1/*
2 * Copyright (c) 2016 Intel Corporation
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting documentation, and
8 * that the name of the copyright holders not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. The copyright holders make no representations
11 * about the suitability of this software for any purpose. It is provided "as
12 * is" without express or implied warranty.
13 *
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20 * OF THIS SOFTWARE.
21 */
22
23#ifndef __DRM_BRIDGE_H__
24#define __DRM_BRIDGE_H__
25
26#include <linux/ctype.h>
27#include <linux/list.h>
28#include <linux/mutex.h>
29
30#include <drm/drm_atomic.h>
31#include <drm/drm_encoder.h>
32#include <drm/drm_mode_object.h>
33#include <drm/drm_modes.h>
34
35struct device_node;
36
37struct drm_bridge;
38struct drm_bridge_timings;
39struct drm_connector;
40struct drm_display_info;
41struct drm_minor;
42struct drm_panel;
43struct edid;
44struct hdmi_codec_daifmt;
45struct hdmi_codec_params;
46struct i2c_adapter;
47
48/**
49 * enum drm_bridge_attach_flags - Flags for &drm_bridge_funcs.attach
50 */
51enum drm_bridge_attach_flags {
52 /**
53 * @DRM_BRIDGE_ATTACH_NO_CONNECTOR: When this flag is set the bridge
54 * shall not create a drm_connector.
55 */
56 DRM_BRIDGE_ATTACH_NO_CONNECTOR = BIT(0),
57};
58
59/**
60 * struct drm_bridge_funcs - drm_bridge control functions
61 */
62struct drm_bridge_funcs {
63 /**
64 * @attach:
65 *
66 * This callback is invoked whenever our bridge is being attached to a
67 * &drm_encoder. The flags argument tunes the behaviour of the attach
68 * operation (see DRM_BRIDGE_ATTACH_*).
69 *
70 * The @attach callback is optional.
71 *
72 * RETURNS:
73 *
74 * Zero on success, error code on failure.
75 */
76 int (*attach)(struct drm_bridge *bridge, struct drm_encoder *encoder,
77 enum drm_bridge_attach_flags flags);
78
79 /**
80 * @detach:
81 *
82 * This callback is invoked whenever our bridge is being detached from a
83 * &drm_encoder.
84 *
85 * The @detach callback is optional.
86 */
87 void (*detach)(struct drm_bridge *bridge);
88
89 /**
90 * @mode_valid:
91 *
92 * This callback is used to check if a specific mode is valid in this
93 * bridge. This should be implemented if the bridge has some sort of
94 * restriction in the modes it can display. For example, a given bridge
95 * may be responsible to set a clock value. If the clock can not
96 * produce all the values for the available modes then this callback
97 * can be used to restrict the number of modes to only the ones that
98 * can be displayed.
99 *
100 * This hook is used by the probe helpers to filter the mode list in
101 * drm_helper_probe_single_connector_modes(), and it is used by the
102 * atomic helpers to validate modes supplied by userspace in
103 * drm_atomic_helper_check_modeset().
104 *
105 * The @mode_valid callback is optional.
106 *
107 * NOTE:
108 *
109 * Since this function is both called from the check phase of an atomic
110 * commit, and the mode validation in the probe paths it is not allowed
111 * to look at anything else but the passed-in mode, and validate it
112 * against configuration-invariant hardware constraints. Any further
113 * limits which depend upon the configuration can only be checked in
114 * @mode_fixup.
115 *
116 * RETURNS:
117 *
118 * drm_mode_status Enum
119 */
120 enum drm_mode_status (*mode_valid)(struct drm_bridge *bridge,
121 const struct drm_display_info *info,
122 const struct drm_display_mode *mode);
123
124 /**
125 * @mode_fixup:
126 *
127 * This callback is used to validate and adjust a mode. The parameter
128 * mode is the display mode that should be fed to the next element in
129 * the display chain, either the final &drm_connector or the next
130 * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
131 * requires. It can be modified by this callback and does not need to
132 * match mode. See also &drm_crtc_state.adjusted_mode for more details.
133 *
134 * This is the only hook that allows a bridge to reject a modeset. If
135 * this function passes all other callbacks must succeed for this
136 * configuration.
137 *
138 * The mode_fixup callback is optional. &drm_bridge_funcs.mode_fixup()
139 * is not called when &drm_bridge_funcs.atomic_check() is implemented,
140 * so only one of them should be provided.
141 *
142 * NOTE:
143 *
144 * This function is called in the check phase of atomic modesets, which
145 * can be aborted for any reason (including on userspace's request to
146 * just check whether a configuration would be possible). Drivers MUST
147 * NOT touch any persistent state (hardware or software) or data
148 * structures except the passed in @state parameter.
149 *
150 * Also beware that userspace can request its own custom modes, neither
151 * core nor helpers filter modes to the list of probe modes reported by
152 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
153 * that modes are filtered consistently put any bridge constraints and
154 * limits checks into @mode_valid.
155 *
156 * RETURNS:
157 *
158 * True if an acceptable configuration is possible, false if the modeset
159 * operation should be rejected.
160 */
161 bool (*mode_fixup)(struct drm_bridge *bridge,
162 const struct drm_display_mode *mode,
163 struct drm_display_mode *adjusted_mode);
164 /**
165 * @disable:
166 *
167 * This callback should disable the bridge. It is called right before
168 * the preceding element in the display pipe is disabled. If the
169 * preceding element is a bridge this means it's called before that
170 * bridge's @disable vfunc. If the preceding element is a &drm_encoder
171 * it's called right before the &drm_encoder_helper_funcs.disable,
172 * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
173 * hook.
174 *
175 * The bridge can assume that the display pipe (i.e. clocks and timing
176 * signals) feeding it is still running when this callback is called.
177 *
178 * The @disable callback is optional.
179 *
180 * NOTE:
181 *
182 * This is deprecated, do not use!
183 * New drivers shall use &drm_bridge_funcs.atomic_disable.
