1/*
   2 * Copyright (c) 2014 Samsung Electronics Co., Ltd
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sub license,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice (including the
  12 * next paragraph) shall be included in all copies or substantial portions
  13 * of the Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21 * DEALINGS IN THE SOFTWARE.
  22 */
  23
  24#include <linux/err.h>
  25#include <linux/media-bus-format.h>
  26#include <linux/module.h>
  27#include <linux/mutex.h>
  28
  29#include <drm/drm_atomic_state_helper.h>
  30#include <drm/drm_debugfs.h>
  31#include <drm/drm_bridge.h>
 
 
  32#include <drm/drm_encoder.h>
  33#include <drm/drm_file.h>
  34#include <drm/drm_of.h>
  35#include <drm/drm_print.h>
  36
  37#include "drm_crtc_internal.h"
  38
  39/**
  40 * DOC: overview
  41 *
  42 * &struct drm_bridge represents a device that hangs on to an encoder. These are
  43 * handy when a regular &drm_encoder entity isn't enough to represent the entire
  44 * encoder chain.
  45 *
  46 * A bridge is always attached to a single &drm_encoder at a time, but can be
  47 * either connected to it directly, or through a chain of bridges::
  48 *
  49 *     [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B
  50 *
  51 * Here, the output of the encoder feeds to bridge A, and that furthers feeds to
  52 * bridge B. Bridge chains can be arbitrarily long, and shall be fully linear:
  53 * Chaining multiple bridges to the output of a bridge, or the same bridge to
  54 * the output of different bridges, is not supported.
  55 *
  56 * &drm_bridge, like &drm_panel, aren't &drm_mode_object entities like planes,
  57 * CRTCs, encoders or connectors and hence are not visible to userspace. They
  58 * just provide additional hooks to get the desired output at the end of the
  59 * encoder chain.
  60 */
  61
  62/**
  63 * DOC:	display driver integration
  64 *
  65 * Display drivers are responsible for linking encoders with the first bridge
  66 * in the chains. This is done by acquiring the appropriate bridge with
  67 * devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
  68 * encoder with a call to drm_bridge_attach().
  69 *
  70 * Bridges are responsible for linking themselves with the next bridge in the
  71 * chain, if any. This is done the same way as for encoders, with the call to
  72 * drm_bridge_attach() occurring in the &drm_bridge_funcs.attach operation.
  73 *
  74 * Once these links are created, the bridges can participate along with encoder
  75 * functions to perform mode validation and fixup (through
  76 * drm_bridge_chain_mode_valid() and drm_atomic_bridge_chain_check()), mode
  77 * setting (through drm_bridge_chain_mode_set()), enable (through
  78 * drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_enable())
  79 * and disable (through drm_atomic_bridge_chain_disable() and
  80 * drm_atomic_bridge_chain_post_disable()). Those functions call the
  81 * corresponding operations provided in &drm_bridge_funcs in sequence for all
  82 * bridges in the chain.
  83 *
  84 * For display drivers that use the atomic helpers
  85 * drm_atomic_helper_check_modeset(),
  86 * drm_atomic_helper_commit_modeset_enables() and
  87 * drm_atomic_helper_commit_modeset_disables() (either directly in hand-rolled
  88 * commit check and commit tail handlers, or through the higher-level
  89 * drm_atomic_helper_check() and drm_atomic_helper_commit_tail() or
  90 * drm_atomic_helper_commit_tail_rpm() helpers), this is done transparently and
  91 * requires no intervention from the driver. For other drivers, the relevant
  92 * DRM bridge chain functions shall be called manually.
  93 *
  94 * Bridges also participate in implementing the &drm_connector at the end of
  95 * the bridge chain. Display drivers may use the drm_bridge_connector_init()
  96 * helper to create the &drm_connector, or implement it manually on top of the
  97 * connector-related operations exposed by the bridge (see the overview
  98 * documentation of bridge operations for more details).
  99 */
 100
 101/**
 102 * DOC: special care dsi
 103 *
 104 * The interaction between the bridges and other frameworks involved in
 105 * the probing of the upstream driver and the bridge driver can be
 106 * challenging. Indeed, there's multiple cases that needs to be
 107 * considered:
 108 *
 109 * - The upstream driver doesn't use the component framework and isn't a
 110 *   MIPI-DSI host. In this case, the bridge driver will probe at some
 111 *   point and the upstream driver should try to probe again by returning
 112 *   EPROBE_DEFER as long as the bridge driver hasn't probed.
 113 *
 114 * - The upstream driver doesn't use the component framework, but is a
 115 *   MIPI-DSI host. The bridge device uses the MIPI-DCS commands to be
 116 *   controlled. In this case, the bridge device is a child of the
 117 *   display device and when it will probe it's assured that the display
 118 *   device (and MIPI-DSI host) is present. The upstream driver will be
 119 *   assured that the bridge driver is connected between the
 120 *   &mipi_dsi_host_ops.attach and &mipi_dsi_host_ops.detach operations.
 121 *   Therefore, it must run mipi_dsi_host_register() in its probe
 122 *   function, and then run drm_bridge_attach() in its
 123 *   &mipi_dsi_host_ops.attach hook.
 124 *
 125 * - The upstream driver uses the component framework and is a MIPI-DSI
 126 *   host. The bridge device uses the MIPI-DCS commands to be
 127 *   controlled. This is the same situation than above, and can run
 128 *   mipi_dsi_host_register() in either its probe or bind hooks.
 129 *
 130 * - The upstream driver uses the component framework and is a MIPI-DSI
 131 *   host. The bridge device uses a separate bus (such as I2C) to be
 132 *   controlled. In this case, there's no correlation between the probe
 133 *   of the bridge and upstream drivers, so care must be taken to avoid
 134 *   an endless EPROBE_DEFER loop, with each driver waiting for the
 135 *   other to probe.
 136 *
 137 * The ideal pattern to cover the last item (and all the others in the
 138 * MIPI-DSI host driver case) is to split the operations like this:
 139 *
 140 * - The MIPI-DSI host driver must run mipi_dsi_host_register() in its
 141 *   probe hook. It will make sure that the MIPI-DSI host sticks around,
 142 *   and that the driver's bind can be called.
 143 *
 144 * - In its probe hook, the bridge driver must try to find its MIPI-DSI
 145 *   host, register as a MIPI-DSI device and attach the MIPI-DSI device
 146 *   to its host. The bridge driver is now functional.
