drivers/gpu/drm/bridge/panel.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  * Copyright (C) 2017 Broadcom
  */

 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_connector.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>

 struct panel_bridge {
 	struct drm_bridge bridge;
 	struct drm_connector connector;
 	struct drm_panel *panel;
 	u32 connector_type;
 };

 static inline struct panel_bridge *
 drm_bridge_to_panel_bridge(struct drm_bridge *bridge)
 {
 	return container_of(bridge, struct panel_bridge, bridge);
 }

 static inline struct panel_bridge *
 drm_connector_to_panel_bridge(struct drm_connector *connector)
 {
 	return container_of(connector, struct panel_bridge, connector);
 }

 static int panel_bridge_connector_get_modes(struct drm_connector *connector)
 {
 	struct panel_bridge *panel_bridge =
 		drm_connector_to_panel_bridge(connector);

 	return drm_panel_get_modes(panel_bridge->panel, connector);
 }

 static const struct drm_connector_helper_funcs
 panel_bridge_connector_helper_funcs = {
 	.get_modes = panel_bridge_connector_get_modes,
 };

 static const struct drm_connector_funcs panel_bridge_connector_funcs = {
 	.reset = drm_atomic_helper_connector_reset,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = drm_connector_cleanup,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };

 static int panel_bridge_attach(struct drm_bridge *bridge,
 			       enum drm_bridge_attach_flags flags)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_connector *connector = &panel_bridge->connector;
 	int ret;

 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
 		return 0;

 	if (!bridge->encoder) {
 		DRM_ERROR("Missing encoder\n");
 		return -ENODEV;
 	}

 	drm_connector_helper_add(connector,
 				 &panel_bridge_connector_helper_funcs);

 	ret = drm_connector_init(bridge->dev, connector,
 				 &panel_bridge_connector_funcs,
 				 panel_bridge->connector_type);
 	if (ret) {
 		DRM_ERROR("Failed to initialize connector\n");
 		return ret;
 	}

 	drm_panel_bridge_set_orientation(connector, bridge);

 	drm_connector_attach_encoder(&panel_bridge->connector,
 					  bridge->encoder);

 	if (bridge->dev->registered) {
 		if (connector->funcs->reset)
 			connector->funcs->reset(connector);
 		drm_connector_register(connector);
 	}

 	return 0;
 }

 static void panel_bridge_detach(struct drm_bridge *bridge)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_connector *connector = &panel_bridge->connector;

 	/*
 	 * Cleanup the connector if we know it was initialized.
 	 *
 	 * FIXME: This wouldn't be needed if the panel_bridge structure was
 	 * allocated with drmm_kzalloc(). This might be tricky since the
 	 * drm_device pointer can only be retrieved when the bridge is attached.
 	 */
 	if (connector->dev)
 		drm_connector_cleanup(connector);
 }

 static void panel_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 				struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
 	struct drm_encoder *encoder = bridge->encoder;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state;

 	crtc = drm_atomic_get_new_crtc_for_encoder(atomic_state, encoder);
 	if (!crtc)
 		return;

 	old_crtc_state = drm_atomic_get_old_crtc_state(atomic_state, crtc);
 	if (old_crtc_state && old_crtc_state->self_refresh_active)
 		return;

 	drm_panel_prepare(panel_bridge->panel);
 }

 static void panel_bridge_atomic_enable(struct drm_bridge *bridge,
 				struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
 	struct drm_encoder *encoder = bridge->encoder;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state;

 	crtc = drm_atomic_get_new_crtc_for_encoder(atomic_state, encoder);
 	if (!crtc)
 		return;

 	old_crtc_state = drm_atomic_get_old_crtc_state(atomic_state, crtc);
 	if (old_crtc_state && old_crtc_state->self_refresh_active)
 		return;

 	drm_panel_enable(panel_bridge->panel);
 }

 static void panel_bridge_atomic_disable(struct drm_bridge *bridge,
 				struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
 	struct drm_encoder *encoder = bridge->encoder;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *new_crtc_state;

 	crtc = drm_atomic_get_old_crtc_for_encoder(atomic_state, encoder);
 	if (!crtc)
 		return;

 	new_crtc_state = drm_atomic_get_new_crtc_state(atomic_state, crtc);
 	if (new_crtc_state && new_crtc_state->self_refresh_active)
 		return;

