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 #include <linux/err.h> 25 #include <linux/module.h> 26 27 #include <drm/drm_crtc.h> 28 #include <drm/drm_panel.h> 29 30 static DEFINE_MUTEX(panel_lock); 31 static LIST_HEAD(panel_list); 32 33 /** 34 * DOC: drm panel 35 * 36 * The DRM panel helpers allow drivers to register panel objects with a 37 * central registry and provide functions to retrieve those panels in display 38 * drivers. 39 * 40 * For easy integration into drivers using the &drm_bridge infrastructure please 41 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add(). 42 */ 43 44 /** 45 * drm_panel_init - initialize a panel 46 * @panel: DRM panel 47 * @dev: parent device of the panel 48 * @funcs: panel operations 49 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to 50 * the panel interface 51 * 52 * Initialize the panel structure for subsequent registration with 53 * drm_panel_add(). 54 */ 55 void drm_panel_init(struct drm_panel *panel, struct device *dev, 56 const struct drm_panel_funcs *funcs, int connector_type) 57 { 58 INIT_LIST_HEAD(&panel->list); 59 panel->dev = dev; 60 panel->funcs = funcs; 61 panel->connector_type = connector_type; 62 } 63 EXPORT_SYMBOL(drm_panel_init); 64 65 /** 66 * drm_panel_add - add a panel to the global registry 67 * @panel: panel to add 68 * 69 * Add a panel to the global registry so that it can be looked up by display 70 * drivers. 71 * 72 * Return: 0 on success or a negative error code on failure. 73 */ 74 int drm_panel_add(struct drm_panel *panel) 75 { 76 mutex_lock(&panel_lock); 77 list_add_tail(&panel->list, &panel_list); 78 mutex_unlock(&panel_lock); 79 80 return 0; 81 } 82 EXPORT_SYMBOL(drm_panel_add); 83 84 /** 85 * drm_panel_remove - remove a panel from the global registry 86 * @panel: DRM panel 87 * 88 * Removes a panel from the global registry. 89 */ 90 void drm_panel_remove(struct drm_panel *panel) 91 { 92 mutex_lock(&panel_lock); 93 list_del_init(&panel->list); 94 mutex_unlock(&panel_lock); 95 } 96 EXPORT_SYMBOL(drm_panel_remove); 97 98 /** 99 * drm_panel_attach - attach a panel to a connector 100 * @panel: DRM panel 101 * @connector: DRM connector 102 * 103 * After obtaining a pointer to a DRM panel a display driver calls this 104 * function to attach a panel to a connector. 105 * 106 * An error is returned if the panel is already attached to another connector. 107 * 108 * When unloading, the driver should detach from the panel by calling 109 * drm_panel_detach(). 110 * 111 * Return: 0 on success or a negative error code on failure. 112 */ 113 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) 114 { 115 if (panel->connector) 116 return -EBUSY; 117 118 panel->connector = connector; 119 panel->drm = connector->dev; 120 121 return 0; 122 } 123 EXPORT_SYMBOL(drm_panel_attach); 124 125 /** 126 * drm_panel_detach - detach a panel from a connector 127 * @panel: DRM panel 128 * 129 * Detaches a panel from the connector it is attached to. If a panel is not 130 * attached to any connector this is effectively a no-op. 131 * 132 * This function should not be called by the panel device itself. It 133 * is only for the drm device that called drm_panel_attach(). 134 */ 135 void drm_panel_detach(struct drm_panel *panel) 136 { 137 panel->connector = NULL; 138 panel->drm = NULL; 139 } 140 EXPORT_SYMBOL(drm_panel_detach); 141 142 /** 143 * drm_panel_prepare - power on a panel 144 * @panel: DRM panel 145 * 146 * Calling this function will enable power and deassert any reset signals to 147 * the panel. After this has completed it is possible to communicate with any 148 * integrated circuitry via a command bus. 149 * 150 * Return: 0 on success or a negative error code on failure. 