 147 *
 148 * - In its &struct mipi_dsi_host_ops.attach hook, the MIPI-DSI host can
 149 *   now add its component. Its bind hook will now be called and since
 150 *   the bridge driver is attached and registered, we can now look for
 151 *   and attach it.
 152 *
 153 * At this point, we're now certain that both the upstream driver and
 154 * the bridge driver are functional and we can't have a deadlock-like
 155 * situation when probing.
 156 */
 157
 158/**
 159 * DOC: dsi bridge operations
 160 *
 161 * DSI host interfaces are expected to be implemented as bridges rather than
 162 * encoders, however there are a few aspects of their operation that need to
 163 * be defined in order to provide a consistent interface.
 164 *
 165 * A DSI host should keep the PHY powered down until the pre_enable operation is
 166 * called. All lanes are in an undefined idle state up to this point, and it
 167 * must not be assumed that it is LP-11.
 168 * pre_enable should initialise the PHY, set the data lanes to LP-11, and the
 169 * clock lane to either LP-11 or HS depending on the mode_flag
 170 * %MIPI_DSI_CLOCK_NON_CONTINUOUS.
 171 *
 172 * Ordinarily the downstream bridge DSI peripheral pre_enable will have been
 173 * called before the DSI host. If the DSI peripheral requires LP-11 and/or
 174 * the clock lane to be in HS mode prior to pre_enable, then it can set the
 175 * &pre_enable_prev_first flag to request the pre_enable (and
 176 * post_disable) order to be altered to enable the DSI host first.
 177 *
 178 * Either the CRTC being enabled, or the DSI host enable operation should switch
 179 * the host to actively transmitting video on the data lanes.
 180 *
 181 * The reverse also applies. The DSI host disable operation or stopping the CRTC
 182 * should stop transmitting video, and the data lanes should return to the LP-11
 183 * state. The DSI host &post_disable operation should disable the PHY.
 184 * If the &pre_enable_prev_first flag is set, then the DSI peripheral's
 185 * bridge &post_disable will be called before the DSI host's post_disable.
 186 *
 187 * Whilst it is valid to call &host_transfer prior to pre_enable or after
 188 * post_disable, the exact state of the lanes is undefined at this point. The
 189 * DSI host should initialise the interface, transmit the data, and then disable
 190 * the interface again.
 191 *
 192 * Ultra Low Power State (ULPS) is not explicitly supported by DRM. If
 193 * implemented, it therefore needs to be handled entirely within the DSI Host
 194 * driver.
 195 */
 196
 197static DEFINE_MUTEX(bridge_lock);
 198static LIST_HEAD(bridge_list);
 199
 200/**
 201 * drm_bridge_add - add the given bridge to the global bridge list
 202 *
 203 * @bridge: bridge control structure
 204 */
 205void drm_bridge_add(struct drm_bridge *bridge)
 206{
 207	mutex_init(&bridge->hpd_mutex);
 208
 209	mutex_lock(&bridge_lock);
 210	list_add_tail(&bridge->list, &bridge_list);
 211	mutex_unlock(&bridge_lock);
 212}
 213EXPORT_SYMBOL(drm_bridge_add);
 214
 215static void drm_bridge_remove_void(void *bridge)
 216{
 217	drm_bridge_remove(bridge);
 218}
 219
 220/**
 221 * devm_drm_bridge_add - devm managed version of drm_bridge_add()
 222 *
 223 * @dev: device to tie the bridge lifetime to
 224 * @bridge: bridge control structure
 225 *
 226 * This is the managed version of drm_bridge_add() which automatically
 227 * calls drm_bridge_remove() when @dev is unbound.
 228 *
 229 * Return: 0 if no error or negative error code.
 230 */
 231int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge)
 232{
 233	drm_bridge_add(bridge);
 234	return devm_add_action_or_reset(dev, drm_bridge_remove_void, bridge);
 235}
 236EXPORT_SYMBOL(devm_drm_bridge_add);
 237
 238/**
 239 * drm_bridge_remove - remove the given bridge from the global bridge list
 240 *
 241 * @bridge: bridge control structure
 242 */
 243void drm_bridge_remove(struct drm_bridge *bridge)
 244{
 245	mutex_lock(&bridge_lock);
 246	list_del_init(&bridge->list);
 247	mutex_unlock(&bridge_lock);
 248
 249	mutex_destroy(&bridge->hpd_mutex);
 250}
 251EXPORT_SYMBOL(drm_bridge_remove);
 252
 253static struct drm_private_state *
 254drm_bridge_atomic_duplicate_priv_state(struct drm_private_obj *obj)
 255{
 256	struct drm_bridge *bridge = drm_priv_to_bridge(obj);
 257	struct drm_bridge_state *state;
 258
 259	state = bridge->funcs->atomic_duplicate_state(bridge);
 260	return state ? &state->base : NULL;
 261}
 262
 263static void
 264drm_bridge_atomic_destroy_priv_state(struct drm_private_obj *obj,
 265				     struct drm_private_state *s)
 266{
 267	struct drm_bridge_state *state = drm_priv_to_bridge_state(s);
 268	struct drm_bridge *bridge = drm_priv_to_bridge(obj);
 269
 270	bridge->funcs->atomic_destroy_state(bridge, state);
 271}
 272
 273static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = {
 274	.atomic_duplicate_state = drm_bridge_atomic_duplicate_priv_state,
 275	.atomic_destroy_state = drm_bridge_atomic_destroy_priv_state,
 276};
 277
 278/**
 279 * drm_bridge_attach - attach the bridge to an encoder's chain
 280 *
 281 * @encoder: DRM encoder
 282 * @bridge: bridge to attach
 283 * @previous: previous bridge in the chain (optional)
 284 * @flags: DRM_BRIDGE_ATTACH_* flags
 285 *
 286 * Called by a kms driver to link the bridge to an encoder's chain. The previous
 287 * argument specifies the previous bridge in the chain. If NULL, the bridge is
 288 * linked directly at the encoder's output. Otherwise it is linked at the
 289 * previous bridge's output.
 290 *
 291 * If non-NULL the previous bridge must be already attached by a call to this
 292 * function.
 293 *
 294 * Note that bridges attached to encoders are auto-detached during encoder
 295 * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
 296 * *not* be balanced with a drm_bridge_detach() in driver code.