184 */
185 void (*disable)(struct drm_bridge *bridge);
186
187 /**
188 * @post_disable:
189 *
190 * This callback should disable the bridge. It is called right after the
191 * preceding element in the display pipe is disabled. If the preceding
192 * element is a bridge this means it's called after that bridge's
193 * @post_disable function. If the preceding element is a &drm_encoder
194 * it's called right after the encoder's
195 * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
196 * or &drm_encoder_helper_funcs.dpms hook.
197 *
198 * The bridge must assume that the display pipe (i.e. clocks and timing
199 * signals) feeding it is no longer running when this callback is
200 * called.
201 *
202 * The @post_disable callback is optional.
203 *
204 * NOTE:
205 *
206 * This is deprecated, do not use!
207 * New drivers shall use &drm_bridge_funcs.atomic_post_disable.
208 */
209 void (*post_disable)(struct drm_bridge *bridge);
210
211 /**
212 * @mode_set:
213 *
214 * This callback should set the given mode on the bridge. It is called
215 * after the @mode_set callback for the preceding element in the display
216 * pipeline has been called already. If the bridge is the first element
217 * then this would be &drm_encoder_helper_funcs.mode_set. The display
218 * pipe (i.e. clocks and timing signals) is off when this function is
219 * called.
220 *
221 * The adjusted_mode parameter is the mode output by the CRTC for the
222 * first bridge in the chain. It can be different from the mode
223 * parameter that contains the desired mode for the connector at the end
224 * of the bridges chain, for instance when the first bridge in the chain
225 * performs scaling. The adjusted mode is mostly useful for the first
226 * bridge in the chain and is likely irrelevant for the other bridges.
227 *
228 * For atomic drivers the adjusted_mode is the mode stored in
229 * &drm_crtc_state.adjusted_mode.
230 *
231 * NOTE:
232 *
233 * This is deprecated, do not use!
234 * New drivers shall set their mode in the
235 * &drm_bridge_funcs.atomic_enable operation.
236 */
237 void (*mode_set)(struct drm_bridge *bridge,
238 const struct drm_display_mode *mode,
239 const struct drm_display_mode *adjusted_mode);
240 /**
241 * @pre_enable:
242 *
243 * This callback should enable the bridge. It is called right before
244 * the preceding element in the display pipe is enabled. If the
245 * preceding element is a bridge this means it's called before that
246 * bridge's @pre_enable function. If the preceding element is a
247 * &drm_encoder it's called right before the encoder's
248 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
249 * &drm_encoder_helper_funcs.dpms hook.
250 *
251 * The display pipe (i.e. clocks and timing signals) feeding this bridge
252 * will not yet be running when this callback is called. The bridge must
253 * not enable the display link feeding the next bridge in the chain (if
254 * there is one) when this callback is called.
255 *
256 * The @pre_enable callback is optional.
257 *
258 * NOTE:
259 *
260 * This is deprecated, do not use!
261 * New drivers shall use &drm_bridge_funcs.atomic_pre_enable.
262 */
263 void (*pre_enable)(struct drm_bridge *bridge);
264
265 /**
266 * @enable:
267 *
268 * This callback should enable the bridge. It is called right after
269 * the preceding element in the display pipe is enabled. If the
270 * preceding element is a bridge this means it's called after that
271 * bridge's @enable function. If the preceding element is a
272 * &drm_encoder it's called right after the encoder's
273 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
274 * &drm_encoder_helper_funcs.dpms hook.
275 *
276 * The bridge can assume that the display pipe (i.e. clocks and timing
277 * signals) feeding it is running when this callback is called. This
278 * callback must enable the display link feeding the next bridge in the
279 * chain if there is one.
280 *
281 * The @enable callback is optional.
282 *
283 * NOTE:
284 *
285 * This is deprecated, do not use!
286 * New drivers shall use &drm_bridge_funcs.atomic_enable.
287 */
288 void (*enable)(struct drm_bridge *bridge);
289
290 /**
291 * @atomic_pre_enable:
292 *
293 * This callback should enable the bridge. It is called right before
294 * the preceding element in the display pipe is enabled. If the
295 * preceding element is a bridge this means it's called before that
296 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
297 * element is a &drm_encoder it's called right before the encoder's
298 * &drm_encoder_helper_funcs.atomic_enable hook.
299 *
300 * The display pipe (i.e. clocks and timing signals) feeding this bridge
301 * will not yet be running when this callback is called. The bridge must
302 * not enable the display link feeding the next bridge in the chain (if
303 * there is one) when this callback is called.
304 *
305 * The @atomic_pre_enable callback is optional.
306 */
307 void (*atomic_pre_enable)(struct drm_bridge *bridge,
308 struct drm_atomic_state *state);
309
310 /**
311 * @atomic_enable:
312 *
313 * This callback should enable the bridge. It is called right after
314 * the preceding element in the display pipe is enabled. If the
315 * preceding element is a bridge this means it's called after that
316 * bridge's @atomic_enable or @enable function. If the preceding element
317 * is a &drm_encoder it's called right after the encoder's
318 * &drm_encoder_helper_funcs.atomic_enable hook.
319 *
320 * The bridge can assume that the display pipe (i.e. clocks and timing
321 * signals) feeding it is running when this callback is called. This
322 * callback must enable the display link feeding the next bridge in the
323 * chain if there is one.
324 *
325 * The @atomic_enable callback is optional.
326 */
327 void (*atomic_enable)(struct drm_bridge *bridge,
328 struct drm_atomic_state *state);
329 /**
330 * @atomic_disable:
331 *
332 * This callback should disable the bridge. It is called right before
333 * the preceding element in the display pipe is disabled. If the
334 * preceding element is a bridge this means it's called before that
335 * bridge's @atomic_disable or @disable vfunc. If the preceding element
336 * is a &drm_encoder it's called right before the
337 * &drm_encoder_helper_funcs.atomic_disable hook.
