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
35 struct drm_bridge;
36 struct drm_bridge_timings;
37 struct drm_connector;
38 struct drm_display_info;
39 struct drm_panel;
40 struct edid;
41 struct i2c_adapter;
42
43 /**
44 * enum drm_bridge_attach_flags - Flags for &drm_bridge_funcs.attach
45 */
46 enum drm_bridge_attach_flags {
47 /**
48 * @DRM_BRIDGE_ATTACH_NO_CONNECTOR: When this flag is set the bridge
49 * shall not create a drm_connector.
50 */
51 DRM_BRIDGE_ATTACH_NO_CONNECTOR = BIT(0),
52 };
53
54 /**
55 * struct drm_bridge_funcs - drm_bridge control functions
56 */
57 struct drm_bridge_funcs {
58 /**
59 * @attach:
60 *
61 * This callback is invoked whenever our bridge is being attached to a
62 * &drm_encoder. The flags argument tunes the behaviour of the attach
63 * operation (see DRM_BRIDGE_ATTACH_*).
64 *
65 * The @attach callback is optional.
66 *
67 * RETURNS:
68 *
69 * Zero on success, error code on failure.
70 */
71 int (*attach)(struct drm_bridge *bridge,
72 enum drm_bridge_attach_flags flags);
73
74 /**
75 * @detach:
76 *
77 * This callback is invoked whenever our bridge is being detached from a
78 * &drm_encoder.
79 *
80 * The @detach callback is optional.
81 */
82 void (*detach)(struct drm_bridge *bridge);
83
84 /**
85 * @mode_valid:
86 *
87 * This callback is used to check if a specific mode is valid in this
88 * bridge. This should be implemented if the bridge has some sort of
89 * restriction in the modes it can display. For example, a given bridge
90 * may be responsible to set a clock value. If the clock can not
91 * produce all the values for the available modes then this callback
92 * can be used to restrict the number of modes to only the ones that
93 * can be displayed.
94 *
95 * This hook is used by the probe helpers to filter the mode list in
96 * drm_helper_probe_single_connector_modes(), and it is used by the
97 * atomic helpers to validate modes supplied by userspace in
98 * drm_atomic_helper_check_modeset().
99 *
100 * The @mode_valid callback is optional.
101 *
102 * NOTE:
103 *
104 * Since this function is both called from the check phase of an atomic
105 * commit, and the mode validation in the probe paths it is not allowed
106 * to look at anything else but the passed-in mode, and validate it
107 * against configuration-invariant hardward constraints. Any further
108 * limits which depend upon the configuration can only be checked in
109 * @mode_fixup.
110 *
111 * RETURNS:
112 *
113 * drm_mode_status Enum
114 */
115 enum drm_mode_status (*mode_valid)(struct drm_bridge *bridge,
116 const struct drm_display_info *info,
117 const struct drm_display_mode *mode);
118
119 /**
120 * @mode_fixup:
121 *
122 * This callback is used to validate and adjust a mode. The parameter
123 * mode is the display mode that should be fed to the next element in
124 * the display chain, either the final &drm_connector or the next
125 * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
126 * requires. It can be modified by this callback and does not need to
127 * match mode. See also &drm_crtc_state.adjusted_mode for more details.
128 *
129 * This is the only hook that allows a bridge to reject a modeset. If
130 * this function passes all other callbacks must succeed for this
131 * configuration.
132 *
133 * The mode_fixup callback is optional. &drm_bridge_funcs.mode_fixup()
134 * is not called when &drm_bridge_funcs.atomic_check() is implemented,
135 * so only one of them should be provided.
136 *
137 * NOTE:
138 *
139 * This function is called in the check phase of atomic modesets, which
140 * can be aborted for any reason (including on userspace's request to
141 * just check whether a configuration would be possible). Drivers MUST
142 * NOT touch any persistent state (hardware or software) or data
143 * structures except the passed in @state parameter.
144 *
145 * Also beware that userspace can request its own custom modes, neither
146 * core nor helpers filter modes to the list of probe modes reported by
147 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
148 * that modes are filtered consistently put any bridge constraints and
149 * limits checks into @mode_valid.
