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 211