 297 *
 298 * RETURNS:
 299 * Zero on success, error code on failure
 300 */
 301int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 302		      struct drm_bridge *previous,
 303		      enum drm_bridge_attach_flags flags)
 304{
 305	int ret;
 306
 307	if (!encoder || !bridge)
 308		return -EINVAL;
 309
 310	if (previous && (!previous->dev || previous->encoder != encoder))
 311		return -EINVAL;
 312
 313	if (bridge->dev)
 314		return -EBUSY;
 315
 316	bridge->dev = encoder->dev;
 317	bridge->encoder = encoder;
 318
 319	if (previous)
 320		list_add(&bridge->chain_node, &previous->chain_node);
 321	else
 322		list_add(&bridge->chain_node, &encoder->bridge_chain);
 323
 324	if (bridge->funcs->attach) {
 325		ret = bridge->funcs->attach(bridge, flags);
 326		if (ret < 0)
 327			goto err_reset_bridge;
 328	}
 329
 330	if (bridge->funcs->atomic_reset) {
 331		struct drm_bridge_state *state;
 332
 333		state = bridge->funcs->atomic_reset(bridge);
 334		if (IS_ERR(state)) {
 335			ret = PTR_ERR(state);
 336			goto err_detach_bridge;
 337		}
 338
 339		drm_atomic_private_obj_init(bridge->dev, &bridge->base,
 340					    &state->base,
 341					    &drm_bridge_priv_state_funcs);
 342	}
 343
 344	return 0;
 345
 346err_detach_bridge:
 347	if (bridge->funcs->detach)
 348		bridge->funcs->detach(bridge);
 349
 350err_reset_bridge:
 351	bridge->dev = NULL;
 352	bridge->encoder = NULL;
 353	list_del(&bridge->chain_node);
 354
 355#ifdef CONFIG_OF
 356	DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n",
 357		  bridge->of_node, encoder->name, ret);
 358#else
 359	DRM_ERROR("failed to attach bridge to encoder %s: %d\n",
 360		  encoder->name, ret);
 361#endif
 362
 363	return ret;
 364}
 365EXPORT_SYMBOL(drm_bridge_attach);
 366
 367void drm_bridge_detach(struct drm_bridge *bridge)
 368{
 369	if (WARN_ON(!bridge))
 370		return;
 371
 372	if (WARN_ON(!bridge->dev))
 373		return;
 374
 375	if (bridge->funcs->atomic_reset)
 376		drm_atomic_private_obj_fini(&bridge->base);
 377
 378	if (bridge->funcs->detach)
 379		bridge->funcs->detach(bridge);
 380
 381	list_del(&bridge->chain_node);
 382	bridge->dev = NULL;
 383}
 384
 385/**
 386 * DOC: bridge operations
 387 *
 388 * Bridge drivers expose operations through the &drm_bridge_funcs structure.
 389 * The DRM internals (atomic and CRTC helpers) use the helpers defined in
 390 * drm_bridge.c to call bridge operations. Those operations are divided in
 391 * three big categories to support different parts of the bridge usage.
 392 *
 393 * - The encoder-related operations support control of the bridges in the
 394 *   chain, and are roughly counterparts to the &drm_encoder_helper_funcs
 395 *   operations. They are used by the legacy CRTC and the atomic modeset
 396 *   helpers to perform mode validation, fixup and setting, and enable and
 397 *   disable the bridge automatically.
 398 *
 399 *   The enable and disable operations are split in
 400 *   &drm_bridge_funcs.pre_enable, &drm_bridge_funcs.enable,
 401 *   &drm_bridge_funcs.disable and &drm_bridge_funcs.post_disable to provide
 402 *   finer-grained control.
 403 *
 404 *   Bridge drivers may implement the legacy version of those operations, or
 405 *   the atomic version (prefixed with atomic\_), in which case they shall also
 406 *   implement the atomic state bookkeeping operations
 407 *   (&drm_bridge_funcs.atomic_duplicate_state,
 408 *   &drm_bridge_funcs.atomic_destroy_state and &drm_bridge_funcs.reset).
 409 *   Mixing atomic and non-atomic versions of the operations is not supported.
 410 *
 411 * - The bus format negotiation operations
 412 *   &drm_bridge_funcs.atomic_get_output_bus_fmts and
 413 *   &drm_bridge_funcs.atomic_get_input_bus_fmts allow bridge drivers to
 414 *   negotiate the formats transmitted between bridges in the chain when
 415 *   multiple formats are supported. Negotiation for formats is performed
 416 *   transparently for display drivers by the atomic modeset helpers. Only
 417 *   atomic versions of those operations exist, bridge drivers that need to
 418 *   implement them shall thus also implement the atomic version of the
 419 *   encoder-related operations. This feature is not supported by the legacy
 420 *   CRTC helpers.
 421 *
 422 * - The connector-related operations support implementing a &drm_connector
 423 *   based on a chain of bridges. DRM bridges traditionally create a
 424 *   &drm_connector for bridges meant to be used at the end of the chain. This
 425 *   puts additional burden on bridge drivers, especially for bridges that may
 426 *   be used in the middle of a chain or at the end of it. Furthermore, it
 427 *   requires all operations of the &drm_connector to be handled by a single
 428 *   bridge, which doesn't always match the hardware architecture.
 429 *
 430 *   To simplify bridge drivers and make the connector implementation more
 431 *   flexible, a new model allows bridges to unconditionally skip creation of
 432 *   &drm_connector and instead expose &drm_bridge_funcs operations to support
 433 *   an externally-implemented &drm_connector. Those operations are
 434 *   &drm_bridge_funcs.detect, &drm_bridge_funcs.get_modes,
 435 *   &drm_bridge_funcs.get_edid, &drm_bridge_funcs.hpd_notify,
 436 *   &drm_bridge_funcs.hpd_enable and &drm_bridge_funcs.hpd_disable. When
 437 *   implemented, display drivers shall create a &drm_connector instance for
 438 *   each chain of bridges, and implement those connector instances based on
 439 *   the bridge connector operations.
