41  * A bridge is always attached to a single &drm_encoder at a time, but can be
44  *     [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B
46  * Here, the output of the encoder feeds to bridge A, and that furthers feeds to
47  * bridge B. Bridge chains can be arbitrarily long, and shall be fully linear:
48  * Chaining multiple bridges to the output of a bridge, or the same bridge to
51  * Display drivers are responsible for linking encoders with the first bridge
52  * in the chains. This is done by acquiring the appropriate bridge with
55  * devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
58  * Bridges are responsible for linking themselves with the next bridge in the
80  * DRM bridge chain functions shall be called manually.
83  * the bridge chain. Display drivers may use the drm_bridge_connector_init()
85  * connector-related operations exposed by the bridge (see the overview
86  * documentation of bridge operations for more details).
98  * drm_bridge_add - add the given bridge to the global bridge list
100  * @bridge: bridge control structure
102 void drm_bridge_add(struct drm_bridge *bridge)  in drm_bridge_add()  argument
104 	mutex_init(&bridge->hpd_mutex);  in drm_bridge_add()
107 	list_add_tail(&bridge->list, &bridge_list);  in drm_bridge_add()
113  * drm_bridge_remove - remove the given bridge from the global bridge list
115  * @bridge: bridge control structure
117 void drm_bridge_remove(struct drm_bridge *bridge)  in drm_bridge_remove()  argument
120 	list_del_init(&bridge->list);  in drm_bridge_remove()
123 	mutex_destroy(&bridge->hpd_mutex);  in drm_bridge_remove()
130 	struct drm_bridge *bridge = drm_priv_to_bridge(obj);  in drm_bridge_atomic_duplicate_priv_state()  local
133 	state = bridge->funcs->atomic_duplicate_state(bridge);  in drm_bridge_atomic_duplicate_priv_state()
142 	struct drm_bridge *bridge = drm_priv_to_bridge(obj);  in drm_bridge_atomic_destroy_priv_state()  local
144 	bridge->funcs->atomic_destroy_state(bridge, state);  in drm_bridge_atomic_destroy_priv_state()
153  * drm_bridge_attach - attach the bridge to an encoder's chain
156  * @bridge: bridge to attach
157  * @previous: previous bridge in the chain (optional)
160  * Called by a kms driver to link the bridge to an encoder's chain. The previous
161  * argument specifies the previous bridge in the chain. If NULL, the bridge is
163  * previous bridge's output.
165  * If non-NULL the previous bridge must be already attached by a call to this
175 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,  in drm_bridge_attach()  argument
181 	if (!encoder || !bridge)  in drm_bridge_attach()
187 	if (bridge->dev)  in drm_bridge_attach()
190 	bridge->dev = encoder->dev;  in drm_bridge_attach()
191 	bridge->encoder = encoder;  in drm_bridge_attach()
194 		list_add(&bridge->chain_node, &previous->chain_node);  in drm_bridge_attach()
196 		list_add(&bridge->chain_node, &encoder->bridge_chain);  in drm_bridge_attach()
198 	if (bridge->funcs->attach) {  in drm_bridge_attach()
199 		ret = bridge->funcs->attach(bridge, flags);  in drm_bridge_attach()
204 	if (bridge->funcs->atomic_reset) {  in drm_bridge_attach()
207 		state = bridge->funcs->atomic_reset(bridge);  in drm_bridge_attach()
213 		drm_atomic_private_obj_init(bridge->dev, &bridge->base,  in drm_bridge_attach()
221 	if (bridge->funcs->detach)  in drm_bridge_attach()
222 		bridge->funcs->detach(bridge);  in drm_bridge_attach()
225 	bridge->dev = NULL;  in drm_bridge_attach()
226 	bridge->encoder = NULL;  in drm_bridge_attach()
227 	list_del(&bridge->chain_node);  in drm_bridge_attach()
232 void drm_bridge_detach(struct drm_bridge *bridge)  in drm_bridge_detach()  argument
234 	if (WARN_ON(!bridge))  in drm_bridge_detach()
237 	if (WARN_ON(!bridge->dev))  in drm_bridge_detach()
240 	if (bridge->funcs->atomic_reset)  in drm_bridge_detach()
241 		drm_atomic_private_obj_fini(&bridge->base);  in drm_bridge_detach()
243 	if (bridge->funcs->detach)  in drm_bridge_detach()
244 		bridge->funcs->detach(bridge);  in drm_bridge_detach()
246 	list_del(&bridge->chain_node);  in drm_bridge_detach()
247 	bridge->dev = NULL;  in drm_bridge_detach()
251  * DOC: bridge operations
253  * Bridge drivers expose operations through the &drm_bridge_funcs structure.
