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TOMOYO Linux Cross Reference
Linux/include/drm/drm_bridge.h

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  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 *
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 *
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 *
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 *
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 

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