// SPDX-License-Identifier: GPL-2.0-only

  #include <linux/component.h>

  #include <linux/export.h>
  #include <linux/list.h>
  #include <linux/of_graph.h>

  #include <drm/drm_bridge.h>

  #include <drm/drm_crtc.h>

  #include <drm/drm_device.h>

  #include <drm/drm_encoder.h>

  #include <drm/drm_of.h>

  #include <drm/drm_panel.h>

  /**
   * DOC: overview
   *
   * A set of helper functions to aid DRM drivers in parsing standard DT
   * properties.
   */

  static void drm_release_of(struct device *dev, void *data)
  {
  	of_node_put(data);
  }

  /**

   * drm_of_crtc_port_mask - find the mask of a registered CRTC by port OF node

   * @dev: DRM device
   * @port: port OF node
   *
   * Given a port OF node, return the possible mask of the corresponding
   * CRTC within a device's list of CRTCs.  Returns zero if not found.
   */

  uint32_t drm_of_crtc_port_mask(struct drm_device *dev,
  			    struct device_node *port)

  {
  	unsigned int index = 0;
  	struct drm_crtc *tmp;

  	drm_for_each_crtc(tmp, dev) {

  		if (tmp->port == port)
  			return 1 << index;
  
  		index++;
  	}
  
  	return 0;
  }

  EXPORT_SYMBOL(drm_of_crtc_port_mask);

  
  /**
   * drm_of_find_possible_crtcs - find the possible CRTCs for an encoder port
   * @dev: DRM device
   * @port: encoder port to scan for endpoints
   *
   * Scan all endpoints attached to a port, locate their attached CRTCs,
   * and generate the DRM mask of CRTCs which may be attached to this
   * encoder.
   *
   * See Documentation/devicetree/bindings/graph.txt for the bindings.
   */
  uint32_t drm_of_find_possible_crtcs(struct drm_device *dev,
  				    struct device_node *port)
  {

  	struct device_node *remote_port, *ep;

  	uint32_t possible_crtcs = 0;

  	for_each_endpoint_of_node(port, ep) {

  		remote_port = of_graph_get_remote_port(ep);
  		if (!remote_port) {
  			of_node_put(ep);
  			return 0;
  		}

  		possible_crtcs |= drm_of_crtc_port_mask(dev, remote_port);

  
  		of_node_put(remote_port);

  	}

  
  	return possible_crtcs;
  }
  EXPORT_SYMBOL(drm_of_find_possible_crtcs);

  
  /**

   * drm_of_component_match_add - Add a component helper OF node match rule
   * @master: master device
   * @matchptr: component match pointer
   * @compare: compare function used for matching component
   * @node: of_node
   */
  void drm_of_component_match_add(struct device *master,
  				struct component_match **matchptr,
  				int (*compare)(struct device *, void *),
  				struct device_node *node)
  {
  	of_node_get(node);
  	component_match_add_release(master, matchptr, drm_release_of,
  				    compare, node);
  }
  EXPORT_SYMBOL_GPL(drm_of_component_match_add);
  
  /**

   * drm_of_component_probe_with_match - Generic probe function with match
   *                                     entries for a component based master

   * @dev: master device containing the OF node

   * @match: component match pointer provided to store matches

   * @compare_of: compare function used for matching components

   * @m_ops: component master ops to be used

   *
   * Parse the platform device OF node and bind all the components associated
   * with the master. Interface ports are added before the encoders in order to
   * satisfy their .bind requirements
   * See Documentation/devicetree/bindings/graph.txt for the bindings.
   *
   * Returns zero if successful, or one of the standard error codes if it fails.
   */

  int drm_of_component_probe_with_match(struct device *dev,
  			   struct component_match *match,

  			   int (*compare_of)(struct device *, void *),
  			   const struct component_master_ops *m_ops)
  {
  	struct device_node *ep, *port, *remote;

  	int i;
  
  	if (!dev->of_node)
  		return -EINVAL;
  