255  * drm_bridge.c to call bridge operations. Those operations are divided in
256  * three big categories to support different parts of the bridge usage.
262  *   disable the bridge automatically.
269  *   Bridge drivers may implement the legacy version of those operations, or
278  *   &drm_bridge_funcs.atomic_get_input_bus_fmts allow bridge drivers to
282  *   atomic versions of those operations exist, bridge drivers that need to
290  *   puts additional burden on bridge drivers, especially for bridges that may
293  *   bridge, which doesn't always match the hardware architecture.
295  *   To simplify bridge drivers and make the connector implementation more
304  *   the bridge connector operations.
306  *   Bridge drivers shall implement the connector-related operations for all
307  *   the features that the bridge hardware support. For instance, if a bridge
310  *   bridge on a particular platform, as they could also be connected to an I2C
312  *   running platform is reported through the &drm_bridge.ops flags. Bridge
319  *   decide which bridge to delegate a connector operation to. This mechanism
321  *   bridge drivers, improving security by storing function pointers in
324  *   In order to ease transition, bridge drivers may support both the old and
326  *   connected-related bridge operations. Connector creation is then controlled
329  *   %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag, and bridge drivers shall then skip
331  *   be passed to the drm_bridge_attach() call for the downstream bridge.
332  *   Bridge drivers that implement the new model only shall return an error
335  *   should use the new model, and convert the bridge drivers they use if
342  * @bridge: bridge control structure
343  * @mode: desired mode to be set for the bridge
344  * @adjusted_mode: updated mode that works for this bridge
347  * encoder chain, starting from the first bridge to the last.
349  * Note: the bridge passed should be the one closest to the encoder
354 bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,  in drm_bridge_chain_mode_fixup()  argument
360 	if (!bridge)  in drm_bridge_chain_mode_fixup()
363 	encoder = bridge->encoder;  in drm_bridge_chain_mode_fixup()
364 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_bridge_chain_mode_fixup()
365 		if (!bridge->funcs->mode_fixup)  in drm_bridge_chain_mode_fixup()
368 		if (!bridge->funcs->mode_fixup(bridge, mode, adjusted_mode))  in drm_bridge_chain_mode_fixup()
379  * @bridge: bridge control structure
384  * chain, starting from the first bridge to the last. If at least one bridge
387  * Note: the bridge passed should be the one closest to the encoder.
393 drm_bridge_chain_mode_valid(struct drm_bridge *bridge,  in drm_bridge_chain_mode_valid()  argument
399 	if (!bridge)  in drm_bridge_chain_mode_valid()
402 	encoder = bridge->encoder;  in drm_bridge_chain_mode_valid()
403 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_bridge_chain_mode_valid()
406 		if (!bridge->funcs->mode_valid)  in drm_bridge_chain_mode_valid()
409 		ret = bridge->funcs->mode_valid(bridge, info, mode);  in drm_bridge_chain_mode_valid()
420  * @bridge: bridge control structure
423  * chain, starting from the last bridge to the first. These are called before
426  * Note: the bridge passed should be the one closest to the encoder
428 void drm_bridge_chain_disable(struct drm_bridge *bridge)  in drm_bridge_chain_disable()  argument
433 	if (!bridge)  in drm_bridge_chain_disable()
436 	encoder = bridge->encoder;  in drm_bridge_chain_disable()
441 		if (iter == bridge)  in drm_bridge_chain_disable()
450  * @bridge: bridge control structure
453  * encoder chain, starting from the first bridge to the last. These are called
456  * Note: the bridge passed should be the one closest to the encoder
458 void drm_bridge_chain_post_disable(struct drm_bridge *bridge)  in drm_bridge_chain_post_disable()  argument
462 	if (!bridge)  in drm_bridge_chain_post_disable()
465 	encoder = bridge->encoder;  in drm_bridge_chain_post_disable()
466 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_bridge_chain_post_disable()
467 		if (bridge->funcs->post_disable)  in drm_bridge_chain_post_disable()
468 			bridge->funcs->post_disable(bridge);  in drm_bridge_chain_post_disable()
476  * @bridge: bridge control structure
481  * encoder chain, starting from the first bridge to the last.