 	drm_panel_disable(panel_bridge->panel);
 }

 static void panel_bridge_atomic_post_disable(struct drm_bridge *bridge,
 				struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
 	struct drm_encoder *encoder = bridge->encoder;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *new_crtc_state;

 	crtc = drm_atomic_get_old_crtc_for_encoder(atomic_state, encoder);
 	if (!crtc)
 		return;

 	new_crtc_state = drm_atomic_get_new_crtc_state(atomic_state, crtc);
 	if (new_crtc_state && new_crtc_state->self_refresh_active)
 		return;

 	drm_panel_unprepare(panel_bridge->panel);
 }

 static int panel_bridge_get_modes(struct drm_bridge *bridge,
 				  struct drm_connector *connector)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);

 	return drm_panel_get_modes(panel_bridge->panel, connector);
 }

 static void panel_bridge_debugfs_init(struct drm_bridge *bridge,
 				      struct dentry *root)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
 	struct drm_panel *panel = panel_bridge->panel;

 	root = debugfs_create_dir("panel", root);
 	if (panel->funcs->debugfs_init)
 		panel->funcs->debugfs_init(panel, root);
 }

 static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
 	.attach = panel_bridge_attach,
 	.detach = panel_bridge_detach,
 	.atomic_pre_enable = panel_bridge_atomic_pre_enable,
 	.atomic_enable = panel_bridge_atomic_enable,
 	.atomic_disable = panel_bridge_atomic_disable,
 	.atomic_post_disable = panel_bridge_atomic_post_disable,
 	.get_modes = panel_bridge_get_modes,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 	.atomic_get_input_bus_fmts = drm_atomic_helper_bridge_propagate_bus_fmt,
 	.debugfs_init = panel_bridge_debugfs_init,
 };

 /**
  * drm_bridge_is_panel - Checks if a drm_bridge is a panel_bridge.
  *
  * @bridge: The drm_bridge to be checked.
  *
  * Returns true if the bridge is a panel bridge, or false otherwise.
  */
 bool drm_bridge_is_panel(const struct drm_bridge *bridge)
 {
 	return bridge->funcs == &panel_bridge_bridge_funcs;
 }
 EXPORT_SYMBOL(drm_bridge_is_panel);

 /**
  * drm_panel_bridge_add - Creates a &drm_bridge and &drm_connector that
  * just calls the appropriate functions from &drm_panel.
  *
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
  *
  * For drivers converting from directly using drm_panel: The expected
  * usage pattern is that during either encoder module probe or DSI
  * host attach, a drm_panel will be looked up through
  * drm_of_find_panel_or_bridge().  drm_panel_bridge_add() is used to
  * wrap that panel in the new bridge, and the result can then be
  * passed to drm_bridge_attach().  The drm_panel_prepare() and related
  * functions can be dropped from the encoder driver (they're now
  * called by the KMS helpers before calling into the encoder), along
  * with connector creation.  When done with the bridge (after
  * drm_mode_config_cleanup() if the bridge has already been attached), then
  * drm_panel_bridge_remove() to free it.
  *
  * The connector type is set to @panel->connector_type, which must be set to a
  * known type. Calling this function with a panel whose connector type is
  * DRM_MODE_CONNECTOR_Unknown will return ERR_PTR(-EINVAL).
  *
  * See devm_drm_panel_bridge_add() for an automatically managed version of this
  * function.
  */
 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel)
 {
 	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
 		return ERR_PTR(-EINVAL);

 	return drm_panel_bridge_add_typed(panel, panel->connector_type);
 }
 EXPORT_SYMBOL(drm_panel_bridge_add);

 /**
  * drm_panel_bridge_add_typed - Creates a &drm_bridge and &drm_connector with
  * an explicit connector type.
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
  * @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
  *
  * This is just like drm_panel_bridge_add(), but forces the connector type to
  * @connector_type instead of infering it from the panel.
  *
  * This function is deprecated and should not be used in new drivers. Use
  * drm_panel_bridge_add() instead, and fix panel drivers as necessary if they
  * don't report a connector type.
  */
 struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
 					      u32 connector_type)
 {
 	struct panel_bridge *panel_bridge;

 	if (!panel)
 		return ERR_PTR(-EINVAL);

 	panel_bridge = devm_kzalloc(panel->dev, sizeof(*panel_bridge),
 				    GFP_KERNEL);
 	if (!panel_bridge)
 		return ERR_PTR(-ENOMEM);

 	panel_bridge->connector_type = connector_type;
 	panel_bridge->panel = panel;

 	panel_bridge->bridge.funcs = &panel_bridge_bridge_funcs;
 	panel_bridge->bridge.of_node = panel->dev->of_node;
 	panel_bridge->bridge.ops = DRM_BRIDGE_OP_MODES;
 	panel_bridge->bridge.type = connector_type;

 	drm_bridge_add(&panel_bridge->bridge);

 	return &panel_bridge->bridge;
 }
 EXPORT_SYMBOL(drm_panel_bridge_add_typed);