 440 *
 441 *   Bridge drivers shall implement the connector-related operations for all
 442 *   the features that the bridge hardware support. For instance, if a bridge
 443 *   supports reading EDID, the &drm_bridge_funcs.get_edid shall be
 444 *   implemented. This however doesn't mean that the DDC lines are wired to the
 445 *   bridge on a particular platform, as they could also be connected to an I2C
 446 *   controller of the SoC. Support for the connector-related operations on the
 447 *   running platform is reported through the &drm_bridge.ops flags. Bridge
 448 *   drivers shall detect which operations they can support on the platform
 449 *   (usually this information is provided by ACPI or DT), and set the
 450 *   &drm_bridge.ops flags for all supported operations. A flag shall only be
 451 *   set if the corresponding &drm_bridge_funcs operation is implemented, but
 452 *   an implemented operation doesn't necessarily imply that the corresponding
 453 *   flag will be set. Display drivers shall use the &drm_bridge.ops flags to
 454 *   decide which bridge to delegate a connector operation to. This mechanism
 455 *   allows providing a single static const &drm_bridge_funcs instance in
 456 *   bridge drivers, improving security by storing function pointers in
 457 *   read-only memory.
 458 *
 459 *   In order to ease transition, bridge drivers may support both the old and
 460 *   new models by making connector creation optional and implementing the
 461 *   connected-related bridge operations. Connector creation is then controlled
 462 *   by the flags argument to the drm_bridge_attach() function. Display drivers
 463 *   that support the new model and create connectors themselves shall set the
 464 *   %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag, and bridge drivers shall then skip
 465 *   connector creation. For intermediate bridges in the chain, the flag shall
 466 *   be passed to the drm_bridge_attach() call for the downstream bridge.
 467 *   Bridge drivers that implement the new model only shall return an error
 468 *   from their &drm_bridge_funcs.attach handler when the
 469 *   %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is not set. New display drivers
 470 *   should use the new model, and convert the bridge drivers they use if
 471 *   needed, in order to gradually transition to the new model.
 472 */
 473
 474/**
 475 * drm_bridge_chain_mode_fixup - fixup proposed mode for all bridges in the
 476 *				 encoder chain
 477 * @bridge: bridge control structure
 478 * @mode: desired mode to be set for the bridge
 479 * @adjusted_mode: updated mode that works for this bridge
 480 *
 481 * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
 482 * encoder chain, starting from the first bridge to the last.
 483 *
 484 * Note: the bridge passed should be the one closest to the encoder
 485 *
 486 * RETURNS:
 487 * true on success, false on failure
 488 */
 489bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
 490				 const struct drm_display_mode *mode,
 491				 struct drm_display_mode *adjusted_mode)
 492{
 493	struct drm_encoder *encoder;
 494
 495	if (!bridge)
 496		return true;
 497
 498	encoder = bridge->encoder;
 499	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 500		if (!bridge->funcs->mode_fixup)
 501			continue;
 502
 503		if (!bridge->funcs->mode_fixup(bridge, mode, adjusted_mode))
 504			return false;
 505	}
 506
 507	return true;
 508}
 509EXPORT_SYMBOL(drm_bridge_chain_mode_fixup);
 510
 511/**
 512 * drm_bridge_chain_mode_valid - validate the mode against all bridges in the
 513 *				 encoder chain.
 514 * @bridge: bridge control structure
 515 * @info: display info against which the mode shall be validated
 516 * @mode: desired mode to be validated
 517 *
 518 * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
 519 * chain, starting from the first bridge to the last. If at least one bridge
 520 * does not accept the mode the function returns the error code.
 521 *
 522 * Note: the bridge passed should be the one closest to the encoder.
 523 *
 524 * RETURNS:
 525 * MODE_OK on success, drm_mode_status Enum error code on failure
 526 */
 527enum drm_mode_status
 528drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
 529			    const struct drm_display_info *info,
 530			    const struct drm_display_mode *mode)
 531{
 532	struct drm_encoder *encoder;
 533
 534	if (!bridge)
 535		return MODE_OK;
 536
 537	encoder = bridge->encoder;
 538	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 539		enum drm_mode_status ret;
 540
 541		if (!bridge->funcs->mode_valid)
 542			continue;
 543
 544		ret = bridge->funcs->mode_valid(bridge, info, mode);
 545		if (ret != MODE_OK)
 546			return ret;
 547	}
 548
 549	return MODE_OK;
 550}
 551EXPORT_SYMBOL(drm_bridge_chain_mode_valid);
 552
 553/**
 554 * drm_bridge_chain_mode_set - set proposed mode for all bridges in the
 555 *			       encoder chain
 556 * @bridge: bridge control structure
 557 * @mode: desired mode to be set for the encoder chain
 558 * @adjusted_mode: updated mode that works for this encoder chain
 559 *
 560 * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
 561 * encoder chain, starting from the first bridge to the last.
 562 *
 563 * Note: the bridge passed should be the one closest to the encoder
 564 */
 565void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
 566			       const struct drm_display_mode *mode,
 567			       const struct drm_display_mode *adjusted_mode)
 568{
 569	struct drm_encoder *encoder;
 570
 571	if (!bridge)
 572		return;
 573
 574	encoder = bridge->encoder;
 575	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 576		if (bridge->funcs->mode_set)
 577			bridge->funcs->mode_set(bridge, mode, adjusted_mode);
 578	}
 579}
 580EXPORT_SYMBOL(drm_bridge_chain_mode_set);
 581
 582/**
 583 * drm_atomic_bridge_chain_disable - disables all bridges in the encoder chain
 584 * @bridge: bridge control structure
 585 * @old_state: old atomic state
 586 *
 587 * Calls &drm_bridge_funcs.atomic_disable (falls back on
 588 * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
 589 * starting from the last bridge to the first. These are called before calling
 590 * &drm_encoder_helper_funcs.atomic_disable
 591 *
 592 * Note: the bridge passed should be the one closest to the encoder
 593 */
 594void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
 595				     struct drm_atomic_state *old_state)
 596{
 597	struct drm_encoder *encoder;
 598	struct drm_bridge *iter;
 599
 600	if (!bridge)
 601		return;
 602
 603	encoder = bridge->encoder;
 604	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
 605		if (iter->funcs->atomic_disable) {
 606			struct drm_bridge_state *old_bridge_state;
 607
 608			old_bridge_state =
 609				drm_atomic_get_old_bridge_state(old_state,
 610								iter);
 611			if (WARN_ON(!old_bridge_state))
 612				return;
 613
 614			iter->funcs->atomic_disable(iter, old_bridge_state);
 615		} else if (iter->funcs->disable) {
 616			iter->funcs->disable(iter);
 617		}
 618
 619		if (iter == bridge)
 620			break;
 621	}
 622}
 623EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
 624
 625static void drm_atomic_bridge_call_post_disable(struct drm_bridge *bridge,
 626						struct drm_atomic_state *old_state)
 627{
 628	if (old_state && bridge->funcs->atomic_post_disable) {
 629		struct drm_bridge_state *old_bridge_state;
 630
 631		old_bridge_state =
 632			drm_atomic_get_old_bridge_state(old_state,
 633							bridge);
 634		if (WARN_ON(!old_bridge_state))
 635			return;
 636
 637		bridge->funcs->atomic_post_disable(bridge,
 638						   old_bridge_state);
 639	} else if (bridge->funcs->post_disable) {
 640		bridge->funcs->post_disable(bridge);
 641	}
 642}
 643
 644/**
 645 * drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges
 646 *					  in the encoder chain
 647 * @bridge: bridge control structure
 648 * @old_state: old atomic state
 649 *
 650 * Calls &drm_bridge_funcs.atomic_post_disable (falls back on
 651 * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
 652 * starting from the first bridge to the last. These are called after completing
 653 * &drm_encoder_helper_funcs.atomic_disable
 654 *
 655 * If a bridge sets @pre_enable_prev_first, then the @post_disable for that
 656 * bridge will be called before the previous one to reverse the @pre_enable
 657 * calling direction.