338 *
339 * The bridge can assume that the display pipe (i.e. clocks and timing
340 * signals) feeding it is still running when this callback is called.
341 *
342 * The @atomic_disable callback is optional.
343 */
344 void (*atomic_disable)(struct drm_bridge *bridge,
345 struct drm_atomic_state *state);
346
347 /**
348 * @atomic_post_disable:
349 *
350 * This callback should disable the bridge. It is called right after the
351 * preceding element in the display pipe is disabled. If the preceding
352 * element is a bridge this means it's called after that bridge's
353 * @atomic_post_disable or @post_disable function. If the preceding
354 * element is a &drm_encoder it's called right after the encoder's
355 * &drm_encoder_helper_funcs.atomic_disable hook.
356 *
357 * The bridge must assume that the display pipe (i.e. clocks and timing
358 * signals) feeding it is no longer running when this callback is
359 * called.
360 *
361 * The @atomic_post_disable callback is optional.
362 */
363 void (*atomic_post_disable)(struct drm_bridge *bridge,
364 struct drm_atomic_state *state);
365
366 /**
367 * @atomic_duplicate_state:
368 *
369 * Duplicate the current bridge state object (which is guaranteed to be
370 * non-NULL).
371 *
372 * The atomic_duplicate_state hook is mandatory if the bridge
373 * implements any of the atomic hooks, and should be left unassigned
374 * otherwise. For bridges that don't subclass &drm_bridge_state, the
375 * drm_atomic_helper_bridge_duplicate_state() helper function shall be
376 * used to implement this hook.
377 *
378 * RETURNS:
379 * A valid drm_bridge_state object or NULL if the allocation fails.
380 */
381 struct drm_bridge_state *(*atomic_duplicate_state)(struct drm_bridge *bridge);
382
383 /**
384 * @atomic_destroy_state:
385 *
386 * Destroy a bridge state object previously allocated by
387 * &drm_bridge_funcs.atomic_duplicate_state().
388 *
389 * The atomic_destroy_state hook is mandatory if the bridge implements
390 * any of the atomic hooks, and should be left unassigned otherwise.
391 * For bridges that don't subclass &drm_bridge_state, the
392 * drm_atomic_helper_bridge_destroy_state() helper function shall be
393 * used to implement this hook.
394 */
395 void (*atomic_destroy_state)(struct drm_bridge *bridge,
396 struct drm_bridge_state *state);
397
398 /**
399 * @atomic_get_output_bus_fmts:
400 *
401 * Return the supported bus formats on the output end of a bridge.
402 * The returned array must be allocated with kmalloc() and will be
403 * freed by the caller. If the allocation fails, NULL should be
404 * returned. num_output_fmts must be set to the returned array size.
405 * Formats listed in the returned array should be listed in decreasing
406 * preference order (the core will try all formats until it finds one
407 * that works).
408 *
409 * This method is only called on the last element of the bridge chain
410 * as part of the bus format negotiation process that happens in
411 * &drm_atomic_bridge_chain_select_bus_fmts().
412 * This method is optional. When not implemented, the core will
413 * fall back to &drm_connector.display_info.bus_formats[0] if
414 * &drm_connector.display_info.num_bus_formats > 0,
415 * or to MEDIA_BUS_FMT_FIXED otherwise.
416 */
417 u32 *(*atomic_get_output_bus_fmts)(struct drm_bridge *bridge,
418 struct drm_bridge_state *bridge_state,
419 struct drm_crtc_state *crtc_state,
420 struct drm_connector_state *conn_state,
421 unsigned int *num_output_fmts);
422
423 /**
424 * @atomic_get_input_bus_fmts:
425 *
426 * Return the supported bus formats on the input end of a bridge for
427 * a specific output bus format.
428 *
429 * The returned array must be allocated with kmalloc() and will be
430 * freed by the caller. If the allocation fails, NULL should be
431 * returned. num_input_fmts must be set to the returned array size.
432 * Formats listed in the returned array should be listed in decreasing
433 * preference order (the core will try all formats until it finds one
434 * that works). When the format is not supported NULL should be
435 * returned and num_input_fmts should be set to 0.
436 *
437 * This method is called on all elements of the bridge chain as part of
438 * the bus format negotiation process that happens in
439 * drm_atomic_bridge_chain_select_bus_fmts().
440 * This method is optional. When not implemented, the core will bypass
441 * bus format negotiation on this element of the bridge without
442 * failing, and the previous element in the chain will be passed
443 * MEDIA_BUS_FMT_FIXED as its output bus format.
444 *
445 * Bridge drivers that need to support being linked to bridges that are
446 * not supporting bus format negotiation should handle the
447 * output_fmt == MEDIA_BUS_FMT_FIXED case appropriately, by selecting a
448 * sensible default value or extracting this information from somewhere
449 * else (FW property, &drm_display_mode, &drm_display_info, ...)
450 *
451 * Note: Even if input format selection on the first bridge has no
452 * impact on the negotiation process (bus format negotiation stops once
453 * we reach the first element of the chain), drivers are expected to
454 * return accurate input formats as the input format may be used to
455 * configure the CRTC output appropriately.
456 */
457 u32 *(*atomic_get_input_bus_fmts)(struct drm_bridge *bridge,
458 struct drm_bridge_state *bridge_state,
459 struct drm_crtc_state *crtc_state,
460 struct drm_connector_state *conn_state,
461 u32 output_fmt,
462 unsigned int *num_input_fmts);
463
464 /**
465 * @atomic_check:
466 *
467 * This method is responsible for checking bridge state correctness.
468 * It can also check the state of the surrounding components in chain
469 * to make sure the whole pipeline can work properly.
470 *
471 * &drm_bridge_funcs.atomic_check() hooks are called in reverse
472 * order (from the last to the first bridge).
473 *
474 * This method is optional. &drm_bridge_funcs.mode_fixup() is not
475 * called when &drm_bridge_funcs.atomic_check() is implemented, so only
476 * one of them should be provided.
