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 	 * NOTE:
176 	 *
177 	 * This is deprecated, do not use!
178 	 * New drivers shall use &drm_bridge_funcs.atomic_disable.
179 	 */
180 	void (*disable)(struct drm_bridge *bridge);
181 
182 	/**
183 	 * @post_disable:
184 	 *
185 	 * This callback should disable the bridge. It is called right after the
186 	 * preceding element in the display pipe is disabled. If the preceding
187 	 * element is a bridge this means it's called after that bridge's
188 	 * @post_disable function. If the preceding element is a &drm_encoder
189 	 * it's called right after the encoder's
190 	 * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
191 	 * or &drm_encoder_helper_funcs.dpms hook.
192 	 *
193 	 * The bridge must assume that the display pipe (i.e. clocks and timing
194 	 * singals) feeding it is no longer running when this callback is
195 	 * called.
196 	 *
197 	 * The @post_disable callback is optional.
198 	 *
199 	 * NOTE:
200 	 *
201 	 * This is deprecated, do not use!
202 	 * New drivers shall use &drm_bridge_funcs.atomic_post_disable.
203 	 */
204 	void (*post_disable)(struct drm_bridge *bridge);
205 
206 	/**
207 	 * @mode_set:
208 	 *
209 	 * This callback should set the given mode on the bridge. It is called
210 	 * after the @mode_set callback for the preceding element in the display
211 	 * pipeline has been called already. If the bridge is the first element
212 	 * then this would be &drm_encoder_helper_funcs.mode_set. The display
213 	 * pipe (i.e.  clocks and timing signals) is off when this function is
214 	 * called.
215 	 *
216 	 * The adjusted_mode parameter is the mode output by the CRTC for the
217 	 * first bridge in the chain. It can be different from the mode
218 	 * parameter that contains the desired mode for the connector at the end
219 	 * of the bridges chain, for instance when the first bridge in the chain
220 	 * performs scaling. The adjusted mode is mostly useful for the first
221 	 * bridge in the chain and is likely irrelevant for the other bridges.
222 	 *
223 	 * For atomic drivers the adjusted_mode is the mode stored in
224 	 * &drm_crtc_state.adjusted_mode.
225 	 *
226 	 * NOTE:
227 	 *
228 	 * This is deprecated, do not use!
229 	 * New drivers shall set their mode in the
230 	 * &drm_bridge_funcs.atomic_enable operation.
231 	 */
232 	void (*mode_set)(struct drm_bridge *bridge,
233 			 const struct drm_display_mode *mode,
234 			 const struct drm_display_mode *adjusted_mode);
235 	/**
236 	 * @pre_enable:
237 	 *
238 	 * This callback should enable the bridge. It is called right before
239 	 * the preceding element in the display pipe is enabled. If the
240 	 * preceding element is a bridge this means it's called before that
241 	 * bridge's @pre_enable function. If the preceding element is a
242 	 * &drm_encoder it's called right before the encoder's
243 	 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
244 	 * &drm_encoder_helper_funcs.dpms hook.
245 	 *
246 	 * The display pipe (i.e. clocks and timing signals) feeding this bridge
247 	 * will not yet be running when this callback is called. The bridge must
248 	 * not enable the display link feeding the next bridge in the chain (if
249 	 * there is one) when this callback is called.
250 	 *
251 	 * The @pre_enable callback is optional.
252 	 *
253 	 * NOTE:
254 	 *
255 	 * This is deprecated, do not use!
256 	 * New drivers shall use &drm_bridge_funcs.atomic_pre_enable.
257 	 */
258 	void (*pre_enable)(struct drm_bridge *bridge);
259 
260 	/**
261 	 * @enable:
262 	 *
263 	 * This callback should enable the bridge. It is called right after
264 	 * the preceding element in the display pipe is enabled. If the
265 	 * preceding element is a bridge this means it's called after that
266 	 * bridge's @enable function. If the preceding element is a
267 	 * &drm_encoder it's called right after the encoder's
268 	 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
269 	 * &drm_encoder_helper_funcs.dpms hook.
270 	 *
271 	 * The bridge can assume that the display pipe (i.e. clocks and timing
272 	 * signals) feeding it is running when this callback is called. This
273 	 * callback must enable the display link feeding the next bridge in the
274 	 * chain if there is one.
