36  * DOC: drm panel
38  * The DRM panel helpers allow drivers to register panel objects with a
47  * drm_panel_init - initialize a panel
48  * @panel: DRM panel
49  * @dev: parent device of the panel
50  * @funcs: panel operations
52  *	the panel interface
54  * Initialize the panel structure for subsequent registration with
57 void drm_panel_init(struct drm_panel *panel, struct device *dev,  in drm_panel_init()  argument
60 	INIT_LIST_HEAD(&panel->list);  in drm_panel_init()
61 	INIT_LIST_HEAD(&panel->followers);  in drm_panel_init()
62 	mutex_init(&panel->follower_lock);  in drm_panel_init()
63 	panel->dev = dev;  in drm_panel_init()
64 	panel->funcs = funcs;  in drm_panel_init()
65 	panel->connector_type = connector_type;  in drm_panel_init()
70  * drm_panel_add - add a panel to the global registry
71  * @panel: panel to add
73  * Add a panel to the global registry so that it can be looked up by display
76 void drm_panel_add(struct drm_panel *panel)  in drm_panel_add()  argument
79 	list_add_tail(&panel->list, &panel_list);  in drm_panel_add()
85  * drm_panel_remove - remove a panel from the global registry
86  * @panel: DRM panel
88  * Removes a panel from the global registry.
90 void drm_panel_remove(struct drm_panel *panel)  in drm_panel_remove()  argument
93 	list_del_init(&panel->list);  in drm_panel_remove()
99  * drm_panel_prepare - power on a panel
100  * @panel: DRM panel
103  * the panel. After this has completed it is possible to communicate with any
108 int drm_panel_prepare(struct drm_panel *panel)  in drm_panel_prepare()  argument
113 	if (!panel)  in drm_panel_prepare()
116 	if (panel->prepared) {  in drm_panel_prepare()
117 		dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");  in drm_panel_prepare()
121 	mutex_lock(&panel->follower_lock);  in drm_panel_prepare()
123 	if (panel->funcs && panel->funcs->prepare) {  in drm_panel_prepare()
124 		ret = panel->funcs->prepare(panel);  in drm_panel_prepare()
128 	panel->prepared = true;  in drm_panel_prepare()
130 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_prepare()
133 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_prepare()
139 	mutex_unlock(&panel->follower_lock);  in drm_panel_prepare()
146  * drm_panel_unprepare - power off a panel
147  * @panel: DRM panel
149  * Calling this function will completely power off a panel (assert the panel's
151  * is usually no longer possible to communicate with the panel until another
156 int drm_panel_unprepare(struct drm_panel *panel)  in drm_panel_unprepare()  argument
161 	if (!panel)  in drm_panel_unprepare()
166 	 * - Your panel driver incorrectly calls drm_panel_unprepare() in its  in drm_panel_unprepare()
168 	 * - You are using panel-edp or panel-simple and your DRM modeset  in drm_panel_unprepare()
169 	 *   driver's shutdown() callback happened after the panel's shutdown().  in drm_panel_unprepare()
173 	if (!panel->prepared) {  in drm_panel_unprepare()
174 		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");  in drm_panel_unprepare()
178 	mutex_lock(&panel->follower_lock);  in drm_panel_unprepare()
180 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_unprepare()
183 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_unprepare()
187 	if (panel->funcs && panel->funcs->unprepare) {  in drm_panel_unprepare()
188 		ret = panel->funcs->unprepare(panel);  in drm_panel_unprepare()
192 	panel->prepared = false;  in drm_panel_unprepare()
196 	mutex_unlock(&panel->follower_lock);  in drm_panel_unprepare()
203  * drm_panel_enable - enable a panel
204  * @panel: DRM panel
206  * Calling this function will cause the panel display drivers to be turned on
212 int drm_panel_enable(struct drm_panel *panel)  in drm_panel_enable()  argument
216 	if (!panel)  in drm_panel_enable()
219 	if (panel->enabled) {  in drm_panel_enable()
220 		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");  in drm_panel_enable()
224 	if (panel->funcs && panel->funcs->enable) {  in drm_panel_enable()
225 		ret = panel->funcs->enable(panel);  in drm_panel_enable()
229 	panel->enabled = true;  in drm_panel_enable()
231 	ret = backlight_enable(panel->backlight);  in drm_panel_enable()
233 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",  in drm_panel_enable()
241  * drm_panel_disable - disable a panel
242  * @panel: DRM panel
244  * This will typically turn off the panel's backlight or disable the display
250 int drm_panel_disable(struct drm_panel *panel)  in drm_panel_disable()  argument
254 	if (!panel)  in drm_panel_disable()
259 	 * - Your panel driver incorrectly calls drm_panel_disable() in its  in drm_panel_disable()
261 	 * - You are using panel-edp or panel-simple and your DRM modeset  in drm_panel_disable()
262 	 *   driver's shutdown() callback happened after the panel's shutdown().  in drm_panel_disable()
266 	if (!panel->enabled) {  in drm_panel_disable()
267 		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");  in drm_panel_disable()
271 	ret = backlight_disable(panel->backlight);  in drm_panel_disable()
273 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",  in drm_panel_disable()
276 	if (panel->funcs && panel->funcs->disable) {  in drm_panel_disable()
277 		ret = panel->funcs->disable(panel);  in drm_panel_disable()
281 	panel->enabled = false;  in drm_panel_disable()
288  * drm_panel_get_modes - probe the available display modes of a panel
289  * @panel: DRM panel
292  * The modes probed from the panel are automatically added to the connector
293  * that the panel is attached to.
