include/drm/drm_bridge.h

   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