drivers/gpu/drm/drm_bridge.c - kernel/quantenna - Git at Google

 /*
  * 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/err.h>
 #include <linux/module.h>

 #include <drm/drm_crtc.h>

 #include "drm/drmP.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 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 and hence are not visible to userspace. They
  * just provide additional hooks to get the desired output at the end of the
  * encoder chain.
  *
  * Bridges can also be chained up using the next pointer in struct &drm_bridge.
  *
  * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
  */

 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.
  *
  * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
  */

 /**
  * 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);

 	if (bridge->funcs->disable)
 		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;

 	if (bridge->funcs->post_disable)
 		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);

 	if (bridge->funcs->pre_enable)
 		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;

 	if (bridge->funcs->enable)
 		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 <ajaykumar.rs@samsung.com>");
 MODULE_DESCRIPTION("DRM bridge infrastructure");
 MODULE_LICENSE("GPL and additional rights");
	/*
	* 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/err.h>
	#include <linux/module.h>

	#include <drm/drm_crtc.h>

	#include "drm/drmP.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 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 and hence are not visible to userspace. They
	* just provide additional hooks to get the desired output at the end of the
	* encoder chain.
	*
	* Bridges can also be chained up using the next pointer in struct &drm_bridge.
	*
	* Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
	*/

	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.
	*
	* For detailed specification of the bridge callbacks see &drm_bridge_funcs.
	*/

	/**
	* 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);

	if (bridge->funcs->disable)
	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;

	if (bridge->funcs->post_disable)
	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);

	if (bridge->funcs->pre_enable)
	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;

	if (bridge->funcs->enable)
	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 <ajaykumar.rs@samsung.com>");
	MODULE_DESCRIPTION("DRM bridge infrastructure");
	MODULE_LICENSE("GPL and additional rights");