 /**
  * drm_panel_bridge_remove - Unregisters and frees a drm_bridge
  * created by drm_panel_bridge_add().
  *
  * @bridge: The drm_bridge being freed.
  */
 void drm_panel_bridge_remove(struct drm_bridge *bridge)
 {
 	struct panel_bridge *panel_bridge;

 	if (!bridge)
 		return;

 	if (bridge->funcs != &panel_bridge_bridge_funcs)
 		return;

 	panel_bridge = drm_bridge_to_panel_bridge(bridge);

 	drm_bridge_remove(bridge);
 	devm_kfree(panel_bridge->panel->dev, bridge);
 }
 EXPORT_SYMBOL(drm_panel_bridge_remove);

 /**
  * drm_panel_bridge_set_orientation - Set the connector's panel orientation
  * from the bridge that can be transformed to panel bridge.
  *
  * @connector: The connector to be set panel orientation.
  * @bridge: The drm_bridge to be transformed to panel bridge.
  *
  * Returns 0 on success, negative errno on failure.
  */
 int drm_panel_bridge_set_orientation(struct drm_connector *connector,
 				     struct drm_bridge *bridge)
 {
 	struct panel_bridge *panel_bridge;

 	panel_bridge = drm_bridge_to_panel_bridge(bridge);

 	return drm_connector_set_orientation_from_panel(connector,
 							panel_bridge->panel);
 }
 EXPORT_SYMBOL(drm_panel_bridge_set_orientation);

 static void devm_drm_panel_bridge_release(struct device *dev, void *res)
 {
 	struct drm_bridge **bridge = res;

 	drm_panel_bridge_remove(*bridge);
 }

 /**
  * devm_drm_panel_bridge_add - Creates a managed &drm_bridge and &drm_connector
  * that just calls the appropriate functions from &drm_panel.
  * @dev: device to tie the bridge lifetime to
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
  *
  * This is the managed version of drm_panel_bridge_add() which automatically
  * calls drm_panel_bridge_remove() when @dev is unbound.
  */
 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
 					     struct drm_panel *panel)
 {
 	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
 		return ERR_PTR(-EINVAL);

 	return devm_drm_panel_bridge_add_typed(dev, panel,
 					       panel->connector_type);
 }
 EXPORT_SYMBOL(devm_drm_panel_bridge_add);

 /**
  * devm_drm_panel_bridge_add_typed - Creates a managed &drm_bridge and
  * &drm_connector with an explicit connector type.
  * @dev: device to tie the bridge lifetime to
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
  * @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
  *
  * This is just like devm_drm_panel_bridge_add(), but forces the connector type
  * to @connector_type instead of infering it from the panel.
  *
  * This function is deprecated and should not be used in new drivers. Use
  * devm_drm_panel_bridge_add() instead, and fix panel drivers as necessary if
  * they don't report a connector type.
  */
 struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
 						   struct drm_panel *panel,
 						   u32 connector_type)
 {
 	struct drm_bridge **ptr, *bridge;

 	ptr = devres_alloc(devm_drm_panel_bridge_release, sizeof(*ptr),
 			   GFP_KERNEL);
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);

 	bridge = drm_panel_bridge_add_typed(panel, connector_type);
 	if (IS_ERR(bridge)) {
 		devres_free(ptr);
 		return bridge;
 	}

 	bridge->pre_enable_prev_first = panel->prepare_prev_first;