477 *
478 * If drivers need to tweak &drm_bridge_state.input_bus_cfg.flags or
479 * &drm_bridge_state.output_bus_cfg.flags it should happen in
480 * this function. By default the &drm_bridge_state.output_bus_cfg.flags
481 * field is set to the next bridge
482 * &drm_bridge_state.input_bus_cfg.flags value or
483 * &drm_connector.display_info.bus_flags if the bridge is the last
484 * element in the chain.
485 *
486 * RETURNS:
487 * zero if the check passed, a negative error code otherwise.
488 */
489 int (*atomic_check)(struct drm_bridge *bridge,
490 struct drm_bridge_state *bridge_state,
491 struct drm_crtc_state *crtc_state,
492 struct drm_connector_state *conn_state);
493
494 /**
495 * @atomic_reset:
496 *
497 * Reset the bridge to a predefined state (or retrieve its current
498 * state) and return a &drm_bridge_state object matching this state.
499 * This function is called at attach time.
500 *
501 * The atomic_reset hook is mandatory if the bridge implements any of
502 * the atomic hooks, and should be left unassigned otherwise. For
503 * bridges that don't subclass &drm_bridge_state, the
504 * drm_atomic_helper_bridge_reset() helper function shall be used to
505 * implement this hook.
506 *
507 * Note that the atomic_reset() semantics is not exactly matching the
508 * reset() semantics found on other components (connector, plane, ...).
509 *
510 * 1. The reset operation happens when the bridge is attached, not when
511 * drm_mode_config_reset() is called
512 * 2. It's meant to be used exclusively on bridges that have been
513 * converted to the ATOMIC API
514 *
515 * RETURNS:
516 * A valid drm_bridge_state object in case of success, an ERR_PTR()
517 * giving the reason of the failure otherwise.
518 */
519 struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
520
521 /**
522 * @detect:
523 *
524 * Check if anything is attached to the bridge output.
525 *
526 * This callback is optional, if not implemented the bridge will be
527 * considered as always having a component attached to its output.
528 * Bridges that implement this callback shall set the
529 * DRM_BRIDGE_OP_DETECT flag in their &drm_bridge->ops.
530 *
531 * RETURNS:
532 *
533 * drm_connector_status indicating the bridge output status.
534 */
535 enum drm_connector_status (*detect)(struct drm_bridge *bridge);
536
537 /**
538 * @get_modes:
539 *
540 * Fill all modes currently valid for the sink into the &drm_connector
541 * with drm_mode_probed_add().
542 *
543 * The @get_modes callback is mostly intended to support non-probeable
544 * displays such as many fixed panels. Bridges that support reading
545 * EDID shall leave @get_modes unimplemented and implement the
546 * &drm_bridge_funcs->edid_read callback instead.
547 *
548 * This callback is optional. Bridges that implement it shall set the
549 * DRM_BRIDGE_OP_MODES flag in their &drm_bridge->ops.
550 *
551 * The connector parameter shall be used for the sole purpose of
552 * filling modes, and shall not be stored internally by bridge drivers
553 * for future usage.
554 *
555 * RETURNS:
556 *
557 * The number of modes added by calling drm_mode_probed_add().
558 */
559 int (*get_modes)(struct drm_bridge *bridge,
560 struct drm_connector *connector);
561
562 /**
563 * @edid_read:
564 *
565 * Read the EDID data of the connected display.
566 *
567 * The @edid_read callback is the preferred way of reporting mode
568 * information for a display connected to the bridge output. Bridges
569 * that support reading EDID shall implement this callback and leave
570 * the @get_modes callback unimplemented.
571 *
572 * The caller of this operation shall first verify the output
573 * connection status and refrain from reading EDID from a disconnected
574 * output.
575 *
576 * This callback is optional. Bridges that implement it shall set the
577 * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
578 *
579 * The connector parameter shall be used for the sole purpose of EDID
580 * retrieval, and shall not be stored internally by bridge drivers for
581 * future usage.
582 *
583 * RETURNS:
584 *
585 * An edid structure newly allocated with drm_edid_alloc() or returned
586 * from drm_edid_read() family of functions on success, or NULL
587 * otherwise. The caller is responsible for freeing the returned edid
588 * structure with drm_edid_free().
589 */
590 const struct drm_edid *(*edid_read)(struct drm_bridge *bridge,
591 struct drm_connector *connector);
592
593 /**
594 * @hpd_notify:
595 *
596 * Notify the bridge of hot plug detection.
597 *
598 * This callback is optional, it may be implemented by bridges that
599 * need to be notified of display connection or disconnection for
600 * internal reasons. One use case is to reset the internal state of CEC
601 * controllers for HDMI bridges.
602 */
603 void (*hpd_notify)(struct drm_bridge *bridge,
604 enum drm_connector_status status);
605
606 /**
607 * @hpd_enable:
608 *
609 * Enable hot plug detection. From now on the bridge shall call
610 * drm_bridge_hpd_notify() each time a change is detected in the output
611 * connection status, until hot plug detection gets disabled with
612 * @hpd_disable.
613 *
614 * This callback is optional and shall only be implemented by bridges
615 * that support hot-plug notification without polling. Bridges that
616 * implement it shall also implement the @hpd_disable callback and set
617 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
618 */
619 void (*hpd_enable)(struct drm_bridge *bridge);
620
621 /**
622 * @hpd_disable:
623 *
624 * Disable hot plug detection. Once this function returns the bridge
625 * shall not call drm_bridge_hpd_notify() when a change in the output
626 * connection status occurs.
627 *
628 * This callback is optional and shall only be implemented by bridges
629 * that support hot-plug notification without polling. Bridges that
630 * implement it shall also implement the @hpd_enable callback and set
631 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
632 */
633 void (*hpd_disable)(struct drm_bridge *bridge);
634
635 /**
636 * @hdmi_tmds_char_rate_valid:
637 *
638 * Check whether a particular TMDS character rate is supported by the
639 * driver.
