LXR linux/drivers/gpu/drm/drm

   1/*
   2 * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sub license,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice (including the
  12 * next paragraph) shall be included in all copies or substantial portions
  13 * of the Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21 * DEALINGS IN THE SOFTWARE.
  22 */
  23
  24#include <linux/err.h>
  25#include <linux/module.h>
  26
  27#include <drm/drm_crtc.h>
  28#include <drm/drm_panel.h>
  29
  30static DEFINE_MUTEX(panel_lock);
  31static LIST_HEAD(panel_list);
  32
  33/**
  34 * DOC: drm panel
  35 *
  36 * The DRM panel helpers allow drivers to register panel objects with a
  37 * central registry and provide functions to retrieve those panels in display
  38 * drivers.
  39 */
  40
  41/**
  42 * drm_panel_init - initialize a panel
  43 * @panel: DRM panel
  44 *
  45 * Sets up internal fields of the panel so that it can subsequently be added
  46 * to the registry.
  47 */
  48void drm_panel_init(struct drm_panel *panel)
  49{
  50        INIT_LIST_HEAD(&panel->list);
  51}
  52EXPORT_SYMBOL(drm_panel_init);
  53
  54/**
  55 * drm_panel_add - add a panel to the global registry
  56 * @panel: panel to add
  57 *
  58 * Add a panel to the global registry so that it can be looked up by display
  59 * drivers.
  60 *
  61 * Return: 0 on success or a negative error code on failure.
  62 */
  63int drm_panel_add(struct drm_panel *panel)
  64{
  65        mutex_lock(&panel_lock);
  66        list_add_tail(&panel->list, &panel_list);
  67        mutex_unlock(&panel_lock);
  68
  69        return 0;
  70}
  71EXPORT_SYMBOL(drm_panel_add);
  72
  73/**
  74 * drm_panel_remove - remove a panel from the global registry
  75 * @panel: DRM panel
  76 *
  77 * Removes a panel from the global registry.
  78 */
  79void drm_panel_remove(struct drm_panel *panel)
  80{
  81        mutex_lock(&panel_lock);
  82        list_del_init(&panel->list);
  83        mutex_unlock(&panel_lock);
  84}
  85EXPORT_SYMBOL(drm_panel_remove);
  86
  87/**
  88 * drm_panel_attach - attach a panel to a connector
  89 * @panel: DRM panel
  90 * @connector: DRM connector
  91 *
  92 * After obtaining a pointer to a DRM panel a display driver calls this
  93 * function to attach a panel to a connector.
  94 *
  95 * An error is returned if the panel is already attached to another connector.
  96 *
  97 * Return: 0 on success or a negative error code on failure.
  98 */
  99int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 100{
 101        if (panel->connector)
 102                return -EBUSY;
 103
 104        panel->connector = connector;
 105        panel->drm = connector->dev;
 106
 107        return 0;
 108}
 109EXPORT_SYMBOL(drm_panel_attach);
 110
 111/**
 112 * drm_panel_detach - detach a panel from a connector
 113 * @panel: DRM panel
 114 *
 115 * Detaches a panel from the connector it is attached to. If a panel is not
 116 * attached to any connector this is effectively a no-op.
 117 *
 118 * Return: 0 on success or a negative error code on failure.
 119 */
 120int drm_panel_detach(struct drm_panel *panel)
 121{
 122        panel->connector = NULL;
 123        panel->drm = NULL;
 124
 125        return 0;
 126}
 127EXPORT_SYMBOL(drm_panel_detach);
 128
 129#ifdef CONFIG_OF
 130/**
 131 * of_drm_find_panel - look up a panel using a device tree node
 132 * @np: device tree node of the panel
 133 *
 134 * Searches the set of registered panels for one that matches the given device
 135 * tree node. If a matching panel is found, return a pointer to it.
 136 *
 137 * Return: A pointer to the panel registered for the specified device tree
 138 * node or NULL if no panel matching the device tree node can be found.
 139 */
 140struct drm_panel *of_drm_find_panel(struct device_node *np)
 141{
 142        struct drm_panel *panel;
 143
 144        mutex_lock(&panel_lock);
 145
 146        list_for_each_entry(panel, &panel_list, list) {
 147                if (panel->dev->of_node == np) {
 148                        mutex_unlock(&panel_lock);
 149                        return panel;
 150                }
 151        }
 152
 153        mutex_unlock(&panel_lock);
 154        return NULL;
 155}
 156EXPORT_SYMBOL(of_drm_find_panel);
 157#endif
 158
 159MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
 160MODULE_DESCRIPTION("DRM panel infrastructure");
 161MODULE_LICENSE("GPL and additional rights");
 162