1 // SPDX-License-Identifier: GPL-2.0-only
5  * Copyright (C) 2003,2004 Hewlett-Packard Company
33  * When the core detect changes in for example brightness or power state
39  * - brightness         R/W, set the requested brightness level
40  * - actual_brightness  RO, the brightness level used by the HW
41  * - max_brightness     RO, the maximum  brightness level supported
43  * See Documentation/ABI/stable/sysfs-class-backlight for the full list.
47  * a hot-key or some other platform or firmware specific way.
51  * brightness, thus providing user-space access to the actual level
54  * When the backlight changes this is reported to user-space using
56  * When brightness is set by platform specific means, for example
57  * a hot-key to adjust backlight, the driver must notify the backlight
58  * core that brightness has changed using backlight_force_update().
79 	[BACKLIGHT_SCALE_NON_LINEAR]	= "non-linear",
101 	int node = evdata->info->node;  in fb_notifier_callback()
109 	mutex_lock(&bd->ops_lock);  in fb_notifier_callback()
111 	if (!bd->ops)  in fb_notifier_callback()
113 	if (bd->ops->check_fb && !bd->ops->check_fb(bd, evdata->info))  in fb_notifier_callback()
116 	fb_blank = *(int *)evdata->data;  in fb_notifier_callback()
117 	if (fb_blank == FB_BLANK_UNBLANK && !bd->fb_bl_on[node]) {  in fb_notifier_callback()
118 		bd->fb_bl_on[node] = true;  in fb_notifier_callback()
119 		if (!bd->use_count++) {  in fb_notifier_callback()
120 			bd->props.state &= ~BL_CORE_FBBLANK;  in fb_notifier_callback()
121 			bd->props.fb_blank = FB_BLANK_UNBLANK;  in fb_notifier_callback()
124 	} else if (fb_blank != FB_BLANK_UNBLANK && bd->fb_bl_on[node]) {  in fb_notifier_callback()
125 		bd->fb_bl_on[node] = false;  in fb_notifier_callback()
126 		if (!(--bd->use_count)) {  in fb_notifier_callback()
127 			bd->props.state |= BL_CORE_FBBLANK;  in fb_notifier_callback()
128 			bd->props.fb_blank = fb_blank;  in fb_notifier_callback()
133 	mutex_unlock(&bd->ops_lock);  in fb_notifier_callback()
139 	memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));  in backlight_register_fb()
140 	bd->fb_notif.notifier_call = fb_notifier_callback;  in backlight_register_fb()
142 	return fb_register_client(&bd->fb_notif);  in backlight_register_fb()
147 	fb_unregister_client(&bd->fb_notif);  in backlight_unregister_fb()
177 	kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);  in backlight_generate_event()
178 	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");  in backlight_generate_event()
186 	return sprintf(buf, "%d\n", bd->props.power);  in bl_power_show()
200 	rc = -ENXIO;  in bl_power_store()
201 	mutex_lock(&bd->ops_lock);  in bl_power_store()
202 	if (bd->ops) {  in bl_power_store()
204 		if (bd->props.power != power) {  in bl_power_store()
205 			old_power = bd->props.power;  in bl_power_store()
206 			bd->props.power = power;  in bl_power_store()
209 				bd->props.power = old_power;  in bl_power_store()
216 	mutex_unlock(&bd->ops_lock);  in bl_power_store()
227 	return sprintf(buf, "%d\n", bd->props.brightness);  in brightness_show()
231 				    unsigned long brightness)  in backlight_device_set_brightness()  argument
233 	int rc = -ENXIO;  in backlight_device_set_brightness()
235 	mutex_lock(&bd->ops_lock);  in backlight_device_set_brightness()
236 	if (bd->ops) {  in backlight_device_set_brightness()
237 		if (brightness > bd->props.max_brightness)  in backlight_device_set_brightness()
238 			rc = -EINVAL;  in backlight_device_set_brightness()
240 			pr_debug("set brightness to %lu\n", brightness);  in backlight_device_set_brightness()
241 			bd->props.brightness = brightness;  in backlight_device_set_brightness()
245 	mutex_unlock(&bd->ops_lock);  in backlight_device_set_brightness()
258 	unsigned long brightness;  in brightness_store()  local
260 	rc = kstrtoul(buf, 0, &brightness);  in brightness_store()
264 	rc = backlight_device_set_brightness(bd, brightness);  in brightness_store()
268 static DEVICE_ATTR_RW(brightness);
275 	return sprintf(buf, "%s\n", backlight_types[bd->props.type]);  in type_show()
284 	return sprintf(buf, "%d\n", bd->props.max_brightness);  in max_brightness_show()
291 	int rc = -ENXIO;  in actual_brightness_show()
294 	mutex_lock(&bd->ops_lock);  in actual_brightness_show()
295 	if (bd->ops && bd->ops->get_brightness) {  in actual_brightness_show()
296 		rc = bd->ops->get_brightness(bd);  in actual_brightness_show()
300 		rc = sprintf(buf, "%d\n", bd->props.brightness);  in actual_brightness_show()
302 	mutex_unlock(&bd->ops_lock);  in actual_brightness_show()
313 	if (WARN_ON(bd->props.scale > BACKLIGHT_SCALE_NON_LINEAR))  in scale_show()
316 	return sprintf(buf, "%s\n", backlight_scale_types[bd->props.scale]);  in scale_show()
327 	mutex_lock(&bd->ops_lock);  in backlight_suspend()
328 	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {  in backlight_suspend()
329 		bd->props.state |= BL_CORE_SUSPENDED;  in backlight_suspend()
332 	mutex_unlock(&bd->ops_lock);  in backlight_suspend()
341 	mutex_lock(&bd->ops_lock);  in backlight_resume()
342 	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {  in backlight_resume()
343 		bd->props.state &= ~BL_CORE_SUSPENDED;  in backlight_resume()
346 	mutex_unlock(&bd->ops_lock);  in backlight_resume()
373  * backlight_force_update - tell the backlight subsystem that hardware state
381  * a hot-key. The updated brightness is read using get_brightness() and the
382  * brightness value is reported using an uevent.