640 *
641 * This callback is optional and should only be implemented by the
642 * bridges that take part in the HDMI connector implementation. Bridges
643 * that implement it shall set the DRM_BRIDGE_OP_HDMI flag in their
644 * &drm_bridge->ops.
645 *
646 * Returns:
647 *
648 * Either &drm_mode_status.MODE_OK or one of the failure reasons
649 * in &enum drm_mode_status.
650 */
651 enum drm_mode_status
652 (*hdmi_tmds_char_rate_valid)(const struct drm_bridge *bridge,
653 const struct drm_display_mode *mode,
654 unsigned long long tmds_rate);
655
656 /**
657 * @hdmi_clear_infoframe:
658 *
659 * This callback clears the infoframes in the hardware during commit.
660 * It will be called multiple times, once for every disabled infoframe
661 * type.
662 *
663 * This callback is optional but it must be implemented by bridges that
664 * set the DRM_BRIDGE_OP_HDMI flag in their &drm_bridge->ops.
665 */
666 int (*hdmi_clear_infoframe)(struct drm_bridge *bridge,
667 enum hdmi_infoframe_type type);
668 /**
669 * @hdmi_write_infoframe:
670 *
671 * Program the infoframe into the hardware. It will be called multiple
672 * times, once for every updated infoframe type.
673 *
674 * This callback is optional but it must be implemented by bridges that
675 * set the DRM_BRIDGE_OP_HDMI flag in their &drm_bridge->ops.
676 */
677 int (*hdmi_write_infoframe)(struct drm_bridge *bridge,
678 enum hdmi_infoframe_type type,
679 const u8 *buffer, size_t len);
680
681 /**
682 * @hdmi_audio_startup:
683 *
684 * Called when ASoC starts an audio stream setup.
685 *
686 * This callback is optional, it can be implemented by bridges that
687 * set the @DRM_BRIDGE_OP_HDMI_AUDIO flag in their &drm_bridge->ops.
688 *
689 * Returns:
690 * 0 on success, a negative error code otherwise
691 */
692 int (*hdmi_audio_startup)(struct drm_connector *connector,
693 struct drm_bridge *bridge);
694
695 /**
696 * @hdmi_audio_prepare:
697 * Configures HDMI-encoder for audio stream. Can be called multiple
698 * times for each setup.
699 *
700 * This callback is optional but it must be implemented by bridges that
701 * set the @DRM_BRIDGE_OP_HDMI_AUDIO flag in their &drm_bridge->ops.
702 *
703 * Returns:
704 * 0 on success, a negative error code otherwise
705 */
706 int (*hdmi_audio_prepare)(struct drm_connector *connector,
707 struct drm_bridge *bridge,
708 struct hdmi_codec_daifmt *fmt,
709 struct hdmi_codec_params *hparms);
710
711 /**
712 * @hdmi_audio_shutdown:
713 *
714 * Shut down the audio stream.
715 *
716 * This callback is optional but it must be implemented by bridges that
717 * set the @DRM_BRIDGE_OP_HDMI_AUDIO flag in their &drm_bridge->ops.
718 *
719 * Returns:
720 * 0 on success, a negative error code otherwise
721 */
722 void (*hdmi_audio_shutdown)(struct drm_connector *connector,
723 struct drm_bridge *bridge);
724
725 /**
726 * @hdmi_audio_mute_stream:
727 *
728 * Mute/unmute HDMI audio stream.
729 *
730 * This callback is optional, it can be implemented by bridges that
731 * set the @DRM_BRIDGE_OP_HDMI_AUDIO flag in their &drm_bridge->ops.
732 *
733 * Returns:
734 * 0 on success, a negative error code otherwise
735 */
736 int (*hdmi_audio_mute_stream)(struct drm_connector *connector,
737 struct drm_bridge *bridge,
738 bool enable, int direction);
739
740 /**
741 * @dp_audio_startup:
742 *
743 * Called when ASoC starts a DisplayPort audio stream setup.
744 *
745 * This callback is optional, it can be implemented by bridges that
746 * set the @DRM_BRIDGE_OP_DP_AUDIO flag in their &drm_bridge->ops.
747 *
748 * Returns:
749 * 0 on success, a negative error code otherwise
750 */
751 int (*dp_audio_startup)(struct drm_connector *connector,
752 struct drm_bridge *bridge);
753
754 /**
755 * @dp_audio_prepare:
756 * Configures DisplayPort audio stream. Can be called multiple
757 * times for each setup.
758 *
759 * This callback is optional but it must be implemented by bridges that
760 * set the @DRM_BRIDGE_OP_DP_AUDIO flag in their &drm_bridge->ops.
761 *
762 * Returns:
763 * 0 on success, a negative error code otherwise
764 */
765 int (*dp_audio_prepare)(struct drm_connector *connector,
766 struct drm_bridge *bridge,
767 struct hdmi_codec_daifmt *fmt,
768 struct hdmi_codec_params *hparms);
769
770 /**
771 * @dp_audio_shutdown:
772 *
773 * Shut down the DisplayPort audio stream.
774 *
775 * This callback is optional but it must be implemented by bridges that
776 * set the @DRM_BRIDGE_OP_DP_AUDIO flag in their &drm_bridge->ops.
777 *
778 * Returns:
779 * 0 on success, a negative error code otherwise
780 */
781 void (*dp_audio_shutdown)(struct drm_connector *connector,
782 struct drm_bridge *bridge);
783
784 /**
785 * @dp_audio_mute_stream:
786 *
787 * Mute/unmute DisplayPort audio stream.
788 *
789 * This callback is optional, it can be implemented by bridges that
790 * set the @DRM_BRIDGE_OP_DP_AUDIO flag in their &drm_bridge->ops.
791 *
792 * Returns:
793 * 0 on success, a negative error code otherwise
794 */
795 int (*dp_audio_mute_stream)(struct drm_connector *connector,
796 struct drm_bridge *bridge,
797 bool enable, int direction);
798
799 /**
800 * @debugfs_init:
801 *
802 * Allows bridges to create bridge-specific debugfs files.
