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(const struct device_node *np); 197 #else 198 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) 199 { 200 return NULL; 201 } 202 #endif 203 204 #endif 205