 658 *
 659 * Note: the bridge passed should be the one closest to the encoder
 660 */
 661void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
 662					  struct drm_atomic_state *old_state)
 663{
 664	struct drm_encoder *encoder;
 665	struct drm_bridge *next, *limit;
 666
 667	if (!bridge)
 668		return;
 669
 670	encoder = bridge->encoder;
 671
 672	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 673		limit = NULL;
 674
 675		if (!list_is_last(&bridge->chain_node, &encoder->bridge_chain)) {
 676			next = list_next_entry(bridge, chain_node);
 677
 678			if (next->pre_enable_prev_first) {
 679				/* next bridge had requested that prev
 680				 * was enabled first, so disabled last
 681				 */
 682				limit = next;
 683
 684				/* Find the next bridge that has NOT requested
 685				 * prev to be enabled first / disabled last
 686				 */
 687				list_for_each_entry_from(next, &encoder->bridge_chain,
 688							 chain_node) {
 689					if (next->pre_enable_prev_first) {
 690						next = list_prev_entry(next, chain_node);
 691						limit = next;
 692						break;
 693					}
 
 
 
 
 
 
 694				}
 695
 696				/* Call these bridges in reverse order */
 697				list_for_each_entry_from_reverse(next, &encoder->bridge_chain,
 698								 chain_node) {
 699					if (next == bridge)
 700						break;
 701
 702					drm_atomic_bridge_call_post_disable(next,
 703									    old_state);
 704				}
 705			}
 706		}
 707
 708		drm_atomic_bridge_call_post_disable(bridge, old_state);
 709
 710		if (limit)
 711			/* Jump all bridges that we have already post_disabled */
 712			bridge = limit;
 713	}
 714}
 715EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
 716
 717static void drm_atomic_bridge_call_pre_enable(struct drm_bridge *bridge,
 718					      struct drm_atomic_state *old_state)
 719{
 720	if (old_state && bridge->funcs->atomic_pre_enable) {
 721		struct drm_bridge_state *old_bridge_state;
 722
 723		old_bridge_state =
 724			drm_atomic_get_old_bridge_state(old_state,
 725							bridge);
 726		if (WARN_ON(!old_bridge_state))
 727			return;
 728
 729		bridge->funcs->atomic_pre_enable(bridge, old_bridge_state);
 730	} else if (bridge->funcs->pre_enable) {
 731		bridge->funcs->pre_enable(bridge);
 732	}
 733}
 734
 735/**
 736 * drm_atomic_bridge_chain_pre_enable - prepares for enabling all bridges in
 737 *					the encoder chain
 738 * @bridge: bridge control structure
 739 * @old_state: old atomic state
 740 *
 741 * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
 742 * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
 743 * starting from the last bridge to the first. These are called before calling
 744 * &drm_encoder_helper_funcs.atomic_enable
 745 *
 746 * If a bridge sets @pre_enable_prev_first, then the pre_enable for the
 747 * prev bridge will be called before pre_enable of this bridge.
 748 *
 749 * Note: the bridge passed should be the one closest to the encoder
 750 */
 751void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
 752					struct drm_atomic_state *old_state)
 753{
 754	struct drm_encoder *encoder;
 755	struct drm_bridge *iter, *next, *limit;
 756
 757	if (!bridge)
 758		return;
 759
 760	encoder = bridge->encoder;
 761
 762	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
 763		if (iter->pre_enable_prev_first) {
 764			next = iter;
 765			limit = bridge;
 766			list_for_each_entry_from_reverse(next,
 767							 &encoder->bridge_chain,
 768							 chain_node) {
 769				if (next == bridge)
 770					break;
 771
 772				if (!next->pre_enable_prev_first) {
 773					/* Found first bridge that does NOT
 774					 * request prev to be enabled first
 775					 */
 776					limit = list_prev_entry(next, chain_node);
 777					break;
 778				}
 779			}
 780
 781			list_for_each_entry_from(next, &encoder->bridge_chain, chain_node) {
 782				/* Call requested prev bridge pre_enable
 783				 * in order.
 784				 */
 785				if (next == iter)
 786					/* At the first bridge to request prev
 787					 * bridges called first.