803 */
804 void (*debugfs_init)(struct drm_bridge *bridge, struct dentry *root);
805};
806
807/**
808 * struct drm_bridge_timings - timing information for the bridge
809 */
810struct drm_bridge_timings {
811 /**
812 * @input_bus_flags:
813 *
814 * Tells what additional settings for the pixel data on the bus
815 * this bridge requires (like pixel signal polarity). See also
816 * &drm_display_info->bus_flags.
817 */
818 u32 input_bus_flags;
819 /**
820 * @setup_time_ps:
821 *
822 * Defines the time in picoseconds the input data lines must be
823 * stable before the clock edge.
824 */
825 u32 setup_time_ps;
826 /**
827 * @hold_time_ps:
828 *
829 * Defines the time in picoseconds taken for the bridge to sample the
830 * input signal after the clock edge.
831 */
832 u32 hold_time_ps;
833 /**
834 * @dual_link:
835 *
836 * True if the bus operates in dual-link mode. The exact meaning is
837 * dependent on the bus type. For LVDS buses, this indicates that even-
838 * and odd-numbered pixels are received on separate links.
839 */
840 bool dual_link;
841};
842
843/**
844 * enum drm_bridge_ops - Bitmask of operations supported by the bridge
845 */
846enum drm_bridge_ops {
847 /**
848 * @DRM_BRIDGE_OP_DETECT: The bridge can detect displays connected to
849 * its output. Bridges that set this flag shall implement the
850 * &drm_bridge_funcs->detect callback.
851 */
852 DRM_BRIDGE_OP_DETECT = BIT(0),
853 /**
854 * @DRM_BRIDGE_OP_EDID: The bridge can retrieve the EDID of the display
855 * connected to its output. Bridges that set this flag shall implement
856 * the &drm_bridge_funcs->edid_read callback.
857 */
858 DRM_BRIDGE_OP_EDID = BIT(1),
859 /**
860 * @DRM_BRIDGE_OP_HPD: The bridge can detect hot-plug and hot-unplug
861 * without requiring polling. Bridges that set this flag shall
862 * implement the &drm_bridge_funcs->hpd_enable and
863 * &drm_bridge_funcs->hpd_disable callbacks if they support enabling
864 * and disabling hot-plug detection dynamically.
865 */
866 DRM_BRIDGE_OP_HPD = BIT(2),
867 /**
868 * @DRM_BRIDGE_OP_MODES: The bridge can retrieve the modes supported
869 * by the display at its output. This does not include reading EDID
870 * which is separately covered by @DRM_BRIDGE_OP_EDID. Bridges that set
871 * this flag shall implement the &drm_bridge_funcs->get_modes callback.
872 */
873 DRM_BRIDGE_OP_MODES = BIT(3),
874 /**
875 * @DRM_BRIDGE_OP_HDMI: The bridge provides HDMI connector operations,
876 * including infoframes support. Bridges that set this flag must
877 * implement the &drm_bridge_funcs->write_infoframe callback.
878 *
879 * Note: currently there can be at most one bridge in a chain that sets
880 * this bit. This is to simplify corresponding glue code in connector
881 * drivers.
882 */
883 DRM_BRIDGE_OP_HDMI = BIT(4),
884 /**
885 * @DRM_BRIDGE_OP_HDMI_AUDIO: The bridge provides HDMI audio operations.
886 * Bridges that set this flag must implement the
887 * &drm_bridge_funcs->hdmi_audio_prepare and
888 * &drm_bridge_funcs->hdmi_audio_shutdown callbacks.
889 *
890 * Note: currently there can be at most one bridge in a chain that sets
891 * this bit. This is to simplify corresponding glue code in connector
892 * drivers. Also it is not possible to have a bridge in the chain that
893 * sets @DRM_BRIDGE_OP_DP_AUDIO if there is a bridge that sets this
894 * flag.
895 */
896 DRM_BRIDGE_OP_HDMI_AUDIO = BIT(5),
897 /**
898 * @DRM_BRIDGE_OP_DP_AUDIO: The bridge provides DisplayPort audio operations.
899 * Bridges that set this flag must implement the
900 * &drm_bridge_funcs->dp_audio_prepare and
901 * &drm_bridge_funcs->dp_audio_shutdown callbacks.
902 *
903 * Note: currently there can be at most one bridge in a chain that sets
904 * this bit. This is to simplify corresponding glue code in connector
905 * drivers. Also it is not possible to have a bridge in the chain that
906 * sets @DRM_BRIDGE_OP_HDMI_AUDIO if there is a bridge that sets this
907 * flag.
908 */
909 DRM_BRIDGE_OP_DP_AUDIO = BIT(6),
910};
911
912/**
913 * struct drm_bridge - central DRM bridge control structure
914 */
915struct drm_bridge {
916 /** @base: inherit from &drm_private_object */
917 struct drm_private_obj base;
918 /** @dev: DRM device this bridge belongs to */
919 struct drm_device *dev;
920 /** @encoder: encoder to which this bridge is connected */
921 struct drm_encoder *encoder;
922 /** @chain_node: used to form a bridge chain */
923 struct list_head chain_node;
924 /** @of_node: device node pointer to the bridge */
925 struct device_node *of_node;
926 /** @list: to keep track of all added bridges */
927 struct list_head list;
928 /**
929 * @timings:
930 *
931 * the timing specification for the bridge, if any (may be NULL)
932 */
933 const struct drm_bridge_timings *timings;
934 /** @funcs: control functions */
935 const struct drm_bridge_funcs *funcs;
936
937 /**
938 * @container: Pointer to the private driver struct embedding this
939 * @struct drm_bridge.
940 */
941 void *container;
942
943 /**
944 * @refcount: reference count of users referencing this bridge.
