drivers/gpu/drm/bridge/lvds-encoder.c

   1 /*
   2  * Copyright (C) 2016 Laurent Pinchart <[email protected]>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of
   7  * the License, or (at your option) any later version.
   8  */
   9
  10 #include <drm/drmP.h>
  11 #include <drm/drm_bridge.h>
  12 #include <drm/drm_panel.h>
  13
  14 #include <linux/of_graph.h>
  15
  16 struct lvds_encoder {
  17         struct drm_bridge bridge;
  18         struct drm_bridge *panel_bridge;
  19 };
  20
  21 static int lvds_encoder_attach(struct drm_bridge *bridge)
  22 {
  23         struct lvds_encoder *lvds_encoder = container_of(bridge,
  24                                                          struct lvds_encoder,
  25                                                          bridge);
  26
  27         return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
  28                                  bridge);
  29 }
  30
  31 static struct drm_bridge_funcs funcs = {
  32         .attach = lvds_encoder_attach,
  33 };
  34
  35 static int lvds_encoder_probe(struct platform_device *pdev)
  36 {
  37         struct device_node *port;
  38         struct device_node *endpoint;
  39         struct device_node *panel_node;
  40         struct drm_panel *panel;
  41         struct lvds_encoder *lvds_encoder;
  42
  43         lvds_encoder = devm_kzalloc(&pdev->dev, sizeof(*lvds_encoder),
  44                                     GFP_KERNEL);
  45         if (!lvds_encoder)
  46                 return -ENOMEM;
  47
  48         /* Locate the panel DT node. */
  49         port = of_graph_get_port_by_id(pdev->dev.of_node, 1);
  50         if (!port) {
  51                 dev_dbg(&pdev->dev, "port 1 not found\n");
  52                 return -ENXIO;
  53         }
  54
  55         endpoint = of_get_child_by_name(port, "endpoint");
  56         of_node_put(port);
  57         if (!endpoint) {
  58                 dev_dbg(&pdev->dev, "no endpoint for port 1\n");
  59                 return -ENXIO;
  60         }
  61
  62         panel_node = of_graph_get_remote_port_parent(endpoint);
  63         of_node_put(endpoint);
  64         if (!panel_node) {
  65                 dev_dbg(&pdev->dev, "no remote endpoint for port 1\n");
  66                 return -ENXIO;
  67         }
  68
  69         panel = of_drm_find_panel(panel_node);
  70         of_node_put(panel_node);
  71         if (!panel) {
  72                 dev_dbg(&pdev->dev, "panel not found, deferring probe\n");
  73                 return -EPROBE_DEFER;
  74         }
  75
  76         lvds_encoder->panel_bridge =
  77                 devm_drm_panel_bridge_add(&pdev->dev,
  78                                           panel, DRM_MODE_CONNECTOR_LVDS);
  79         if (IS_ERR(lvds_encoder->panel_bridge))
  80                 return PTR_ERR(lvds_encoder->panel_bridge);
  81
  82         /* The panel_bridge bridge is attached to the panel's of_node,
  83          * but we need a bridge attached to our of_node for our user
  84          * to look up.
  85          */
  86         lvds_encoder->bridge.of_node = pdev->dev.of_node;
  87         lvds_encoder->bridge.funcs = &funcs;
  88         drm_bridge_add(&lvds_encoder->bridge);
  89
  90         platform_set_drvdata(pdev, lvds_encoder);
  91
  92         return 0;
  93 }
  94
  95 static int lvds_encoder_remove(struct platform_device *pdev)
  96 {
  97         struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
  98
  99         drm_bridge_remove(&lvds_encoder->bridge);
 100
 101         return 0;
 102 }
 103
 104 static const struct of_device_id lvds_encoder_match[] = {
 105         { .compatible = "lvds-encoder" },
 106         { .compatible = "thine,thc63lvdm83d" },
 107         {},
 108 };
 109 MODULE_DEVICE_TABLE(of, lvds_encoder_match);
 110
 111 static struct platform_driver lvds_encoder_driver = {
 112         .probe  = lvds_encoder_probe,
 113         .remove = lvds_encoder_remove,
 114         .driver         = {
 115                 .name           = "lvds-encoder",
 116                 .of_match_table = lvds_encoder_match,
 117         },
 118 };
 119 module_platform_driver(lvds_encoder_driver);
 120
 121 MODULE_AUTHOR("Laurent Pinchart <[email protected]>");
 122 MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
 123 MODULE_LICENSE("GPL");