275 	 *
276 	 * The @enable callback is optional.
277 	 *
278 	 * NOTE:
279 	 *
280 	 * This is deprecated, do not use!
281 	 * New drivers shall use &drm_bridge_funcs.atomic_enable.
282 	 */
283 	void (*enable)(struct drm_bridge *bridge);
284 
285 	/**
286 	 * @atomic_pre_enable:
287 	 *
288 	 * This callback should enable the bridge. It is called right before
289 	 * the preceding element in the display pipe is enabled. If the
290 	 * preceding element is a bridge this means it's called before that
291 	 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
292 	 * element is a &drm_encoder it's called right before the encoder's
293 	 * &drm_encoder_helper_funcs.atomic_enable hook.
294 	 *
295 	 * The display pipe (i.e. clocks and timing signals) feeding this bridge
296 	 * will not yet be running when this callback is called. The bridge must
297 	 * not enable the display link feeding the next bridge in the chain (if
298 	 * there is one) when this callback is called.
299 	 *
300 	 * Note that this function will only be invoked in the context of an
301 	 * atomic commit. It will not be invoked from
302 	 * &drm_bridge_chain_pre_enable. It would be prudent to also provide an
303 	 * implementation of @pre_enable if you are expecting driver calls into
304 	 * &drm_bridge_chain_pre_enable.
305 	 *
306 	 * The @atomic_pre_enable callback is optional.
307 	 */
308 	void (*atomic_pre_enable)(struct drm_bridge *bridge,
309 				  struct drm_bridge_state *old_bridge_state);
310 
311 	/**
312 	 * @atomic_enable:
313 	 *
314 	 * This callback should enable the bridge. It is called right after
315 	 * the preceding element in the display pipe is enabled. If the
316 	 * preceding element is a bridge this means it's called after that
317 	 * bridge's @atomic_enable or @enable function. If the preceding element
318 	 * is a &drm_encoder it's called right after the encoder's
319 	 * &drm_encoder_helper_funcs.atomic_enable hook.
320 	 *
321 	 * The bridge can assume that the display pipe (i.e. clocks and timing
322 	 * signals) feeding it is running when this callback is called. This
323 	 * callback must enable the display link feeding the next bridge in the
324 	 * chain if there is one.
325 	 *
326 	 * Note that this function will only be invoked in the context of an
327 	 * atomic commit. It will not be invoked from &drm_bridge_chain_enable.
328 	 * It would be prudent to also provide an implementation of @enable if
329 	 * you are expecting driver calls into &drm_bridge_chain_enable.
330 	 *
331 	 * The @atomic_enable callback is optional.
332 	 */
333 	void (*atomic_enable)(struct drm_bridge *bridge,
334 			      struct drm_bridge_state *old_bridge_state);
335 	/**
336 	 * @atomic_disable:
337 	 *
338 	 * This callback should disable the bridge. It is called right before
339 	 * the preceding element in the display pipe is disabled. If the
340 	 * preceding element is a bridge this means it's called before that
341 	 * bridge's @atomic_disable or @disable vfunc. If the preceding element
342 	 * is a &drm_encoder it's called right before the
343 	 * &drm_encoder_helper_funcs.atomic_disable hook.
344 	 *
345 	 * The bridge can assume that the display pipe (i.e. clocks and timing
346 	 * signals) feeding it is still running when this callback is called.
347 	 *
348 	 * Note that this function will only be invoked in the context of an
349 	 * atomic commit. It will not be invoked from
350 	 * &drm_bridge_chain_disable. It would be prudent to also provide an
351 	 * implementation of @disable if you are expecting driver calls into
352 	 * &drm_bridge_chain_disable.
353 	 *
354 	 * The @atomic_disable callback is optional.
355 	 */
356 	void (*atomic_disable)(struct drm_bridge *bridge,
357 			       struct drm_bridge_state *old_bridge_state);
358 
359 	/**
360 	 * @atomic_post_disable:
361 	 *
362 	 * This callback should disable the bridge. It is called right after the
363 	 * preceding element in the display pipe is disabled. If the preceding
364 	 * element is a bridge this means it's called after that bridge's
365 	 * @atomic_post_disable or @post_disable function. If the preceding
366 	 * element is a &drm_encoder it's called right after the encoder's
367 	 * &drm_encoder_helper_funcs.atomic_disable hook.
