xref: /linux/drivers/gpu/drm/display/drm_bridge_connector.c (revision 7abdafd2343ab199367c8243d6a5f06a9aa6976b)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/of.h>
9 #include <linux/property.h>
10 #include <linux/slab.h>
11 
12 #include <drm/drm_atomic_state_helper.h>
13 #include <drm/drm_bridge.h>
14 #include <drm/drm_bridge_connector.h>
15 #include <drm/drm_connector.h>
16 #include <drm/drm_device.h>
17 #include <drm/drm_edid.h>
18 #include <drm/drm_managed.h>
19 #include <drm/drm_modeset_helper_vtables.h>
20 #include <drm/drm_print.h>
21 #include <drm/drm_probe_helper.h>
22 #include <drm/display/drm_hdmi_audio_helper.h>
23 #include <drm/display/drm_hdmi_helper.h>
24 #include <drm/display/drm_hdmi_state_helper.h>
25 
26 /**
27  * DOC: overview
28  *
29  * The DRM bridge connector helper object provides a DRM connector
30  * implementation that wraps a chain of &struct drm_bridge. The connector
31  * operations are fully implemented based on the operations of the bridges in
32  * the chain, and don't require any intervention from the display controller
33  * driver at runtime.
34  *
35  * To use the helper, display controller drivers create a bridge connector with
36  * a call to drm_bridge_connector_init(). This associates the newly created
37  * connector with the chain of bridges passed to the function and registers it
38  * with the DRM device. At that point the connector becomes fully usable, no
39  * further operation is needed.
40  *
41  * The DRM bridge connector operations are implemented based on the operations
42  * provided by the bridges in the chain. Each connector operation is delegated
43  * to the bridge closest to the connector (at the end of the chain) that
44  * provides the relevant functionality.
45  *
46  * To make use of this helper, all bridges in the chain shall report bridge
47  * operation flags (&drm_bridge->ops) and bridge output type
48  * (&drm_bridge->type), as well as the DRM_BRIDGE_ATTACH_NO_CONNECTOR attach
49  * flag (none of the bridges shall create a DRM connector directly).
50  */
51 
52 /**
53  * struct drm_bridge_connector - A connector backed by a chain of bridges
54  */
55 struct drm_bridge_connector {
56 	/**
57 	 * @base: The base DRM connector
58 	 */
59 	struct drm_connector base;
60 	/**
61 	 * @encoder:
62 	 *
63 	 * The encoder at the start of the bridges chain.
64 	 */
65 	struct drm_encoder *encoder;
66 	/**
67 	 * @bridge_edid:
68 	 *
69 	 * The last bridge in the chain (closest to the connector) that provides
70 	 * EDID read support, if any (see &DRM_BRIDGE_OP_EDID).
71 	 */
72 	struct drm_bridge *bridge_edid;
73 	/**
74 	 * @bridge_hpd:
75 	 *
76 	 * The last bridge in the chain (closest to the connector) that provides
77 	 * hot-plug detection notification, if any (see &DRM_BRIDGE_OP_HPD).
78 	 */
79 	struct drm_bridge *bridge_hpd;
80 	/**
81 	 * @bridge_detect:
82 	 *
83 	 * The last bridge in the chain (closest to the connector) that provides
84 	 * connector detection, if any (see &DRM_BRIDGE_OP_DETECT).
85 	 */
86 	struct drm_bridge *bridge_detect;
87 	/**
88 	 * @bridge_modes:
89 	 *
90 	 * The last bridge in the chain (closest to the connector) that provides
91 	 * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES).
92 	 */
93 	struct drm_bridge *bridge_modes;
94 	/**
95 	 * @bridge_hdmi:
96 	 *
97 	 * The bridge in the chain that implements necessary support for the
98 	 * HDMI connector infrastructure, if any (see &DRM_BRIDGE_OP_HDMI).
