include/drm/drm_panel.h

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