150 *
151 * RETURNS:
152 *
153 * True if an acceptable configuration is possible, false if the modeset
154 * operation should be rejected.
155 */
156 bool (*mode_fixup)(struct drm_bridge *bridge,
157 const struct drm_display_mode *mode,
158 struct drm_display_mode *adjusted_mode);
159 /**
160 * @disable:
161 *
162 * This callback should disable the bridge. It is called right before
163 * the preceding element in the display pipe is disabled. If the
164 * preceding element is a bridge this means it's called before that
165 * bridge's @disable vfunc. If the preceding element is a &drm_encoder
166 * it's called right before the &drm_encoder_helper_funcs.disable,
167 * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
168 * hook.
169 *
170 * The bridge can assume that the display pipe (i.e. clocks and timing
171 * signals) feeding it is still running when this callback is called.
172 *
173 * The @disable callback is optional.
174 */
175 void (*disable)(struct drm_bridge *bridge);
176
177 /**
178 * @post_disable:
179 *
180 * This callback should disable the bridge. It is called right after the
181 * preceding element in the display pipe is disabled. If the preceding
182 * element is a bridge this means it's called after that bridge's
183 * @post_disable function. If the preceding element is a &drm_encoder
184 * it's called right after the encoder's
185 * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
186 * or &drm_encoder_helper_funcs.dpms hook.
187 *
188 * The bridge must assume that the display pipe (i.e. clocks and timing
189 * singals) feeding it is no longer running when this callback is
190 * called.
191 *
192 * The @post_disable callback is optional.
193 */
194 void (*post_disable)(struct drm_bridge *bridge);
195
196 /**
197 * @mode_set:
198 *
199 * This callback should set the given mode on the bridge. It is called
200 * after the @mode_set callback for the preceding element in the display
201 * pipeline has been called already. If the bridge is the first element
202 * then this would be &drm_encoder_helper_funcs.mode_set. The display
203 * pipe (i.e. clocks and timing signals) is off when this function is
204 * called.
205 *
206 * The adjusted_mode parameter is the mode output by the CRTC for the
207 * first bridge in the chain. It can be different from the mode
208 * parameter that contains the desired mode for the connector at the end
209 * of the bridges chain, for instance when the first bridge in the chain
210 * performs scaling. The adjusted mode is mostly useful for the first
211 * bridge in the chain and is likely irrelevant for the other bridges.
212 *
213 * For atomic drivers the adjusted_mode is the mode stored in
214 * &drm_crtc_state.adjusted_mode.
215 *
216 * NOTE:
217 *
218 * If a need arises to store and access modes adjusted for other
219 * locations than the connection between the CRTC and the first bridge,
220 * the DRM framework will have to be extended with DRM bridge states.
221 */
222 void (*mode_set)(struct drm_bridge *bridge,
223 const struct drm_display_mode *mode,
224 const struct drm_display_mode *adjusted_mode);
225 /**
226 * @pre_enable:
227 *
228 * This callback should enable the bridge. It is called right before
229 * the preceding element in the display pipe is enabled. If the
230 * preceding element is a bridge this means it's called before that
231 * bridge's @pre_enable function. If the preceding element is a
232 * &drm_encoder it's called right before the encoder's
233 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
234 * &drm_encoder_helper_funcs.dpms hook.
235 *
236 * The display pipe (i.e. clocks and timing signals) feeding this bridge
237 * will not yet be running when this callback is called. The bridge must
238 * not enable the display link feeding the next bridge in the chain (if
239 * there is one) when this callback is called.
240 *
241 * The @pre_enable callback is optional.
242 */
243 void (*pre_enable)(struct drm_bridge *bridge);
244
245 /**
246 * @enable:
247 *
248 * This callback should enable the bridge. It is called right after
249 * the preceding element in the display pipe is enabled. If the
250 * preceding element is a bridge this means it's called after that
251 * bridge's @enable function. If the preceding element is a
252 * &drm_encoder it's called right after the encoder's
253 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
254 * &drm_encoder_helper_funcs.dpms hook.