483  * Note: the bridge passed should be the one closest to the encoder
485 void drm_bridge_chain_mode_set(struct drm_bridge *bridge,  in drm_bridge_chain_mode_set()  argument
491 	if (!bridge)  in drm_bridge_chain_mode_set()
494 	encoder = bridge->encoder;  in drm_bridge_chain_mode_set()
495 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_bridge_chain_mode_set()
496 		if (bridge->funcs->mode_set)  in drm_bridge_chain_mode_set()
497 			bridge->funcs->mode_set(bridge, mode, adjusted_mode);  in drm_bridge_chain_mode_set()
505  * @bridge: bridge control structure
508  * chain, starting from the last bridge to the first. These are called
511  * Note: the bridge passed should be the one closest to the encoder
513 void drm_bridge_chain_pre_enable(struct drm_bridge *bridge)  in drm_bridge_chain_pre_enable()  argument
518 	if (!bridge)  in drm_bridge_chain_pre_enable()
521 	encoder = bridge->encoder;  in drm_bridge_chain_pre_enable()
531  * @bridge: bridge control structure
534  * chain, starting from the first bridge to the last. These are called
537  * Note that the bridge passed should be the one closest to the encoder
539 void drm_bridge_chain_enable(struct drm_bridge *bridge)  in drm_bridge_chain_enable()  argument
543 	if (!bridge)  in drm_bridge_chain_enable()
546 	encoder = bridge->encoder;  in drm_bridge_chain_enable()
547 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_bridge_chain_enable()
548 		if (bridge->funcs->enable)  in drm_bridge_chain_enable()
549 			bridge->funcs->enable(bridge);  in drm_bridge_chain_enable()
556  * @bridge: bridge control structure
561  * starting from the last bridge to the first. These are called before calling
564  * Note: the bridge passed should be the one closest to the encoder
566 void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_disable()  argument
572 	if (!bridge)  in drm_atomic_bridge_chain_disable()
575 	encoder = bridge->encoder;  in drm_atomic_bridge_chain_disable()
591 		if (iter == bridge)  in drm_atomic_bridge_chain_disable()
600  * @bridge: bridge control structure
605  * starting from the first bridge to the last. These are called after completing
608  * Note: the bridge passed should be the one closest to the encoder
610 void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_post_disable()  argument
615 	if (!bridge)  in drm_atomic_bridge_chain_post_disable()
618 	encoder = bridge->encoder;  in drm_atomic_bridge_chain_post_disable()
619 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_atomic_bridge_chain_post_disable()
620 		if (bridge->funcs->atomic_post_disable) {  in drm_atomic_bridge_chain_post_disable()
625 								bridge);  in drm_atomic_bridge_chain_post_disable()
629 			bridge->funcs->atomic_post_disable(bridge,  in drm_atomic_bridge_chain_post_disable()
631 		} else if (bridge->funcs->post_disable) {  in drm_atomic_bridge_chain_post_disable()
632 			bridge->funcs->post_disable(bridge);  in drm_atomic_bridge_chain_post_disable()
641  * @bridge: bridge control structure
646  * starting from the last bridge to the first. These are called before calling
649  * Note: the bridge passed should be the one closest to the encoder
651 void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_pre_enable()  argument
657 	if (!bridge)  in drm_atomic_bridge_chain_pre_enable()
660 	encoder = bridge->encoder;  in drm_atomic_bridge_chain_pre_enable()
676 		if (iter == bridge)  in drm_atomic_bridge_chain_pre_enable()
684  * @bridge: bridge control structure
689  * starting from the first bridge to the last. These are called after completing
692  * Note: the bridge passed should be the one closest to the encoder
694 void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_enable()  argument
699 	if (!bridge)  in drm_atomic_bridge_chain_enable()
702 	encoder = bridge->encoder;  in drm_atomic_bridge_chain_enable()
703 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {  in drm_atomic_bridge_chain_enable()
704 		if (bridge->funcs->atomic_enable) {  in drm_atomic_bridge_chain_enable()
709 								bridge);  in drm_atomic_bridge_chain_enable()
713 			bridge->funcs->atomic_enable(bridge, old_bridge_state);  in drm_atomic_bridge_chain_enable()
714 		} else if (bridge->funcs->enable) {  in drm_atomic_bridge_chain_enable()
715 			bridge->funcs->enable(bridge);  in drm_atomic_bridge_chain_enable()
721 static int drm_atomic_bridge_check(struct drm_bridge *bridge,  in drm_atomic_bridge_check()  argument
725 	if (bridge->funcs->atomic_check) {  in drm_atomic_bridge_check()
730 							       bridge);  in drm_atomic_bridge_check()
734 		ret = bridge->funcs->atomic_check(bridge, bridge_state,  in drm_atomic_bridge_check()