 	*ptr = bridge;
 	devres_add(dev, ptr);

 	return bridge;
 }
 EXPORT_SYMBOL(devm_drm_panel_bridge_add_typed);

 static void drmm_drm_panel_bridge_release(struct drm_device *drm, void *ptr)
 {
 	struct drm_bridge *bridge = ptr;

 	drm_panel_bridge_remove(bridge);
 }

 /**
  * drmm_panel_bridge_add - Creates a DRM-managed &drm_bridge and
  *                         &drm_connector that just calls the
  *                         appropriate functions from &drm_panel.
  *
  * @drm: DRM device to tie the bridge lifetime to
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
  *
  * This is the DRM-managed version of drm_panel_bridge_add() which
  * automatically calls drm_panel_bridge_remove() when @dev is cleaned
  * up.
  */
 struct drm_bridge *drmm_panel_bridge_add(struct drm_device *drm,
 					 struct drm_panel *panel)
 {
 	struct drm_bridge *bridge;
 	int ret;

 	bridge = drm_panel_bridge_add_typed(panel, panel->connector_type);
 	if (IS_ERR(bridge))
 		return bridge;

 	ret = drmm_add_action_or_reset(drm, drmm_drm_panel_bridge_release,
 				       bridge);
 	if (ret)
 		return ERR_PTR(ret);

 	bridge->pre_enable_prev_first = panel->prepare_prev_first;

 	return bridge;
 }
 EXPORT_SYMBOL(drmm_panel_bridge_add);

 /**
  * drm_panel_bridge_connector - return the connector for the panel bridge
  * @bridge: The drm_bridge.
  *
  * drm_panel_bridge creates the connector.
  * This function gives external access to the connector.
  *
  * Returns: Pointer to drm_connector
  */
 struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge)
 {
 	struct panel_bridge *panel_bridge;

 	panel_bridge = drm_bridge_to_panel_bridge(bridge);

 	return &panel_bridge->connector;
 }
 EXPORT_SYMBOL(drm_panel_bridge_connector);

 #ifdef CONFIG_OF
 /**
  * devm_drm_of_get_bridge - Return next bridge in the chain
  * @dev: device to tie the bridge lifetime to
  * @np: device tree node containing encoder output ports
  * @port: port in the device tree node
  * @endpoint: endpoint in the device tree node
  *
  * Given a DT node's port and endpoint number, finds the connected node
  * and returns the associated bridge if any, or creates and returns a
  * drm panel bridge instance if a panel is connected.
  *
  * Returns a pointer to the bridge if successful, or an error pointer
  * otherwise.
  */
 struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 					  struct device_node *np,
 					  u32 port, u32 endpoint)
 {
 	struct drm_bridge *bridge;
 	struct drm_panel *panel;
 	int ret;

 	ret = drm_of_find_panel_or_bridge(np, port, endpoint,
 					  &panel, &bridge);
 	if (ret)
 		return ERR_PTR(ret);

 	if (panel)
 		bridge = devm_drm_panel_bridge_add(dev, panel);

 	return bridge;
 }
 EXPORT_SYMBOL(devm_drm_of_get_bridge);

 /**
  * drmm_of_get_bridge - Return next bridge in the chain
  * @drm: device to tie the bridge lifetime to
  * @np: device tree node containing encoder output ports
  * @port: port in the device tree node
  * @endpoint: endpoint in the device tree node
  *
  * Given a DT node's port and endpoint number, finds the connected node
  * and returns the associated bridge if any, or creates and returns a
  * drm panel bridge instance if a panel is connected.
  *
  * Returns a drmm managed pointer to the bridge if successful, or an error
  * pointer otherwise.
  */
 struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 				      struct device_node *np,
 				      u32 port, u32 endpoint)
 {
 	struct drm_bridge *bridge;
 	struct drm_panel *panel;
 	int ret;

 	ret = drm_of_find_panel_or_bridge(np, port, endpoint,
 					  &panel, &bridge);
 	if (ret)
 		return ERR_PTR(ret);

 	if (panel)
 		bridge = drmm_panel_bridge_add(drm, panel);

 	return bridge;
 }
 EXPORT_SYMBOL(drmm_of_get_bridge);

 #endif
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
	* Copyright (C) 2017 Broadcom
	*/