  	/*
  	 * Bind the crtc's ports first, so that drm_of_find_possible_crtcs()
  	 * called from encoder's .bind callbacks works as expected
  	 */
  	for (i = 0; ; i++) {
  		port = of_parse_phandle(dev->of_node, "ports", i);
  		if (!port)
  			break;

  		if (of_device_is_available(port->parent))
  			drm_of_component_match_add(dev, &match, compare_of,
  						   port);

  		of_node_put(port);
  	}
  
  	if (i == 0) {
  		dev_err(dev, "missing 'ports' property
  ");
  		return -ENODEV;
  	}
  
  	if (!match) {
  		dev_err(dev, "no available port
  ");
  		return -ENODEV;
  	}
  
  	/*
  	 * For bound crtcs, bind the encoders attached to their remote endpoint
  	 */
  	for (i = 0; ; i++) {
  		port = of_parse_phandle(dev->of_node, "ports", i);
  		if (!port)
  			break;
  
  		if (!of_device_is_available(port->parent)) {
  			of_node_put(port);
  			continue;
  		}
  
  		for_each_child_of_node(port, ep) {
  			remote = of_graph_get_remote_port_parent(ep);
  			if (!remote || !of_device_is_available(remote)) {
  				of_node_put(remote);
  				continue;
  			} else if (!of_device_is_available(remote->parent)) {

  				dev_warn(dev, "parent device of %pOF is not available
  ",
  					 remote);

  				of_node_put(remote);
  				continue;
  			}

  			drm_of_component_match_add(dev, &match, compare_of,
  						   remote);

  			of_node_put(remote);
  		}
  		of_node_put(port);
  	}
  
  	return component_master_add_with_match(dev, m_ops, match);
  }

  EXPORT_SYMBOL(drm_of_component_probe_with_match);
  
  /**
   * drm_of_component_probe - Generic probe function for a component based master
   * @dev: master device containing the OF node
   * @compare_of: compare function used for matching components
   * @master_ops: component master ops to be used
   *
   * Parse the platform device OF node and bind all the components associated
   * with the master. Interface ports are added before the encoders in order to
   * satisfy their .bind requirements
   * See Documentation/devicetree/bindings/graph.txt for the bindings.
   *
   * Returns zero if successful, or one of the standard error codes if it fails.
   */
  int drm_of_component_probe(struct device *dev,
  			   int (*compare_of)(struct device *, void *),
  			   const struct component_master_ops *m_ops)
  {
  	struct component_match *match = NULL;
  
  	return drm_of_component_probe_with_match(dev, match, compare_of, m_ops);
  }

  EXPORT_SYMBOL(drm_of_component_probe);

  
  /*
   * drm_of_encoder_active_endpoint - return the active encoder endpoint
   * @node: device tree node containing encoder input ports
   * @encoder: drm_encoder
   *
   * Given an encoder device node and a drm_encoder with a connected crtc,
   * parse the encoder endpoint connecting to the crtc port.
   */
  int drm_of_encoder_active_endpoint(struct device_node *node,
  				   struct drm_encoder *encoder,
  				   struct of_endpoint *endpoint)
  {
  	struct device_node *ep;
  	struct drm_crtc *crtc = encoder->crtc;
  	struct device_node *port;
  	int ret;
  
  	if (!node || !crtc)
  		return -EINVAL;
  
  	for_each_endpoint_of_node(node, ep) {
  		port = of_graph_get_remote_port(ep);
  		of_node_put(port);
  		if (port == crtc->port) {
  			ret = of_graph_parse_endpoint(ep, endpoint);
  			of_node_put(ep);
  			return ret;
  		}
  	}
  
  	return -EINVAL;
  }
  EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);

  /**

   * drm_of_find_panel_or_bridge - return connected panel or bridge device
   * @np: device tree node containing encoder output ports

   * @port: port in the device tree node
   * @endpoint: endpoint in the device tree node

   * @panel: pointer to hold returned drm_panel
   * @bridge: pointer to hold returned drm_bridge
   *
   * Given a DT node's port and endpoint number, find the connected node and
   * return either the associated struct drm_panel or drm_bridge device. Either
   * @panel or @bridge must not be NULL.
   *
   * Returns zero if successful, or one of the standard error codes if it fails.
   */
  int drm_of_find_panel_or_bridge(const struct device_node *np,
  				int port, int endpoint,
  				struct drm_panel **panel,
  				struct drm_bridge **bridge)
  {
  	int ret = -EPROBE_DEFER;
  	struct device_node *remote;
  
  	if (!panel && !bridge)
  		return -EINVAL;

  	if (panel)
  		*panel = NULL;

  	/*
  	 * of_graph_get_remote_node() produces a noisy error message if port
  	 * node isn't found and the absence of the port is a legit case here,
  	 * so at first we silently check whether graph presents in the
  	 * device-tree node.
  	 */
  	if (!of_graph_is_present(np))
  		return -ENODEV;

  	remote = of_graph_get_remote_node(np, port, endpoint);
  	if (!remote)
  		return -ENODEV;
  
  	if (panel) {
  		*panel = of_drm_find_panel(remote);

  		if (!IS_ERR(*panel))

  			ret = 0;

  		else
  			*panel = NULL;