 788					 */
 789					break;
 790
 791				drm_atomic_bridge_call_pre_enable(next, old_state);
 792			}
 793		}
 794
 795		drm_atomic_bridge_call_pre_enable(iter, old_state);
 796
 797		if (iter->pre_enable_prev_first)
 798			/* Jump all bridges that we have already pre_enabled */
 799			iter = limit;
 800
 801		if (iter == bridge)
 802			break;
 803	}
 804}
 805EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
 806
 807/**
 808 * drm_atomic_bridge_chain_enable - enables all bridges in the encoder chain
 809 * @bridge: bridge control structure
 810 * @old_state: old atomic state
 811 *
 812 * Calls &drm_bridge_funcs.atomic_enable (falls back on
 813 * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain,
 814 * starting from the first bridge to the last. These are called after completing
 815 * &drm_encoder_helper_funcs.atomic_enable
 816 *
 817 * Note: the bridge passed should be the one closest to the encoder
 818 */
 819void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
 820				    struct drm_atomic_state *old_state)
 821{
 822	struct drm_encoder *encoder;
 823
 824	if (!bridge)
 825		return;
 826
 827	encoder = bridge->encoder;
 828	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 829		if (bridge->funcs->atomic_enable) {
 830			struct drm_bridge_state *old_bridge_state;
 831
 832			old_bridge_state =
 833				drm_atomic_get_old_bridge_state(old_state,
 834								bridge);
 835			if (WARN_ON(!old_bridge_state))
 836				return;
 837
 838			bridge->funcs->atomic_enable(bridge, old_bridge_state);
 839		} else if (bridge->funcs->enable) {
 840			bridge->funcs->enable(bridge);
 841		}
 842	}
 843}
 844EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
 845
 846static int drm_atomic_bridge_check(struct drm_bridge *bridge,
 847				   struct drm_crtc_state *crtc_state,
 848				   struct drm_connector_state *conn_state)
 849{
 850	if (bridge->funcs->atomic_check) {
 851		struct drm_bridge_state *bridge_state;
 852		int ret;
 853
 854		bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
 855							       bridge);
 856		if (WARN_ON(!bridge_state))
 857			return -EINVAL;
 858
 859		ret = bridge->funcs->atomic_check(bridge, bridge_state,
 860						  crtc_state, conn_state);
 861		if (ret)
 862			return ret;
 863	} else if (bridge->funcs->mode_fixup) {
 864		if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode,
 865					       &crtc_state->adjusted_mode))
 866			return -EINVAL;
 867	}
 868
 869	return 0;
 870}
 871
 872static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
 873				    struct drm_bridge *cur_bridge,
 874				    struct drm_crtc_state *crtc_state,
 875				    struct drm_connector_state *conn_state,
 876				    u32 out_bus_fmt)
 877{
 878	unsigned int i, num_in_bus_fmts = 0;
 879	struct drm_bridge_state *cur_state;
 880	struct drm_bridge *prev_bridge;
 881	u32 *in_bus_fmts;
 882	int ret;
 883
 884	prev_bridge = drm_bridge_get_prev_bridge(cur_bridge);
 885	cur_state = drm_atomic_get_new_bridge_state(crtc_state->state,
 886						    cur_bridge);
 887
 888	/*
 889	 * If bus format negotiation is not supported by this bridge, let's
 890	 * pass MEDIA_BUS_FMT_FIXED to the previous bridge in the chain and
 891	 * hope that it can handle this situation gracefully (by providing
 892	 * appropriate default values).
 893	 */
 894	if (!cur_bridge->funcs->atomic_get_input_bus_fmts) {
 895		if (cur_bridge != first_bridge) {
 896			ret = select_bus_fmt_recursive(first_bridge,
 897						       prev_bridge, crtc_state,
 898						       conn_state,
 899						       MEDIA_BUS_FMT_FIXED);
 900			if (ret)
 901				return ret;
 902		}
 903
 904		/*
 905		 * Driver does not implement the atomic state hooks, but that's
 906		 * fine, as long as it does not access the bridge state.
 907		 */
 908		if (cur_state) {
 909			cur_state->input_bus_cfg.format = MEDIA_BUS_FMT_FIXED;
 910			cur_state->output_bus_cfg.format = out_bus_fmt;
 911		}
 912
 913		return 0;
 914	}
 915
 916	/*
 917	 * If the driver implements ->atomic_get_input_bus_fmts() it
 918	 * should also implement the atomic state hooks.
 919	 */
 920	if (WARN_ON(!cur_state))
 921		return -EINVAL;
 922
 923	in_bus_fmts = cur_bridge->funcs->atomic_get_input_bus_fmts(cur_bridge,
 924							cur_state,
 925							crtc_state,
 926							conn_state,
 927							out_bus_fmt,
 928							&num_in_bus_fmts);
 929	if (!num_in_bus_fmts)
 930		return -ENOTSUPP;
 931	else if (!in_bus_fmts)
 932		return -ENOMEM;
 933
 934	if (first_bridge == cur_bridge) {
 935		cur_state->input_bus_cfg.format = in_bus_fmts[0];
 936		cur_state->output_bus_cfg.format = out_bus_fmt;
 937		kfree(in_bus_fmts);
 938		return 0;
 939	}
 940
 941	for (i = 0; i < num_in_bus_fmts; i++) {
 942		ret = select_bus_fmt_recursive(first_bridge, prev_bridge,
 943					       crtc_state, conn_state,
 944					       in_bus_fmts[i]);
 945		if (ret != -ENOTSUPP)
 946			break;
 947	}
 948
 949	if (!ret) {
 950		cur_state->input_bus_cfg.format = in_bus_fmts[i];
 951		cur_state->output_bus_cfg.format = out_bus_fmt;
 952	}
 953
 954	kfree(in_bus_fmts);
 955	return ret;
 956}
 957
 958/*
 959 * This function is called by &drm_atomic_bridge_chain_check() just before
 960 * calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
 961 * It performs bus format negotiation between bridge elements. The negotiation
 962 * happens in reverse order, starting from the last element in the chain up to
 963 * @bridge.
 964 *
 965 * Negotiation starts by retrieving supported output bus formats on the last
 966 * bridge element and testing them one by one. The test is recursive, meaning
 967 * that for each tested output format, the whole chain will be walked backward,
 968 * and each element will have to choose an input bus format that can be
 969 * transcoded to the requested output format. When a bridge element does not
 970 * support transcoding into a specific output format -ENOTSUPP is returned and
 971 * the next bridge element will have to try a different format. If none of the
 972 * combinations worked, -ENOTSUPP is returned and the atomic modeset will fail.
 973 *
 974 * This implementation is relying on
 975 * &drm_bridge_funcs.atomic_get_output_bus_fmts() and
 976 * &drm_bridge_funcs.atomic_get_input_bus_fmts() to gather supported
 977 * input/output formats.
 978 *
 979 * When &drm_bridge_funcs.atomic_get_output_bus_fmts() is not implemented by
 980 * the last element of the chain, &drm_atomic_bridge_chain_select_bus_fmts()
 981 * tries a single format: &drm_connector.display_info.bus_formats[0] if
 982 * available, MEDIA_BUS_FMT_FIXED otherwise.
 983 *
 984 * When &drm_bridge_funcs.atomic_get_input_bus_fmts() is not implemented,
 985 * &drm_atomic_bridge_chain_select_bus_fmts() skips the negotiation on the
 986 * bridge element that lacks this hook and asks the previous element in the
 987 * chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what
 988 * to do in that case (fail if they want to enforce bus format negotiation, or
 989 * provide a reasonable default if they need to support pipelines where not
 990 * all elements support bus format negotiation).