	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_bridge.h>
	#include <drm/drm_connector.h>
	#include <drm/drm_encoder.h>
	#include <drm/drm_managed.h>
	#include <drm/drm_modeset_helper_vtables.h>
	#include <drm/drm_of.h>
	#include <drm/drm_panel.h>
	#include <drm/drm_print.h>
	#include <drm/drm_probe_helper.h>

	struct panel_bridge {
	struct drm_bridge bridge;
	struct drm_connector connector;
	struct drm_panel *panel;
	u32 connector_type;
	};

	static inline struct panel_bridge *
	drm_bridge_to_panel_bridge(struct drm_bridge *bridge)
	{
	return container_of(bridge, struct panel_bridge, bridge);
	}

	static inline struct panel_bridge *
	drm_connector_to_panel_bridge(struct drm_connector *connector)
	{
	return container_of(connector, struct panel_bridge, connector);
	}

	static int panel_bridge_connector_get_modes(struct drm_connector *connector)
	{
	struct panel_bridge *panel_bridge =
	drm_connector_to_panel_bridge(connector);

	return drm_panel_get_modes(panel_bridge->panel, connector);
	}

	static const struct drm_connector_helper_funcs
	panel_bridge_connector_helper_funcs = {
	.get_modes = panel_bridge_connector_get_modes,
	};

	static const struct drm_connector_funcs panel_bridge_connector_funcs = {
	.reset = drm_atomic_helper_connector_reset,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.destroy = drm_connector_cleanup,
	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
	};

	static int panel_bridge_attach(struct drm_bridge *bridge,
	enum drm_bridge_attach_flags flags)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_connector *connector = &panel_bridge->connector;
	int ret;

	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
	return 0;

	if (!bridge->encoder) {
	DRM_ERROR("Missing encoder\n");
	return -ENODEV;
	}

	drm_connector_helper_add(connector,
	&panel_bridge_connector_helper_funcs);

	ret = drm_connector_init(bridge->dev, connector,
	&panel_bridge_connector_funcs,
	panel_bridge->connector_type);
	if (ret) {
	DRM_ERROR("Failed to initialize connector\n");
	return ret;
	}

	drm_panel_bridge_set_orientation(connector, bridge);

	drm_connector_attach_encoder(&panel_bridge->connector,
	bridge->encoder);

	if (bridge->dev->registered) {
	if (connector->funcs->reset)
	connector->funcs->reset(connector);
	drm_connector_register(connector);
	}

	return 0;
	}

	static void panel_bridge_detach(struct drm_bridge *bridge)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_connector *connector = &panel_bridge->connector;

	/*
	* Cleanup the connector if we know it was initialized.
	*
	* FIXME: This wouldn't be needed if the panel_bridge structure was
	* allocated with drmm_kzalloc(). This might be tricky since the
	* drm_device pointer can only be retrieved when the bridge is attached.
	*/
	if (connector->dev)
	drm_connector_cleanup(connector);
	}

	static void panel_bridge_atomic_pre_enable(struct drm_bridge *bridge,
	struct drm_bridge_state *old_bridge_state)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
	struct drm_encoder *encoder = bridge->encoder;
	struct drm_crtc *crtc;
	struct drm_crtc_state *old_crtc_state;

	crtc = drm_atomic_get_new_crtc_for_encoder(atomic_state, encoder);
	if (!crtc)
	return;

	old_crtc_state = drm_atomic_get_old_crtc_state(atomic_state, crtc);
	if (old_crtc_state && old_crtc_state->self_refresh_active)
	return;

	drm_panel_prepare(panel_bridge->panel);
	}

	static void panel_bridge_atomic_enable(struct drm_bridge *bridge,
	struct drm_bridge_state *old_bridge_state)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
	struct drm_encoder *encoder = bridge->encoder;
	struct drm_crtc *crtc;
	struct drm_crtc_state *old_crtc_state;

	crtc = drm_atomic_get_new_crtc_for_encoder(atomic_state, encoder);
	if (!crtc)
	return;

	old_crtc_state = drm_atomic_get_old_crtc_state(atomic_state, crtc);
	if (old_crtc_state && old_crtc_state->self_refresh_active)
	return;

	drm_panel_enable(panel_bridge->panel);
	}

	static void panel_bridge_atomic_disable(struct drm_bridge *bridge,
	struct drm_bridge_state *old_bridge_state)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
	struct drm_encoder *encoder = bridge->encoder;
	struct drm_crtc *crtc;
	struct drm_crtc_state *new_crtc_state;

	crtc = drm_atomic_get_old_crtc_for_encoder(atomic_state, encoder);
	if (!crtc)
	return;

	new_crtc_state = drm_atomic_get_new_crtc_state(atomic_state, crtc);
	if (new_crtc_state && new_crtc_state->self_refresh_active)
	return;