368 	 *
369 	 * The bridge must assume that the display pipe (i.e. clocks and timing
370 	 * signals) feeding it is no longer running when this callback is
371 	 * called.
372 	 *
373 	 * Note that this function will only be invoked in the context of an
374 	 * atomic commit. It will not be invoked from
375 	 * &drm_bridge_chain_post_disable.
376 	 * It would be prudent to also provide an implementation of
377 	 * @post_disable if you are expecting driver calls into
378 	 * &drm_bridge_chain_post_disable.
379 	 *
380 	 * The @atomic_post_disable callback is optional.
381 	 */
382 	void (*atomic_post_disable)(struct drm_bridge *bridge,
383 				    struct drm_bridge_state *old_bridge_state);
384 
385 	/**
386 	 * @atomic_duplicate_state:
387 	 *
388 	 * Duplicate the current bridge state object (which is guaranteed to be
389 	 * non-NULL).
390 	 *
391 	 * The atomic_duplicate_state hook is mandatory if the bridge
392 	 * implements any of the atomic hooks, and should be left unassigned
393 	 * otherwise. For bridges that don't subclass &drm_bridge_state, the
394 	 * drm_atomic_helper_bridge_duplicate_state() helper function shall be
395 	 * used to implement this hook.
396 	 *
397 	 * RETURNS:
398 	 * A valid drm_bridge_state object or NULL if the allocation fails.
399 	 */
400 	struct drm_bridge_state *(*atomic_duplicate_state)(struct drm_bridge *bridge);
401 
402 	/**
403 	 * @atomic_destroy_state:
404 	 *
405 	 * Destroy a bridge state object previously allocated by
406 	 * &drm_bridge_funcs.atomic_duplicate_state().
407 	 *
408 	 * The atomic_destroy_state hook is mandatory if the bridge implements
409 	 * any of the atomic hooks, and should be left unassigned otherwise.
410 	 * For bridges that don't subclass &drm_bridge_state, the
411 	 * drm_atomic_helper_bridge_destroy_state() helper function shall be
412 	 * used to implement this hook.
413 	 */
414 	void (*atomic_destroy_state)(struct drm_bridge *bridge,
415 				     struct drm_bridge_state *state);
416 
417 	/**
418 	 * @atomic_get_output_bus_fmts:
419 	 *
420 	 * Return the supported bus formats on the output end of a bridge.
421 	 * The returned array must be allocated with kmalloc() and will be
422 	 * freed by the caller. If the allocation fails, NULL should be
423 	 * returned. num_output_fmts must be set to the returned array size.
424 	 * Formats listed in the returned array should be listed in decreasing
425 	 * preference order (the core will try all formats until it finds one
426 	 * that works).
427 	 *
428 	 * This method is only called on the last element of the bridge chain
429 	 * as part of the bus format negotiation process that happens in
430 	 * &drm_atomic_bridge_chain_select_bus_fmts().
431 	 * This method is optional. When not implemented, the core will
432 	 * fall back to &drm_connector.display_info.bus_formats[0] if
433 	 * &drm_connector.display_info.num_bus_formats > 0,
434 	 * or to MEDIA_BUS_FMT_FIXED otherwise.
435 	 */
436 	u32 *(*atomic_get_output_bus_fmts)(struct drm_bridge *bridge,
437 					   struct drm_bridge_state *bridge_state,
438 					   struct drm_crtc_state *crtc_state,
439 					   struct drm_connector_state *conn_state,
440 					   unsigned int *num_output_fmts);
441 
442 	/**
443 	 * @atomic_get_input_bus_fmts:
444 	 *
445 	 * Return the supported bus formats on the input end of a bridge for
446 	 * a specific output bus format.
447 	 *
448 	 * The returned array must be allocated with kmalloc() and will be
449 	 * freed by the caller. If the allocation fails, NULL should be
450 	 * returned. num_output_fmts must be set to the returned array size.
