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1/*2 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved.3 *4 * Permission is hereby granted, free of charge, to any person obtaining a5 * copy of this software and associated documentation files (the "Software"),6 * to deal in the Software without restriction, including without limitation7 * 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 the9 * Software is furnished to do so, subject to the following conditions:10 *11 * The above copyright notice and this permission notice (including the12 * next paragraph) shall be included in all copies or substantial portions13 * of the Software.14 *15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER21 * 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 32static DEFINE_MUTEX(panel_lock);33static LIST_HEAD(panel_list);34 35/**36 * DOC: drm panel37 *38 * The DRM panel helpers allow drivers to register panel objects with a39 * central registry and provide functions to retrieve those panels in display40 * drivers.41 *42 * For easy integration into drivers using the &drm_bridge infrastructure please43 * take look at drm_panel_bridge_add() and devm_drm_panel_bridge_add().44 */45 46/**47 * drm_panel_init - initialize a panel48 * @panel: DRM panel49 * @dev: parent device of the panel50 * @funcs: panel operations51 * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to52 * the panel interface53 *54 * Initialize the panel structure for subsequent registration with55 * drm_panel_add().56 */57void 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 INIT_LIST_HEAD(&panel->followers);62 mutex_init(&panel->follower_lock);63 panel->dev = dev;64 panel->funcs = funcs;65 panel->connector_type = connector_type;66}67EXPORT_SYMBOL(drm_panel_init);68 69/**70 * drm_panel_add - add a panel to the global registry71 * @panel: panel to add72 *73 * Add a panel to the global registry so that it can be looked up by display74 * drivers.75 */76void 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}82EXPORT_SYMBOL(drm_panel_add);83 84/**85 * drm_panel_remove - remove a panel from the global registry86 * @panel: DRM panel87 *88 * Removes a panel from the global registry.89 */90void 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}96EXPORT_SYMBOL(drm_panel_remove);97 98/**99 * drm_panel_prepare - power on a panel100 * @panel: DRM panel101 *102 * Calling this function will enable power and deassert any reset signals to103 * the panel. After this has completed it is possible to communicate with any104 * integrated circuitry via a command bus.105 *106 * Return: 0 on success or a negative error code on failure.107 */108int drm_panel_prepare(struct drm_panel *panel)109{110 struct drm_panel_follower *follower;111 int ret;112 113 if (!panel)114 return -EINVAL;115 116 if (panel->prepared) {117 dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");118 return 0;119 }120 121 mutex_lock(&panel->follower_lock);122 123 if (panel->funcs && panel->funcs->prepare) {124 ret = panel->funcs->prepare(panel);125 if (ret < 0)126 goto exit;127 }128 panel->prepared = true;129 130 list_for_each_entry(follower, &panel->followers, list) {131 ret = follower->funcs->panel_prepared(follower);132 if (ret < 0)133 dev_info(panel->dev, "%ps failed: %d\n",134 follower->funcs->panel_prepared, ret);135 }136 137 ret = 0;138exit:139 mutex_unlock(&panel->follower_lock);140 141 return ret;142}143EXPORT_SYMBOL(drm_panel_prepare);144 145/**146 * drm_panel_unprepare - power off a panel147 * @panel: DRM panel148 *149 * Calling this function will completely power off a panel (assert the panel's150 * reset, turn off power supplies, ...). After this function has completed, it151 * is usually no longer possible to communicate with the panel until another152 * call to drm_panel_prepare().153 *154 * Return: 0 on success or a negative error code on failure.155 */156int drm_panel_unprepare(struct drm_panel *panel)157{158 struct drm_panel_follower *follower;159 int ret;160 161 if (!panel)162 return -EINVAL;163 164 /*165 * If you are seeing the warning below it likely means one of two things:166 * - Your panel driver incorrectly calls