	drm_panel_disable(panel_bridge->panel);
	}

	static void panel_bridge_atomic_post_disable(struct drm_bridge *bridge,
	struct drm_bridge_state *old_bridge_state)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_atomic_state *atomic_state = old_bridge_state->base.state;
	struct drm_encoder *encoder = bridge->encoder;
	struct drm_crtc *crtc;
	struct drm_crtc_state *new_crtc_state;

	crtc = drm_atomic_get_old_crtc_for_encoder(atomic_state, encoder);
	if (!crtc)
	return;

	new_crtc_state = drm_atomic_get_new_crtc_state(atomic_state, crtc);
	if (new_crtc_state && new_crtc_state->self_refresh_active)
	return;

	drm_panel_unprepare(panel_bridge->panel);
	}

	static int panel_bridge_get_modes(struct drm_bridge *bridge,
	struct drm_connector *connector)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);

	return drm_panel_get_modes(panel_bridge->panel, connector);
	}

	static void panel_bridge_debugfs_init(struct drm_bridge *bridge,
	struct dentry *root)
	{
	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
	struct drm_panel *panel = panel_bridge->panel;

	root = debugfs_create_dir("panel", root);
	if (panel->funcs->debugfs_init)
	panel->funcs->debugfs_init(panel, root);
	}

	static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
	.attach = panel_bridge_attach,
	.detach = panel_bridge_detach,
	.atomic_pre_enable = panel_bridge_atomic_pre_enable,
	.atomic_enable = panel_bridge_atomic_enable,
	.atomic_disable = panel_bridge_atomic_disable,
	.atomic_post_disable = panel_bridge_atomic_post_disable,
	.get_modes = panel_bridge_get_modes,
	.atomic_reset = drm_atomic_helper_bridge_reset,
	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
	.atomic_get_input_bus_fmts = drm_atomic_helper_bridge_propagate_bus_fmt,
	.debugfs_init = panel_bridge_debugfs_init,
	};

	/**
	* drm_bridge_is_panel - Checks if a drm_bridge is a panel_bridge.
	*
	* @bridge: The drm_bridge to be checked.
	*
	* Returns true if the bridge is a panel bridge, or false otherwise.
	*/
	bool drm_bridge_is_panel(const struct drm_bridge *bridge)
	{
	return bridge->funcs == &panel_bridge_bridge_funcs;
	}
	EXPORT_SYMBOL(drm_bridge_is_panel);

	/**
	* drm_panel_bridge_add - Creates a &drm_bridge and &drm_connector that
	* just calls the appropriate functions from &drm_panel.
	*
	* @panel: The drm_panel being wrapped. Must be non-NULL.
	*
	* For drivers converting from directly using drm_panel: The expected
	* usage pattern is that during either encoder module probe or DSI
	* host attach, a drm_panel will be looked up through
	* drm_of_find_panel_or_bridge(). drm_panel_bridge_add() is used to
	* wrap that panel in the new bridge, and the result can then be
	* passed to drm_bridge_attach(). The drm_panel_prepare() and related
	* functions can be dropped from the encoder driver (they're now
	* called by the KMS helpers before calling into the encoder), along
	* with connector creation. When done with the bridge (after
	* drm_mode_config_cleanup() if the bridge has already been attached), then
	* drm_panel_bridge_remove() to free it.
	*
	* The connector type is set to @panel->connector_type, which must be set to a
	* known type. Calling this function with a panel whose connector type is
	* DRM_MODE_CONNECTOR_Unknown will return ERR_PTR(-EINVAL).
	*
	* See devm_drm_panel_bridge_add() for an automatically managed version of this
	* function.
	*/
	struct drm_bridge drm_panel_bridge_add(struct drm_panel panel)
	{
	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
	return ERR_PTR(-EINVAL);

	return drm_panel_bridge_add_typed(panel, panel->connector_type);
	}
	EXPORT_SYMBOL(drm_panel_bridge_add);

	/**
	* drm_panel_bridge_add_typed - Creates a &drm_bridge and &drm_connector with
	* an explicit connector type.
	* @panel: The drm_panel being wrapped. Must be non-NULL.
	* @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
	*
	* This is just like drm_panel_bridge_add(), but forces the connector type to
	* @connector_type instead of infering it from the panel.
	*
	* This function is deprecated and should not be used in new drivers. Use
	* drm_panel_bridge_add() instead, and fix panel drivers as necessary if they
	* don't report a connector type.
	*/
	struct drm_bridge drm_panel_bridge_add_typed(struct drm_panel panel,
	u32 connector_type)
	{
	struct panel_bridge *panel_bridge;