451 	 * Formats listed in the returned array should be listed in decreasing
452 	 * preference order (the core will try all formats until it finds one
453 	 * that works). When the format is not supported NULL should be
454 	 * returned and num_output_fmts should be set to 0.
455 	 *
456 	 * This method is called on all elements of the bridge chain as part of
457 	 * the bus format negotiation process that happens in
458 	 * drm_atomic_bridge_chain_select_bus_fmts().
459 	 * This method is optional. When not implemented, the core will bypass
460 	 * bus format negotiation on this element of the bridge without
461 	 * failing, and the previous element in the chain will be passed
462 	 * MEDIA_BUS_FMT_FIXED as its output bus format.
463 	 *
464 	 * Bridge drivers that need to support being linked to bridges that are
465 	 * not supporting bus format negotiation should handle the
466 	 * output_fmt == MEDIA_BUS_FMT_FIXED case appropriately, by selecting a
467 	 * sensible default value or extracting this information from somewhere
468 	 * else (FW property, &drm_display_mode, &drm_display_info, ...)
469 	 *
470 	 * Note: Even if input format selection on the first bridge has no
471 	 * impact on the negotiation process (bus format negotiation stops once
472 	 * we reach the first element of the chain), drivers are expected to
473 	 * return accurate input formats as the input format may be used to
474 	 * configure the CRTC output appropriately.
475 	 */
476 	u32 *(*atomic_get_input_bus_fmts)(struct drm_bridge *bridge,
477 					  struct drm_bridge_state *bridge_state,
478 					  struct drm_crtc_state *crtc_state,
479 					  struct drm_connector_state *conn_state,
480 					  u32 output_fmt,
481 					  unsigned int *num_input_fmts);
482 
483 	/**
484 	 * @atomic_check:
485 	 *
486 	 * This method is responsible for checking bridge state correctness.
487 	 * It can also check the state of the surrounding components in chain
488 	 * to make sure the whole pipeline can work properly.
489 	 *
490 	 * &drm_bridge_funcs.atomic_check() hooks are called in reverse
491 	 * order (from the last to the first bridge).
492 	 *
493 	 * This method is optional. &drm_bridge_funcs.mode_fixup() is not
494 	 * called when &drm_bridge_funcs.atomic_check() is implemented, so only
495 	 * one of them should be provided.
496 	 *
497 	 * If drivers need to tweak &drm_bridge_state.input_bus_cfg.flags or
498 	 * &drm_bridge_state.output_bus_cfg.flags it should happen in
499 	 * this function. By default the &drm_bridge_state.output_bus_cfg.flags
500 	 * field is set to the next bridge
501 	 * &drm_bridge_state.input_bus_cfg.flags value or
502 	 * &drm_connector.display_info.bus_flags if the bridge is the last
503 	 * element in the chain.
504 	 *
505 	 * RETURNS:
506 	 * zero if the check passed, a negative error code otherwise.
507 	 */
508 	int (*atomic_check)(struct drm_bridge *bridge,
509 			    struct drm_bridge_state *bridge_state,
510 			    struct drm_crtc_state *crtc_state,
511 			    struct drm_connector_state *conn_state);
512 
513 	/**
514 	 * @atomic_reset:
515 	 *
516 	 * Reset the bridge to a predefined state (or retrieve its current
517 	 * state) and return a &drm_bridge_state object matching this state.
518 	 * This function is called at attach time.
519 	 *
520 	 * The atomic_reset hook is mandatory if the bridge implements any of
521 	 * the atomic hooks, and should be left unassigned otherwise. For
522 	 * bridges that don't subclass &drm_bridge_state, the
523 	 * drm_atomic_helper_bridge_reset() helper function shall be used to
524 	 * implement this hook.
525 	 *
526 	 * Note that the atomic_reset() semantics is not exactly matching the
527 	 * reset() semantics found on other components (connector, plane, ...).
528 	 *
529 	 * 1. The reset operation happens when the bridge is attached, not when
530 	 *    drm_mode_config_reset() is called
531 	 * 2. It's meant to be used exclusively on bridges that have been
532 	 *    converted to the ATOMIC API
533 	 *
534 	 * RETURNS:
535 	 * A valid drm_bridge_state object in case of success, an ERR_PTR()
536 	 * giving the reason of the failure otherwise.
