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(const 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");