linux/include/drm/drm_panel.h
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   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#ifndef __DRM_PANEL_H__
  25#define __DRM_PANEL_H__
  26
  27#include <linux/errno.h>
  28#include <linux/list.h>
  29
  30struct device_node;
  31struct drm_connector;
  32struct drm_device;
  33struct drm_panel;
  34struct display_timing;
  35
  36/**
  37 * struct drm_panel_funcs - perform operations on a given panel
  38 * @disable: disable panel (turn off back light, etc.)
  39 * @unprepare: turn off panel
  40 * @prepare: turn on panel and perform set up
  41 * @enable: enable panel (turn on back light, etc.)
  42 * @get_modes: add modes to the connector that the panel is attached to and
  43 * return the number of modes added
  44 * @get_timings: copy display timings into the provided array and return
  45 * the number of display timings available
  46 *
  47 * The .prepare() function is typically called before the display controller
  48 * starts to transmit video data. Panel drivers can use this to turn the panel
  49 * on and wait for it to become ready. If additional configuration is required
  50 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
  51 * to do that.
  52 *
  53 * After the display controller has started transmitting video data, it's safe
  54 * to call the .enable() function. This will typically enable the backlight to
  55 * make the image on screen visible. Some panels require a certain amount of
  56 * time or frames before the image is displayed. This function is responsible
  57 * for taking this into account before enabling the backlight to avoid visual
  58 * glitches.
  59 *
  60 * Before stopping video transmission from the display controller it can be
  61 * necessary to turn off the panel to avoid visual glitches. This is done in
  62 * the .disable() function. Analogously to .enable() this typically involves
  63 * turning off the backlight and waiting for some time to make sure no image
  64 * is visible on the panel. It is then safe for the display controller to
  65 * cease transmission of video data.
  66 *
  67 * To save power when no video data is transmitted, a driver can power down
  68 * the panel. This is the job of the .unprepare() function.
  69 */
  70struct drm_panel_funcs {
  71        int (*disable)(struct drm_panel *panel);
  72        int (*unprepare)(struct drm_panel *panel);
  73        int (*prepare)(struct drm_panel *panel);
  74        int (*enable)(struct drm_panel *panel);
  75        int (*get_modes)(struct drm_panel *panel);
  76        int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
  77                           struct display_timing *timings);
  78};
  79
  80/**
  81 * struct drm_panel - DRM panel object
  82 * @drm: DRM device owning the panel
  83 * @connector: DRM connector that the panel is attached to
  84 * @dev: parent device of the panel
  85 * @funcs: operations that can be performed on the panel
  86 * @list: panel entry in registry
  87 */
  88struct drm_panel {
  89        struct drm_device *drm;
  90        struct drm_connector *connector;
  91        struct device *dev;
  92
  93        const struct drm_panel_funcs *funcs;
  94
  95        struct list_head list;
  96};
  97
  98/**
  99 * drm_disable_unprepare - power off a panel
 100 * @panel: DRM panel
 101 *
 102 * Calling this function will completely power off a panel (assert the panel's
 103 * reset, turn off power supplies, ...). After this function has completed, it
 104 * is usually no longer possible to communicate with the panel until another
 105 * call to drm_panel_prepare().
 106 *
 107 * Return: 0 on success or a negative error code on failure.
 108 */
 109static inline int drm_panel_unprepare(struct drm_panel *panel)
 110{
 111        if (panel && panel->funcs && panel->funcs->unprepare)
 112                return panel->funcs->unprepare(panel);
 113
 114        return panel ? -ENOSYS : -EINVAL;
 115}
 116
 117/**
 118 * drm_panel_disable - disable a panel
 119 * @panel: DRM panel
 120 *
 121 * This will typically turn off the panel's backlight or disable the display
 122 * drivers. For smart panels it should still be possible to communicate with
 123 * the integrated circuitry via any command bus after this call.
 124 *
 125 * Return: 0 on success or a negative error code on failure.
 126 */
 127static inline int drm_panel_disable(struct drm_panel *panel)
 128{
 129        if (panel && panel->funcs && panel->funcs->disable)
 130                return panel->funcs->disable(panel);
 131
 132        return panel ? -ENOSYS : -EINVAL;
 133}
 134
 135/**
 136 * drm_panel_prepare - power on a panel
 137 * @panel: DRM panel
 138 *
 139 * Calling this function will enable power and deassert any reset signals to
 140 * the panel. After this has completed it is possible to communicate with any
 141 * integrated circuitry via a command bus.
 142 *
 143 * Return: 0 on success or a negative error code on failure.
 144 */
 145static inline int drm_panel_prepare(struct drm_panel *panel)
 146{
 147        if (panel && panel->funcs && panel->funcs->prepare)
 148                return panel->funcs->prepare(panel);
 149
 150        return panel ? -ENOSYS : -EINVAL;
 151}
 152
 153/**
 154 * drm_panel_enable - enable a panel
 155 * @panel: DRM panel
 156 *
 157 * Calling this function will cause the panel display drivers to be turned on
 158 * and the backlight to be enabled. Content will be visible on screen after
 159 * this call completes.
 160 *
 161 * Return: 0 on success or a negative error code on failure.
 162 */
 163static inline int drm_panel_enable(struct drm_panel *panel)
 164{
 165        if (panel && panel->funcs && panel->funcs->enable)
 166                return panel->funcs->enable(panel);
 167
 168        return panel ? -ENOSYS : -EINVAL;
 169}
 170
 171/**
 172 * drm_panel_get_modes - probe the available display modes of a panel
 173 * @panel: DRM panel
 174 *
 175 * The modes probed from the panel are automatically added to the connector
 176 * that the panel is attached to.
 177 *
 178 * Return: The number of modes available from the panel on success or a
 179 * negative error code on failure.
 180 */
 181static inline int drm_panel_get_modes(struct drm_panel *panel)
 182{
 183        if (panel && panel->funcs && panel->funcs->get_modes)
 184                return panel->funcs->get_modes(panel);
 185
 186        return panel ? -ENOSYS : -EINVAL;
 187}
 188
 189void drm_panel_init(struct drm_panel *panel);
 190
 191int drm_panel_add(struct drm_panel *panel);
 192void drm_panel_remove(struct drm_panel *panel);
 193
 194int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
 195int drm_panel_detach(struct drm_panel *panel);
 196
 197#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
 198struct drm_panel *of_drm_find_panel(const struct device_node *np);
 199#else
 200static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
 201{
 202        return NULL;
 203}
 204#endif
 205
 206#endif
 207