537 	 */
538 	struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
539 
540 	/**
541 	 * @detect:
542 	 *
543 	 * Check if anything is attached to the bridge output.
544 	 *
545 	 * This callback is optional, if not implemented the bridge will be
546 	 * considered as always having a component attached to its output.
547 	 * Bridges that implement this callback shall set the
548 	 * DRM_BRIDGE_OP_DETECT flag in their &drm_bridge->ops.
549 	 *
550 	 * RETURNS:
551 	 *
552 	 * drm_connector_status indicating the bridge output status.
553 	 */
554 	enum drm_connector_status (*detect)(struct drm_bridge *bridge);
555 
556 	/**
557 	 * @get_modes:
558 	 *
559 	 * Fill all modes currently valid for the sink into the &drm_connector
560 	 * with drm_mode_probed_add().
561 	 *
562 	 * The @get_modes callback is mostly intended to support non-probeable
563 	 * displays such as many fixed panels. Bridges that support reading
564 	 * EDID shall leave @get_modes unimplemented and implement the
565 	 * &drm_bridge_funcs->get_edid callback instead.
566 	 *
567 	 * This callback is optional. Bridges that implement it shall set the
568 	 * DRM_BRIDGE_OP_MODES flag in their &drm_bridge->ops.
569 	 *
570 	 * The connector parameter shall be used for the sole purpose of
571 	 * filling modes, and shall not be stored internally by bridge drivers
572 	 * for future usage.
573 	 *
574 	 * RETURNS:
575 	 *
576 	 * The number of modes added by calling drm_mode_probed_add().
577 	 */
578 	int (*get_modes)(struct drm_bridge *bridge,
579 			 struct drm_connector *connector);
580 
581 	/**
582 	 * @get_edid:
583 	 *
584 	 * Read and parse the EDID data of the connected display.
585 	 *
586 	 * The @get_edid callback is the preferred way of reporting mode
587 	 * information for a display connected to the bridge output. Bridges
588 	 * that support reading EDID shall implement this callback and leave
589 	 * the @get_modes callback unimplemented.
590 	 *
591 	 * The caller of this operation shall first verify the output
592 	 * connection status and refrain from reading EDID from a disconnected
593 	 * output.
594 	 *
595 	 * This callback is optional. Bridges that implement it shall set the
596 	 * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
597 	 *
598 	 * The connector parameter shall be used for the sole purpose of EDID
599 	 * retrieval and parsing, and shall not be stored internally by bridge
600 	 * drivers for future usage.
601 	 *
602 	 * RETURNS:
603 	 *
604 	 * An edid structure newly allocated with kmalloc() (or similar) on
605 	 * success, or NULL otherwise. The caller is responsible for freeing
606 	 * the returned edid structure with kfree().
607 	 */
608 	struct edid *(*get_edid)(struct drm_bridge *bridge,
609 				 struct drm_connector *connector);
610 
611 	/**
612 	 * @hpd_notify:
613 	 *
614 	 * Notify the bridge of hot plug detection.
615 	 *
616 	 * This callback is optional, it may be implemented by bridges that
617 	 * need to be notified of display connection or disconnection for
618 	 * internal reasons. One use case is to reset the internal state of CEC
619 	 * controllers for HDMI bridges.
620 	 */
621 	void (*hpd_notify)(struct drm_bridge *bridge,
622 			   enum drm_connector_status status);
623 
624 	/**
625 	 * @hpd_enable:
626 	 *
627 	 * Enable hot plug detection. From now on the bridge shall call
628 	 * drm_bridge_hpd_notify() each time a change is detected in the output
629 	 * connection status, until hot plug detection gets disabled with
630 	 * @hpd_disable.
631 	 *
632 	 * This callback is optional and shall only be implemented by bridges
633 	 * that support hot-plug notification without polling. Bridges that
634 	 * implement it shall also implement the @hpd_disable callback and set
635 	 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
636 	 */
637 	void (*hpd_enable)(struct drm_bridge *bridge);
638 
639 	/**
640 	 * @hpd_disable:
641 	 *
642 	 * Disable hot plug detection. Once this function returns the bridge
643 	 * shall not call drm_bridge_hpd_notify() when a change in the output
644 	 * connection status occurs.