 991 */
 992static int
 993drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
 994					struct drm_crtc_state *crtc_state,
 995					struct drm_connector_state *conn_state)
 996{
 997	struct drm_connector *conn = conn_state->connector;
 998	struct drm_encoder *encoder = bridge->encoder;
 999	struct drm_bridge_state *last_bridge_state;
1000	unsigned int i, num_out_bus_fmts = 0;
1001	struct drm_bridge *last_bridge;
1002	u32 *out_bus_fmts;
1003	int ret = 0;
1004
1005	last_bridge = list_last_entry(&encoder->bridge_chain,
1006				      struct drm_bridge, chain_node);
1007	last_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
1008							    last_bridge);
1009
1010	if (last_bridge->funcs->atomic_get_output_bus_fmts) {
1011		const struct drm_bridge_funcs *funcs = last_bridge->funcs;
1012
1013		/*
1014		 * If the driver implements ->atomic_get_output_bus_fmts() it
1015		 * should also implement the atomic state hooks.
1016		 */
1017		if (WARN_ON(!last_bridge_state))
1018			return -EINVAL;
1019
1020		out_bus_fmts = funcs->atomic_get_output_bus_fmts(last_bridge,
1021							last_bridge_state,
1022							crtc_state,
1023							conn_state,
1024							&num_out_bus_fmts);
1025		if (!num_out_bus_fmts)
1026			return -ENOTSUPP;
1027		else if (!out_bus_fmts)
1028			return -ENOMEM;
1029	} else {
1030		num_out_bus_fmts = 1;
1031		out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
1032		if (!out_bus_fmts)
1033			return -ENOMEM;
1034
1035		if (conn->display_info.num_bus_formats &&
1036		    conn->display_info.bus_formats)
1037			out_bus_fmts[0] = conn->display_info.bus_formats[0];
1038		else
1039			out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
1040	}
1041
1042	for (i = 0; i < num_out_bus_fmts; i++) {
1043		ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
1044					       conn_state, out_bus_fmts[i]);
1045		if (ret != -ENOTSUPP)
1046			break;
1047	}
1048
1049	kfree(out_bus_fmts);
1050
1051	return ret;
1052}
1053
1054static void
1055drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge,
1056				      struct drm_connector *conn,
1057				      struct drm_atomic_state *state)
1058{
1059	struct drm_bridge_state *bridge_state, *next_bridge_state;
1060	struct drm_bridge *next_bridge;
1061	u32 output_flags = 0;
1062
1063	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
1064
1065	/* No bridge state attached to this bridge => nothing to propagate. */
1066	if (!bridge_state)
1067		return;
1068
1069	next_bridge = drm_bridge_get_next_bridge(bridge);
1070
1071	/*
1072	 * Let's try to apply the most common case here, that is, propagate
1073	 * display_info flags for the last bridge, and propagate the input
1074	 * flags of the next bridge element to the output end of the current
1075	 * bridge when the bridge is not the last one.
1076	 * There are exceptions to this rule, like when signal inversion is
1077	 * happening at the board level, but that's something drivers can deal
1078	 * with from their &drm_bridge_funcs.atomic_check() implementation by
1079	 * simply overriding the flags value we've set here.
1080	 */
1081	if (!next_bridge) {
1082		output_flags = conn->display_info.bus_flags;
1083	} else {
1084		next_bridge_state = drm_atomic_get_new_bridge_state(state,
1085								next_bridge);
1086		/*
1087		 * No bridge state attached to the next bridge, just leave the
1088		 * flags to 0.
1089		 */
1090		if (next_bridge_state)
1091			output_flags = next_bridge_state->input_bus_cfg.flags;
1092	}
1093
1094	bridge_state->output_bus_cfg.flags = output_flags;
1095
1096	/*
1097	 * Propagate the output flags to the input end of the bridge. Again, it's
1098	 * not necessarily what all bridges want, but that's what most of them
1099	 * do, and by doing that by default we avoid forcing drivers to
1100	 * duplicate the "dummy propagation" logic.
1101	 */
1102	bridge_state->input_bus_cfg.flags = output_flags;
1103}
1104
1105/**
1106 * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
1107 * @bridge: bridge control structure
1108 * @crtc_state: new CRTC state
1109 * @conn_state: new connector state
1110 *
1111 * First trigger a bus format negotiation before calling
1112 * &drm_bridge_funcs.atomic_check() (falls back on
1113 * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain,
1114 * starting from the last bridge to the first. These are called before calling
1115 * &drm_encoder_helper_funcs.atomic_check()
1116 *
1117 * RETURNS:
1118 * 0 on success, a negative error code on failure
1119 */
1120int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
1121				  struct drm_crtc_state *crtc_state,
1122				  struct drm_connector_state *conn_state)
1123{
1124	struct drm_connector *conn = conn_state->connector;
1125	struct drm_encoder *encoder;
1126	struct drm_bridge *iter;
1127	int ret;
1128
1129	if (!bridge)
1130		return 0;
1131
1132	ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state,
1133						      conn_state);
1134	if (ret)
1135		return ret;
1136
1137	encoder = bridge->encoder;
1138	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
1139		int ret;
1140
1141		/*
1142		 * Bus flags are propagated by default. If a bridge needs to
1143		 * tweak the input bus flags for any reason, it should happen
1144		 * in its &drm_bridge_funcs.atomic_check() implementation such
1145		 * that preceding bridges in the chain can propagate the new
1146		 * bus flags.
1147		 */
1148		drm_atomic_bridge_propagate_bus_flags(iter, conn,
1149						      crtc_state->state);
1150
1151		ret = drm_atomic_bridge_check(iter, crtc_state, conn_state);
1152		if (ret)
1153			return ret;
1154
1155		if (iter == bridge)
1156			break;
1157	}
1158
1159	return 0;
1160}
1161EXPORT_SYMBOL(drm_atomic_bridge_chain_check);
1162
1163/**
1164 * drm_bridge_detect - check if anything is attached to the bridge output
1165 * @bridge: bridge control structure
1166 *
1167 * If the bridge supports output detection, as reported by the
1168 * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the
1169 * bridge and return the connection status. Otherwise return
1170 * connector_status_unknown.
