(struct hid_device *hdev, struct hid_field *field,

        struct hid_usage *usage, __s32 value)

{

    /* No other conditions due to usage_table. */

​

    /* This fixes the "jumpy" cursor occuring due to invalid events sent

     * by the device. Some devices only send them with value==+256, others

     * don't. However, catching abs(value)>=256 is restrictive enough not

     * to interfere with devices that were bug-free (has been tested).

     */

    if (abs(value) >= 256)

        return 1;

    /* Drop useless distance 0 events (on button clicks etc.) as well */

    if (value == 0)

        return 1;

​

    return 0;

}

​