645 	 *
646 	 * This callback is optional and shall only be implemented by bridges
647 	 * that support hot-plug notification without polling. Bridges that
648 	 * implement it shall also implement the @hpd_enable callback and set
649 	 * the DRM_BRIDGE_OP_HPD flag in their &drm_bridge->ops.
650 	 */
651 	void (*hpd_disable)(struct drm_bridge *bridge);
652 
653 	/**
654 	 * @debugfs_init:
655 	 *
656 	 * Allows bridges to create bridge-specific debugfs files.
657 	 */
658 	void (*debugfs_init)(struct drm_bridge *bridge, struct dentry *root);
659 };
660 
661 /**
662  * struct drm_bridge_timings - timing information for the bridge
663  */
664 struct drm_bridge_timings {
665 	/**
666 	 * @input_bus_flags:
667 	 *
668 	 * Tells what additional settings for the pixel data on the bus
669 	 * this bridge requires (like pixel signal polarity). See also
670 	 * &drm_display_info->bus_flags.
671 	 */
672 	u32 input_bus_flags;
673 	/**
674 	 * @setup_time_ps:
675 	 *
676 	 * Defines the time in picoseconds the input data lines must be
677 	 * stable before the clock edge.
678 	 */
679 	u32 setup_time_ps;
680 	/**
681 	 * @hold_time_ps:
682 	 *
683 	 * Defines the time in picoseconds taken for the bridge to sample the
684 	 * input signal after the clock edge.
685 	 */
686 	u32 hold_time_ps;
687 	/**
688 	 * @dual_link:
689 	 *
690 	 * True if the bus operates in dual-link mode. The exact meaning is
691 	 * dependent on the bus type. For LVDS buses, this indicates that even-
692 	 * and odd-numbered pixels are received on separate links.
693 	 */
694 	bool dual_link;
695 };
696 
697 /**
698  * enum drm_bridge_ops - Bitmask of operations supported by the bridge
699  */
700 enum drm_bridge_ops {
701 	/**
702 	 * @DRM_BRIDGE_OP_DETECT: The bridge can detect displays connected to
703 	 * its output. Bridges that set this flag shall implement the
704 	 * &drm_bridge_funcs->detect callback.
705 	 */
706 	DRM_BRIDGE_OP_DETECT = BIT(0),
707 	/**
708 	 * @DRM_BRIDGE_OP_EDID: The bridge can retrieve the EDID of the display
709 	 * connected to its output. Bridges that set this flag shall implement
710 	 * the &drm_bridge_funcs->get_edid callback.
711 	 */
712 	DRM_BRIDGE_OP_EDID = BIT(1),
713 	/**
714 	 * @DRM_BRIDGE_OP_HPD: The bridge can detect hot-plug and hot-unplug
715 	 * without requiring polling. Bridges that set this flag shall
716 	 * implement the &drm_bridge_funcs->hpd_enable and
717 	 * &drm_bridge_funcs->hpd_disable callbacks if they support enabling
718 	 * and disabling hot-plug detection dynamically.
719 	 */
720 	DRM_BRIDGE_OP_HPD = BIT(2),
721 	/**
722 	 * @DRM_BRIDGE_OP_MODES: The bridge can retrieve the modes supported
723 	 * by the display at its output. This does not include reading EDID
724 	 * which is separately covered by @DRM_BRIDGE_OP_EDID. Bridges that set
725 	 * this flag shall implement the &drm_bridge_funcs->get_modes callback.