1171 *
1172 * RETURNS:
1173 * The detection status on success, or connector_status_unknown if the bridge
1174 * doesn't support output detection.
1175 */
1176enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge)
1177{
1178	if (!(bridge->ops & DRM_BRIDGE_OP_DETECT))
1179		return connector_status_unknown;
1180
1181	return bridge->funcs->detect(bridge);
1182}
1183EXPORT_SYMBOL_GPL(drm_bridge_detect);
1184
1185/**
1186 * drm_bridge_get_modes - fill all modes currently valid for the sink into the
1187 * @connector
1188 * @bridge: bridge control structure
1189 * @connector: the connector to fill with modes
1190 *
1191 * If the bridge supports output modes retrieval, as reported by the
1192 * DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to
1193 * fill the connector with all valid modes and return the number of modes
1194 * added. Otherwise return 0.
1195 *
1196 * RETURNS:
1197 * The number of modes added to the connector.
1198 */
1199int drm_bridge_get_modes(struct drm_bridge *bridge,
1200			 struct drm_connector *connector)
1201{
1202	if (!(bridge->ops & DRM_BRIDGE_OP_MODES))
1203		return 0;
1204
1205	return bridge->funcs->get_modes(bridge, connector);
1206}
1207EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
1208
1209/**
1210 * drm_bridge_get_edid - get the EDID data of the connected display
1211 * @bridge: bridge control structure
1212 * @connector: the connector to read EDID for
1213 *
1214 * If the bridge supports output EDID retrieval, as reported by the
1215 * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
1216 * get the EDID and return it. Otherwise return NULL.
1217 *
1218 * RETURNS:
1219 * The retrieved EDID on success, or NULL otherwise.
1220 */
1221struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
1222				 struct drm_connector *connector)
1223{
1224	if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
1225		return NULL;
1226
1227	return bridge->funcs->get_edid(bridge, connector);
1228}
1229EXPORT_SYMBOL_GPL(drm_bridge_get_edid);
1230
1231/**
1232 * drm_bridge_hpd_enable - enable hot plug detection for the bridge
1233 * @bridge: bridge control structure
1234 * @cb: hot-plug detection callback
1235 * @data: data to be passed to the hot-plug detection callback
1236 *
1237 * Call &drm_bridge_funcs.hpd_enable if implemented and register the given @cb
1238 * and @data as hot plug notification callback. From now on the @cb will be
1239 * called with @data when an output status change is detected by the bridge,
1240 * until hot plug notification gets disabled with drm_bridge_hpd_disable().
1241 *
1242 * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
1243 * bridge->ops. This function shall not be called when the flag is not set.
1244 *
1245 * Only one hot plug detection callback can be registered at a time, it is an
1246 * error to call this function when hot plug detection is already enabled for
1247 * the bridge.
1248 */
1249void drm_bridge_hpd_enable(struct drm_bridge *bridge,
1250			   void (*cb)(void *data,
1251				      enum drm_connector_status status),
1252			   void *data)
1253{
1254	if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
1255		return;
1256
1257	mutex_lock(&bridge->hpd_mutex);
1258
1259	if (WARN(bridge->hpd_cb, "Hot plug detection already enabled\n"))
1260		goto unlock;
1261
1262	bridge->hpd_cb = cb;
1263	bridge->hpd_data = data;
1264
1265	if (bridge->funcs->hpd_enable)
1266		bridge->funcs->hpd_enable(bridge);
1267
1268unlock:
1269	mutex_unlock(&bridge->hpd_mutex);
1270}
1271EXPORT_SYMBOL_GPL(drm_bridge_hpd_enable);
1272
1273/**
1274 * drm_bridge_hpd_disable - disable hot plug detection for the bridge
1275 * @bridge: bridge control structure
1276 *
1277 * Call &drm_bridge_funcs.hpd_disable if implemented and unregister the hot
1278 * plug detection callback previously registered with drm_bridge_hpd_enable().
1279 * Once this function returns the callback will not be called by the bridge
1280 * when an output status change occurs.
1281 *
1282 * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
1283 * bridge->ops. This function shall not be called when the flag is not set.
1284 */
1285void drm_bridge_hpd_disable(struct drm_bridge *bridge)
1286{
1287	if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
1288		return;
1289
1290	mutex_lock(&bridge->hpd_mutex);
1291	if (bridge->funcs->hpd_disable)
1292		bridge->funcs->hpd_disable(bridge);
1293
1294	bridge->hpd_cb = NULL;
1295	bridge->hpd_data = NULL;
1296	mutex_unlock(&bridge->hpd_mutex);
1297}
1298EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
1299
1300/**
1301 * drm_bridge_hpd_notify - notify hot plug detection events
1302 * @bridge: bridge control structure
1303 * @status: output connection status
1304 *
1305 * Bridge drivers shall call this function to report hot plug events when they
1306 * detect a change in the output status, when hot plug detection has been
1307 * enabled by drm_bridge_hpd_enable().
1308 *
1309 * This function shall be called in a context that can sleep.
1310 */
1311void drm_bridge_hpd_notify(struct drm_bridge *bridge,
1312			   enum drm_connector_status status)
1313{
1314	mutex_lock(&bridge->hpd_mutex);
1315	if (bridge->hpd_cb)
1316		bridge->hpd_cb(bridge->hpd_data, status);
1317	mutex_unlock(&bridge->hpd_mutex);
1318}
1319EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
1320
1321#ifdef CONFIG_OF
1322/**
1323 * of_drm_find_bridge - find the bridge corresponding to the device node in
1324 *			the global bridge list
1325 *
1326 * @np: device node
1327 *
1328 * RETURNS:
1329 * drm_bridge control struct on success, NULL on failure
1330 */
1331struct drm_bridge *of_drm_find_bridge(struct device_node *np)
1332{
1333	struct drm_bridge *bridge;
1334
1335	mutex_lock(&bridge_lock);
1336
1337	list_for_each_entry(bridge, &bridge_list, list) {
1338		if (bridge->of_node == np) {
1339			mutex_unlock(&bridge_lock);
1340			return bridge;
1341		}
1342	}
1343
1344	mutex_unlock(&bridge_lock);
1345	return NULL;
1346}
1347EXPORT_SYMBOL(of_drm_find_bridge);
1348#endif
1349
1350MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
1351MODULE_DESCRIPTION("DRM bridge infrastructure");
1352MODULE_LICENSE("GPL and additional rights");