255 *
256 * The bridge can assume that the display pipe (i.e. clocks and timing
257 * signals) feeding it is running when this callback is called. This
258 * callback must enable the display link feeding the next bridge in the
259 * chain if there is one.
260 *
261 * The @enable callback is optional.
262 */
263 void (*enable)(struct drm_bridge *bridge);
264
265 /**
266 * @atomic_pre_enable:
267 *
268 * This callback should enable the bridge. It is called right before
269 * the preceding element in the display pipe is enabled. If the
270 * preceding element is a bridge this means it's called before that
271 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
272 * element is a &drm_encoder it's called right before the encoder's
273 * &drm_encoder_helper_funcs.atomic_enable hook.
274 *
275 * The display pipe (i.e. clocks and timing signals) feeding this bridge
276 * will not yet be running when this callback is called. The bridge must
277 * not enable the display link feeding the next bridge in the chain (if
278 * there is one) when this callback is called.
279 *
280 * Note that this function will only be invoked in the context of an
281 * atomic commit. It will not be invoked from
282 * &drm_bridge_chain_pre_enable. It would be prudent to also provide an
283 * implementation of @pre_enable if you are expecting driver calls into
284 * &drm_bridge_chain_pre_enable.
285 *
286 * The @atomic_pre_enable callback is optional.
287 */
288 void (*atomic_pre_enable)(struct drm_bridge *bridge,
289 struct drm_bridge_state *old_bridge_state);
290
291 /**
292 * @atomic_enable:
293 *
294 * This callback should enable the bridge. It is called right after
295 * the preceding element in the display pipe is enabled. If the
296 * preceding element is a bridge this means it's called after that
297 * bridge's @atomic_enable or @enable function. If the preceding element
298 * is a &drm_encoder it's called right after the encoder's
299 * &drm_encoder_helper_funcs.atomic_enable hook.
300 *
301 * The bridge can assume that the display pipe (i.e. clocks and timing
302 * signals) feeding it is running when this callback is called. This
303 * callback must enable the display link feeding the next bridge in the
304 * chain if there is one.
305 *
306 * Note that this function will only be invoked in the context of an
307 * atomic commit. It will not be invoked from &drm_bridge_chain_enable.
308 * It would be prudent to also provide an implementation of @enable if
309 * you are expecting driver calls into &drm_bridge_chain_enable.
310 *
311 * The @atomic_enable callback is optional.
312 */
313 void (*atomic_enable)(struct drm_bridge *bridge,
314 struct drm_bridge_state *old_bridge_state);
315 /**
316 * @atomic_disable:
317 *
318 * This callback should disable the bridge. It is called right before
319 * the preceding element in the display pipe is disabled. If the
320 * preceding element is a bridge this means it's called before that
321 * bridge's @atomic_disable or @disable vfunc. If the preceding element
322 * is a &drm_encoder it's called right before the
323 * &drm_encoder_helper_funcs.atomic_disable hook.
324 *
325 * The bridge can assume that the display pipe (i.e. clocks and timing
326 * signals) feeding it is still running when this callback is called.
327 *
328 * Note that this function will only be invoked in the context of an
329 * atomic commit. It will not be invoked from
330 * &drm_bridge_chain_disable. It would be prudent to also provide an
331 * implementation of @disable if you are expecting driver calls into
332 * &drm_bridge_chain_disable.
333 *
334 * The @atomic_disable callback is optional.
335 */
336 void (*atomic_disable)(struct drm_bridge *bridge,
337 struct drm_bridge_state *old_bridge_state);
338
339 /**
340 * @atomic_post_disable:
341 *
342 * This callback should disable the bridge. It is called right after the
343 * preceding element in the display pipe is disabled. If the preceding
344 * element is a bridge this means it's called after that bridge's
345 * @atomic_post_disable or @post_disable function. If the preceding
346 * element is a &drm_encoder it's called right after the encoder's
347 * &drm_encoder_helper_funcs.atomic_disable hook.
348 *
349 * The bridge must assume that the display pipe (i.e. clocks and timing
350 * signals) feeding it is no longer running when this callback is
351 * called.
352 *
353 * Note that this function will only be invoked in the context of an
354 * atomic commit. It will not be invoked from
355 * &drm_bridge_chain_post_disable.