738 	} else if (bridge->funcs->mode_fixup) {  in drm_atomic_bridge_check()
739 		if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode,  in drm_atomic_bridge_check()
764 	 * If bus format negotiation is not supported by this bridge, let's  in select_bus_fmt_recursive()
765 	 * pass MEDIA_BUS_FMT_FIXED to the previous bridge in the chain and  in select_bus_fmt_recursive()
781 		 * fine, as long as it does not access the bridge state.  in select_bus_fmt_recursive()
836  * It performs bus format negotiation between bridge elements. The negotiation
838  * @bridge.
841  * bridge element and testing them one by one. The test is recursive, meaning
844  * transcoded to the requested output format. When a bridge element does not
846  * the next bridge element will have to try a different format. If none of the
861  * bridge element that lacks this hook and asks the previous element in the
862  * chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what
868 drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_select_bus_fmts()  argument
873 	struct drm_encoder *encoder = bridge->encoder;  in drm_atomic_bridge_chain_select_bus_fmts()
918 		ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,  in drm_atomic_bridge_chain_select_bus_fmts()
930 drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge,  in drm_atomic_bridge_propagate_bus_flags()  argument
938 	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);  in drm_atomic_bridge_propagate_bus_flags()
940 	/* No bridge state attached to this bridge => nothing to propagate. */  in drm_atomic_bridge_propagate_bus_flags()
944 	next_bridge = drm_bridge_get_next_bridge(bridge);  in drm_atomic_bridge_propagate_bus_flags()
948 	 * display_info flags for the last bridge, and propagate the input  in drm_atomic_bridge_propagate_bus_flags()
949 	 * flags of the next bridge element to the output end of the current  in drm_atomic_bridge_propagate_bus_flags()
950 	 * bridge when the bridge is not the last one.  in drm_atomic_bridge_propagate_bus_flags()
962 		 * No bridge state attached to the next bridge, just leave the  in drm_atomic_bridge_propagate_bus_flags()
972 	 * Propage the output flags to the input end of the bridge. Again, it's  in drm_atomic_bridge_propagate_bus_flags()
981  * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
982  * @bridge: bridge control structure
989  * starting from the last bridge to the first. These are called before calling
995 int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,  in drm_atomic_bridge_chain_check()  argument
1004 	if (!bridge)  in drm_atomic_bridge_chain_check()
1007 	ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state,  in drm_atomic_bridge_chain_check()
1012 	encoder = bridge->encoder;  in drm_atomic_bridge_chain_check()
1017 		 * Bus flags are propagated by default. If a bridge needs to  in drm_atomic_bridge_chain_check()
1030 		if (iter == bridge)  in drm_atomic_bridge_chain_check()
1039  * drm_bridge_detect - check if anything is attached to the bridge output
1040  * @bridge: bridge control structure
1042  * If the bridge supports output detection, as reported by the
1043  * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the
1044  * bridge and return the connection status. Otherwise return
1048  * The detection status on success, or connector_status_unknown if the bridge
1051 enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge)  in drm_bridge_detect()  argument
1053 	if (!(bridge->ops & DRM_BRIDGE_OP_DETECT))  in drm_bridge_detect()
1056 	return bridge->funcs->detect(bridge);  in drm_bridge_detect()
1063  * @bridge: bridge control structure
1066  * If the bridge supports output modes retrieval, as reported by the
1067  * DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to
1074 int drm_bridge_get_modes(struct drm_bridge *bridge,  in drm_bridge_get_modes()  argument
1077 	if (!(bridge->ops & DRM_BRIDGE_OP_MODES))  in drm_bridge_get_modes()
1080 	return bridge->funcs->get_modes(bridge, connector);  in drm_bridge_get_modes()
1086  * @bridge: bridge control structure
1089  * If the bridge supports output EDID retrieval, as reported by the
1090  * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
1096 struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,  in drm_bridge_get_edid()  argument
1099 	if (!(bridge->ops & DRM_BRIDGE_OP_EDID))  in drm_bridge_get_edid()
1102 	return bridge->funcs->get_edid(bridge, connector);  in drm_bridge_get_edid()
1107  * drm_bridge_hpd_enable - enable hot plug detection for the bridge
1108  * @bridge: bridge control structure
1114  * called with @data when an output status change is detected by the bridge,
1118  * bridge->ops. This function shall not be called when the flag is not set.
