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()
164 	if (!panel->prepared) {  in drm_panel_unprepare()
165 		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");  in drm_panel_unprepare()
169 	mutex_lock(&panel->follower_lock);  in drm_panel_unprepare()
171 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_unprepare()
174 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_unprepare()
178 	if (panel->funcs && panel->funcs->unprepare) {  in drm_panel_unprepare()
179 		ret = panel->funcs->unprepare(panel);  in drm_panel_unprepare()
183 	panel->prepared = false;  in drm_panel_unprepare()
187 	mutex_unlock(&panel->follower_lock);  in drm_panel_unprepare()
194  * drm_panel_enable - enable a panel
195  * @panel: DRM panel
197  * Calling this function will cause the panel display drivers to be turned on
203 int drm_panel_enable(struct drm_panel *panel)  in drm_panel_enable()  argument
207 	if (!panel)  in drm_panel_enable()
210 	if (panel->enabled) {  in drm_panel_enable()
211 		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");  in drm_panel_enable()
215 	if (panel->funcs && panel->funcs->enable) {  in drm_panel_enable()
216 		ret = panel->funcs->enable(panel);  in drm_panel_enable()
220 	panel->enabled = true;  in drm_panel_enable()
222 	ret = backlight_enable(panel->backlight);  in drm_panel_enable()
224 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",  in drm_panel_enable()
232  * drm_panel_disable - disable a panel
233  * @panel: DRM panel
235  * This will typically turn off the panel's backlight or disable the display
241 int drm_panel_disable(struct drm_panel *panel)  in drm_panel_disable()  argument
245 	if (!panel)  in drm_panel_disable()
248 	if (!panel->enabled) {  in drm_panel_disable()
249 		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");  in drm_panel_disable()
253 	ret = backlight_disable(panel->backlight);  in drm_panel_disable()
255 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",  in drm_panel_disable()
258 	if (panel->funcs && panel->funcs->disable) {  in drm_panel_disable()
259 		ret = panel->funcs->disable(panel);  in drm_panel_disable()
263 	panel->enabled = false;  in drm_panel_disable()
270  * drm_panel_get_modes - probe the available display modes of a panel
271  * @panel: DRM panel
274  * The modes probed from the panel are automatically added to the connector
275  * that the panel is attached to.
277  * Return: The number of modes available from the panel on success, or 0 on
280 int drm_panel_get_modes(struct drm_panel *panel,  in drm_panel_get_modes()  argument
283 	if (!panel)  in drm_panel_get_modes()
286 	if (panel->funcs && panel->funcs->get_modes) {  in drm_panel_get_modes()
289 		num = panel->funcs->get_modes(panel, connector);  in drm_panel_get_modes()
300  * of_drm_find_panel - look up a panel using a device tree node
301  * @np: device tree node of the panel
304  * tree node. If a matching panel is found, return a pointer to it.
306  * Return: A pointer to the panel registered for the specified device tree
307  * node or an ERR_PTR() if no panel matching the device tree node can be found.
311  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
317 	struct drm_panel *panel;  in of_drm_find_panel()  local
324 	list_for_each_entry(panel, &panel_list, list) {  in of_drm_find_panel()
325 		if (panel->dev->of_node == np) {  in of_drm_find_panel()
327 			return panel;  in of_drm_find_panel()
337  * of_drm_get_panel_orientation - look up the orientation of the panel through
339  * @np: device tree node of the panel
342  * Looks up the rotation of a panel in the device tree. The orientation of the
343  * panel is expressed as a property name "rotation" in the device tree. The
381  * drm_is_panel_follower() - Check if the device is a panel follower
385  * a panel using the panel follower API.
387  * The "panel" property of the follower points to the panel to be followed.
389  * Return: true if we should be power sequenced with a panel; false otherwise.
394 	 * The "panel" property is actually a phandle, but for simplicity we  in drm_is_panel_follower()
398 	return of_property_read_bool(dev->of_node, "panel");  in drm_is_panel_follower()
403  * drm_panel_add_follower() - Register something to follow panel state.
405  * @follower:     The panel follower descriptor for the follower.
407  * A panel follower is called right after preparing the panel and right before
408  * unpreparing the panel. It's primary intention is to power on an associated
410  * devices are allowed the follow the same panel.
412  * If a follower is added to a panel that's already been turned on, the
416  * The "panel" property of the follower points to the panel to be followed.
419  *         follower_dev is not actually following a panel. The caller may
420  *         choose to ignore this return value if following a panel is optional.
426 	struct drm_panel *panel;  in drm_panel_add_follower()  local
429 	panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);  in drm_panel_add_follower()
433 	panel = of_drm_find_panel(panel_np);  in drm_panel_add_follower()
435 	if (IS_ERR(panel))  in drm_panel_add_follower()
436 		return PTR_ERR(panel);  in drm_panel_add_follower()
438 	get_device(panel->dev);  in drm_panel_add_follower()
439 	follower->panel = panel;  in drm_panel_add_follower()
441 	mutex_lock(&panel->follower_lock);  in drm_panel_add_follower()
443 	list_add_tail(&follower->list, &panel->followers);  in drm_panel_add_follower()
444 	if (panel->prepared) {  in drm_panel_add_follower()
447 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_add_follower()
451 	mutex_unlock(&panel->follower_lock);  in drm_panel_add_follower()
459  * @follower:     The panel follower descriptor for the follower.
462  * unprepare function if we're removed from a panel that's currently prepared.
468 	struct drm_panel *panel = follower->panel;  in drm_panel_remove_follower()  local
471 	mutex_lock(&panel->follower_lock);  in drm_panel_remove_follower()
473 	if (panel->prepared) {  in drm_panel_remove_follower()
476 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_remove_follower()
481 	mutex_unlock(&panel->follower_lock);  in drm_panel_remove_follower()
483 	put_device(panel->dev);  in drm_panel_remove_follower()
495  * @follower:     The panel follower descriptor for the follower.
518  * @panel: DRM panel
520  * Use this function to enable backlight handling if your panel
523  * When the panel is enabled backlight will be enabled after a
526  * When the panel is disabled backlight will be disabled before the
529  * A typical implementation for a panel driver supporting device tree
536 int drm_panel_of_backlight(struct drm_panel *panel)  in drm_panel_of_backlight()  argument
540 	if (!panel || !panel->dev)  in drm_panel_of_backlight()
543 	backlight = devm_of_find_backlight(panel->dev);  in drm_panel_of_backlight()
548 	panel->backlight = backlight;  in drm_panel_of_backlight()
555 MODULE_DESCRIPTION("DRM panel infrastructure");