726 	 */
727 	DRM_BRIDGE_OP_MODES = BIT(3),
728 };
729 
730 /**
731  * struct drm_bridge - central DRM bridge control structure
732  */
733 struct drm_bridge {
734 	/** @base: inherit from &drm_private_object */
735 	struct drm_private_obj base;
736 	/** @dev: DRM device this bridge belongs to */
737 	struct drm_device *dev;
738 	/** @encoder: encoder to which this bridge is connected */
739 	struct drm_encoder *encoder;
740 	/** @chain_node: used to form a bridge chain */
741 	struct list_head chain_node;
742 #ifdef CONFIG_OF
743 	/** @of_node: device node pointer to the bridge */
744 	struct device_node *of_node;
745 #endif
746 	/** @list: to keep track of all added bridges */
747 	struct list_head list;
748 	/**
749 	 * @timings:
750 	 *
751 	 * the timing specification for the bridge, if any (may be NULL)
752 	 */
753 	const struct drm_bridge_timings *timings;
754 	/** @funcs: control functions */
755 	const struct drm_bridge_funcs *funcs;
756 	/** @driver_private: pointer to the bridge driver's internal context */
757 	void *driver_private;
758 	/** @ops: bitmask of operations supported by the bridge */
759 	enum drm_bridge_ops ops;
760 	/**
761 	 * @type: Type of the connection at the bridge output
762 	 * (DRM_MODE_CONNECTOR_*). For bridges at the end of this chain this
763 	 * identifies the type of connected display.
764 	 */
765 	int type;
766 	/**
767 	 * @interlace_allowed: Indicate that the bridge can handle interlaced
768 	 * modes.
769 	 */
770 	bool interlace_allowed;
771 	/**
772 	 * @ddc: Associated I2C adapter for DDC access, if any.
773 	 */
774 	struct i2c_adapter *ddc;
775 	/** private: */
776 	/**
777 	 * @hpd_mutex: Protects the @hpd_cb and @hpd_data fields.
778 	 */
779 	struct mutex hpd_mutex;
780 	/**
781 	 * @hpd_cb: Hot plug detection callback, registered with
782 	 * drm_bridge_hpd_enable().
783 	 */
784 	void (*hpd_cb)(void *data, enum drm_connector_status status);
785 	/**
786 	 * @hpd_data: Private data passed to the Hot plug detection callback
787 	 * @hpd_cb.
788 	 */
789 	void *hpd_data;
790 };
791 
792 static inline struct drm_bridge *
drm_priv_to_bridge(struct drm_private_obj * priv)793 drm_priv_to_bridge(struct drm_private_obj *priv)
794 {
795 	return container_of(priv, struct drm_bridge, base);
796 }
797 
798 void drm_bridge_add(struct drm_bridge *bridge);
799 int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge);
800 void drm_bridge_remove(struct drm_bridge *bridge);
801 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
802 		      struct drm_bridge *previous,
803 		      enum drm_bridge_attach_flags flags);
804 
805 #ifdef CONFIG_OF
806 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
807 #else
of_drm_find_bridge(struct device_node * np)808 static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np)
809 {
810 	return NULL;
811 }
812 #endif
813 
814 /**
815  * drm_bridge_get_next_bridge() - Get the next bridge in the chain
816  * @bridge: bridge object
817  *
818  * RETURNS:
819  * the next bridge in the chain after @bridge, or NULL if @bridge is the last.
820  */
821 static inline struct drm_bridge *
drm_bridge_get_next_bridge(struct drm_bridge * bridge)822 drm_bridge_get_next_bridge(struct drm_bridge *bridge)
823 {
824 	if (list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain))
825 		return NULL;
826 
827 	return list_next_entry(bridge, chain_node);
828 }
829 
830 /**
831  * drm_bridge_get_prev_bridge() - Get the previous bridge in the chain
832  * @bridge: bridge object
833  *
834  * RETURNS:
835  * the previous bridge in the chain, or NULL if @bridge is the first.
836  */
837 static inline struct drm_bridge *
drm_bridge_get_prev_bridge(struct drm_bridge * bridge)838 drm_bridge_get_prev_bridge(struct drm_bridge *bridge)
839 {
840 	if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
841 		return NULL;
842 
843 	return list_prev_entry(bridge, chain_node);
844 }
845 
846 /**
847  * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
848  * @encoder: encoder object
849  *
850  * RETURNS:
851  * the first bridge in the chain, or NULL if @encoder has no bridge attached
852  * to it.
853  */
854 static inline struct drm_bridge *
drm_bridge_chain_get_first_bridge(struct drm_encoder * encoder)855 drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
856 {
857 	return list_first_entry_or_null(&encoder->bridge_chain,
858 					struct drm_bridge, chain_node);
859 }
860 
861 /**
862  * drm_for_each_bridge_in_chain() - Iterate over all bridges present in a chain
863  * @encoder: the encoder to iterate bridges on
864  * @bridge: a bridge pointer updated to point to the current bridge at each
865  *	    iteration
866  *
867  * Iterate over all bridges present in the bridge chain attached to @encoder.