	if (!panel)
	return ERR_PTR(-EINVAL);

	panel_bridge = devm_kzalloc(panel->dev, sizeof(*panel_bridge),
	GFP_KERNEL);
	if (!panel_bridge)
	return ERR_PTR(-ENOMEM);

	panel_bridge->connector_type = connector_type;
	panel_bridge->panel = panel;

	panel_bridge->bridge.funcs = &panel_bridge_bridge_funcs;
	panel_bridge->bridge.of_node = panel->dev->of_node;
	panel_bridge->bridge.ops = DRM_BRIDGE_OP_MODES;
	panel_bridge->bridge.type = connector_type;

	drm_bridge_add(&panel_bridge->bridge);

	return &panel_bridge->bridge;
	}
	EXPORT_SYMBOL(drm_panel_bridge_add_typed);

	/**
	* drm_panel_bridge_remove - Unregisters and frees a drm_bridge
	* created by drm_panel_bridge_add().
	*
	* @bridge: The drm_bridge being freed.
	*/
	void drm_panel_bridge_remove(struct drm_bridge *bridge)
	{
	struct panel_bridge *panel_bridge;

	if (!bridge)
	return;

	if (bridge->funcs != &panel_bridge_bridge_funcs)
	return;

	panel_bridge = drm_bridge_to_panel_bridge(bridge);

	drm_bridge_remove(bridge);
	devm_kfree(panel_bridge->panel->dev, bridge);
	}
	EXPORT_SYMBOL(drm_panel_bridge_remove);

	/**
	* drm_panel_bridge_set_orientation - Set the connector's panel orientation
	* from the bridge that can be transformed to panel bridge.
	*
	* @connector: The connector to be set panel orientation.
	* @bridge: The drm_bridge to be transformed to panel bridge.
	*
	* Returns 0 on success, negative errno on failure.
	*/
	int drm_panel_bridge_set_orientation(struct drm_connector *connector,
	struct drm_bridge *bridge)
	{
	struct panel_bridge *panel_bridge;

	panel_bridge = drm_bridge_to_panel_bridge(bridge);

	return drm_connector_set_orientation_from_panel(connector,
	panel_bridge->panel);
	}
	EXPORT_SYMBOL(drm_panel_bridge_set_orientation);

	static void devm_drm_panel_bridge_release(struct device dev, void res)
	{
	struct drm_bridge **bridge = res;

	drm_panel_bridge_remove(*bridge);
	}

	/**
	* devm_drm_panel_bridge_add - Creates a managed &drm_bridge and &drm_connector
	* that just calls the appropriate functions from &drm_panel.
	* @dev: device to tie the bridge lifetime to
	* @panel: The drm_panel being wrapped. Must be non-NULL.
	*
	* This is the managed version of drm_panel_bridge_add() which automatically
	* calls drm_panel_bridge_remove() when @dev is unbound.
	*/
	struct drm_bridge devm_drm_panel_bridge_add(struct device dev,
	struct drm_panel *panel)
	{
	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
	return ERR_PTR(-EINVAL);

	return devm_drm_panel_bridge_add_typed(dev, panel,
	panel->connector_type);
	}
	EXPORT_SYMBOL(devm_drm_panel_bridge_add);

	/**
	* devm_drm_panel_bridge_add_typed - Creates a managed &drm_bridge and
	* &drm_connector with an explicit connector type.
	* @dev: device to tie the bridge lifetime to
	* @panel: The drm_panel being wrapped. Must be non-NULL.
	* @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
	*
	* This is just like devm_drm_panel_bridge_add(), but forces the connector type
	* to @connector_type instead of infering it from the panel.
	*
	* This function is deprecated and should not be used in new drivers. Use
	* devm_drm_panel_bridge_add() instead, and fix panel drivers as necessary if
	* they don't report a connector type.
	*/
	struct drm_bridge devm_drm_panel_bridge_add_typed(struct device dev,
	struct drm_panel *panel,
	u32 connector_type)
	{
	struct drm_bridge *ptr, bridge;

	ptr = devres_alloc(devm_drm_panel_bridge_release, sizeof(*ptr),
	GFP_KERNEL);
	if (!ptr)
	return ERR_PTR(-ENOMEM);

	bridge = drm_panel_bridge_add_typed(panel, connector_type);
	if (IS_ERR(bridge)) {
	devres_free(ptr);
	return bridge;
	}

	bridge->pre_enable_prev_first = panel->prepare_prev_first;