99 	 */
100 	struct drm_bridge *bridge_hdmi;
101 	/**
102 	 * @bridge_hdmi_audio:
103 	 *
104 	 * The bridge in the chain that implements necessary support for the
105 	 * HDMI Audio infrastructure, if any (see &DRM_BRIDGE_OP_HDMI_AUDIO).
106 	 */
107 	struct drm_bridge *bridge_hdmi_audio;
108 	/**
109 	 * @bridge_dp_audio:
110 	 *
111 	 * The bridge in the chain that implements necessary support for the
112 	 * DisplayPort Audio infrastructure, if any (see
113 	 * &DRM_BRIDGE_OP_DP_AUDIO).
114 	 */
115 	struct drm_bridge *bridge_dp_audio;
116 };
117 
118 #define to_drm_bridge_connector(x) \
119 	container_of(x, struct drm_bridge_connector, base)
120 
121 /* -----------------------------------------------------------------------------
122  * Bridge Connector Hot-Plug Handling
123  */
124 
drm_bridge_connector_hpd_notify(struct drm_connector * connector,enum drm_connector_status status)125 static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
126 					    enum drm_connector_status status)
127 {
128 	struct drm_bridge_connector *bridge_connector =
129 		to_drm_bridge_connector(connector);
130 	struct drm_bridge *bridge;
131 
132 	/* Notify all bridges in the pipeline of hotplug events. */
133 	drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) {
134 		if (bridge->funcs->hpd_notify)
135 			bridge->funcs->hpd_notify(bridge, status);
136 	}
137 }
138 
drm_bridge_connector_handle_hpd(struct drm_bridge_connector * drm_bridge_connector,enum drm_connector_status status)139 static void drm_bridge_connector_handle_hpd(struct drm_bridge_connector *drm_bridge_connector,
140 					    enum drm_connector_status status)
141 {
142 	struct drm_connector *connector = &drm_bridge_connector->base;
143 	struct drm_device *dev = connector->dev;
144 
145 	mutex_lock(&dev->mode_config.mutex);
146 	connector->status = status;
147 	mutex_unlock(&dev->mode_config.mutex);
148 
149 	drm_bridge_connector_hpd_notify(connector, status);
150 
151 	drm_kms_helper_connector_hotplug_event(connector);
152 }
153 
drm_bridge_connector_hpd_cb(void * cb_data,enum drm_connector_status status)154 static void drm_bridge_connector_hpd_cb(void *cb_data,
155 					enum drm_connector_status status)
156 {
157 	drm_bridge_connector_handle_hpd(cb_data, status);
158 }
159 
drm_bridge_connector_oob_hotplug_event(struct drm_connector * connector,enum drm_connector_status status)160 static void drm_bridge_connector_oob_hotplug_event(struct drm_connector *connector,
161 						   enum drm_connector_status status)
162 {
163 	struct drm_bridge_connector *bridge_connector =
164 		to_drm_bridge_connector(connector);
165 
166 	drm_bridge_connector_handle_hpd(bridge_connector, status);
167 }
168 
drm_bridge_connector_enable_hpd(struct drm_connector * connector)169 static void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
170 {
171 	struct drm_bridge_connector *bridge_connector =
172 		to_drm_bridge_connector(connector);
173 	struct drm_bridge *hpd = bridge_connector->bridge_hpd;
174 
175 	if (hpd)
176 		drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb,
177 				      bridge_connector);
178 }
179 
drm_bridge_connector_disable_hpd(struct drm_connector * connector)180 static void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
181 {
182 	struct drm_bridge_connector *bridge_connector =
183 		to_drm_bridge_connector(connector);
184 	struct drm_bridge *hpd = bridge_connector->bridge_hpd;
185 
186 	if (hpd)
187 		drm_bridge_hpd_disable(hpd);
188 }
189 
190 /* -----------------------------------------------------------------------------
191  * Bridge Connector Functions
192  */
193 
194 static enum drm_connector_status
drm_bridge_connector_detect(struct drm_connector * connector,bool force)195 drm_bridge_connector_detect(struct drm_connector *connector, bool force)
196 {
197 	struct drm_bridge_connector *bridge_connector =
198 		to_drm_bridge_connector(connector);
199 	struct drm_bridge *detect = bridge_connector->bridge_detect;
