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/err.h>
  28 #include <linux/errno.h>
  29 #include <linux/list.h>
  30
  31 struct backlight_device;
  32 struct device_node;
  33 struct drm_connector;
  34 struct drm_device;
  35 struct drm_panel;
  36 struct display_timing;
  37
  38 /**
  39  * struct drm_panel_funcs - perform operations on a given panel
  40  *
  41  * The .prepare() function is typically called before the display controller
  42  * starts to transmit video data. Panel drivers can use this to turn the panel
  43  * on and wait for it to become ready. If additional configuration is required
  44  * (via a control bus such as I2C, SPI or DSI for example) this is a good time
  45  * to do that.
  46  *
  47  * After the display controller has started transmitting video data, it's safe
  48  * to call the .enable() function. This will typically enable the backlight to
  49  * make the image on screen visible. Some panels require a certain amount of
  50  * time or frames before the image is displayed. This function is responsible
  51  * for taking this into account before enabling the backlight to avoid visual
  52  * glitches.
  53  *
  54  * Before stopping video transmission from the display controller it can be
  55  * necessary to turn off the panel to avoid visual glitches. This is done in
  56  * the .disable() function. Analogously to .enable() this typically involves
  57  * turning off the backlight and waiting for some time to make sure no image
  58  * is visible on the panel. It is then safe for the display controller to
  59  * cease transmission of video data.
  60  *
  61  * To save power when no video data is transmitted, a driver can power down
  62  * the panel. This is the job of the .unprepare() function.
  63  *
  64  * Backlight can be handled automatically if configured using
  65  * drm_panel_of_backlight(). Then the driver does not need to implement the
  66  * functionality to enable/disable backlight.
  67  */
  68 struct drm_panel_funcs {
  69         /**
  70          * @prepare:
  71          *
  72          * Turn on panel and perform set up.
  73          *
  74          * This function is optional.
  75          */
  76         int (*prepare)(struct drm_panel *panel);
  77
  78         /**
  79          * @enable:
  80          *
  81          * Enable panel (turn on back light, etc.).
  82          *
  83          * This function is optional.
  84          */
  85         int (*enable)(struct drm_panel *panel);
  86
  87         /**
  88          * @disable:
  89          *
  90          * Disable panel (turn off back light, etc.).
  91          *
  92          * This function is optional.
  93          */
  94         int (*disable)(struct drm_panel *panel);
  95
  96         /**
  97          * @unprepare:
  98          *
  99          * Turn off panel.
 100          *
 101          * This function is optional.
 102          */
 103         int (*unprepare)(struct drm_panel *panel);
 104
 105         /**
 106          * @get_modes:
 107          *
 108          * Add modes to the connector that the panel is attached to
 109          * and returns the number of modes added.
 110          *
 111          * This function is mandatory.
 112          */
 113         int (*get_modes)(struct drm_panel *panel,
 114                          struct drm_connector *connector);
 115
 116         /**
 117          * @get_timings:
 118          *
 119          * Copy display timings into the provided array and return
 120          * the number of display timings available.
 121          *
 122          * This function is optional.
 123          */
 124         int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
 125                            struct display_timing *timings);
 126 };
 127
 128 /**
 129  * struct drm_panel - DRM panel object
 130  */
 131 struct drm_panel {
 132         /**
 133          * @dev:
 134          *
 135          * Parent device of the panel.
 136          */
 137         struct device *dev;
 138
 139         /**
 140          * @backlight:
 141          *
 142          * Backlight device, used to turn on backlight after the call
 143          * to enable(), and to turn off backlight before the call to
 144          * disable().
 145          * backlight is set by drm_panel_of_backlight() and drivers
 146          * shall not assign it.
 147          */
 148         struct backlight_device *backlight;
 149
 150         /**
 151          * @funcs:
 152          *
 153          * Operations that can be performed on the panel.
 154          */
 155         const struct drm_panel_funcs *funcs;
 156
 157         /**
 158          * @connector_type:
 159          *
 160          * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
 161          * initialise the drm_connector corresponding to the panel with the
 162          * correct connector type.
 163          */
 164         int connector_type;
 165
 166         /**
 167          * @list:
 168          *
 169          * Panel entry in registry.
 170          */
 171         struct list_head list;
 172 };
 173
 174 void drm_panel_init(struct drm_panel *panel, struct device *dev,
 175                     const struct drm_panel_funcs *funcs,
 176                     int connector_type);
 177
 178 int drm_panel_add(struct drm_panel *panel);
 179 void drm_panel_remove(struct drm_panel *panel);
 180
 181 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
 182 void drm_panel_detach(struct drm_panel *panel);
 183
 184 int drm_panel_prepare(struct drm_panel *panel);
 185 int drm_panel_unprepare(struct drm_panel *panel);
 186
 187 int drm_panel_enable(struct drm_panel *panel);
 188 int drm_panel_disable(struct drm_panel *panel);
 189
 190 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
 191
 192 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
 193 struct drm_panel *of_drm_find_panel(const struct device_node *np);
 194 #else
 195 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
 196 {
 197         return ERR_PTR(-ENODEV);
 198 }
 199 #endif
 200
 201 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 202 int drm_panel_of_backlight(struct drm_panel *panel);
 203 #else
 204 static inline int drm_panel_of_backlight(struct drm_panel *panel)
 205 {
 206         return 0;
 207 }
 208 #endif
 209
 210 #endif