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 * @link: link from panel device (supplier) to DRM device (consumer) 86 * @funcs: operations that can be performed on the panel 87 * @list: panel entry in registry 88 */ 89 struct drm_panel { 90 struct drm_device *drm; 91 struct drm_connector *connector; 92 struct device *dev; 93 94 const struct drm_panel_funcs *funcs; 95 96 struct list_head list; 97 }; 98 99 /** 100 * drm_disable_unprepare - power off a panel 101 * @panel: DRM panel 102 * 103 * Calling this function will completely power off a panel (assert the panel's 104 * reset, turn off power supplies, ...). After this function has completed, it 105 * is usually no longer possible to communicate with the panel until another 106 * call to drm_panel_prepare(). 107 * 108 * Return: 0 on success or a negative error code on failure. 109 */ 110 static inline int drm_panel_unprepare(struct drm_panel *panel) 111 { 112 if (panel && panel->funcs && panel->funcs->unprepare) 113 return panel->funcs->unprepare(panel); 114 115 return panel ? -ENOSYS : -EINVAL; 116 } 117 118 /** 119 * drm_panel_disable - disable a panel 120 * @panel: DRM panel 121 * 122 * This will typically turn off the panel's backlight or disable the display 123 * drivers. For smart panels it should still be possible to communicate with 124 * the integrated circuitry via any command bus after this call. 125 * 126 * Return: 0 on success or a negative error code on failure. 127 */ 128 static inline int drm_panel_disable(struct drm_panel *panel) 129 { 130 if (panel && panel->funcs && panel->funcs->disable) 131 return panel->funcs->disable(panel); 132 133 return panel ? -ENOSYS : -EINVAL; 134 } 135 136 /** 137 * drm_panel_prepare - power on a panel 138 * @panel: DRM panel 139 * 140 * Calling this function will enable power and deassert any reset signals to 141 * the panel. After this has completed it is possible to communicate with any 142 * integrated circuitry via a command bus. 143 * 144 * Return: 0 on success or a negative error code on failure. 145 */ 146 static inline int drm_panel_prepare(struct drm_panel *panel) 147 { 148 if (panel && panel->funcs && panel->funcs->prepare) 149 return panel->funcs->prepare(panel); 150 151 return panel ? -ENOSYS : -EINVAL; 152 } 153 154 /** 155 * drm_panel_enable - enable a panel 156 * @panel: DRM panel 157 * 158 * Calling this function will cause the panel display drivers to be turned on 159 * and the backlight to be enabled. Content will be visible on screen after 160 * this call completes. 161 * 162 * Return: 0 on success or a negative error code on failure. 163 */ 164 static inline int drm_panel_enable(struct drm_panel *panel) 165 { 166 if (panel && panel->funcs && panel->funcs->enable) 167 return panel->funcs->enable(panel); 168 169 return panel ? -ENOSYS : -EINVAL; 170 } 171 172 /** 173 * drm_panel_get_modes - probe the available display modes of a panel 174 * @panel: DRM panel 175 * 176 * The modes probed from the panel are automatically added to the connector 177 * that the panel is attached to. 178 * 179 * Return: The number of modes available from the panel on success or a 180 * negative error code on failure. 181 */ 182 static inline int drm_panel_get_modes(struct drm_panel *panel) 183 { 184 if (panel && panel->funcs && panel->funcs->get_modes) 185 return panel->funcs->get_modes(panel); 186 187 return panel ? -ENOSYS : -EINVAL; 188 } 189 190 void drm_panel_init(struct drm_panel *panel); 191 192 int drm_panel_add(struct drm_panel *panel); 193 void drm_panel_remove(struct drm_panel *panel); 194 195 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector); 196 int drm_panel_detach(struct drm_panel *panel); 197 198 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL) 199 struct drm_panel *of_drm_find_panel(const struct device_node *np); 200 #else 201 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) 202 { 203 return ERR_PTR(-ENODEV); 204 } 205 #endif 206 207 #endif 208