drm_panel_unprepare() in its167 * shutdown routine. You should delete this.168 * - You are using panel-edp or panel-simple and your DRM modeset169 * driver's shutdown() callback happened after the panel's shutdown().170 * In this case the warning is harmless though ideally you should171 * figure out how to reverse the order of the shutdown() callbacks.172 */173 if (!panel->prepared) {174 dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");175 return 0;176 }177 178 mutex_lock(&panel->follower_lock);179 180 list_for_each_entry(follower, &panel->followers, list) {181 ret = follower->funcs->panel_unpreparing(follower);182 if (ret < 0)183 dev_info(panel->dev, "%ps failed: %d\n",184 follower->funcs->panel_unpreparing, ret);185 }186 187 if (panel->funcs && panel->funcs->unprepare) {188 ret = panel->funcs->unprepare(panel);189 if (ret < 0)190 goto exit;191 }192 panel->prepared = false;193 194 ret = 0;195exit:196 mutex_unlock(&panel->follower_lock);197 198 return ret;199}200EXPORT_SYMBOL(drm_panel_unprepare);201 202/**203 * drm_panel_enable - enable a panel204 * @panel: DRM panel205 *206 * Calling this function will cause the panel display drivers to be turned on207 * and the backlight to be enabled. Content will be visible on screen after208 * this call completes.209 *210 * Return: 0 on success or a negative error code on failure.211 */212int drm_panel_enable(struct drm_panel *panel)213{214 int ret;215 216 if (!panel)217 return -EINVAL;218 219 if (panel->enabled) {220 dev_warn(panel->dev, "Skipping enable of already enabled panel\n");221 return 0;222 }223 224 if (panel->funcs && panel->funcs->enable) {225 ret = panel->funcs->enable(panel);226 if (ret < 0)227 return ret;228 }229 panel->enabled = true;230 231 ret = backlight_enable(panel->backlight);232 if (ret < 0)233 DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",234 ret);235 236 return 0;237}238EXPORT_SYMBOL(drm_panel_enable);239 240/**241 * drm_panel_disable - disable a panel242 * @panel: DRM panel243 *244 * This will typically turn off the panel's backlight or disable the display245 * drivers. For smart panels it should still be possible to communicate with246 * the integrated circuitry via any command bus after this call.247 *248 * Return: 0 on success or a negative error code on failure.249 */250int drm_panel_disable(struct drm_panel *panel)251{252 int ret;253 254 if (!panel)255 return -EINVAL;256 257 /*258 * If you are seeing the warning below it likely means one of two things:259 * - Your panel driver incorrectly calls drm_panel_disable() in its260 * shutdown routine. You should delete this.261 * - You are using panel-edp or panel-simple and your DRM modeset262 * driver's shutdown() callback happened after the panel's shutdown().263 * In this case the warning is harmless though ideally you should264 * figure out how to reverse the order of the shutdown() callbacks.265 */266 if (!panel->enabled) {267 dev_warn(panel->dev, "Skipping disable of already disabled panel\n");268 return 0;269 }270 271 ret = backlight_disable(panel->backlight);272 if (ret < 0)273 DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",274 ret);275 276 if (panel->funcs && panel->funcs->disable) {277 ret = panel->funcs->disable(panel);278 if (ret < 0)279 return ret;280 }281 panel->enabled = false;282 283 return 0;284}285EXPORT_SYMBOL(drm_panel_disable);286 287/**288 * drm_panel_get_modes - probe the available display modes of a panel289 * @panel: DRM panel290 * @connector: DRM connector291 *292 * The modes probed from the panel are automatically added to the connector293 * that the panel is attached to.294 *295 * Return: The number of modes available from the panel on success, or 0 on296 * failure (no modes).297 */298int drm_panel_get_modes(struct drm_panel *panel,299 struct drm_connector *connector)300{301 if (!panel)302 return 0;303 304 if (panel->funcs && panel->funcs->get_modes) {305 int num;306 307 num = panel->funcs->get_modes(panel, connector);308 if (num > 0)309 return num;310 }311 312 return 0;313}314EXPORT_SYMBOL(drm_panel_get_modes);315 316#ifdef CONFIG_OF317/**318 * of_drm_find_panel - look up a panel using a device tree node319 * @np: device tree node of the panel320 *321 * Searches the set of registered panels for one that matches the given device322 * tree node. If a matching panel is found, return a pointer to it.323 *324 * Return: A pointer to the panel registered for the specified device tree325 * node or an ERR_PTR() if no panel matching the device tree node can be found.326 *327 * Possible error codes returned by this function:328 *329 * - EPROBE_DEFER: the panel device has not been probed yet, and the caller330 * should retry later331 * - ENODEV: the device is not available (status != "okay" or "ok")332 */333struct drm_panel *of_drm_find_panel(const struct device_node *np)334{335 struct drm_panel *panel;336 337 if (!of_device_is_available(np))338 return ERR_PTR(-ENODEV);339 340 mutex_lock(&panel_lock);341 342 list_for_each_entry(panel, &panel_list, list) {343 if (panel->dev->of_node == np) {344 mutex_unlock(&panel_lock);345 return panel;346 }347 }348 349 mutex_unlock(&panel_lock);350 return ERR_PTR(-EPROBE_DEFER);351}352EXPORT_SYMBOL(of_drm_find_panel);353 354/**355 * of_drm_get_panel_orientation - look up the orientation of the panel through356 * the "rotation" binding from a device tree node357 * @np: device tree node of the panel358 * @orientation: orientation enum to be filled in359 *360 * Looks up the rotation of a panel in the device tree. The orientation of the361 * panel is expressed as a property name "rotation" in the device tree. The362 * rotation in the device tree is counter clockwise.363 *364 * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the365 * rotation property doesn't exist. Return a negative error code on failure.366 */367int of_drm_get_panel_orientation(const struct device_node *np,368 enum drm_panel_orientation *orientation)369{370 int rotation, ret;371 372 ret = of_property_read_u32(np, "rotation", &rotation);373 if (ret == -EINVAL) {374 /* Don't return an error if there's no rotation property. */375 *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;376 return 0;377 }378 379 if (ret < 0)380 return ret;381 382 if (rotation == 0)383 *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;384 else if (rotation == 90)385 *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;386 else if (rotation == 180)387 *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;388 else if (rotation == 270)389 *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;390 else391 return -EINVAL;392 393 return 0;394}395EXPORT_SYMBOL(of_drm_get_panel_orientation);396#endif397 398/**399 * drm_is_panel_follower() - Check if the device is a panel follower400 * @dev: The 'struct device' to check401 *402 * This checks to see if a device needs to be power sequenced together with403 * a panel using the panel follower API.404 * At the moment panels can only be followed on device tree enabled systems.405 * The "panel" property of the follower points to the panel to be followed.406 *407 * Return: true if we should be power sequenced with a panel; false otherwise.408 */409bool drm_is_panel_follower(struct device *dev)410{411 /*412 * The "panel" property is actually a phandle, but for simplicity we413 * don't bother trying to parse it here. We just need to know if the414 * property is there.415 */416 return of_property_read_bool(dev->of_node, "panel");417}418EXPORT_SYMBOL(drm_is_panel_follower);419 420/**421 * drm_panel_add_follower() - Register something to follow panel state.422 * @follower_dev: The 'struct device' for the follower.423 * @follower: The panel follower descriptor for the follower.424 *425 * A panel follower is called right after preparing the panel and right before426 * unpreparing the panel. It's primary intention is to power on an associated427 * touchscreen, though it could be used for any similar devices. Multiple428 * devices are allowed the follow the same panel.429 *430 * If a follower is added to a panel that's already been turned on, the431 * follower's prepare callback is called right away.432 *433 * At the moment panels can only be followed on device tree enabled systems.434 * The "panel" property of the follower points to the panel to be followed.435 *436 * Return: 0 or an error