295  * Return: The number of modes available from the panel on success, or 0 on
298 int drm_panel_get_modes(struct drm_panel *panel,  in drm_panel_get_modes()  argument
301 	if (!panel)  in drm_panel_get_modes()
304 	if (panel->funcs && panel->funcs->get_modes) {  in drm_panel_get_modes()
307 		num = panel->funcs->get_modes(panel, connector);  in drm_panel_get_modes()
318  * of_drm_find_panel - look up a panel using a device tree node
319  * @np: device tree node of the panel
322  * tree node. If a matching panel is found, return a pointer to it.
324  * Return: A pointer to the panel registered for the specified device tree
325  * node or an ERR_PTR() if no panel matching the device tree node can be found.
329  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
335 	struct drm_panel *panel;  in of_drm_find_panel()  local
342 	list_for_each_entry(panel, &panel_list, list) {  in of_drm_find_panel()
343 		if (panel->dev->of_node == np) {  in of_drm_find_panel()
345 			return panel;  in of_drm_find_panel()
355  * of_drm_get_panel_orientation - look up the orientation of the panel through
357  * @np: device tree node of the panel
360  * Looks up the rotation of a panel in the device tree. The orientation of the
361  * panel is expressed as a property name "rotation" in the device tree. The
399  * drm_is_panel_follower() - Check if the device is a panel follower
403  * a panel using the panel follower API.
405  * The "panel" property of the follower points to the panel to be followed.
407  * Return: true if we should be power sequenced with a panel; false otherwise.
412 	 * The "panel" property is actually a phandle, but for simplicity we  in drm_is_panel_follower()
416 	return of_property_read_bool(dev->of_node, "panel");  in drm_is_panel_follower()
421  * drm_panel_add_follower() - Register something to follow panel state.
423  * @follower:     The panel follower descriptor for the follower.
425  * A panel follower is called right after preparing the panel and right before
426  * unpreparing the panel. It's primary intention is to power on an associated
428  * devices are allowed the follow the same panel.
430  * If a follower is added to a panel that's already been turned on, the
434  * The "panel" property of the follower points to the panel to be followed.
437  *         follower_dev is not actually following a panel. The caller may
438  *         choose to ignore this return value if following a panel is optional.
444 	struct drm_panel *panel;  in drm_panel_add_follower()  local
447 	panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);  in drm_panel_add_follower()
451 	panel = of_drm_find_panel(panel_np);  in drm_panel_add_follower()
453 	if (IS_ERR(panel))  in drm_panel_add_follower()
454 		return PTR_ERR(panel);  in drm_panel_add_follower()
456 	get_device(panel->dev);  in drm_panel_add_follower()
457 	follower->panel = panel;  in drm_panel_add_follower()
459 	mutex_lock(&panel->follower_lock);  in drm_panel_add_follower()
461 	list_add_tail(&follower->list, &panel->followers);  in drm_panel_add_follower()
462 	if (panel->prepared) {  in drm_panel_add_follower()
465 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_add_follower()
469 	mutex_unlock(&panel->follower_lock);  in drm_panel_add_follower()
477  * @follower:     The panel follower descriptor for the follower.
480  * unprepare function if we're removed from a panel that's currently prepared.
486 	struct drm_panel *panel = follower->panel;  in drm_panel_remove_follower()  local
489 	mutex_lock(&panel->follower_lock);  in drm_panel_remove_follower()
491 	if (panel->prepared) {  in drm_panel_remove_follower()
494 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_remove_follower()
499 	mutex_unlock(&panel->follower_lock);  in drm_panel_remove_follower()
501 	put_device(panel->dev);  in drm_panel_remove_follower()
513  * @follower:     The panel follower descriptor for the follower.
536  * @panel: DRM panel
538  * Use this function to enable backlight handling if your panel
541  * When the panel is enabled backlight will be enabled after a
544  * When the panel is disabled backlight will be disabled before the
547  * A typical implementation for a panel driver supporting device tree
554 int drm_panel_of_backlight(struct drm_panel *panel)  in drm_panel_of_backlight()  argument
558 	if (!panel || !panel->dev)  in drm_panel_of_backlight()
561 	backlight = devm_of_find_backlight(panel->dev);  in drm_panel_of_backlight()
566 	panel->backlight = backlight;  in drm_panel_of_backlight()
573 MODULE_DESCRIPTION("DRM panel infrastructure");