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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   4  */
   5
   6 #include <linux/gpio/consumer.h>
   7 #include <linux/module.h>
   8 #include <linux/of.h>
   9 #include <linux/of_graph.h>
  10 #include <linux/platform_device.h>
  11
  12 #include <drm/drm_bridge.h>
  13 #include <drm/drm_panel.h>
  14
  15 struct lvds_encoder {
  16         struct drm_bridge bridge;
  17         struct drm_bridge *panel_bridge;
  18         struct gpio_desc *powerdown_gpio;
  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 void lvds_encoder_enable(struct drm_bridge *bridge)
  32 {
  33         struct lvds_encoder *lvds_encoder = container_of(bridge,
  34                                                          struct lvds_encoder,
  35                                                          bridge);
  36
  37         if (lvds_encoder->powerdown_gpio)
  38                 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);
  39 }
  40
  41 static void lvds_encoder_disable(struct drm_bridge *bridge)
  42 {
  43         struct lvds_encoder *lvds_encoder = container_of(bridge,
  44                                                          struct lvds_encoder,
  45                                                          bridge);
  46
  47         if (lvds_encoder->powerdown_gpio)
  48                 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);
  49 }
  50
  51 static struct drm_bridge_funcs funcs = {
  52         .attach = lvds_encoder_attach,
  53         .enable = lvds_encoder_enable,
  54         .disable = lvds_encoder_disable,
  55 };
  56
  57 static int lvds_encoder_probe(struct platform_device *pdev)
  58 {
  59         struct device *dev = &pdev->dev;
  60         struct device_node *port;
  61         struct device_node *endpoint;
  62         struct device_node *panel_node;
  63         struct drm_panel *panel;
  64         struct lvds_encoder *lvds_encoder;
  65
  66         lvds_encoder = devm_kzalloc(dev, sizeof(*lvds_encoder), GFP_KERNEL);
  67         if (!lvds_encoder)
  68                 return -ENOMEM;
  69
  70         lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
  71                                                                GPIOD_OUT_HIGH);
  72         if (IS_ERR(lvds_encoder->powerdown_gpio)) {
  73                 int err = PTR_ERR(lvds_encoder->powerdown_gpio);
  74
  75                 if (err != -EPROBE_DEFER)
  76                         dev_err(dev, "powerdown GPIO failure: %d\n", err);
  77                 return err;
  78         }
  79
  80         /* Locate the panel DT node. */
  81         port = of_graph_get_port_by_id(dev->of_node, 1);
  82         if (!port) {
  83                 dev_dbg(dev, "port 1 not found\n");
  84                 return -ENXIO;
  85         }
  86
  87         endpoint = of_get_child_by_name(port, "endpoint");
  88         of_node_put(port);
  89         if (!endpoint) {
  90                 dev_dbg(dev, "no endpoint for port 1\n");
  91                 return -ENXIO;
  92         }
  93
  94         panel_node = of_graph_get_remote_port_parent(endpoint);
  95         of_node_put(endpoint);
  96         if (!panel_node) {
  97                 dev_dbg(dev, "no remote endpoint for port 1\n");
  98                 return -ENXIO;
  99         }
 100
 101         panel = of_drm_find_panel(panel_node);
 102         of_node_put(panel_node);
 103         if (IS_ERR(panel)) {
 104                 dev_dbg(dev, "panel not found, deferring probe\n");
 105                 return PTR_ERR(panel);
 106         }
 107
 108         lvds_encoder->panel_bridge =
 109                 devm_drm_panel_bridge_add_typed(dev, panel,
 110                                                 DRM_MODE_CONNECTOR_LVDS);
 111         if (IS_ERR(lvds_encoder->panel_bridge))
 112                 return PTR_ERR(lvds_encoder->panel_bridge);
 113
 114         /* The panel_bridge bridge is attached to the panel's of_node,
 115          * but we need a bridge attached to our of_node for our user
 116          * to look up.
 117          */
 118         lvds_encoder->bridge.of_node = dev->of_node;
 119         lvds_encoder->bridge.funcs = &funcs;
 120         drm_bridge_add(&lvds_encoder->bridge);
 121
 122         platform_set_drvdata(pdev, lvds_encoder);
 123
 124         return 0;
 125 }
 126
 127 static int lvds_encoder_remove(struct platform_device *pdev)
 128 {
 129         struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
 130
 131         drm_bridge_remove(&lvds_encoder->bridge);
 132
 133         return 0;
 134 }
 135
 136 static const struct of_device_id lvds_encoder_match[] = {
 137         { .compatible = "lvds-encoder" },
 138         { .compatible = "thine,thc63lvdm83d" },
 139         {},
 140 };
 141 MODULE_DEVICE_TABLE(of, lvds_encoder_match);
 142
 143 static struct platform_driver lvds_encoder_driver = {
 144         .probe  = lvds_encoder_probe,
 145         .remove = lvds_encoder_remove,
 146         .driver         = {
 147                 .name           = "lvds-encoder",
 148                 .of_match_table = lvds_encoder_match,
 149         },
 150 };
 151 module_platform_driver(lvds_encoder_driver);
 152
 153 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
 154 MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
 155 MODULE_LICENSE("GPL");