356 * It would be prudent to also provide an implementation of
357 * @post_disable if you are expecting driver calls into
358 * &drm_bridge_chain_post_disable.
359 *
360 * The @atomic_post_disable callback is optional.
361 */
362 void (*atomic_post_disable)(struct drm_bridge *bridge,
363 struct drm_bridge_state *old_bridge_state);
364
365 /**
366 * @atomic_duplicate_state:
367 *
368 * Duplicate the current bridge state object (which is guaranteed to be
369 * non-NULL).
370 *
371 * The atomic_duplicate_state hook is mandatory if the bridge
372 * implements any of the atomic hooks, and should be left unassigned
373 * otherwise. For bridges that don't subclass &drm_bridge_state, the
374 * drm_atomic_helper_bridge_duplicate_state() helper function shall be
375 * used to implement this hook.
376 *
377 * RETURNS:
378 * A valid drm_bridge_state object or NULL if the allocation fails.
379 */
380 struct drm_bridge_state *(*atomic_duplicate_state)(struct drm_bridge *bridge);
381
382 /**
383 * @atomic_destroy_state:
384 *
385 * Destroy a bridge state object previously allocated by
386 * &drm_bridge_funcs.atomic_duplicate_state().
387 *
388 * The atomic_destroy_state hook is mandatory if the bridge implements
389 * any of the atomic hooks, and should be left unassigned otherwise.
390 * For bridges that don't subclass &drm_bridge_state, the
391 * drm_atomic_helper_bridge_destroy_state() helper function shall be
392 * used to implement this hook.
393 */
394 void (*atomic_destroy_state)(struct drm_bridge *bridge,
395 struct drm_bridge_state *state);
396
397 /**
398 * @atomic_get_output_bus_fmts:
399 *
400 * Return the supported bus formats on the output end of a bridge.
401 * The returned array must be allocated with kmalloc() and will be
402 * freed by the caller. If the allocation fails, NULL should be
403 * returned. num_output_fmts must be set to the returned array size.
404 * Formats listed in the returned array should be listed in decreasing
405 * preference order (the core will try all formats until it finds one
406 * that works).
407 *
408 * This method is only called on the last element of the bridge chain
409 * as part of the bus format negotiation process that happens in
410 * &drm_atomic_bridge_chain_select_bus_fmts().
411 * This method is optional. When not implemented, the core will
412 * fall back to &drm_connector.display_info.bus_formats[0] if
413 * &drm_connector.display_info.num_bus_formats > 0,
414 * or to MEDIA_BUS_FMT_FIXED otherwise.
415 */
416 u32 *(*atomic_get_output_bus_fmts)(struct drm_bridge *bridge,
417 struct drm_bridge_state *bridge_state,
418 struct drm_crtc_state *crtc_state,
419 struct drm_connector_state *conn_state,
420 unsigned int *num_output_fmts);
421
422 /**
423 * @atomic_get_input_bus_fmts:
424 *
425 * Return the supported bus formats on the input end of a bridge for
426 * a specific output bus format.
427 *
428 * The returned array must be allocated with kmalloc() and will be
429 * freed by the caller. If the allocation fails, NULL should be
430 * returned. num_output_fmts must be set to the returned array size.
431 * Formats listed in the returned array should be listed in decreasing
432 * preference order (the core will try all formats until it finds one
433 * that works). When the format is not supported NULL should be
434 * returned and num_output_fmts should be set to 0.
435 *
436 * This method is called on all elements of the bridge chain as part of
437 * the bus format negotiation process that happens in
438 * drm_atomic_bridge_chain_select_bus_fmts().
439 * This method is optional. When not implemented, the core will bypass
440 * bus format negotiation on this element of the bridge without
441 * failing, and the previous element in the chain will be passed
442 * MEDIA_BUS_FMT_FIXED as its output bus format.
443 *
444 * Bridge drivers that need to support being linked to bridges that are
445 * not supporting bus format negotiation should handle the
446 * output_fmt == MEDIA_BUS_FMT_FIXED case appropriately, by selecting a
447 * sensible default value or extracting this information from somewhere
448 * else (FW property, &drm_display_mode, &drm_display_info, ...)
