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/backlight.h> 25 #include <linux/err.h> 26 #include <linux/module.h> 27 28 #include <drm/drm_crtc.h> 29 #include <drm/drm_panel.h> 30 #include <drm/drm_print.h> 31 32 static DEFINE_MUTEX(panel_lock); 33 static LIST_HEAD(panel_list); 34 35 /** 36 * DOC: drm panel 37 * 38 * The DRM panel helpers allow drivers to register panel objects with a 39 * central registry and provide functions to retrieve those panels in display 40 * drivers. 41 * 42 * For easy integration into drivers using the &drm_bridge infrastructure please 43 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add(). 44 */ 45 46 /** 47 * drm_panel_init - initialize a panel 48 * @panel: DRM panel 49 * @dev: parent device of the panel 50 * @funcs: panel operations 51 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to 52 * the panel interface 53 * 54 * Initialize the panel structure for subsequent registration with 55 * drm_panel_add(). 56 */ 57 void drm_panel_init(struct drm_panel *panel, struct device *dev, 58 const struct drm_panel_funcs *funcs, int connector_type) 59 { 60 INIT_LIST_HEAD(&panel->list); 61 panel->dev = dev; 62 panel->funcs = funcs; 63 panel->connector_type = connector_type; 64 } 65 EXPORT_SYMBOL(drm_panel_init); 66 67 /** 68 * drm_panel_add - add a panel to the global registry 69 * @panel: panel to add 70 * 71 * Add a panel to the global registry so that it can be looked up by display 72 * drivers. 73 * 74 * Return: 0 on success or a negative error code on failure. 75 */ 76 int drm_panel_add(struct drm_panel *panel) 77 { 78 mutex_lock(&panel_lock); 79 list_add_tail(&panel->list, &panel_list); 80 mutex_unlock(&panel_lock); 81 82 return 0; 83 } 84 EXPORT_SYMBOL(drm_panel_add); 85 86 /** 87 * drm_panel_remove - remove a panel from the global registry 88 * @panel: DRM panel 89 * 90 * Removes a panel from the global registry. 91 */ 92 void drm_panel_remove(struct drm_panel *panel) 93 { 94 mutex_lock(&panel_lock); 95 list_del_init(&panel->list); 96 mutex_unlock(&panel_lock); 97 } 98 EXPORT_SYMBOL(drm_panel_remove); 99 100 /** 101 * drm_panel_attach - attach a panel to a connector 102 * @panel: DRM panel 103 * @connector: DRM connector 104 * 105 * After obtaining a pointer to a DRM panel a display driver calls this 106 * function to attach a panel to a connector. 107 * 108 * An error is returned if the panel is already attached to another connector. 109 * 110 * When unloading, the driver should detach from the panel by calling 111 * drm_panel_detach(). 112 * 113 * Return: 0 on success or a negative error code on failure. 114 */ 115 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector) 116 { 117 return 0; 118 } 119 EXPORT_SYMBOL(drm_panel_attach); 120 121 /** 122 * drm_panel_detach - detach a panel from a connector 123 * @panel: DRM panel 124 * 125 * Detaches a panel from the connector it is attached to. If a panel is not 126 * attached to any connector this is effectively a no-op. 127 * 128 * This function should not be called by the panel device itself. It 129 * is only for the drm device that called drm_panel_attach(). 130 */ 131 void drm_panel_detach(struct drm_panel *panel) 132 { 133 } 134 EXPORT_SYMBOL(drm_panel_detach); 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 int drm_panel_prepare(struct drm_panel *panel) 147 { 148 if (!panel) 149 return -EINVAL; 150 151 if (panel->funcs && panel->funcs->prepare) 152 return panel->funcs->prepare(panel); 153 154 return 0; 155 } 156 EXPORT_SYMBOL(drm_panel_prepare); 157 158 /** 159 * drm_panel_unprepare - power off a panel 160 * @panel: DRM panel 161 * 162 * Calling this function will completely power off a panel (assert the panel's 163 * reset, turn off power supplies, ...). After this function has completed, it 164 * is usually no longer possible to communicate with the panel until another 165 * call to drm_panel_prepare(). 166 * 167 * Return: 0 on success or a negative error code on failure. 