text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * rcar_du_encoder.c  --  R-Car Display Unit Encoder
   *
   * Copyright (C) 2013-2014 Renesas Electronics Corporation
   *
   * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   */
  
  #include <linux/export.h>
  
  #include <drm/drm_crtc.h>
  #include <drm/drm_modeset_helper_vtables.h>
  #include <drm/drm_panel.h>
  
  #include "rcar_du_drv.h"
  #include "rcar_du_encoder.h"
  #include "rcar_du_kms.h"
  #include "rcar_lvds.h"
  
  /* -----------------------------------------------------------------------------
   * Encoder
   */
  
  static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
  };
  
  static const struct drm_encoder_funcs encoder_funcs = {
  	.destroy = drm_encoder_cleanup,
  };
  
  static unsigned int rcar_du_encoder_count_ports(struct device_node *node)
  {
  	struct device_node *ports;
  	struct device_node *port;
  	unsigned int num_ports = 0;
  
  	ports = of_get_child_by_name(node, "ports");
  	if (!ports)
  		ports = of_node_get(node);
  
  	for_each_child_of_node(ports, port) {
  		if (of_node_name_eq(port, "port"))
  			num_ports++;
  	}
  
  	of_node_put(ports);
  
  	return num_ports;
  }
  
  int rcar_du_encoder_init(struct rcar_du_device *rcdu,
  			 enum rcar_du_output output,
  			 struct device_node *enc_node)
  {
  	struct rcar_du_encoder *renc;
  	struct drm_encoder *encoder;
  	struct drm_bridge *bridge;
  	int ret;
  
  	renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL);
  	if (renc == NULL)
  		return -ENOMEM;
  
  	rcdu->encoders[output] = renc;
  	renc->output = output;
  	encoder = rcar_encoder_to_drm_encoder(renc);
  
  	dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
  		enc_node, output);
  
  	/*
  	 * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
  	 * DT node has a single port, assume that it describes a panel and
  	 * create a panel bridge.
  	 */
  	if ((output == RCAR_DU_OUTPUT_DPAD0 ||
  	     output == RCAR_DU_OUTPUT_DPAD1) &&
  	    rcar_du_encoder_count_ports(enc_node) == 1) {
  		struct drm_panel *panel = of_drm_find_panel(enc_node);
  
  		if (IS_ERR(panel)) {
  			ret = PTR_ERR(panel);
  			goto done;
  		}
  
  		bridge = devm_drm_panel_bridge_add(rcdu->dev, panel,
  						   DRM_MODE_CONNECTOR_DPI);
  		if (IS_ERR(bridge)) {
  			ret = PTR_ERR(bridge);
  			goto done;
  		}
  	} else {
  		bridge = of_drm_find_bridge(enc_node);
  		if (!bridge) {
  			ret = -EPROBE_DEFER;
  			goto done;
  		}
  	}
  
  	/*
  	 * On Gen3 skip the LVDS1 output if the LVDS1 encoder is used as a
  	 * companion for LVDS0 in dual-link mode.
  	 */
  	if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
  		if (rcar_lvds_dual_link(bridge)) {
  			ret = -ENOLINK;
  			goto done;
  		}
  	}
  
  	ret = drm_encoder_init(rcdu->ddev, encoder, &encoder_funcs,
  			       DRM_MODE_ENCODER_NONE, NULL);
  	if (ret < 0)
  		goto done;
  
  	drm_encoder_helper_add(encoder, &encoder_helper_funcs);
  
  	/*
  	 * Attach the bridge to the encoder. The bridge will create the
  	 * connector.
  	 */
  	ret = drm_bridge_attach(encoder, bridge, NULL);
  	if (ret) {
  		drm_encoder_cleanup(encoder);
  		return ret;
  	}
  
  done:
  	if (ret < 0) {
  		if (encoder->name)
  			encoder->funcs->destroy(encoder);
  		devm_kfree(rcdu->dev, renc);
  	}
  
  	return ret;
  }
  