449 *
450 * Note: Even if input format selection on the first bridge has no
451 * impact on the negotiation process (bus format negotiation stops once
452 * we reach the first element of the chain), drivers are expected to
453 * return accurate input formats as the input format may be used to
454 * configure the CRTC output appropriately.
455 */
456 u32 *(*atomic_get_input_bus_fmts)(struct drm_bridge *bridge,
457 struct drm_bridge_state *bridge_state,
458 struct drm_crtc_state *crtc_state,
459 struct drm_connector_state *conn_state,
460 u32 output_fmt,
461 unsigned int *num_input_fmts);
462
463 /**
464 * @atomic_check:
465 *
466 * This method is responsible for checking bridge state correctness.
467 * It can also check the state of the surrounding components in chain
468 * to make sure the whole pipeline can work properly.
469 *
470 * &drm_bridge_funcs.atomic_check() hooks are called in reverse
471 * order (from the last to the first bridge).
472 *
473 * This method is optional. &drm_bridge_funcs.mode_fixup() is not
474 * called when &drm_bridge_funcs.atomic_check() is implemented, so only
475 * one of them should be provided.
476 *
477 * If drivers need to tweak &drm_bridge_state.input_bus_cfg.flags or
478 * &drm_bridge_state.output_bus_cfg.flags it should happen in
479 * this function. By default the &drm_bridge_state.output_bus_cfg.flags
480 * field is set to the next bridge
481 * &drm_bridge_state.input_bus_cfg.flags value or
482 * &drm_connector.display_info.bus_flags if the bridge is the last
483 * element in the chain.
484 *
485 * RETURNS:
486 * zero if the check passed, a negative error code otherwise.
487 */
488 int (*atomic_check)(struct drm_bridge *bridge,
489 struct drm_bridge_state *bridge_state,
490 struct drm_crtc_state *crtc_state,
491 struct drm_connector_state *conn_state);
492
493 /**
494 * @atomic_reset:
495 *
496 * Reset the bridge to a predefined state (or retrieve its current
497 * state) and return a &drm_bridge_state object matching this state.
498 * This function is called at attach time.
499 *
500 * The atomic_reset hook is mandatory if the bridge implements any of
501 * the atomic hooks, and should be left unassigned otherwise. For
502 * bridges that don't subclass &drm_bridge_state, the
503 * drm_atomic_helper_bridge_reset() helper function shall be used to
504 * implement this hook.
505 *
506 * Note that the atomic_reset() semantics is not exactly matching the
507 * reset() semantics found on other components (connector, plane, ...).
508 *
509 * 1. The reset operation happens when the bridge is attached, not when
510 * drm_mode_config_reset() is called
511 * 2. It's meant to be used exclusively on bridges that have been
512 * converted to the ATOMIC API
513 *
514 * RETURNS:
515 * A valid drm_bridge_state object in case of success, an ERR_PTR()
516 * giving the reason of the failure otherwise.
517 */
518 struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
519
520 /**
521 * @detect:
522 *
523 * Check if anything is attached to the bridge output.
524 *
525 * This callback is optional, if not implemented the bridge will be
526 * considered as always having a component attached to its output.
527 * Bridges that implement this callback shall set the
528 * DRM_BRIDGE_OP_DETECT flag in their &drm_bridge->ops.
529 *
530 * RETURNS:
531 *
532 * drm_connector_status indicating the bridge output status.
533 */
534 enum drm_connector_status (*detect)(struct drm_bridge *bridge);
535
536 /**
537 * @get_modes:
538 *
539 * Fill all modes currently valid for the sink into the &drm_connector
540 * with drm_mode_probed_add().
541 *
542 * The @get_modes callback is mostly intended to support non-probeable
543 * displays such as many fixed panels. Bridges that support reading
544 * EDID shall leave @get_modes unimplemented and implement the
545 * &drm_bridge_funcs->get_edid callback instead.
546 *
547 * This callback is optional. Bridges that implement it shall set the
548 * DRM_BRIDGE_OP_MODES flag in their &drm_bridge->ops.