	*ptr = bridge;
	devres_add(dev, ptr);

	return bridge;
	}
	EXPORT_SYMBOL(devm_drm_panel_bridge_add_typed);

	static void drmm_drm_panel_bridge_release(struct drm_device drm, void ptr)
	{
	struct drm_bridge *bridge = ptr;

	drm_panel_bridge_remove(bridge);
	}

	/**
	* drmm_panel_bridge_add - Creates a DRM-managed &drm_bridge and
	* &drm_connector that just calls the
	* appropriate functions from &drm_panel.
	*
	* @drm: DRM device to tie the bridge lifetime to
	* @panel: The drm_panel being wrapped. Must be non-NULL.
	*
	* This is the DRM-managed version of drm_panel_bridge_add() which
	* automatically calls drm_panel_bridge_remove() when @dev is cleaned
	* up.
	*/
	struct drm_bridge drmm_panel_bridge_add(struct drm_device drm,
	struct drm_panel *panel)
	{
	struct drm_bridge *bridge;
	int ret;

	bridge = drm_panel_bridge_add_typed(panel, panel->connector_type);
	if (IS_ERR(bridge))
	return bridge;

	ret = drmm_add_action_or_reset(drm, drmm_drm_panel_bridge_release,
	bridge);
	if (ret)
	return ERR_PTR(ret);

	bridge->pre_enable_prev_first = panel->prepare_prev_first;

	return bridge;
	}
	EXPORT_SYMBOL(drmm_panel_bridge_add);

	/**
	* drm_panel_bridge_connector - return the connector for the panel bridge
	* @bridge: The drm_bridge.
	*
	* drm_panel_bridge creates the connector.
	* This function gives external access to the connector.
	*
	* Returns: Pointer to drm_connector
	*/
	struct drm_connector drm_panel_bridge_connector(struct drm_bridge bridge)
	{
	struct panel_bridge *panel_bridge;

	panel_bridge = drm_bridge_to_panel_bridge(bridge);

	return &panel_bridge->connector;
	}
	EXPORT_SYMBOL(drm_panel_bridge_connector);

	#ifdef CONFIG_OF
	/**
	* devm_drm_of_get_bridge - Return next bridge in the chain
	* @dev: device to tie the bridge lifetime to
	* @np: device tree node containing encoder output ports
	* @port: port in the device tree node
	* @endpoint: endpoint in the device tree node
	*
	* Given a DT node's port and endpoint number, finds the connected node
	* and returns the associated bridge if any, or creates and returns a
	* drm panel bridge instance if a panel is connected.
	*
	* Returns a pointer to the bridge if successful, or an error pointer
	* otherwise.
	*/
	struct drm_bridge devm_drm_of_get_bridge(struct device dev,
	struct device_node *np,
	u32 port, u32 endpoint)
	{
	struct drm_bridge *bridge;
	struct drm_panel *panel;
	int ret;

	ret = drm_of_find_panel_or_bridge(np, port, endpoint,
	&panel, &bridge);
	if (ret)
	return ERR_PTR(ret);

	if (panel)
	bridge = devm_drm_panel_bridge_add(dev, panel);

	return bridge;
	}
	EXPORT_SYMBOL(devm_drm_of_get_bridge);

	/**
	* drmm_of_get_bridge - Return next bridge in the chain
	* @drm: device to tie the bridge lifetime to
	* @np: device tree node containing encoder output ports
	* @port: port in the device tree node
	* @endpoint: endpoint in the device tree node
	*
	* Given a DT node's port and endpoint number, finds the connected node
	* and returns the associated bridge if any, or creates and returns a
	* drm panel bridge instance if a panel is connected.
	*
	* Returns a drmm managed pointer to the bridge if successful, or an error
	* pointer otherwise.
	*/
	struct drm_bridge drmm_of_get_bridge(struct drm_device drm,
	struct device_node *np,
	u32 port, u32 endpoint)
	{
	struct drm_bridge *bridge;
	struct drm_panel *panel;
	int ret;

	ret = drm_of_find_panel_or_bridge(np, port, endpoint,
	&panel, &bridge);
	if (ret)
	return ERR_PTR(ret);

	if (panel)
	bridge = drmm_panel_bridge_add(drm, panel);

	return bridge;
	}
	EXPORT_SYMBOL(drmm_of_get_bridge);

	#endif