200 	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
201 	enum drm_connector_status status;
202 
203 	if (detect) {
204 		status = detect->funcs->detect(detect);
205 
206 		if (hdmi)
207 			drm_atomic_helper_connector_hdmi_hotplug(connector, status);
208 
209 		drm_bridge_connector_hpd_notify(connector, status);
210 	} else {
211 		switch (connector->connector_type) {
212 		case DRM_MODE_CONNECTOR_DPI:
213 		case DRM_MODE_CONNECTOR_LVDS:
214 		case DRM_MODE_CONNECTOR_DSI:
215 		case DRM_MODE_CONNECTOR_eDP:
216 			status = connector_status_connected;
217 			break;
218 		default:
219 			status = connector_status_unknown;
220 			break;
221 		}
222 	}
223 
224 	return status;
225 }
226 
drm_bridge_connector_force(struct drm_connector * connector)227 static void drm_bridge_connector_force(struct drm_connector *connector)
228 {
229 	struct drm_bridge_connector *bridge_connector =
230 		to_drm_bridge_connector(connector);
231 	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
232 
233 	if (hdmi)
234 		drm_atomic_helper_connector_hdmi_force(connector);
235 }
236 
drm_bridge_connector_debugfs_init(struct drm_connector * connector,struct dentry * root)237 static void drm_bridge_connector_debugfs_init(struct drm_connector *connector,
238 					      struct dentry *root)
239 {
240 	struct drm_bridge_connector *bridge_connector =
241 		to_drm_bridge_connector(connector);
242 	struct drm_encoder *encoder = bridge_connector->encoder;
243 	struct drm_bridge *bridge;
244 
245 	list_for_each_entry(bridge, &encoder->bridge_chain, chain_node) {
246 		if (bridge->funcs->debugfs_init)
247 			bridge->funcs->debugfs_init(bridge, root);
248 	}
249 }
250 
drm_bridge_connector_reset(struct drm_connector * connector)251 static void drm_bridge_connector_reset(struct drm_connector *connector)
252 {
253 	struct drm_bridge_connector *bridge_connector =
254 		to_drm_bridge_connector(connector);
255 
256 	drm_atomic_helper_connector_reset(connector);
257 	if (bridge_connector->bridge_hdmi)
258 		__drm_atomic_helper_connector_hdmi_reset(connector,
259 							 connector->state);
260 }
261 
262 static const struct drm_connector_funcs drm_bridge_connector_funcs = {
263 	.reset = drm_bridge_connector_reset,
264 	.detect = drm_bridge_connector_detect,
265 	.force = drm_bridge_connector_force,
266 	.fill_modes = drm_helper_probe_single_connector_modes,
267 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
268 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
269 	.debugfs_init = drm_bridge_connector_debugfs_init,
270 	.oob_hotplug_event = drm_bridge_connector_oob_hotplug_event,
271 };
272 
273 /* -----------------------------------------------------------------------------
274  * Bridge Connector Helper Functions
275  */
276 
drm_bridge_connector_get_modes_edid(struct drm_connector * connector,struct drm_bridge * bridge)277 static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector,
278 					       struct drm_bridge *bridge)
279 {
280 	enum drm_connector_status status;
281 	const struct drm_edid *drm_edid;
282 	int n;
283 
284 	status = drm_bridge_connector_detect(connector, false);
285 	if (status != connector_status_connected)
286 		goto no_edid;
287 
288 	drm_edid = drm_bridge_edid_read(bridge, connector);
289 	if (!drm_edid_valid(drm_edid)) {
290 		drm_edid_free(drm_edid);
291 		goto no_edid;
292 	}
293 
294 	drm_edid_connector_update(connector, drm_edid);
295 	n = drm_edid_connector_add_modes(connector);
296 
297 	drm_edid_free(drm_edid);
298 	return n;
299 
300 no_edid:
301 	drm_edid_connector_update(connector, NULL);
302 	return 0;
303 }
304 
drm_bridge_connector_get_modes(struct drm_connector * connector)305 static int drm_bridge_connector_get_modes(struct drm_connector *connector)
306 {
307 	struct drm_bridge_connector *bridge_connector =
308 		to_drm_bridge_connector(connector);
309 	struct drm_bridge *bridge;
310 
311 	/*
312 	 * If there is a HDMI bridge, EDID has been updated as a part of
313 	 * the .detect(). Just update the modes here.