549 *
550 * The connector parameter shall be used for the sole purpose of
551 * filling modes, and shall not be stored internally by bridge drivers
552 * for future usage.
553 *
554 * RETURNS:
555 *
556 * The number of modes added by calling drm_mode_probed_add().
557 */
558 int (*get_modes)(struct drm_bridge *bridge,
559 struct drm_connector *connector);
560
561 /**
562 * @get_edid:
563 *
564 * Read and parse the EDID data of the connected display.
565 *
566 * The @get_edid callback is the preferred way of reporting mode
567 * information for a display connected to the bridge output. Bridges
568 * that support reading EDID shall implement this callback and leave
569 * the @get_modes callback unimplemented.
570 *
571 * The caller of this operation shall first verify the output
572 * connection status and refrain from reading EDID from a disconnected
573 * output.
574 *
575 * This callback is optional. Bridges that implement it shall set the
576 * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
577 *
578 * The connector parameter shall be used for the sole purpose of EDID
579 * retrieval and parsing, and shall not be stored internally by bridge
580 * drivers for future usage.
581 *
582 * RETURNS:
583 *
584 * An edid structure newly allocated with kmalloc() (or similar) on
585 * success, or NULL otherwise. The caller is responsible for freeing
586 * the returned edid structure with kfree().
587 */
588 struct edid *(*get_edid)(struct drm_bridge *bridge,
589 struct drm_connector *connector);
590
591 /**
592 * @hpd_notify:
593 *
594 * Notify the bridge of hot plug detection.
595 *
596 * This callback is optional, it may be implemented by bridges that
597 * need to be notified of display connection or disconnection for
598 * internal reasons. One use case is to reset the internal state of CEC
599 * controllers for HDMI bridges.
600 */
601 void (*hpd_notify)(struct drm_bridge *bridge,
602 enum drm_connector_status status);
603
604 /**
605 * @hpd_enable:
606 *
607 * Enable hot plug detection. From now on the bridge shall call
608 * drm_bridge_hpd_notify() each time a change is detected in the output
609 * connection status, until hot plug detection gets disabled with
610 * @hpd_disable.
611 *
612 * This callback is optional and shall only be implemented by bridges
613 * that support hot-plug notification without polling. Bridges that
614 * implement it shall also implement the @hpd_disable callback and set
615 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
616 */
617 void (*hpd_enable)(struct drm_bridge *bridge);
618
619 /**
620 * @hpd_disable:
621 *
622 * Disable hot plug detection. Once this function returns the bridge
623 * shall not call drm_bridge_hpd_notify() when a change in the output
624 * connection status occurs.
625 *
626 * This callback is optional and shall only be implemented by bridges
627 * that support hot-plug notification without polling. Bridges that
628 * implement it shall also implement the @hpd_enable callback and set
629 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
630 */
631 void (*hpd_disable)(struct drm_bridge *bridge);
632 };
633
634 /**
635 * struct drm_bridge_timings - timing information for the bridge
636 */
637 struct drm_bridge_timings {
638 /**
639 * @input_bus_flags:
640 *
641 * Tells what additional settings for the pixel data on the bus
642 * this bridge requires (like pixel signal polarity). See also
643 * &drm_display_info->bus_flags.
644 */
645 u32 input_bus_flags;
646 /**
647 * @setup_time_ps:
648 *
649 * Defines the time in picoseconds the input data lines must be
650 * stable before the clock edge.
651 */
652 u32 setup_time_ps;
653 /**
654 * @hold_time_ps:
655 *
656 * Defines the time in picoseconds taken for the bridge to sample the
657 * input signal after the clock edge.
658 */
659 u32 hold_time_ps;
660 /**
661 * @dual_link:
662 *
663 * True if the bus operates in dual-link mode. The exact meaning is
664 * dependent on the bus type. For LVDS buses, this indicates that even-
665 * and odd-numbered pixels are received on separate links.
666 */
667 bool dual_link;
668 };
669
670 /**
671 * enum drm_bridge_ops - Bitmask of operations supported by the bridge
672 */
673 enum drm_bridge_ops {
674 /**
675 * @DRM_BRIDGE_OP_DETECT: The bridge can detect displays connected to
676 * its output. Bridges that set this flag shall implement the
677 * &drm_bridge_funcs->detect callback.
