LXR linux/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
  15struct lvds_encoder {
  16        struct drm_bridge bridge;
  17        struct drm_bridge *panel_bridge;
  18        struct gpio_desc *powerdown_gpio;
  19};
  20
  21static 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
  31static 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
  41static 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
  51static struct drm_bridge_funcs funcs = {
  52        .attach = lvds_encoder_attach,
  53        .enable = lvds_encoder_enable,
  54        .disable = lvds_encoder_disable,
  55};
  56
  57static 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(dev, panel, DRM_MODE_CONNECTOR_LVDS);
 110        if (IS_ERR(lvds_encoder->panel_bridge))
 111                return PTR_ERR(lvds_encoder->panel_bridge);
 112
 113        /* The panel_bridge bridge is attached to the panel's of_node,
 114         * but we need a bridge attached to our of_node for our user
 115         * to look up.
 116         */
 117        lvds_encoder->bridge.of_node = dev->of_node;
 118        lvds_encoder->bridge.funcs = &funcs;
 119        drm_bridge_add(&lvds_encoder->bridge);
 120
 121        platform_set_drvdata(pdev, lvds_encoder);
 122
 123        return 0;
 124}
 125
 126static int lvds_encoder_remove(struct platform_device *pdev)
 127{
 128        struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
 129
 130        drm_bridge_remove(&lvds_encoder->bridge);
 131
 132        return 0;
 133}
 134
 135static const struct of_device_id lvds_encoder_match[] = {
 136        { .compatible = "lvds-encoder" },
 137        { .compatible = "thine,thc63lvdm83d" },
 138        {},
 139};
 140MODULE_DEVICE_TABLE(of, lvds_encoder_match);
 141
 142static struct platform_driver lvds_encoder_driver = {
 143        .probe  = lvds_encoder_probe,
 144        .remove = lvds_encoder_remove,
 145        .driver         = {
 146                .name           = "lvds-encoder",
 147                .of_match_table = lvds_encoder_match,
 148        },
 149};
 150module_platform_driver(lvds_encoder_driver);
 151
 152MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
 153MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
 154MODULE_LICENSE("GPL");
 155