  	}
  
  	/* No panel found yet, check for a bridge next. */
  	if (bridge) {
  		if (ret) {
  			*bridge = of_drm_find_bridge(remote);
  			if (*bridge)
  				ret = 0;
  		} else {
  			*bridge = NULL;
  		}
  
  	}
  
  	of_node_put(remote);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);

  
  enum drm_of_lvds_pixels {
  	DRM_OF_LVDS_EVEN = BIT(0),
  	DRM_OF_LVDS_ODD = BIT(1),
  };
  
  static int drm_of_lvds_get_port_pixels_type(struct device_node *port_node)
  {
  	bool even_pixels =
  		of_property_read_bool(port_node, "dual-lvds-even-pixels");
  	bool odd_pixels =
  		of_property_read_bool(port_node, "dual-lvds-odd-pixels");
  
  	return (even_pixels ? DRM_OF_LVDS_EVEN : 0) |
  	       (odd_pixels ? DRM_OF_LVDS_ODD : 0);
  }
  
  static int drm_of_lvds_get_remote_pixels_type(
  			const struct device_node *port_node)
  {
  	struct device_node *endpoint = NULL;
  	int pixels_type = -EPIPE;
  
  	for_each_child_of_node(port_node, endpoint) {
  		struct device_node *remote_port;
  		int current_pt;
  
  		if (!of_node_name_eq(endpoint, "endpoint"))
  			continue;
  
  		remote_port = of_graph_get_remote_port(endpoint);
  		if (!remote_port) {
  			of_node_put(remote_port);
  			return -EPIPE;
  		}
  
  		current_pt = drm_of_lvds_get_port_pixels_type(remote_port);
  		of_node_put(remote_port);
  		if (pixels_type < 0)
  			pixels_type = current_pt;
  
  		/*
  		 * Sanity check, ensure that all remote endpoints have the same
  		 * pixel type. We may lift this restriction later if we need to
  		 * support multiple sinks with different dual-link
  		 * configurations by passing the endpoints explicitly to
  		 * drm_of_lvds_get_dual_link_pixel_order().
  		 */

  		if (!current_pt || pixels_type != current_pt)

  			return -EINVAL;

  	}
  
  	return pixels_type;
  }
  
  /**
   * drm_of_lvds_get_dual_link_pixel_order - Get LVDS dual-link pixel order
   * @port1: First DT port node of the Dual-link LVDS source
   * @port2: Second DT port node of the Dual-link LVDS source
   *
   * An LVDS dual-link connection is made of two links, with even pixels
   * transitting on one link, and odd pixels on the other link. This function
   * returns, for two ports of an LVDS dual-link source, which port shall transmit
   * the even and odd pixels, based on the requirements of the connected sink.
   *
   * The pixel order is determined from the dual-lvds-even-pixels and
   * dual-lvds-odd-pixels properties in the sink's DT port nodes. If those
   * properties are not present, or if their usage is not valid, this function
   * returns -EINVAL.
   *
   * If either port is not connected, this function returns -EPIPE.
   *
   * @port1 and @port2 are typically DT sibling nodes, but may have different
   * parents when, for instance, two separate LVDS encoders carry the even and odd
   * pixels.
   *
   * Return:
   * * DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS - @port1 carries even pixels and @port2
   *   carries odd pixels
   * * DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS - @port1 carries odd pixels and @port2
   *   carries even pixels
   * * -EINVAL - @port1 and @port2 are not connected to a dual-link LVDS sink, or
   *   the sink configuration is invalid
   * * -EPIPE - when @port1 or @port2 are not connected
   */
  int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
  					  const struct device_node *port2)
  {
  	int remote_p1_pt, remote_p2_pt;
  
  	if (!port1 || !port2)
  		return -EINVAL;
  
  	remote_p1_pt = drm_of_lvds_get_remote_pixels_type(port1);
  	if (remote_p1_pt < 0)
  		return remote_p1_pt;
  
  	remote_p2_pt = drm_of_lvds_get_remote_pixels_type(port2);
  	if (remote_p2_pt < 0)
  		return remote_p2_pt;
  
  	/*
  	 * A valid dual-lVDS bus is found when one remote port is marked with
  	 * "dual-lvds-even-pixels", and the other remote port is marked with
  	 * "dual-lvds-odd-pixels", bail out if the markers are not right.
  	 */
  	if (remote_p1_pt + remote_p2_pt != DRM_OF_LVDS_EVEN + DRM_OF_LVDS_ODD)
  		return -EINVAL;
  
  	return remote_p1_pt == DRM_OF_LVDS_EVEN ?
  		DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS :
  		DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS;
  }
  EXPORT_SYMBOL_GPL(drm_of_lvds_get_dual_link_pixel_order);