314 	 */
315 	bridge = bridge_connector->bridge_hdmi;
316 	if (bridge)
317 		return drm_edid_connector_add_modes(connector);
318 
319 	/*
320 	 * If display exposes EDID, then we parse that in the normal way to
321 	 * build table of supported modes.
322 	 */
323 	bridge = bridge_connector->bridge_edid;
324 	if (bridge)
325 		return drm_bridge_connector_get_modes_edid(connector, bridge);
326 
327 	/*
328 	 * Otherwise if the display pipeline reports modes (e.g. with a fixed
329 	 * resolution panel or an analog TV output), query it.
330 	 */
331 	bridge = bridge_connector->bridge_modes;
332 	if (bridge)
333 		return bridge->funcs->get_modes(bridge, connector);
334 
335 	/*
336 	 * We can't retrieve modes, which can happen for instance for a DVI or
337 	 * VGA output with the DDC bus unconnected. The KMS core will add the
338 	 * default modes.
339 	 */
340 	return 0;
341 }
342 
343 static enum drm_mode_status
drm_bridge_connector_mode_valid(struct drm_connector * connector,const struct drm_display_mode * mode)344 drm_bridge_connector_mode_valid(struct drm_connector *connector,
345 				const struct drm_display_mode *mode)
346 {
347 	struct drm_bridge_connector *bridge_connector =
348 		to_drm_bridge_connector(connector);
349 
350 	if (bridge_connector->bridge_hdmi)
351 		return drm_hdmi_connector_mode_valid(connector, mode);
352 
353 	return MODE_OK;
354 }
355 
drm_bridge_connector_atomic_check(struct drm_connector * connector,struct drm_atomic_state * state)356 static int drm_bridge_connector_atomic_check(struct drm_connector *connector,
357 					     struct drm_atomic_state *state)
358 {
359 	struct drm_bridge_connector *bridge_connector =
360 		to_drm_bridge_connector(connector);
361 
362 	if (bridge_connector->bridge_hdmi)
363 		return drm_atomic_helper_connector_hdmi_check(connector, state);
364 
365 	return 0;
366 }
367 
368 static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = {
369 	.get_modes = drm_bridge_connector_get_modes,
370 	.mode_valid = drm_bridge_connector_mode_valid,
371 	.enable_hpd = drm_bridge_connector_enable_hpd,
372 	.disable_hpd = drm_bridge_connector_disable_hpd,
373 	.atomic_check = drm_bridge_connector_atomic_check,
374 };
375 
376 static enum drm_mode_status
drm_bridge_connector_tmds_char_rate_valid(const struct drm_connector * connector,const struct drm_display_mode * mode,unsigned long long tmds_rate)377 drm_bridge_connector_tmds_char_rate_valid(const struct drm_connector *connector,
378 					  const struct drm_display_mode *mode,
379 					  unsigned long long tmds_rate)
380 {
381 	struct drm_bridge_connector *bridge_connector =
382 		to_drm_bridge_connector(connector);
383 	struct drm_bridge *bridge;
384 
385 	bridge = bridge_connector->bridge_hdmi;
386 	if (!bridge)
387 		return MODE_ERROR;
388 
389 	if (bridge->funcs->hdmi_tmds_char_rate_valid)
390 		return bridge->funcs->hdmi_tmds_char_rate_valid(bridge, mode, tmds_rate);
391 	else
392 		return MODE_OK;
393 }
394 
drm_bridge_connector_clear_infoframe(struct drm_connector * connector,enum hdmi_infoframe_type type)395 static int drm_bridge_connector_clear_infoframe(struct drm_connector *connector,
