linux-imx

/*

 * User-space I/O driver support for HID subsystem

 * Copyright (c) 2012 David Herrmann

 */

​

/*

 * 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/atomic.h>

#include <linux/compat.h>

#include <linux/cred.h>

#include <linux/device.h>

#include <linux/fs.h>

#include <linux/hid.h>

#include <linux/input.h>

#include <linux/miscdevice.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/poll.h>

#include <linux/sched.h>

#include <linux/spinlock.h>

#include <linux/uhid.h>

#include <linux/wait.h>

​

#define UHID_NAME   "uhid"

#define UHID_BUFSIZE    32

​

struct uhid_device {

    struct mutex devlock;

    bool running;

​

    __u8 *rd_data;

    uint rd_size;

​

    struct hid_device *hid;

    struct uhid_event input_buf;

​

    wait_queue_head_t waitq;

    spinlock_t qlock;

    __u8 head;

    __u8 tail;

    struct uhid_event *outq[UHID_BUFSIZE];

​

    /* blocking GET_REPORT support; state changes protected by qlock */

    struct mutex report_lock;

    wait_queue_head_t report_wait;

    bool report_running;

    u32 report_id;

    u32 report_type;

    struct uhid_event report_buf;

    struct work_struct worker;

};

​

static struct miscdevice uhid_misc;

​

static void uhid_device_add_worker(struct work_struct *work)

{

    struct uhid_device *uhid = container_of(work, struct uhid_device, worker);

    int ret;

​

    ret = hid_add_device(uhid->hid);

    if (ret) {

        hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret);

​

        hid_destroy_device(uhid->hid);

        uhid->hid = NULL;

        uhid->running = false;

    }

}

​

static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)

{

    __u8 newhead;

​

    newhead = (uhid->head + 1) % UHID_BUFSIZE;

​

    if (newhead != uhid->tail) {

        uhid->outq[uhid->head] = ev;

        uhid->head = newhead;

        wake_up_interruptible(&uhid->waitq);

    } else {

        hid_warn(uhid->hid, "Output queue is full\n");

        kfree(ev);

    }

}

​

static int uhid_queue_event(struct uhid_device *uhid, __u32 event)

{