151 */ 152 int drm_panel_prepare(struct drm_panel *panel) 153 { 154 if (panel && panel->funcs && panel->funcs->prepare) 155 return panel->funcs->prepare(panel); 156 157 return panel ? -ENOSYS : -EINVAL; 158 } 159 EXPORT_SYMBOL(drm_panel_prepare); 160 161 /** 162 * drm_panel_unprepare - power off a panel 163 * @panel: DRM panel 164 * 165 * Calling this function will completely power off a panel (assert the panel's 166 * reset, turn off power supplies, ...). After this function has completed, it 167 * is usually no longer possible to communicate with the panel until another 168 * call to drm_panel_prepare(). 169 * 170 * Return: 0 on success or a negative error code on failure. 171 */ 172 int drm_panel_unprepare(struct drm_panel *panel) 173 { 174 if (panel && panel->funcs && panel->funcs->unprepare) 175 return panel->funcs->unprepare(panel); 176 177 return panel ? -ENOSYS : -EINVAL; 178 } 179 EXPORT_SYMBOL(drm_panel_unprepare); 180 181 /** 182 * drm_panel_enable - enable a panel 183 * @panel: DRM panel 184 * 185 * Calling this function will cause the panel display drivers to be turned on 186 * and the backlight to be enabled. Content will be visible on screen after 187 * this call completes. 188 * 189 * Return: 0 on success or a negative error code on failure. 190 */ 191 int drm_panel_enable(struct drm_panel *panel) 192 { 193 if (panel && panel->funcs && panel->funcs->enable) 194 return panel->funcs->enable(panel); 195 196 return panel ? -ENOSYS : -EINVAL; 197 } 198 EXPORT_SYMBOL(drm_panel_enable); 199 200 /** 201 * drm_panel_disable - disable a panel 202 * @panel: DRM panel 203 * 204 * This will typically turn off the panel's backlight or disable the display 205 * drivers. For smart panels it should still be possible to communicate with 206 * the integrated circuitry via any command bus after this call. 207 * 208 * Return: 0 on success or a negative error code on failure. 209 */ 210 int drm_panel_disable(struct drm_panel *panel) 211 { 212 if (panel && panel->funcs && panel->funcs->disable) 213 return panel->funcs->disable(panel); 214 215 return panel ? -ENOSYS : -EINVAL; 216 } 217 EXPORT_SYMBOL(drm_panel_disable); 218 219 /** 220 * drm_panel_get_modes - probe the available display modes of a panel 221 * @panel: DRM panel 222 * 223 * The modes probed from the panel are automatically added to the connector 224 * that the panel is attached to. 225 * 226 * Return: The number of modes available from the panel on success or a 227 * negative error code on failure. 228 */ 229 int drm_panel_get_modes(struct drm_panel *panel) 230 { 231 if (panel && panel->funcs && panel->funcs->get_modes) 232 return panel->funcs->get_modes(panel); 233 234 return panel ? -ENOSYS : -EINVAL; 235 } 236 EXPORT_SYMBOL(drm_panel_get_modes); 237 238 #ifdef CONFIG_OF 239 /** 240 * of_drm_find_panel - look up a panel using a device tree node 241 * @np: device tree node of the panel 242 * 243 * Searches the set of registered panels for one that matches the given device 244 * tree node. If a matching panel is found, return a pointer to it. 245 * 246 * Return: A pointer to the panel registered for the specified device tree 247 * node or an ERR_PTR() if no panel matching the device tree node can be found. 248 * 249 * Possible error codes returned by this function: 250 * 251 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller 252 * should retry later 253 * - ENODEV: the device is not available (status != "okay" or "ok") 254 */ 255 struct drm_panel *of_drm_find_panel(const struct device_node *np) 256 { 257 struct drm_panel *panel; 258 259 if (!of_device_is_available(np)) 260 return ERR_PTR(-ENODEV); 261 262 mutex_lock(&panel_lock); 263 264 list_for_each_entry(panel, &panel_list, list) { 265 if (panel->dev->of_node == np) { 266 mutex_unlock(&panel_lock); 267 return panel; 268 } 269 } 270 271 mutex_unlock(&panel_lock); 272 return ERR_PTR(-EPROBE_DEFER); 273 } 274 EXPORT_SYMBOL(of_drm_find_panel); 275 #endif 276 277 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); 278 MODULE_DESCRIPTION("DRM panel infrastructure"); 279 MODULE_LICENSE("GPL and additional rights"); 280