868  */
869 #define drm_for_each_bridge_in_chain(encoder, bridge)			\
870 	list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)
871 
872 bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
873 				 const struct drm_display_mode *mode,
874 				 struct drm_display_mode *adjusted_mode);
875 enum drm_mode_status
876 drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
877 			    const struct drm_display_info *info,
878 			    const struct drm_display_mode *mode);
879 void drm_bridge_chain_disable(struct drm_bridge *bridge);
880 void drm_bridge_chain_post_disable(struct drm_bridge *bridge);
881 void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
882 			       const struct drm_display_mode *mode,
883 			       const struct drm_display_mode *adjusted_mode);
884 void drm_bridge_chain_pre_enable(struct drm_bridge *bridge);
885 void drm_bridge_chain_enable(struct drm_bridge *bridge);
886 
887 int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
888 				  struct drm_crtc_state *crtc_state,
889 				  struct drm_connector_state *conn_state);
890 void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
891 				     struct drm_atomic_state *state);
892 void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
893 					  struct drm_atomic_state *state);
894 void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
895 					struct drm_atomic_state *state);
896 void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
897 				    struct drm_atomic_state *state);
898 
899 u32 *
900 drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
901 					struct drm_bridge_state *bridge_state,
902 					struct drm_crtc_state *crtc_state,
903 					struct drm_connector_state *conn_state,
904 					u32 output_fmt,
905 					unsigned int *num_input_fmts);
906 
907 enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
908 int drm_bridge_get_modes(struct drm_bridge *bridge,
909 			 struct drm_connector *connector);
910 struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
911 				 struct drm_connector *connector);
912 void drm_bridge_hpd_enable(struct drm_bridge *bridge,
913 			   void (*cb)(void *data,
914 				      enum drm_connector_status status),
915 			   void *data);
916 void drm_bridge_hpd_disable(struct drm_bridge *bridge);
917 void drm_bridge_hpd_notify(struct drm_bridge *bridge,
918 			   enum drm_connector_status status);
919 
920 #ifdef CONFIG_DRM_PANEL_BRIDGE
921 bool drm_bridge_is_panel(const struct drm_bridge *bridge);
922 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
923 struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
924 					      u32 connector_type);
925 void drm_panel_bridge_remove(struct drm_bridge *bridge);
926 int drm_panel_bridge_set_orientation(struct drm_connector *connector,
927 				     struct drm_bridge *bridge);
928 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
929 					     struct drm_panel *panel);
930 struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
931 						   struct drm_panel *panel,
932 						   u32 connector_type);
933 struct drm_bridge *drmm_panel_bridge_add(struct drm_device *drm,
934 					     struct drm_panel *panel);
935 struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge);
936 #else
drm_bridge_is_panel(const struct drm_bridge * bridge)937 static inline bool drm_bridge_is_panel(const struct drm_bridge *bridge)
938 {
939 	return false;
940 }
941 
drm_panel_bridge_set_orientation(struct drm_connector * connector,struct drm_bridge * bridge)942 static inline int drm_panel_bridge_set_orientation(struct drm_connector *connector,
943 						   struct drm_bridge *bridge)
944 {
945 	return -EINVAL;
946 }
947 #endif
948 
949 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
950 struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
951 					  u32 port, u32 endpoint);
952 struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, struct device_node *node,
953 					  u32 port, u32 endpoint);
954 #else
devm_drm_of_get_bridge(struct device * dev,struct device_node * node,u32 port,u32 endpoint)955 static inline struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
956 							struct device_node *node,
957 							u32 port,
958 							u32 endpoint)
959 {
960 	return ERR_PTR(-ENODEV);
961 }
962 
drmm_of_get_bridge(struct drm_device * drm,struct device_node * node,u32 port,u32 endpoint)963 static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
964 						     struct device_node *node,
965 						     u32 port,
966 						     u32 endpoint)
967 {
968 	return ERR_PTR(-ENODEV);
969 }
970 #endif
971 
972 #endif
973