sys/dev/drm/drm_panel.c

   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/drmP.h>
  28 #include <drm/drm_crtc.h>
  29 #include <drm/drm_panel.h>
  30
  31 static DEFINE_MUTEX(panel_lock);
  32 static LINUX_LIST_HEAD(panel_list);
  33
  34 /**
  35  * DOC: drm panel
  36  *
  37  * The DRM panel helpers allow drivers to register panel objects with a
  38  * central registry and provide functions to retrieve those panels in display
  39  * drivers.
  40  */
  41
  42 /**
  43  * drm_panel_init - initialize a panel
  44  * @panel: DRM panel
  45  *
  46  * Sets up internal fields of the panel so that it can subsequently be added
  47  * to the registry.
  48  */
  49 void drm_panel_init(struct drm_panel *panel)
  50 {
  51         INIT_LIST_HEAD(&panel->list);
  52 }
  53 EXPORT_SYMBOL(drm_panel_init);
  54
  55 /**
  56  * drm_panel_add - add a panel to the global registry
  57  * @panel: panel to add
  58  *
  59  * Add a panel to the global registry so that it can be looked up by display
  60  * drivers.
  61  *
  62  * Return: 0 on success or a negative error code on failure.
  63  */
  64 int drm_panel_add(struct drm_panel *panel)
  65 {
  66         mutex_lock(&panel_lock);
  67         list_add_tail(&panel->list, &panel_list);
  68         mutex_unlock(&panel_lock);
  69
  70         return 0;
  71 }
  72 EXPORT_SYMBOL(drm_panel_add);
  73
  74 /**
  75  * drm_panel_remove - remove a panel from the global registry
  76  * @panel: DRM panel
  77  *
  78  * Removes a panel from the global registry.
  79  */
  80 void drm_panel_remove(struct drm_panel *panel)
  81 {
  82         mutex_lock(&panel_lock);
  83         list_del_init(&panel->list);
  84         mutex_unlock(&panel_lock);
  85 }
  86 EXPORT_SYMBOL(drm_panel_remove);
  87
  88 /**
  89  * drm_panel_attach - attach a panel to a connector
  90  * @panel: DRM panel
  91  * @connector: DRM connector
  92  *
  93  * After obtaining a pointer to a DRM panel a display driver calls this
  94  * function to attach a panel to a connector.
  95  *
  96  * An error is returned if the panel is already attached to another connector.
  97  *
  98  * Return: 0 on success or a negative error code on failure.
  99  */
 100 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 101 {
 102         if (panel->connector)
 103                 return -EBUSY;
 104
 105         panel->connector = connector;
 106         panel->drm = connector->dev;
 107
 108         return 0;
 109 }
 110 EXPORT_SYMBOL(drm_panel_attach);
 111
 112 /**
 113  * drm_panel_detach - detach a panel from a connector
 114  * @panel: DRM panel
 115  *
 116  * Detaches a panel from the connector it is attached to. If a panel is not
 117  * attached to any connector this is effectively a no-op.
 118  *
 119  * Return: 0 on success or a negative error code on failure.
 120  */
 121 int drm_panel_detach(struct drm_panel *panel)
 122 {
 123         panel->connector = NULL;
 124         panel->drm = NULL;
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL(drm_panel_detach);
 129
 130 #ifdef CONFIG_OF
 131 /**
 132  * of_drm_find_panel - look up a panel using a device tree node
 133  * @np: device tree node of the panel
 134  *
 135  * Searches the set of registered panels for one that matches the given device
 136  * tree node. If a matching panel is found, return a pointer to it.
 137  *
 138  * Return: A pointer to the panel registered for the specified device tree
 139  * node or NULL if no panel matching the device tree node can be found.
 140  */
 141 struct drm_panel *of_drm_find_panel(struct device_node *np)
 142 {
 143         struct drm_panel *panel;
 144
 145         mutex_lock(&panel_lock);
 146
 147         list_for_each_entry(panel, &panel_list, list) {
 148                 if (panel->dev->of_node == np) {
 149                         mutex_unlock(&panel_lock);
 150                         return panel;
 151                 }
 152         }
 153
 154         mutex_unlock(&panel_lock);
 155         return NULL;
 156 }
 157 EXPORT_SYMBOL(of_drm_find_panel);
 158 #endif
 159
 160 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
 161 MODULE_DESCRIPTION("DRM panel infrastructure");