396 						enum hdmi_infoframe_type type)
397 {
398 	struct drm_bridge_connector *bridge_connector =
399 		to_drm_bridge_connector(connector);
400 	struct drm_bridge *bridge;
401 
402 	bridge = bridge_connector->bridge_hdmi;
403 	if (!bridge)
404 		return -EINVAL;
405 
406 	return bridge->funcs->hdmi_clear_infoframe(bridge, type);
407 }
408 
drm_bridge_connector_write_infoframe(struct drm_connector * connector,enum hdmi_infoframe_type type,const u8 * buffer,size_t len)409 static int drm_bridge_connector_write_infoframe(struct drm_connector *connector,
410 						enum hdmi_infoframe_type type,
411 						const u8 *buffer, size_t len)
412 {
413 	struct drm_bridge_connector *bridge_connector =
414 		to_drm_bridge_connector(connector);
415 	struct drm_bridge *bridge;
416 
417 	bridge = bridge_connector->bridge_hdmi;
418 	if (!bridge)
419 		return -EINVAL;
420 
421 	return bridge->funcs->hdmi_write_infoframe(bridge, type, buffer, len);
422 }
423 
424 static const struct drm_edid *
drm_bridge_connector_read_edid(struct drm_connector * connector)425 drm_bridge_connector_read_edid(struct drm_connector *connector)
426 {
427 	struct drm_bridge_connector *bridge_connector =
428 		to_drm_bridge_connector(connector);
429 	struct drm_bridge *bridge;
430 
431 	bridge = bridge_connector->bridge_edid;
432 	if (!bridge)
433 		return NULL;
434 
435 	return drm_bridge_edid_read(bridge, connector);
436 }
437 
438 static const struct drm_connector_hdmi_funcs drm_bridge_connector_hdmi_funcs = {
439 	.tmds_char_rate_valid = drm_bridge_connector_tmds_char_rate_valid,
440 	.clear_infoframe = drm_bridge_connector_clear_infoframe,
441 	.write_infoframe = drm_bridge_connector_write_infoframe,
442 	.read_edid = drm_bridge_connector_read_edid,
443 };
444 
drm_bridge_connector_audio_startup(struct drm_connector * connector)445 static int drm_bridge_connector_audio_startup(struct drm_connector *connector)
446 {
447 	struct drm_bridge_connector *bridge_connector =
448 		to_drm_bridge_connector(connector);
449 	struct drm_bridge *bridge;
450 
451 	if (bridge_connector->bridge_hdmi_audio) {
452 		bridge = bridge_connector->bridge_hdmi_audio;
453 
454 		if (!bridge->funcs->hdmi_audio_startup)
455 			return 0;
456 
457 		return bridge->funcs->hdmi_audio_startup(connector, bridge);
458 	}
459 
460 	if (bridge_connector->bridge_dp_audio) {
461 		bridge = bridge_connector->bridge_dp_audio;
462 
463 		if (!bridge->funcs->dp_audio_startup)
464 			return 0;
465 
466 		return bridge->funcs->dp_audio_startup(connector, bridge);
467 	}
468 
469 	return -EINVAL;
470 }
471 
drm_bridge_connector_audio_prepare(struct drm_connector * connector,struct hdmi_codec_daifmt * fmt,struct hdmi_codec_params * hparms)472 static int drm_bridge_connector_audio_prepare(struct drm_connector *connector,
473 					      struct hdmi_codec_daifmt *fmt,
474 					      struct hdmi_codec_params *hparms)
475 {
476 	struct drm_bridge_connector *bridge_connector =
477 		to_drm_bridge_connector(connector);
478 	struct drm_bridge *bridge;
