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

   1 /*
   2  * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   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/gpio/consumer.h>
  15 #include <linux/of_graph.h>
  16
  17 struct lvds_encoder {
  18         struct drm_bridge bridge;
  19         struct drm_bridge *panel_bridge;
  20         struct gpio_desc *powerdown_gpio;
  21 };
  22
  23 static int lvds_encoder_attach(struct drm_bridge *bridge)
  24 {
  25         struct lvds_encoder *lvds_encoder = container_of(bridge,
  26                                                          struct lvds_encoder,
  27                                                          bridge);
  28
  29         return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
  30                                  bridge);
  31 }
  32
  33 static void lvds_encoder_enable(struct drm_bridge *bridge)
  34 {
  35         struct lvds_encoder *lvds_encoder = container_of(bridge,
  36                                                          struct lvds_encoder,
  37                                                          bridge);
  38
  39         if (lvds_encoder->powerdown_gpio)
  40                 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);
  41 }
  42
  43 static void lvds_encoder_disable(struct drm_bridge *bridge)
  44 {
  45         struct lvds_encoder *lvds_encoder = container_of(bridge,
  46                                                          struct lvds_encoder,
  47                                                          bridge);
  48
  49         if (lvds_encoder->powerdown_gpio)
  50                 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);
  51 }
  52
  53 static struct drm_bridge_funcs funcs = {
  54         .attach = lvds_encoder_attach,
  55         .enable = lvds_encoder_enable,
  56         .disable = lvds_encoder_disable,
  57 };
  58
  59 static int lvds_encoder_probe(struct platform_device *pdev)
  60 {
  61         struct device *dev = &pdev->dev;
  62         struct device_node *port;
  63         struct device_node *endpoint;
  64         struct device_node *panel_node;
  65         struct drm_panel *panel;
  66         struct lvds_encoder *lvds_encoder;
  67
  68         lvds_encoder = devm_kzalloc(dev, sizeof(*lvds_encoder), GFP_KERNEL);
  69         if (!lvds_encoder)
  70                 return -ENOMEM;
  71
  72         lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
  73                                                                GPIOD_OUT_HIGH);
  74         if (IS_ERR(lvds_encoder->powerdown_gpio)) {
  75                 int err = PTR_ERR(lvds_encoder->powerdown_gpio);
  76
  77                 if (err != -EPROBE_DEFER)
  78                         dev_err(dev, "powerdown GPIO failure: %d\n", err);
  79                 return err;
  80         }
  81
  82         /* Locate the panel DT node. */
  83         port = of_graph_get_port_by_id(dev->of_node, 1);
  84         if (!port) {
  85                 dev_dbg(dev, "port 1 not found\n");
  86                 return -ENXIO;
  87         }
  88
  89         endpoint = of_get_child_by_name(port, "endpoint");
  90         of_node_put(port);
  91         if (!endpoint) {
  92                 dev_dbg(dev, "no endpoint for port 1\n");
  93                 return -ENXIO;
  94         }
  95
  96         panel_node = of_graph_get_remote_port_parent(endpoint);
  97         of_node_put(endpoint);
  98         if (!panel_node) {
  99                 dev_dbg(dev, "no remote endpoint for port 1\n");
 100                 return -ENXIO;
 101         }
 102
 103         panel = of_drm_find_panel(panel_node);
 104         of_node_put(panel_node);
 105         if (IS_ERR(panel)) {
 106                 dev_dbg(dev, "panel not found, deferring probe\n");
 107                 return PTR_ERR(panel);
 108         }
 109
 110         lvds_encoder->panel_bridge =
 111                 devm_drm_panel_bridge_add(dev, panel, DRM_MODE_CONNECTOR_LVDS);
 112         if (IS_ERR(lvds_encoder->panel_bridge))
 113                 return PTR_ERR(lvds_encoder->panel_bridge);
 114
 115         /* The panel_bridge bridge is attached to the panel's of_node,
 116          * but we need a bridge attached to our of_node for our user
 117          * to look up.
 118          */
 119         lvds_encoder->bridge.of_node = dev->of_node;
 120         lvds_encoder->bridge.funcs = &funcs;
 121         drm_bridge_add(&lvds_encoder->bridge);
 122
 123         platform_set_drvdata(pdev, lvds_encoder);
 124
 125         return 0;
 126 }
 127
 128 static int lvds_encoder_remove(struct platform_device *pdev)
 129 {
 130         struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
 131
 132         drm_bridge_remove(&lvds_encoder->bridge);
 133
 134         return 0;
 135 }
 136
 137 static const struct of_device_id lvds_encoder_match[] = {
 138         { .compatible = "lvds-encoder" },
 139         { .compatible = "thine,thc63lvdm83d" },
 140         {},
 141 };
 142 MODULE_DEVICE_TABLE(of, lvds_encoder_match);
 143
 144 static struct platform_driver lvds_encoder_driver = {
 145         .probe  = lvds_encoder_probe,
 146         .remove = lvds_encoder_remove,
 147         .driver         = {
 148                 .name           = "lvds-encoder",
 149                 .of_match_table = lvds_encoder_match,
 150         },
 151 };
 152 module_platform_driver(lvds_encoder_driver);
 153
 154 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
 155 MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
 156 MODULE_LICENSE("GPL");