678 */
679 DRM_BRIDGE_OP_DETECT = BIT(0),
680 /**
681 * @DRM_BRIDGE_OP_EDID: The bridge can retrieve the EDID of the display
682 * connected to its output. Bridges that set this flag shall implement
683 * the &drm_bridge_funcs->get_edid callback.
684 */
685 DRM_BRIDGE_OP_EDID = BIT(1),
686 /**
687 * @DRM_BRIDGE_OP_HPD: The bridge can detect hot-plug and hot-unplug
688 * without requiring polling. Bridges that set this flag shall
689 * implement the &drm_bridge_funcs->hpd_enable and
690 * &drm_bridge_funcs->hpd_disable callbacks if they support enabling
691 * and disabling hot-plug detection dynamically.
692 */
693 DRM_BRIDGE_OP_HPD = BIT(2),
694 /**
695 * @DRM_BRIDGE_OP_MODES: The bridge can retrieve the modes supported
696 * by the display at its output. This does not include reading EDID
697 * which is separately covered by @DRM_BRIDGE_OP_EDID. Bridges that set
698 * this flag shall implement the &drm_bridge_funcs->get_modes callback.
699 */
700 DRM_BRIDGE_OP_MODES = BIT(3),
701 };
702
703 /**
704 * struct drm_bridge - central DRM bridge control structure
705 */
706 struct drm_bridge {
707 /** @base: inherit from &drm_private_object */
708 struct drm_private_obj base;
709 /** @dev: DRM device this bridge belongs to */
710 struct drm_device *dev;
711 /** @encoder: encoder to which this bridge is connected */
712 struct drm_encoder *encoder;
713 /** @chain_node: used to form a bridge chain */
714 struct list_head chain_node;
715 #ifdef CONFIG_OF
716 /** @of_node: device node pointer to the bridge */
717 struct device_node *of_node;
718 #endif
719 /** @list: to keep track of all added bridges */
720 struct list_head list;
721 /**
722 * @timings:
723 *
724 * the timing specification for the bridge, if any (may be NULL)
725 */
726 const struct drm_bridge_timings *timings;
727 /** @funcs: control functions */
728 const struct drm_bridge_funcs *funcs;
729 /** @driver_private: pointer to the bridge driver's internal context */
730 void *driver_private;
731 /** @ops: bitmask of operations supported by the bridge */
732 enum drm_bridge_ops ops;
733 /**
734 * @type: Type of the connection at the bridge output
735 * (DRM_MODE_CONNECTOR_*). For bridges at the end of this chain this
736 * identifies the type of connected display.
737 */
738 int type;
739 /**
740 * @interlace_allowed: Indicate that the bridge can handle interlaced
741 * modes.
742 */
743 bool interlace_allowed;
744 /**
745 * @ddc: Associated I2C adapter for DDC access, if any.
746 */
747 struct i2c_adapter *ddc;
748 /** private: */
749 /**
750 * @hpd_mutex: Protects the @hpd_cb and @hpd_data fields.
751 */
752 struct mutex hpd_mutex;
753 /**
754 * @hpd_cb: Hot plug detection callback, registered with
755 * drm_bridge_hpd_enable().
756 */
757 void (*hpd_cb)(void *data, enum drm_connector_status status);
758 /**
759 * @hpd_data: Private data passed to the Hot plug detection callback
760 * @hpd_cb.
761 */
762 void *hpd_data;
763 };
764
765 static inline struct drm_bridge *
drm_priv_to_bridge(struct drm_private_obj * priv)766 drm_priv_to_bridge(struct drm_private_obj *priv)
767 {
768 return container_of(priv, struct drm_bridge, base);
769 }
770
771 void drm_bridge_add(struct drm_bridge *bridge);
772 void drm_bridge_remove(struct drm_bridge *bridge);
773 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
774 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
775 struct drm_bridge *previous,
776 enum drm_bridge_attach_flags flags);
777
778 /**
779 * drm_bridge_get_next_bridge() - Get the next bridge in the chain
780 * @bridge: bridge object
781 *
782 * RETURNS:
783 * the next bridge in the chain after @bridge, or NULL if @bridge is the last.
