linux-imx

/*

 * Copyright © 2015 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 *

 * Authors:

 *    Rafael Antognolli <rafael.antognolli@intel.com>

 *

 */

​

#include <linux/device.h>

#include <linux/fs.h>

#include <linux/slab.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/uaccess.h>

#include <linux/uio.h>

#include <drm/drm_dp_helper.h>

#include <drm/drm_crtc.h>

#include <drm/drmP.h>

​

#include "drm_crtc_helper_internal.h"

​

struct drm_dp_aux_dev {

    unsigned index;

    struct drm_dp_aux *aux;

    struct device *dev;

    struct kref refcount;

    atomic_t usecount;

};

​

#define DRM_AUX_MINORS  256

#define AUX_MAX_OFFSET  (1 << 20)

static DEFINE_IDR(aux_idr);

static DEFINE_MUTEX(aux_idr_mutex);

static struct class *drm_dp_aux_dev_class;

static int drm_dev_major = -1;

​

static struct drm_dp_aux_dev *drm_dp_aux_dev_get_by_minor(unsigned index)

{

    struct drm_dp_aux_dev *aux_dev = NULL;

​

    mutex_lock(&aux_idr_mutex);

    aux_dev = idr_find(&aux_idr, index);

    if (!kref_get_unless_zero(&aux_dev->refcount))