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/errno.h>
  28 #include <linux/list.h>
  29
  30 struct device_node;
  31 struct drm_connector;
  32 struct drm_device;
  33 struct drm_panel;
  34 struct 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  */
  70 struct 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  */
  88 struct 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  */
 109 static 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  */
 127 static 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  */
 145 static 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  */
 163 static 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  */
 181 static 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
 189 void drm_panel_init(struct drm_panel *panel);
 190
 191 int drm_panel_add(struct drm_panel *panel);
 192 void drm_panel_remove(struct drm_panel *panel);
 193
 194 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
 195 int drm_panel_detach(struct drm_panel *panel);
 196
 197 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
 198 struct drm_panel *of_drm_find_panel(const struct device_node *np);
 199 #else
 200 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
 201 {
 202         return NULL;
 203 }
 204 #endif
 205
 206 #endif