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/*

 * 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 

#include 

#include 

#include "drm/drmP.h"

/**

 * DOC: overview

 *

 * 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 associated to a single drm_encoder at a time, but can be

 * either connected to it directly, or through an intermediate bridge:

 *

 * encoder ---> bridge B ---> bridge A

 *

 * Here, the output of the encoder feeds to bridge B, and that furthers feeds to

 * bridge A.

 *

 * The driver using the bridge is responsible to make the associations between

 * the encoder and bridges. Once these links are made, the bridges will

 * participate along with encoder functions to perform mode_set/enable/disable

 * through the ops provided in drm_bridge_funcs.

 *

 * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,

 * crtcs, encoders or connectors. They just provide additional hooks to get the

 * desired output at the end of the encoder chain.

 */

static DEFINE_MUTEX(bridge_lock);

static LIST_HEAD(bridge_list);

/**

 * drm_bridge_add - add the given bridge to the global bridge list

 *

 * @bridge: bridge control structure

 *

 * RETURNS:

 * Unconditionally returns Zero.

 */

int drm_bridge_add(struct drm_bridge *bridge)

{

	mutex_lock(&bridge_lock);

	list_add_tail(&bridge->list, &bridge_list);

	mutex_unlock(&bridge_lock);

	return 0;

}

EXPORT_SYMBOL(drm_bridge_add);

/**

 * drm_bridge_remove - remove the given bridge from the global bridge list

 *

 * @bridge: bridge control structure

 */

void drm_bridge_remove(struct drm_bridge *bridge)

{

	mutex_lock(&bridge_lock);

	list_del_init(&bridge->list);

	mutex_unlock(&bridge_lock);

}

EXPORT_SYMBOL(drm_bridge_remove);

/**

 * drm_bridge_attach - associate given bridge to our DRM device

 *

 * @dev: DRM device

 * @bridge: bridge control structure

 *

 * called by a kms driver to link one of our encoder/bridge to the given

 * bridge.

 *

 * Note that setting up links between the bridge and our encoder/bridge

 * objects needs to be handled by the kms driver itself

 *

 * RETURNS:

 * Zero on success, error code on failure

 */

int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge)

{

	if (!dev || !bridge)

		return -EINVAL;

	if (bridge->dev)

		return -EBUSY;

	bridge->dev = dev;

	if (bridge->funcs->attach)

		return bridge->funcs->attach(bridge);

	return 0;

}

EXPORT_SYMBOL(drm_bridge_attach);

/**

 * DOC: bridge callbacks

 *

 * The drm_bridge_funcs ops are populated by the bridge driver. The drm

 * internals(atomic and crtc helpers) use the helpers defined in drm_bridge.c

 * These helpers call a specific drm_bridge_funcs op for all the bridges

 * during encoder configuration.

 *

 * When creating a bridge driver, one can implement drm_bridge_funcs op with

 * the help of these rough rules:

 *

 * pre_enable: this contains things needed to be done for the bridge before

 * its clock and timings are enabled by its source. For a bridge, its source

 * is generally the encoder or bridge just before it in the encoder chain.

 *

 * enable: this contains things needed to be done for the bridge once its

 * source is enabled. In other words, enable is called once the source is

 * ready with clock and timing needed by the bridge.

 *

 * disable: this contains things needed to be done for the bridge assuming

 * that its source is still enabled, i.e. clock and timings are still on.

 *

 * post_disable: this contains things needed to be done for the bridge once

 * its source is disabled, i.e. once clocks and timings are off.

 *

 * mode_fixup: this should fixup the given mode for the bridge. It is called

 * after the encoder's mode fixup. mode_fixup can also reject a mode completely

 * if it's unsuitable for the hardware.

 *

 * mode_set: this sets up the mode for the bridge. It assumes that its source

 * (an encoder or a bridge) has set the mode too.

 */

/**

 * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the

 *			   encoder chain

 * @bridge: bridge control structure

 * @mode: desired mode to be set for the bridge

 * @adjusted_mode: updated mode that works for this bridge

 *

 * Calls 'mode_fixup' drm_bridge_funcs op for all the bridges in the

 * encoder chain, starting from the first bridge to the last.

 *

 * Note: the bridge passed should be the one closest to the encoder

 *

 * RETURNS:

 * true on success, false on failure

 */

bool drm_bridge_mode_fixup(struct drm_bridge *bridge,

			const struct drm_display_mode *mode,

			struct drm_display_mode *adjusted_mode)

{

	bool ret = true;

	if (!bridge)

		return true;

	if (bridge->funcs->mode_fixup)

		ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);

	ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);

	return ret;

}

EXPORT_SYMBOL(drm_bridge_mode_fixup);

/**

 * drm_bridge_disable - calls 'disable' drm_bridge_funcs op for all

 *			bridges in the encoder chain.