945 */
946 struct kref refcount;
947
948 /** @driver_private: pointer to the bridge driver's internal context */
949 void *driver_private;
950 /** @ops: bitmask of operations supported by the bridge */
951 enum drm_bridge_ops ops;
952 /**
953 * @type: Type of the connection at the bridge output
954 * (DRM_MODE_CONNECTOR_*). For bridges at the end of this chain this
955 * identifies the type of connected display.
956 */
957 int type;
958 /**
959 * @interlace_allowed: Indicate that the bridge can handle interlaced
960 * modes.
961 */
962 bool interlace_allowed;
963 /**
964 * @ycbcr_420_allowed: Indicate that the bridge can handle YCbCr 420
965 * output.
966 */
967 bool ycbcr_420_allowed;
968 /**
969 * @pre_enable_prev_first: The bridge requires that the prev
970 * bridge @pre_enable function is called before its @pre_enable,
971 * and conversely for post_disable. This is most frequently a
972 * requirement for DSI devices which need the host to be initialised
973 * before the peripheral.
974 */
975 bool pre_enable_prev_first;
976 /**
977 * @ddc: Associated I2C adapter for DDC access, if any.
978 */
979 struct i2c_adapter *ddc;
980 /** private: */
981 /**
982 * @hpd_mutex: Protects the @hpd_cb and @hpd_data fields.
983 */
984 struct mutex hpd_mutex;
985 /**
986 * @hpd_cb: Hot plug detection callback, registered with
987 * drm_bridge_hpd_enable().
988 */
989 void (*hpd_cb)(void *data, enum drm_connector_status status);
990 /**
991 * @hpd_data: Private data passed to the Hot plug detection callback
992 * @hpd_cb.
993 */
994 void *hpd_data;
995
996 /**
997 * @vendor: Vendor of the product to be used for the SPD InfoFrame
998 * generation. This is required if @DRM_BRIDGE_OP_HDMI is set.
999 */
1000 const char *vendor;
1001
1002 /**
1003 * @product: Name of the product to be used for the SPD InfoFrame
1004 * generation. This is required if @DRM_BRIDGE_OP_HDMI is set.
1005 */
1006 const char *product;
1007
1008 /**
1009 * @supported_formats: Bitmask of @hdmi_colorspace listing supported
1010 * output formats. This is only relevant if @DRM_BRIDGE_OP_HDMI is set.
1011 */
1012 unsigned int supported_formats;
1013
1014 /**
1015 * @max_bpc: Maximum bits per char the HDMI bridge supports. Allowed
1016 * values are 8, 10 and 12. This is only relevant if
1017 * @DRM_BRIDGE_OP_HDMI is set.
1018 */
1019 unsigned int max_bpc;
1020
1021 /**
1022 * @hdmi_audio_dev: device to be used as a parent for the HDMI Codec if
1023 * either of @DRM_BRIDGE_OP_HDMI_AUDIO or @DRM_BRIDGE_OP_DP_AUDIO is set.
1024 */
1025 struct device *hdmi_audio_dev;
1026
1027 /**
1028 * @hdmi_audio_max_i2s_playback_channels: maximum number of playback
1029 * I2S channels for the @DRM_BRIDGE_OP_HDMI_AUDIO or
1030 * @DRM_BRIDGE_OP_DP_AUDIO.
1031 */
1032 int hdmi_audio_max_i2s_playback_channels;
1033
1034 /**
1035 * @hdmi_audio_spdif_playback: set if this bridge has S/PDIF playback
1036 * port for @DRM_BRIDGE_OP_HDMI_AUDIO or @DRM_BRIDGE_OP_DP_AUDIO.
1037 */
1038 unsigned int hdmi_audio_spdif_playback : 1;
1039
1040 /**
1041 * @hdmi_audio_dai_port: sound DAI port for either of
1042 * @DRM_BRIDGE_OP_HDMI_AUDIO and @DRM_BRIDGE_OP_DP_AUDIO, -1 if it is
1043 * not used.
1044 */
1045 int hdmi_audio_dai_port;
1046};
1047
1048static inline struct drm_bridge *
1049drm_priv_to_bridge(struct drm_private_obj *priv)
1050{
1051 return container_of(priv, struct drm_bridge, base);
1052}
1053
1054struct drm_bridge *drm_bridge_get(struct drm_bridge *bridge);
1055void drm_bridge_put(struct drm_bridge *bridge);
1056
1057void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset,
1058 const struct drm_bridge_funcs *funcs);
1059
1060/**
1061 * devm_drm_bridge_alloc - Allocate and initialize a bridge
1062 * @dev: struct device of the bridge device
1063 * @type: the type of the struct which contains struct &drm_bridge
1064 * @member: the name of the &drm_bridge within @type
1065 * @funcs: callbacks for this bridge
1066 *
1067 * The reference count of the returned bridge is initialized to 1. This
1068 * reference will be automatically dropped via devm (by calling
1069 * drm_bridge_put()) when @dev is removed.
1070 *
1071 * Returns:
1072 * Pointer to new bridge, or ERR_PTR on failure.
1073 */
1074#define devm_drm_bridge_alloc(dev, type, member, funcs) \
1075 ((type *)__devm_drm_bridge_alloc(dev, sizeof(type), \
1076 offsetof(type, member), funcs))
1077
1078void drm_bridge_add(struct drm_bridge *bridge);
1079int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge);
1080void drm_bridge_remove(struct drm_bridge *bridge);
1081int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
1082 struct drm_bridge *previous,
1083 enum drm_bridge_attach_flags flags);
1084
1085#ifdef CONFIG_OF
1086struct drm_bridge *of_drm_find_bridge(struct device_node *np);
1087#else
1088static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np)
1089{
1090 return NULL;
1091}
1092#endif
1093
1094/**
1095 * drm_bridge_get_current_state() - Get the current bridge state
1096 * @bridge: bridge object
1097 *
1098 * This function must be called with the modeset lock held.
1099 *
1100 * RETURNS:
1101 *
1102 * The current bridge state, or NULL if there is none.