168 */ 169 int drm_panel_unprepare(struct drm_panel *panel) 170 { 171 if (!panel) 172 return -EINVAL; 173 174 if (panel->funcs && panel->funcs->unprepare) 175 return panel->funcs->unprepare(panel); 176 177 return 0; 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 int ret; 194 195 if (!panel) 196 return -EINVAL; 197 198 if (panel->funcs && panel->funcs->enable) { 199 ret = panel->funcs->enable(panel); 200 if (ret < 0) 201 return ret; 202 } 203 204 ret = backlight_enable(panel->backlight); 205 if (ret < 0) 206 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n", 207 ret); 208 209 return 0; 210 } 211 EXPORT_SYMBOL(drm_panel_enable); 212 213 /** 214 * drm_panel_disable - disable a panel 215 * @panel: DRM panel 216 * 217 * This will typically turn off the panel's backlight or disable the display 218 * drivers. For smart panels it should still be possible to communicate with 219 * the integrated circuitry via any command bus after this call. 220 * 221 * Return: 0 on success or a negative error code on failure. 222 */ 223 int drm_panel_disable(struct drm_panel *panel) 224 { 225 int ret; 226 227 if (!panel) 228 return -EINVAL; 229 230 ret = backlight_disable(panel->backlight); 231 if (ret < 0) 232 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", 233 ret); 234 235 if (panel->funcs && panel->funcs->disable) 236 return panel->funcs->disable(panel); 237 238 return 0; 239 } 240 EXPORT_SYMBOL(drm_panel_disable); 241 242 /** 243 * drm_panel_get_modes - probe the available display modes of a panel 244 * @panel: DRM panel 245 * @connector: DRM connector 246 * 247 * The modes probed from the panel are automatically added to the connector 248 * that the panel is attached to. 249 * 250 * Return: The number of modes available from the panel on success or a 251 * negative error code on failure. 252 */ 253 int drm_panel_get_modes(struct drm_panel *panel, 254 struct drm_connector *connector) 255 { 256 if (!panel) 257 return -EINVAL; 258 259 if (panel->funcs && panel->funcs->get_modes) 260 return panel->funcs->get_modes(panel, connector); 261 262 return -EOPNOTSUPP; 263 } 264 EXPORT_SYMBOL(drm_panel_get_modes); 265 266 #ifdef CONFIG_OF 267 /** 268 * of_drm_find_panel - look up a panel using a device tree node 269 * @np: device tree node of the panel 270 * 271 * Searches the set of registered panels for one that matches the given device 272 * tree node. If a matching panel is found, return a pointer to it. 273 * 274 * Return: A pointer to the panel registered for the specified device tree 275 * node or an ERR_PTR() if no panel matching the device tree node can be found. 276 * 277 * Possible error codes returned by this function: 278 * 279 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller 280 * should retry later 281 * - ENODEV: the device is not available (status != "okay" or "ok") 282 */ 283 struct drm_panel *of_drm_find_panel(const struct device_node *np) 284 { 285 struct drm_panel *panel; 286 287 if (!of_device_is_available(np)) 288 return ERR_PTR(-ENODEV); 289 290 mutex_lock(&panel_lock); 291 292 list_for_each_entry(panel, &panel_list, list) { 293 if (panel->dev->of_node == np) { 294 mutex_unlock(&panel_lock); 295 return panel; 296 } 297 } 298 299 mutex_unlock(&panel_lock); 300 return ERR_PTR(-EPROBE_DEFER); 301 } 302 EXPORT_SYMBOL(of_drm_find_panel); 303 #endif 304 305 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE) 306 /** 307 * drm_panel_of_backlight - use backlight device node for backlight 308 * @panel: DRM panel 309 * 310 * Use this function to enable backlight handling if your panel 311 * uses device tree and has a backlight phandle. 312 * 313 * When the panel is enabled backlight will be enabled after a 314 * successful call to &drm_panel_funcs.enable() 315 * 316 * When the panel is disabled backlight will be disabled before the 317 * call to &drm_panel_funcs.disable(). 318 * 319 * A typical implementation for a panel driver supporting device tree 320 * will call this function at probe time. Backlight will then be handled 321 * transparently without requiring any intervention from the driver. 322 * drm_panel_of_backlight() must be called after the call to drm_panel_init(). 323 * 324 * Return: 0 on success or a negative error code on failure. 325 */ 326 int drm_panel_of_backlight(struct drm_panel *panel) 327 { 328 struct backlight_device *backlight; 329 330 if (!panel || !panel->dev) 331 return -EINVAL; 332 333 backlight = devm_of_find_backlight(panel->dev); 334 335 if (IS_ERR(backlight)) 336 return PTR_ERR(backlight); 337 338 panel->backlight = backlight; 339 return 0; 340 } 341 EXPORT_SYMBOL(drm_panel_of_backlight); 342 #endif 343 344 MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); 345 MODULE_DESCRIPTION("DRM panel infrastructure"); 346 MODULE_LICENSE("GPL and additional rights"); 347