code. Note that -ENODEV means that we detected that437 * follower_dev is not actually following a panel. The caller may438 * choose to ignore this return value if following a panel is optional.439 */440int drm_panel_add_follower(struct device *follower_dev,441 struct drm_panel_follower *follower)442{443 struct device_node *panel_np;444 struct drm_panel *panel;445 int ret;446 447 panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);448 if (!panel_np)449 return -ENODEV;450 451 panel = of_drm_find_panel(panel_np);452 of_node_put(panel_np);453 if (IS_ERR(panel))454 return PTR_ERR(panel);455 456 get_device(panel->dev);457 follower->panel = panel;458 459 mutex_lock(&panel->follower_lock);460 461 list_add_tail(&follower->list, &panel->followers);462 if (panel->prepared) {463 ret = follower->funcs->panel_prepared(follower);464 if (ret < 0)465 dev_info(panel->dev, "%ps failed: %d\n",466 follower->funcs->panel_prepared, ret);467 }468 469 mutex_unlock(&panel->follower_lock);470 471 return 0;472}473EXPORT_SYMBOL(drm_panel_add_follower);474 475/**476 * drm_panel_remove_follower() - Reverse drm_panel_add_follower().477 * @follower: The panel follower descriptor for the follower.478 *479 * Undo drm_panel_add_follower(). This includes calling the follower's480 * unprepare function if we're removed from a panel that's currently prepared.481 *482 * Return: 0 or an error code.483 */484void drm_panel_remove_follower(struct drm_panel_follower *follower)485{486 struct drm_panel *panel = follower->panel;487 int ret;488 489 mutex_lock(&panel->follower_lock);490 491 if (panel->prepared) {492 ret = follower->funcs->panel_unpreparing(follower);493 if (ret < 0)494 dev_info(panel->dev, "%ps failed: %d\n",495 follower->funcs->panel_unpreparing, ret);496 }497 list_del_init(&follower->list);498 499 mutex_unlock(&panel->follower_lock);500 501 put_device(panel->dev);502}503EXPORT_SYMBOL(drm_panel_remove_follower);504 505static void drm_panel_remove_follower_void(void *follower)506{507 drm_panel_remove_follower(follower);508}509 510/**511 * devm_drm_panel_add_follower() - devm version of drm_panel_add_follower()512 * @follower_dev: The 'struct device' for the follower.513 * @follower: The panel follower descriptor for the follower.514 *515 * Handles calling drm_panel_remove_follower() using devm on the follower_dev.516 *517 * Return: 0 or an error code.518 */519int devm_drm_panel_add_follower(struct device *follower_dev,520 struct drm_panel_follower *follower)521{522 int ret;523 524 ret = drm_panel_add_follower(follower_dev, follower);525 if (ret)526 return ret;527 528 return devm_add_action_or_reset(follower_dev,529 drm_panel_remove_follower_void, follower);530}531EXPORT_SYMBOL(devm_drm_panel_add_follower);532 533#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)534/**535 * drm_panel_of_backlight - use backlight device node for backlight536 * @panel: DRM panel537 *538 * Use this function to enable backlight handling if your panel539 * uses device tree and has a backlight phandle.540 *541 * When the panel is enabled backlight will be enabled after a542 * successful call to &drm_panel_funcs.enable()543 *544 * When the panel is disabled backlight will be disabled before the545 * call to &drm_panel_funcs.disable().546 *547 * A typical implementation for a panel driver supporting device tree548 * will call this function at probe time. Backlight will then be handled549 * transparently without requiring any intervention from the driver.550 * drm_panel_of_backlight() must be called after the call to drm_panel_init().551 *552 * Return: 0 on success or a negative error code on failure.553 */554int drm_panel_of_backlight(struct drm_panel *panel)555{556 struct backlight_device *backlight;557 558 if (!panel || !panel->dev)559 return -EINVAL;560 561 backlight = devm_of_find_backlight(panel->dev);562 563 if (IS_ERR(backlight))564 return PTR_ERR(backlight);565 566 panel->backlight = backlight;567 return 0;568}569EXPORT_SYMBOL(drm_panel_of_backlight);570#endif571 572MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");573MODULE_DESCRIPTION("DRM panel infrastructure");574MODULE_LICENSE("GPL and additional rights");575