784 */
785 static inline struct drm_bridge *
drm_bridge_get_next_bridge(struct drm_bridge * bridge)786 drm_bridge_get_next_bridge(struct drm_bridge *bridge)
787 {
788 if (list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain))
789 return NULL;
790
791 return list_next_entry(bridge, chain_node);
792 }
793
794 /**
795 * drm_bridge_get_prev_bridge() - Get the previous bridge in the chain
796 * @bridge: bridge object
797 *
798 * RETURNS:
799 * the previous bridge in the chain, or NULL if @bridge is the first.
800 */
801 static inline struct drm_bridge *
drm_bridge_get_prev_bridge(struct drm_bridge * bridge)802 drm_bridge_get_prev_bridge(struct drm_bridge *bridge)
803 {
804 if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
805 return NULL;
806
807 return list_prev_entry(bridge, chain_node);
808 }
809
810 /**
811 * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
812 * @encoder: encoder object
813 *
814 * RETURNS:
815 * the first bridge in the chain, or NULL if @encoder has no bridge attached
816 * to it.
817 */
818 static inline struct drm_bridge *
drm_bridge_chain_get_first_bridge(struct drm_encoder * encoder)819 drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
820 {
821 return list_first_entry_or_null(&encoder->bridge_chain,
822 struct drm_bridge, chain_node);
823 }
824
825 /**
826 * drm_for_each_bridge_in_chain() - Iterate over all bridges present in a chain
827 * @encoder: the encoder to iterate bridges on
828 * @bridge: a bridge pointer updated to point to the current bridge at each
829 * iteration
830 *
831 * Iterate over all bridges present in the bridge chain attached to @encoder.
832 */
833 #define drm_for_each_bridge_in_chain(encoder, bridge) \
834 list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)
835
836 bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
837 const struct drm_display_mode *mode,
838 struct drm_display_mode *adjusted_mode);
839 enum drm_mode_status
840 drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
841 const struct drm_display_info *info,
842 const struct drm_display_mode *mode);
843 void drm_bridge_chain_disable(struct drm_bridge *bridge);
844 void drm_bridge_chain_post_disable(struct drm_bridge *bridge);
845 void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
846 const struct drm_display_mode *mode,
847 const struct drm_display_mode *adjusted_mode);
848 void drm_bridge_chain_pre_enable(struct drm_bridge *bridge);
849 void drm_bridge_chain_enable(struct drm_bridge *bridge);
850
851 int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
852 struct drm_crtc_state *crtc_state,
853 struct drm_connector_state *conn_state);
854 void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
855 struct drm_atomic_state *state);
856 void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
857 struct drm_atomic_state *state);
858 void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
859 struct drm_atomic_state *state);
860 void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
861 struct drm_atomic_state *state);
862
863 u32 *
864 drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
865 struct drm_bridge_state *bridge_state,
866 struct drm_crtc_state *crtc_state,
867 struct drm_connector_state *conn_state,
868 u32 output_fmt,
869 unsigned int *num_input_fmts);
870
871 enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
872 int drm_bridge_get_modes(struct drm_bridge *bridge,
873 struct drm_connector *connector);
874 struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
875 struct drm_connector *connector);
876 void drm_bridge_hpd_enable(struct drm_bridge *bridge,
877 void (*cb)(void *data,
878 enum drm_connector_status status),
879 void *data);
880 void drm_bridge_hpd_disable(struct drm_bridge *bridge);
881 void drm_bridge_hpd_notify(struct drm_bridge *bridge,
882 enum drm_connector_status status);
883
884 #ifdef CONFIG_DRM_PANEL_BRIDGE
885 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
886 struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
887 u32 connector_type);
888 void drm_panel_bridge_remove(struct drm_bridge *bridge);
889 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
890 struct drm_panel *panel);
891 struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
892 struct drm_panel *panel,
893 u32 connector_type);
894 struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge);
895 #endif
896
897 #endif
898