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 (must NOT be DRM_MODE_CONNECTOR_Unknown)
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
63 	INIT_LIST_HEAD(&panel->list);  in drm_panel_init()
64 	INIT_LIST_HEAD(&panel->followers);  in drm_panel_init()
65 	mutex_init(&panel->follower_lock);  in drm_panel_init()
66 	panel->dev = dev;  in drm_panel_init()
67 	panel->funcs = funcs;  in drm_panel_init()
68 	panel->connector_type = connector_type;  in drm_panel_init()
73  * drm_panel_add - add a panel to the global registry
74  * @panel: panel to add
76  * Add a panel to the global registry so that it can be looked up by display
79 void drm_panel_add(struct drm_panel *panel)  in drm_panel_add()  argument
82 	list_add_tail(&panel->list, &panel_list);  in drm_panel_add()
88  * drm_panel_remove - remove a panel from the global registry
89  * @panel: DRM panel
91  * Removes a panel from the global registry.
93 void drm_panel_remove(struct drm_panel *panel)  in drm_panel_remove()  argument
96 	list_del_init(&panel->list);  in drm_panel_remove()
102  * drm_panel_prepare - power on a panel
103  * @panel: DRM panel
106  * the panel. After this has completed it is possible to communicate with any
111 int drm_panel_prepare(struct drm_panel *panel)  in drm_panel_prepare()  argument
116 	if (!panel)  in drm_panel_prepare()
119 	if (panel->prepared) {  in drm_panel_prepare()
120 		dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");  in drm_panel_prepare()
124 	mutex_lock(&panel->follower_lock);  in drm_panel_prepare()
126 	if (panel->funcs && panel->funcs->prepare) {  in drm_panel_prepare()
127 		ret = panel->funcs->prepare(panel);  in drm_panel_prepare()
131 	panel->prepared = true;  in drm_panel_prepare()
133 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_prepare()
136 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_prepare()
142 	mutex_unlock(&panel->follower_lock);  in drm_panel_prepare()
149  * drm_panel_unprepare - power off a panel
150  * @panel: DRM panel
152  * Calling this function will completely power off a panel (assert the panel's
154  * is usually no longer possible to communicate with the panel until another
159 int drm_panel_unprepare(struct drm_panel *panel)  in drm_panel_unprepare()  argument
164 	if (!panel)  in drm_panel_unprepare()
167 	if (!panel->prepared) {  in drm_panel_unprepare()
168 		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");  in drm_panel_unprepare()
172 	mutex_lock(&panel->follower_lock);  in drm_panel_unprepare()
174 	list_for_each_entry(follower, &panel->followers, list) {  in drm_panel_unprepare()
177 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_unprepare()
181 	if (panel->funcs && panel->funcs->unprepare) {  in drm_panel_unprepare()
182 		ret = panel->funcs->unprepare(panel);  in drm_panel_unprepare()
186 	panel->prepared = false;  in drm_panel_unprepare()
190 	mutex_unlock(&panel->follower_lock);  in drm_panel_unprepare()
197  * drm_panel_enable - enable a panel
198  * @panel: DRM panel
200  * Calling this function will cause the panel display drivers to be turned on
206 int drm_panel_enable(struct drm_panel *panel)  in drm_panel_enable()  argument
210 	if (!panel)  in drm_panel_enable()
213 	if (panel->enabled) {  in drm_panel_enable()
214 		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");  in drm_panel_enable()
218 	if (panel->funcs && panel->funcs->enable) {  in drm_panel_enable()
219 		ret = panel->funcs->enable(panel);  in drm_panel_enable()
223 	panel->enabled = true;  in drm_panel_enable()
225 	ret = backlight_enable(panel->backlight);  in drm_panel_enable()
227 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",  in drm_panel_enable()
235  * drm_panel_disable - disable a panel
236  * @panel: DRM panel
238  * This will typically turn off the panel's backlight or disable the display
244 int drm_panel_disable(struct drm_panel *panel)  in drm_panel_disable()  argument
248 	if (!panel)  in drm_panel_disable()
251 	if (!panel->enabled) {  in drm_panel_disable()
252 		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");  in drm_panel_disable()
256 	ret = backlight_disable(panel->backlight);  in drm_panel_disable()
258 		DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",  in drm_panel_disable()
261 	if (panel->funcs && panel->funcs->disable) {  in drm_panel_disable()
262 		ret = panel->funcs->disable(panel);  in drm_panel_disable()
266 	panel->enabled = false;  in drm_panel_disable()
273  * drm_panel_get_modes - probe the available display modes of a panel
274  * @panel: DRM panel
277  * The modes probed from the panel are automatically added to the connector
278  * that the panel is attached to.