479 
480 	if (bridge_connector->bridge_hdmi_audio) {
481 		bridge = bridge_connector->bridge_hdmi_audio;
482 
483 		return bridge->funcs->hdmi_audio_prepare(connector, bridge, fmt, hparms);
484 	}
485 
486 	if (bridge_connector->bridge_dp_audio) {
487 		bridge = bridge_connector->bridge_dp_audio;
488 
489 		return bridge->funcs->dp_audio_prepare(connector, bridge, fmt, hparms);
490 	}
491 
492 	return -EINVAL;
493 }
494 
drm_bridge_connector_audio_shutdown(struct drm_connector * connector)495 static void drm_bridge_connector_audio_shutdown(struct drm_connector *connector)
496 {
497 	struct drm_bridge_connector *bridge_connector =
498 		to_drm_bridge_connector(connector);
499 	struct drm_bridge *bridge;
500 
501 	if (bridge_connector->bridge_hdmi_audio) {
502 		bridge = bridge_connector->bridge_hdmi_audio;
503 		bridge->funcs->hdmi_audio_shutdown(connector, bridge);
504 	}
505 
506 	if (bridge_connector->bridge_dp_audio) {
507 		bridge = bridge_connector->bridge_dp_audio;
508 		bridge->funcs->dp_audio_shutdown(connector, bridge);
509 	}
510 }
511 
drm_bridge_connector_audio_mute_stream(struct drm_connector * connector,bool enable,int direction)512 static int drm_bridge_connector_audio_mute_stream(struct drm_connector *connector,
513 						  bool enable, int direction)
514 {
515 	struct drm_bridge_connector *bridge_connector =
516 		to_drm_bridge_connector(connector);
517 	struct drm_bridge *bridge;
518 
519 	if (bridge_connector->bridge_hdmi_audio) {
520 		bridge = bridge_connector->bridge_hdmi_audio;
521 
522 		if (!bridge->funcs->hdmi_audio_mute_stream)
523 			return -ENOTSUPP;
524 
525 		return bridge->funcs->hdmi_audio_mute_stream(connector, bridge,
526 							     enable, direction);
527 	}
528 
529 	if (bridge_connector->bridge_dp_audio) {
530 		bridge = bridge_connector->bridge_dp_audio;
531 
532 		if (!bridge->funcs->dp_audio_mute_stream)
533 			return -ENOTSUPP;
534 
535 		return bridge->funcs->dp_audio_mute_stream(connector, bridge,
536 							   enable, direction);
537 	}
538 
539 	return -EINVAL;
540 }
541 
542 static const struct drm_connector_hdmi_audio_funcs drm_bridge_connector_hdmi_audio_funcs = {
543 	.startup = drm_bridge_connector_audio_startup,
544 	.prepare = drm_bridge_connector_audio_prepare,
545 	.shutdown = drm_bridge_connector_audio_shutdown,
546 	.mute_stream = drm_bridge_connector_audio_mute_stream,
547 };
548 
549 /* -----------------------------------------------------------------------------
550  * Bridge Connector Initialisation
551  */
552 
553 /**
554  * drm_bridge_connector_init - Initialise a connector for a chain of bridges
555  * @drm: the DRM device
556  * @encoder: the encoder where the bridge chain starts
557  *
558  * Allocate, initialise and register a &drm_bridge_connector with the @drm
559  * device. The connector is associated with a chain of bridges that starts at
560  * the @encoder. All bridges in the chain shall report bridge operation flags
561  * (&drm_bridge->ops) and bridge output type (&drm_bridge->type), and none of
562  * them may create a DRM connector directly.