1122  * the bridge.
1124 void drm_bridge_hpd_enable(struct drm_bridge *bridge,  in drm_bridge_hpd_enable()  argument
1129 	if (!(bridge->ops & DRM_BRIDGE_OP_HPD))  in drm_bridge_hpd_enable()
1132 	mutex_lock(&bridge->hpd_mutex);  in drm_bridge_hpd_enable()
1134 	if (WARN(bridge->hpd_cb, "Hot plug detection already enabled\n"))  in drm_bridge_hpd_enable()
1137 	bridge->hpd_cb = cb;  in drm_bridge_hpd_enable()
1138 	bridge->hpd_data = data;  in drm_bridge_hpd_enable()
1140 	if (bridge->funcs->hpd_enable)  in drm_bridge_hpd_enable()
1141 		bridge->funcs->hpd_enable(bridge);  in drm_bridge_hpd_enable()
1144 	mutex_unlock(&bridge->hpd_mutex);  in drm_bridge_hpd_enable()
1149  * drm_bridge_hpd_disable - disable hot plug detection for the bridge
1150  * @bridge: bridge control structure
1154  * Once this function returns the callback will not be called by the bridge
1158  * bridge->ops. This function shall not be called when the flag is not set.
1160 void drm_bridge_hpd_disable(struct drm_bridge *bridge)  in drm_bridge_hpd_disable()  argument
1162 	if (!(bridge->ops & DRM_BRIDGE_OP_HPD))  in drm_bridge_hpd_disable()
1165 	mutex_lock(&bridge->hpd_mutex);  in drm_bridge_hpd_disable()
1166 	if (bridge->funcs->hpd_disable)  in drm_bridge_hpd_disable()
1167 		bridge->funcs->hpd_disable(bridge);  in drm_bridge_hpd_disable()
1169 	bridge->hpd_cb = NULL;  in drm_bridge_hpd_disable()
1170 	bridge->hpd_data = NULL;  in drm_bridge_hpd_disable()
1171 	mutex_unlock(&bridge->hpd_mutex);  in drm_bridge_hpd_disable()
1177  * @bridge: bridge control structure
1180  * Bridge drivers shall call this function to report hot plug events when they
1186 void drm_bridge_hpd_notify(struct drm_bridge *bridge,  in drm_bridge_hpd_notify()  argument
1189 	mutex_lock(&bridge->hpd_mutex);  in drm_bridge_hpd_notify()
1190 	if (bridge->hpd_cb)  in drm_bridge_hpd_notify()
1191 		bridge->hpd_cb(bridge->hpd_data, status);  in drm_bridge_hpd_notify()
1192 	mutex_unlock(&bridge->hpd_mutex);  in drm_bridge_hpd_notify()
1198  * of_drm_find_bridge - find the bridge corresponding to the device node in
1199  *			the global bridge list
1208 	struct drm_bridge *bridge;  in of_drm_find_bridge()  local
1212 	list_for_each_entry(bridge, &bridge_list, list) {  in of_drm_find_bridge()
1213 		if (bridge->of_node == np) {  in of_drm_find_bridge()
1215 			return bridge;  in of_drm_find_bridge()
1226 MODULE_DESCRIPTION("DRM bridge infrastructure");