1103 */
1104static inline struct drm_bridge_state *
1105drm_bridge_get_current_state(struct drm_bridge *bridge)
1106{
1107 if (!bridge)
1108 return NULL;
1109
1110 /*
1111 * Only atomic bridges will have bridge->base initialized by
1112 * drm_atomic_private_obj_init(), so we need to make sure we're
1113 * working with one before we try to use the lock.
1114 */
1115 if (!bridge->funcs || !bridge->funcs->atomic_reset)
1116 return NULL;
1117
1118 drm_modeset_lock_assert_held(lock: &bridge->base.lock);
1119
1120 if (!bridge->base.state)
1121 return NULL;
1122
1123 return drm_priv_to_bridge_state(priv: bridge->base.state);
1124}
1125
1126/**
1127 * drm_bridge_get_next_bridge() - Get the next bridge in the chain
1128 * @bridge: bridge object
1129 *
1130 * RETURNS:
1131 * the next bridge in the chain after @bridge, or NULL if @bridge is the last.
1132 */
1133static inline struct drm_bridge *
1134drm_bridge_get_next_bridge(struct drm_bridge *bridge)
1135{
1136 if (list_is_last(list: &bridge->chain_node, head: &bridge->encoder->bridge_chain))
1137 return NULL;
1138
1139 return list_next_entry(bridge, chain_node);
1140}
1141
1142/**
1143 * drm_bridge_get_prev_bridge() - Get the previous bridge in the chain
1144 * @bridge: bridge object
1145 *
1146 * RETURNS:
1147 * the previous bridge in the chain, or NULL if @bridge is the first.
1148 */
1149static inline struct drm_bridge *
1150drm_bridge_get_prev_bridge(struct drm_bridge *bridge)
1151{
1152 if (list_is_first(list: &bridge->chain_node, head: &bridge->encoder->bridge_chain))
1153 return NULL;
1154
1155 return list_prev_entry(bridge, chain_node);
1156}
1157
1158/**
1159 * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
1160 * @encoder: encoder object
1161 *
1162 * RETURNS:
1163 * the first bridge in the chain, or NULL if @encoder has no bridge attached
1164 * to it.
1165 */
1166static inline struct drm_bridge *
1167drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
1168{
1169 return list_first_entry_or_null(&encoder->bridge_chain,
1170 struct drm_bridge, chain_node);
1171}
1172
1173/**
1174 * drm_for_each_bridge_in_chain() - Iterate over all bridges present in a chain
1175 * @encoder: the encoder to iterate bridges on
1176 * @bridge: a bridge pointer updated to point to the current bridge at each
1177 * iteration
1178 *
1179 * Iterate over all bridges present in the bridge chain attached to @encoder.
1180 */
1181#define drm_for_each_bridge_in_chain(encoder, bridge) \
1182 list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)
1183
1184enum drm_mode_status
1185drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
1186 const struct drm_display_info *info,
1187 const struct drm_display_mode *mode);
1188void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
1189 const struct drm_display_mode *mode,
1190 const struct drm_display_mode *adjusted_mode);
1191
1192int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
1193 struct drm_crtc_state *crtc_state,
1194 struct drm_connector_state *conn_state);
1195void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
1196 struct drm_atomic_state *state);
1197void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
1198 struct drm_atomic_state *state);
1199void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
1200 struct drm_atomic_state *state);
1201void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
1202 struct drm_atomic_state *state);
1203
1204u32 *
1205drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
1206 struct drm_bridge_state *bridge_state,
1207 struct drm_crtc_state *crtc_state,
1208 struct drm_connector_state *conn_state,
1209 u32 output_fmt,
1210 unsigned int *num_input_fmts);
1211
1212enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
1213int drm_bridge_get_modes(struct drm_bridge *bridge,
1214 struct drm_connector *connector);
1215const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge,
1216 struct drm_connector *connector);
1217void drm_bridge_hpd_enable(struct drm_bridge *bridge,
1218 void (*cb)(void *data,
1219 enum drm_connector_status status),
1220 void *data);
1221void drm_bridge_hpd_disable(struct drm_bridge *bridge);
1222void drm_bridge_hpd_notify(struct drm_bridge *bridge,
1223 enum drm_connector_status status);
1224
1225#ifdef CONFIG_DRM_PANEL_BRIDGE
1226bool drm_bridge_is_panel(const struct drm_bridge *bridge);
1227struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
1228struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
1229 u32 connector_type);
1230void drm_panel_bridge_remove(struct drm_bridge *bridge);
1231int drm_panel_bridge_set_orientation(struct drm_connector *connector,
1232 struct drm_bridge *bridge);
1233struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
1234 struct drm_panel *panel);
1235struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
1236 struct drm_panel *panel,
1237 u32 connector_type);
1238struct drm_bridge *drmm_panel_bridge_add(struct drm_device *drm,
1239 struct drm_panel *panel);
1240struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge);
1241#else
1242static inline bool drm_bridge_is_panel(const struct drm_bridge *bridge)
1243{
1244 return false;
1245}
1246
1247static inline int drm_panel_bridge_set_orientation(struct drm_connector *connector,
1248 struct drm_bridge *bridge)
1249{
1250 return -EINVAL;
1251}
1252#endif
1253
1254#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
1255struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
1256 u32 port, u32 endpoint);
1257struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, struct device_node *node,
1258 u32 port, u32 endpoint);
1259#else
1260static inline struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
1261 struct device_node *node,
1262 u32 port,
1263 u32 endpoint)
1264{
1265 return ERR_PTR(-ENODEV);
1266}
1267
1268static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
1269 struct device_node *node,
1270 u32 port,
1271 u32 endpoint)
1272{
1273 return ERR_PTR(-ENODEV);
1274}
1275#endif
1276
1277void drm_bridge_debugfs_params(struct dentry *root);
1278void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
1279
1280#endif
1281

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source code of linux/include/drm/drm_bridge.h