563  *
564  * Returns a pointer to the new connector on success, or a negative error
565  * pointer otherwise.
566  */
drm_bridge_connector_init(struct drm_device * drm,struct drm_encoder * encoder)567 struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
568 						struct drm_encoder *encoder)
569 {
570 	struct drm_bridge_connector *bridge_connector;
571 	struct drm_connector *connector;
572 	struct i2c_adapter *ddc = NULL;
573 	struct drm_bridge *bridge, *panel_bridge = NULL;
574 	unsigned int supported_formats = BIT(HDMI_COLORSPACE_RGB);
575 	unsigned int max_bpc = 8;
576 	int connector_type;
577 	int ret;
578 
579 	bridge_connector = drmm_kzalloc(drm, sizeof(*bridge_connector), GFP_KERNEL);
580 	if (!bridge_connector)
581 		return ERR_PTR(-ENOMEM);
582 
583 	bridge_connector->encoder = encoder;
584 
585 	/*
586 	 * TODO: Handle doublescan_allowed and stereo_allowed.
587 	 */
588 	connector = &bridge_connector->base;
589 	connector->interlace_allowed = true;
590 	connector->ycbcr_420_allowed = true;
591 
592 	/*
593 	 * Initialise connector status handling. First locate the furthest
594 	 * bridges in the pipeline that support HPD and output detection. Then
595 	 * initialise the connector polling mode, using HPD if available and
596 	 * falling back to polling if supported. If neither HPD nor output
597 	 * detection are available, we don't support hotplug detection at all.
598 	 */
599 	connector_type = DRM_MODE_CONNECTOR_Unknown;
600 	drm_for_each_bridge_in_chain(encoder, bridge) {
601 		if (!bridge->interlace_allowed)
602 			connector->interlace_allowed = false;
603 		if (!bridge->ycbcr_420_allowed)
604 			connector->ycbcr_420_allowed = false;
605 
606 		if (bridge->ops & DRM_BRIDGE_OP_EDID)
607 			bridge_connector->bridge_edid = bridge;
608 		if (bridge->ops & DRM_BRIDGE_OP_HPD)
609 			bridge_connector->bridge_hpd = bridge;
610 		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
611 			bridge_connector->bridge_detect = bridge;
612 		if (bridge->ops & DRM_BRIDGE_OP_MODES)
613 			bridge_connector->bridge_modes = bridge;
614 		if (bridge->ops & DRM_BRIDGE_OP_HDMI) {
615 			if (bridge_connector->bridge_hdmi)
616 				return ERR_PTR(-EBUSY);
617 			if (!bridge->funcs->hdmi_write_infoframe ||
618 			    !bridge->funcs->hdmi_clear_infoframe)
619 				return ERR_PTR(-EINVAL);
620 
621 			bridge_connector->bridge_hdmi = bridge;
622 
623 			if (bridge->supported_formats)
624 				supported_formats = bridge->supported_formats;
625 			if (bridge->max_bpc)
626 				max_bpc = bridge->max_bpc;
627 		}
628 
629 		if (bridge->ops & DRM_BRIDGE_OP_HDMI_AUDIO) {
630 			if (bridge_connector->bridge_hdmi_audio)
631 				return ERR_PTR(-EBUSY);
632 
633 			if (bridge_connector->bridge_dp_audio)
634 				return ERR_PTR(-EBUSY);
635 
636 			if (!bridge->hdmi_audio_max_i2s_playback_channels &&
637 			    !bridge->hdmi_audio_spdif_playback)
638 				return ERR_PTR(-EINVAL);
639 
640 			if (!bridge->funcs->hdmi_audio_prepare ||
641 			    !bridge->funcs->hdmi_audio_shutdown)
642 				return ERR_PTR(-EINVAL);
643 
