/*
* Copyright (c) 2014 Samsung Electronics Co., Ltd
*
* 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, sub license,
* 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 NON-INFRINGEMENT. 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.
*/
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/srcu.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_debugfs.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
#include <drm/drm_of.h>
#include <drm/drm_print.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* &struct drm_bridge represents a device that hangs on to an encoder. These are
* handy when a regular &drm_encoder entity isn't enough to represent the entire
* encoder chain.
*
* A bridge is always attached to a single &drm_encoder at a time, but can be
* either connected to it directly, or through a chain of bridges::
*
* [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B
*
* Here, the output of the encoder feeds to bridge A, and that furthers feeds to
* bridge B. Bridge chains can be arbitrarily long, and shall be fully linear:
* Chaining multiple bridges to the output of a bridge, or the same bridge to
* the output of different bridges, is not supported.
*
* &drm_bridge, like &drm_panel, aren't &drm_mode_object entities like planes,
* CRTCs, encoders or connectors and hence are not visible to userspace. They
* just provide additional hooks to get the desired output at the end of the
* encoder chain.
*/
/**
* DOC: display driver integration
*
* Display drivers are responsible for linking encoders with the first bridge
* in the chains. This is done by acquiring the appropriate bridge with
* devm_drm_o
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