280  * Return: The number of modes available from the panel on success, or 0 on
283 int drm_panel_get_modes(struct drm_panel *panel,  in drm_panel_get_modes()  argument
286 	if (!panel)  in drm_panel_get_modes()
289 	if (panel->funcs && panel->funcs->get_modes) {  in drm_panel_get_modes()
292 		num = panel->funcs->get_modes(panel, connector);  in drm_panel_get_modes()
303  * of_drm_find_panel - look up a panel using a device tree node
304  * @np: device tree node of the panel
307  * tree node. If a matching panel is found, return a pointer to it.
309  * Return: A pointer to the panel registered for the specified device tree
310  * node or an ERR_PTR() if no panel matching the device tree node can be found.
314  * - EPROBE_DEFER: the panel device has not been probed yet, and the caller
320 	struct drm_panel *panel;  in of_drm_find_panel()  local
327 	list_for_each_entry(panel, &panel_list, list) {  in of_drm_find_panel()
328 		if (panel->dev->of_node == np) {  in of_drm_find_panel()
330 			return panel;  in of_drm_find_panel()
340  * of_drm_get_panel_orientation - look up the orientation of the panel through
342  * @np: device tree node of the panel
345  * Looks up the rotation of a panel in the device tree. The orientation of the
346  * panel is expressed as a property name "rotation" in the device tree. The
384  * drm_is_panel_follower() - Check if the device is a panel follower
388  * a panel using the panel follower API.
390  * The "panel" property of the follower points to the panel to be followed.
392  * Return: true if we should be power sequenced with a panel; false otherwise.
397 	 * The "panel" property is actually a phandle, but for simplicity we  in drm_is_panel_follower()
401 	return of_property_read_bool(dev->of_node, "panel");  in drm_is_panel_follower()
406  * drm_panel_add_follower() - Register something to follow panel state.
408  * @follower:     The panel follower descriptor for the follower.
410  * A panel follower is called right after preparing the panel and right before
411  * unpreparing the panel. It's primary intention is to power on an associated
413  * devices are allowed the follow the same panel.
415  * If a follower is added to a panel that's already been turned on, the
419  * The "panel" property of the follower points to the panel to be followed.
422  *         follower_dev is not actually following a panel. The caller may
423  *         choose to ignore this return value if following a panel is optional.
429 	struct drm_panel *panel;  in drm_panel_add_follower()  local
432 	panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);  in drm_panel_add_follower()
436 	panel = of_drm_find_panel(panel_np);  in drm_panel_add_follower()
438 	if (IS_ERR(panel))  in drm_panel_add_follower()
439 		return PTR_ERR(panel);  in drm_panel_add_follower()
441 	get_device(panel->dev);  in drm_panel_add_follower()
442 	follower->panel = panel;  in drm_panel_add_follower()
444 	mutex_lock(&panel->follower_lock);  in drm_panel_add_follower()
446 	list_add_tail(&follower->list, &panel->followers);  in drm_panel_add_follower()
447 	if (panel->prepared) {  in drm_panel_add_follower()
450 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_add_follower()
454 	mutex_unlock(&panel->follower_lock);  in drm_panel_add_follower()
462  * @follower:     The panel follower descriptor for the follower.
465  * unprepare function if we're removed from a panel that's currently prepared.
471 	struct drm_panel *panel = follower->panel;  in drm_panel_remove_follower()  local
474 	mutex_lock(&panel->follower_lock);  in drm_panel_remove_follower()
476 	if (panel->prepared) {  in drm_panel_remove_follower()
479 			dev_info(panel->dev, "%ps failed: %d\n",  in drm_panel_remove_follower()
484 	mutex_unlock(&panel->follower_lock);  in drm_panel_remove_follower()
486 	put_device(panel->dev);  in drm_panel_remove_follower()
498  * @follower:     The panel follower descriptor for the follower.
521  * @panel: DRM panel
523  * Use this function to enable backlight handling if your panel
526  * When the panel is enabled backlight will be enabled after a
529  * When the panel is disabled backlight will be disabled before the
532  * A typical implementation for a panel driver supporting device tree
539 int drm_panel_of_backlight(struct drm_panel *panel)  in drm_panel_of_backlight()  argument
543 	if (!panel || !panel->dev)  in drm_panel_of_backlight()
546 	backlight = devm_of_find_backlight(panel->dev);  in drm_panel_of_backlight()
551 	panel->backlight = backlight;  in drm_panel_of_backlight()
558 MODULE_DESCRIPTION("DRM panel infrastructure");