644 			bridge_connector->bridge_hdmi_audio = bridge;
645 		}
646 
647 		if (bridge->ops & DRM_BRIDGE_OP_DP_AUDIO) {
648 			if (bridge_connector->bridge_dp_audio)
649 				return ERR_PTR(-EBUSY);
650 
651 			if (bridge_connector->bridge_hdmi_audio)
652 				return ERR_PTR(-EBUSY);
653 
654 			if (!bridge->hdmi_audio_max_i2s_playback_channels &&
655 			    !bridge->hdmi_audio_spdif_playback)
656 				return ERR_PTR(-EINVAL);
657 
658 			if (!bridge->funcs->dp_audio_prepare ||
659 			    !bridge->funcs->dp_audio_shutdown)
660 				return ERR_PTR(-EINVAL);
661 
662 			bridge_connector->bridge_dp_audio = bridge;
663 		}
664 
665 		if (!drm_bridge_get_next_bridge(bridge))
666 			connector_type = bridge->type;
667 
668 #ifdef CONFIG_OF
669 		if (!drm_bridge_get_next_bridge(bridge) &&
670 		    bridge->of_node)
671 			connector->fwnode = fwnode_handle_get(of_fwnode_handle(bridge->of_node));
672 #endif
673 
674 		if (bridge->ddc)
675 			ddc = bridge->ddc;
676 
677 		if (drm_bridge_is_panel(bridge))
678 			panel_bridge = bridge;
679 	}
680 
681 	if (connector_type == DRM_MODE_CONNECTOR_Unknown)
682 		return ERR_PTR(-EINVAL);
683 
684 	if (bridge_connector->bridge_hdmi) {
685 		if (!connector->ycbcr_420_allowed)
686 			supported_formats &= ~BIT(HDMI_COLORSPACE_YUV420);
687 
688 		bridge = bridge_connector->bridge_hdmi;
689 
690 		ret = drmm_connector_hdmi_init(drm, connector,
691 					       bridge_connector->bridge_hdmi->vendor,
692 					       bridge_connector->bridge_hdmi->product,
693 					       &drm_bridge_connector_funcs,
694 					       &drm_bridge_connector_hdmi_funcs,
695 					       connector_type, ddc,
696 					       supported_formats,
697 					       max_bpc);
698 		if (ret)
699 			return ERR_PTR(ret);
700 	} else {
701 		ret = drmm_connector_init(drm, connector,
702 					  &drm_bridge_connector_funcs,
703 					  connector_type, ddc);
704 		if (ret)
705 			return ERR_PTR(ret);
706 	}
707 
708 	if (bridge_connector->bridge_hdmi_audio ||
709 	    bridge_connector->bridge_dp_audio) {
710 		struct device *dev;
711 		struct drm_bridge *bridge;
712 
713 		if (bridge_connector->bridge_hdmi_audio)
714 			bridge = bridge_connector->bridge_hdmi_audio;
715 		else
716 			bridge = bridge_connector->bridge_dp_audio;
717 
718 		dev = bridge->hdmi_audio_dev;
719 
720 		ret = drm_connector_hdmi_audio_init(connector, dev,
721 						    &drm_bridge_connector_hdmi_audio_funcs,
722 						    bridge->hdmi_audio_max_i2s_playback_channels,
723 						    bridge->hdmi_audio_spdif_playback,
724 						    bridge->hdmi_audio_dai_port);
725 		if (ret)
726 			return ERR_PTR(ret);
727 	}
728 
729 	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
730 
731 	if (bridge_connector->bridge_hpd)
732 		connector->polled = DRM_CONNECTOR_POLL_HPD;
733 	else if (bridge_connector->bridge_detect)
734 		connector->polled = DRM_CONNECTOR_POLL_CONNECT
735 				  | DRM_CONNECTOR_POLL_DISCONNECT;
736 
737 	if (panel_bridge)
738 		drm_panel_bridge_set_orientation(connector, panel_bridge);
739 
740 	return connector;
741 }
742 EXPORT_SYMBOL_GPL(drm_bridge_connector_init);
743