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 device_node; 32 struct drm_connector; 33 struct drm_device; 34 struct drm_panel; 35 struct display_timing; 36 37 /** 38 * struct drm_panel_funcs - perform operations on a given panel 39 * @disable: disable panel (turn off back light, etc.) 40 * @unprepare: turn off panel 41 * @prepare: turn on panel and perform set up 42 * @enable: enable panel (turn on back light, etc.) 43 * @get_modes: add modes to the connector that the panel is attached to and 44 * return the number of modes added 45 * @get_timings: copy display timings into the provided array and return 46 * the number of display timings available 47 * 48 * The .prepare() function is typically called before the display controller 49 * starts to transmit video data. Panel drivers can use this to turn the panel 50 * on and wait for it to become ready. If additional configuration is required 51 * (via a control bus such as I2C, SPI or DSI for example) this is a good time 52 * to do that. 53 * 54 * After the display controller has started transmitting video data, it's safe 55 * to call the .enable() function. This will typically enable the backlight to 56 * make the image on screen visible. Some panels require a certain amount of 57 * time or frames before the image is displayed. This function is responsible 58 * for taking this into account before enabling the backlight to avoid visual 59 * glitches. 60 * 61 * Before stopping video transmission from the display controller it can be 62 * necessary to turn off the panel to avoid visual glitches. This is done in 63 * the .disable() function. Analogously to .enable() this typically involves 64 * turning off the backlight and waiting for some time to make sure no image 65 * is visible on the panel. It is then safe for the display controller to 66 * cease transmission of video data. 67 * 68 * To save power when no video data is transmitted, a driver can power down 69 * the panel. This is the job of the .unprepare() function. 70 */ 71 struct drm_panel_funcs { 72 int (*disable)(struct drm_panel *panel); 73 int (*unprepare)(struct drm_panel *panel); 74 int (*prepare)(struct drm_panel *panel); 75 int (*enable)(struct drm_panel *panel); 76 int (*get_modes)(struct drm_panel *panel); 77 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings, 78 struct display_timing *timings); 79 }; 80 81 /** 82 * struct drm_panel - DRM panel object 83 * @drm: DRM device owning the panel 84 * @connector: DRM connector that the panel is attached to 85 * @dev: parent device of the panel 86 * @link: link from panel device (supplier) to DRM device (consumer) 87 * @funcs: operations that can be performed on the panel 88 * @list: panel entry in registry 89 */ 90 struct drm_panel { 91 struct drm_device *drm; 92 struct drm_connector *connector; 93 struct device *dev; 94 95 const struct drm_panel_funcs *funcs; 96 97 struct list_head list; 98 }; 99 100 /** 101 * drm_disable_unprepare - power off a panel 102 * @panel: DRM panel 103 * 104 * Calling this function will completely power off a panel (assert the panel's 105 * reset, turn off power supplies, ...). After this function has completed, it 106 * is usually no longer possible to communicate with the panel until another 107 * call to drm_panel_prepare(). 108 * 109 * Return: 0 on success or a negative error code on failure. 110 */ 111 static inline int drm_panel_unprepare(struct drm_panel *panel) 112 { 113 if (panel && panel->funcs && panel->funcs->unprepare) 114 return panel->funcs->unprepare(panel); 115 116 return panel ? -ENOSYS : -EINVAL; 117 } 118 119 /** 120 * drm_panel_disable - disable a panel 121 * @panel: DRM panel 122 * 123 * This will typically turn off the panel's backlight or disable the display 124 * drivers. For smart panels it should still be possible to communicate with 125 * the integrated circuitry via any command bus after this call. 126 * 127 * Return: 0 on success or a negative error code on failure. 128 */ 129 static inline int drm_panel_disable(struct drm_panel *panel) 130 { 131 if (panel && panel->funcs && panel->funcs->disable) 132 return panel->funcs->disable(panel); 133 134 return panel ? -ENOSYS : -EINVAL; 135 } 136 137 /** 138 * drm_panel_prepare - power on a panel 139 * @panel: DRM panel 140 * 141 * Calling this function will enable power and deassert any reset signals to 142 * the panel. After this has completed it is possible to communicate with any 143 * integrated circuitry via a command bus. 144 * 145 * Return: 0 on success or a negative error code on failure. 146 */ 147 static inline int drm_panel_prepare(struct drm_panel *panel) 148 { 149 if (panel && panel->funcs && panel->funcs->prepare) 150 return panel->funcs->prepare(panel); 151 152 return panel ? -ENOSYS : -EINVAL; 153 } 154 155 /** 156 * drm_panel_enable - enable a panel 157 * @panel: DRM panel 158 * 159 * Calling this function will cause the panel display drivers to be turned on 160 * and the backlight to be enabled. Content will be visible on screen after 161 * this call completes. 162 * 163 * Return: 0 on success or a negative error code on failure. 164 */ 165 static inline int drm_panel_enable(struct drm_panel *panel) 166 { 167 if (panel && panel->funcs && panel->funcs->enable) 168 return panel->funcs->enable(panel); 169 170 return panel ? -ENOSYS : -EINVAL; 171 } 172 173 /** 174 * drm_panel_get_modes - probe the available display modes of a panel 175 * @panel: DRM panel 176 * 177 * The modes probed from the panel are automatically added to the connector 178 * that the panel is attached to. 179 * 180 * Return: The number of modes available from the panel on success or a 181 * negative error code on failure. 182 */ 183 static inline int drm_panel_get_modes(struct drm_panel *panel) 184 { 185 if (panel && panel->funcs && panel->funcs->get_modes) 186 return panel->funcs->get_modes(panel); 187 188 return panel ? -ENOSYS : -EINVAL; 189 } 190 191 void drm_panel_init(struct drm_panel *panel); 192 193 int drm_panel_add(struct drm_panel *panel); 194 void drm_panel_remove(struct drm_panel *panel); 195 196 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector); 197 int drm_panel_detach(struct drm_panel *panel); 198 199 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL) 200 struct drm_panel *of_drm_find_panel(const struct device_node *np); 201 #else 202 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) 203 { 204 return ERR_PTR(-ENODEV); 205 } 206 #endif 207 208 #endif 209