387 	int brightness;  in backlight_force_update()  local
389 	mutex_lock(&bd->ops_lock);  in backlight_force_update()
390 	if (bd->ops && bd->ops->get_brightness) {  in backlight_force_update()
391 		brightness = bd->ops->get_brightness(bd);  in backlight_force_update()
392 		if (brightness >= 0)  in backlight_force_update()
393 			bd->props.brightness = brightness;  in backlight_force_update()
395 			dev_err(&bd->dev,  in backlight_force_update()
396 				"Could not update brightness from device: %pe\n",  in backlight_force_update()
397 				ERR_PTR(brightness));  in backlight_force_update()
399 	mutex_unlock(&bd->ops_lock);  in backlight_force_update()
404 /* deprecated - use devm_backlight_device_register() */
416 		return ERR_PTR(-ENOMEM);  in backlight_device_register()
418 	mutex_init(&new_bd->update_lock);  in backlight_device_register()
419 	mutex_init(&new_bd->ops_lock);  in backlight_device_register()
421 	new_bd->dev.class = backlight_class;  in backlight_device_register()
422 	new_bd->dev.parent = parent;  in backlight_device_register()
423 	new_bd->dev.release = bl_device_release;  in backlight_device_register()
424 	dev_set_name(&new_bd->dev, "%s", name);  in backlight_device_register()
425 	dev_set_drvdata(&new_bd->dev, devdata);  in backlight_device_register()
429 		memcpy(&new_bd->props, props,  in backlight_device_register()
431 		if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) {  in backlight_device_register()
433 			new_bd->props.type = BACKLIGHT_RAW;  in backlight_device_register()
436 		new_bd->props.type = BACKLIGHT_RAW;  in backlight_device_register()
439 	rc = device_register(&new_bd->dev);  in backlight_device_register()
441 		put_device(&new_bd->dev);  in backlight_device_register()
447 		device_unregister(&new_bd->dev);  in backlight_device_register()
451 	new_bd->ops = ops;  in backlight_device_register()
461 	list_add(&new_bd->entry, &backlight_dev_list);  in backlight_device_register()
471 /** backlight_device_get_by_type - find first backlight device of a type
487 		if (bd->props.type == type) {  in backlight_device_get_by_type()
499  * backlight_device_get_by_name - Get backlight device by name
519 /* deprecated - use devm_backlight_device_unregister() */
526 	list_del(&bd->entry);  in backlight_device_unregister()
539 	mutex_lock(&bd->ops_lock);  in backlight_device_unregister()
540 	bd->ops = NULL;  in backlight_device_unregister()
541 	mutex_unlock(&bd->ops_lock);  in backlight_device_unregister()
544 	device_unregister(&bd->dev);  in backlight_device_unregister()
564  * backlight_register_notifier - get notified of backlight (un)registration
581  * backlight_unregister_notifier - unregister a backlight notifier
598  * devm_backlight_device_register - register a new backlight device
624 		return ERR_PTR(-ENOMEM);  in devm_backlight_device_register()
640  * devm_backlight_device_unregister - unregister backlight device
662 	return dev->parent && dev->parent->of_node == data;  in of_parent_match()
666  * of_find_backlight_by_node() - find backlight device by device-tree node
667  * @node: device-tree node of the backlight device
696 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {  in of_find_backlight()
697 		np = of_parse_phandle(dev->of_node, "backlight", 0);  in of_find_backlight()
702 				return ERR_PTR(-EPROBE_DEFER);  in of_find_backlight()
713 	put_device(&bd->dev);  in devm_backlight_release()
717  * devm_of_find_backlight - find backlight for a device
728  * Error pointer -EPROBE_DEFER if the DT property is set, but no backlight
761 	backlight_class->dev_groups = bl_device_groups;  in backlight_class_init()
762 	backlight_class->pm = &backlight_class_dev_pm_ops;  in backlight_class_init()