 * @bridge: bridge control structure

 *

 * Calls 'disable' drm_bridge_funcs op for all the bridges in the encoder

 * chain, starting from the last bridge to the first. These are called before

 * calling the encoder's prepare op.

 *

 * Note: the bridge passed should be the one closest to the encoder

 */

void drm_bridge_disable(struct drm_bridge *bridge)

{

	if (!bridge)

		return;

	drm_bridge_disable(bridge->next);

	bridge->funcs->disable(bridge);

}

EXPORT_SYMBOL(drm_bridge_disable);

/**

 * drm_bridge_post_disable - calls 'post_disable' drm_bridge_funcs op for

 *			     all bridges in the encoder chain.

 * @bridge: bridge control structure

 *

 * Calls 'post_disable' drm_bridge_funcs op for all the bridges in the

 * encoder chain, starting from the first bridge to the last. These are called

 * after completing the encoder's prepare op.

 *

 * Note: the bridge passed should be the one closest to the encoder

 */

void drm_bridge_post_disable(struct drm_bridge *bridge)

{

	if (!bridge)

		return;

	bridge->funcs->post_disable(bridge);

	drm_bridge_post_disable(bridge->next);

}

EXPORT_SYMBOL(drm_bridge_post_disable);

/**

 * drm_bridge_mode_set - set proposed mode for all bridges in the

 *			 encoder chain

 * @bridge: bridge control structure

 * @mode: desired mode to be set for the bridge

 * @adjusted_mode: updated mode that works for this bridge

 *

 * Calls 'mode_set' drm_bridge_funcs op for all the bridges in the

 * encoder chain, starting from the first bridge to the last.

 *

 * Note: the bridge passed should be the one closest to the encoder

 */

void drm_bridge_mode_set(struct drm_bridge *bridge,

			struct drm_display_mode *mode,

			struct drm_display_mode *adjusted_mode)

{

	if (!bridge)

		return;

	if (bridge->funcs->mode_set)

		bridge->funcs->mode_set(bridge, mode, adjusted_mode);

	drm_bridge_mode_set(bridge->next, mode, adjusted_mode);

}

EXPORT_SYMBOL(drm_bridge_mode_set);

/**

 * drm_bridge_pre_enable - calls 'pre_enable' drm_bridge_funcs op for all

 *			   bridges in the encoder chain.

 * @bridge: bridge control structure

 *

 * Calls 'pre_enable' drm_bridge_funcs op for all the bridges in the encoder

 * chain, starting from the last bridge to the first. These are called

 * before calling the encoder's commit op.

 *

 * Note: the bridge passed should be the one closest to the encoder

 */

void drm_bridge_pre_enable(struct drm_bridge *bridge)

{

	if (!bridge)

		return;

	drm_bridge_pre_enable(bridge->next);

	bridge->funcs->pre_enable(bridge);

}

EXPORT_SYMBOL(drm_bridge_pre_enable);

/**

 * drm_bridge_enable - calls 'enable' drm_bridge_funcs op for all bridges

 *		       in the encoder chain.

 * @bridge: bridge control structure

 *

 * Calls 'enable' drm_bridge_funcs op for all the bridges in the encoder

 * chain, starting from the first bridge to the last. These are called

 * after completing the encoder's commit op.

 *

 * Note that the bridge passed should be the one closest to the encoder

 */

void drm_bridge_enable(struct drm_bridge *bridge)

{

	if (!bridge)

		return;

	bridge->funcs->enable(bridge);

	drm_bridge_enable(bridge->next);

}

EXPORT_SYMBOL(drm_bridge_enable);

#ifdef CONFIG_OF

/**

 * of_drm_find_bridge - find the bridge corresponding to the device node in

 *			the global bridge list

 *

 * @np: device node

 *

 * RETURNS:

 * drm_bridge control struct on success, NULL on failure

 */

struct drm_bridge *of_drm_find_bridge(struct device_node *np)

{

	struct drm_bridge *bridge;

	mutex_lock(&bridge_lock);

	list_for_each_entry(bridge, &bridge_list, list) {

		if (bridge->of_node == np) {

			mutex_unlock(&bridge_lock);

			return bridge;

		}

	}

	mutex_unlock(&bridge_lock);

	return NULL;

}

EXPORT_SYMBOL(of_drm_find_bridge);

#endif

MODULE_AUTHOR("Ajay Kumar ");

MODULE_DESCRIPTION("DRM bridge infrastructure");

MODULE_LICENSE("GPL and additional rights");