1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/component.h> 3 #include <linux/export.h> 4 #include <linux/list.h> 5 #include <linux/media-bus-format.h> 6 #include <linux/of.h> 7 #include <linux/of_graph.h> 8 9 #include <drm/drm_bridge.h> 10 #include <drm/drm_connector.h> 11 #include <drm/drm_crtc.h> 12 #include <drm/drm_device.h> 13 #include <drm/drm_encoder.h> 14 #include <drm/drm_mipi_dsi.h> 15 #include <drm/drm_of.h> 16 #include <drm/drm_panel.h> 17 18 /** 19 * DOC: overview 20 * 21 * A set of helper functions to aid DRM drivers in parsing standard DT 22 * properties. 23 */ 24 25 /** 26 * drm_of_crtc_port_mask - find the mask of a registered CRTC by port OF node 27 * @dev: DRM device 28 * @port: port OF node 29 * 30 * Given a port OF node, return the possible mask of the corresponding 31 * CRTC within a device's list of CRTCs. Returns zero if not found. 32 */ 33 uint32_t drm_of_crtc_port_mask(struct drm_device *dev, 34 struct device_node *port) 35 { 36 unsigned int index = 0; 37 struct drm_crtc *tmp; 38 39 drm_for_each_crtc(tmp, dev) { 40 if (tmp->port == port) 41 return 1 << index; 42 43 index++; 44 } 45 46 return 0; 47 } 48 EXPORT_SYMBOL(drm_of_crtc_port_mask); 49 50 /** 51 * drm_of_find_possible_crtcs - find the possible CRTCs for an encoder port 52 * @dev: DRM device 53 * @port: encoder port to scan for endpoints 54 * 55 * Scan all endpoints attached to a port, locate their attached CRTCs, 56 * and generate the DRM mask of CRTCs which may be attached to this 57 * encoder. 58 * 59 * See https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/graph.yaml 60 * for the bindings. 61 */ 62 uint32_t drm_of_find_possible_crtcs(struct drm_device *dev, 63 struct device_node *port) 64 { 65 struct device_node *remote_port, *ep; 66 uint32_t possible_crtcs = 0; 67 68 for_each_endpoint_of_node(port, ep) { 69 remote_port = of_graph_get_remote_port(ep); 70 if (!remote_port) { 71 of_node_put(ep); 72 return 0; 73 } 74 75 possible_crtcs |= drm_of_crtc_port_mask(dev, remote_port); 76 77 of_node_put(remote_port); 78 } 79 80 return possible_crtcs; 81 } 82 EXPORT_SYMBOL(drm_of_find_possible_crtcs); 83 84 /** 85 * drm_of_component_match_add - Add a component helper OF node match rule 86 * @master: master device 87 * @matchptr: component match pointer 88 * @compare: compare function used for matching component 89 * @node: of_node 90 */ 91 void drm_of_component_match_add(struct device *master, 92 struct component_match **matchptr, 93 int (*compare)(struct device *, void *), 94 struct device_node *node) 95 { 96 of_node_get(node); 97 component_match_add_release(master, matchptr, component_release_of, 98 compare, node); 99 } 100 EXPORT_SYMBOL_GPL(drm_of_component_match_add); 101 102 /** 103 * drm_of_component_probe - Generic probe function for a component based master 104 * @dev: master device containing the OF node 105 * @compare_of: compare function used for matching components 106 * @m_ops: component master ops to be used 107 * 108 * Parse the platform device OF node and bind all the components associated 109 * with the master. Interface ports are added before the encoders in order to 110 * satisfy their .bind requirements 111 * 112 * See https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/graph.yaml 113 * for the bindings. 114 * 115 * Returns zero if successful, or one of the standard error codes if it fails. 116 */ 117 int drm_of_component_probe(struct device *dev, 118 int (*compare_of)(struct device *, void *), 119 const struct component_master_ops *m_ops) 120 { 121 struct device_node *ep, *port, *remote; 122 struct component_match *match = NULL; 123 int i; 124 125 if (!dev->of_node) 126 return -EINVAL; 127 128 /* 129 * Bind the crtc's ports first, so that drm_of_find_possible_crtcs() 130 * called from encoder's .bind callbacks works as expected 131 */ 132 for (i = 0; ; i++) { 133 port = of_parse_phandle(dev->of_node, "ports", i); 134 if (!port) 135 break; 136 137 if (of_device_is_available(port->parent)) 138 drm_of_component_match_add(dev, &match, compare_of, 139 port); 140 141 of_node_put(port); 142 } 143 144 if (i == 0) { 145 dev_err(dev, "missing 'ports' property\n"); 146 return -ENODEV; 147 } 148 149 if (!match) { 150 dev_err(dev, "no available port\n"); 151 return -ENODEV; 152 } 153 154 /* 155 * For bound crtcs, bind the encoders attached to their remote endpoint 156 */ 157 for (i = 0; ; i++) { 158 port = of_parse_phandle(dev->of_node, "ports", i); 159 if (!port) 160 break; 161 162 if (!of_device_is_available(port->parent)) { 163 of_node_put(port); 164 continue; 165 } 166 167 for_each_child_of_node(port, ep) { 168 remote = of_graph_get_remote_port_parent(ep); 169 if (!remote || !of_device_is_available(remote)) { 170 of_node_put(remote); 171 continue; 172 } else if (!of_device_is_available(remote->parent)) { 173 dev_warn(dev, "parent device of %pOF is not available\n", 174 remote); 175 of_node_put(remote); 176 continue; 177 } 178 179 drm_of_component_match_add(dev, &match, compare_of, 180 remote); 181 of_node_put(remote); 182 } 183 of_node_put(port); 184 } 185 186 return component_master_add_with_match(dev, m_ops, match); 187 } 188 EXPORT_SYMBOL(drm_of_component_probe); 189 190 /* 191 * drm_of_encoder_active_endpoint - return the active encoder endpoint 192 * @node: device tree node containing encoder input ports 193 * @encoder: drm_encoder 194 * 195 * Given an encoder device node and a drm_encoder with a connected crtc, 196 * parse the encoder endpoint connecting to the crtc port. 197 */ 198 int drm_of_encoder_active_endpoint(struct device_node *node, 199 struct drm_encoder *encoder, 200 struct of_endpoint *endpoint) 201 { 202 struct device_node *ep; 203 struct drm_crtc *crtc = encoder->crtc; 204 struct device_node *port; 205 int ret; 206 207 if (!node || !crtc) 208 return -EINVAL; 209 210 for_each_endpoint_of_node(node, ep) { 211 port = of_graph_get_remote_port(ep); 212 of_node_put(port); 213 if (port == crtc->port) { 214 ret = of_graph_parse_endpoint(ep, endpoint); 215 of_node_put(ep); 216 return ret; 217 } 218 } 219 220 return -EINVAL; 221 } 222 EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint); 223 224 /** 225 * drm_of_get_panel_orientation - look up the orientation of the panel through 226 * the "rotation" binding from a device tree node 227 * @np: device tree node of the panel 228 * @orientation: orientation enum to be filled in 229 * 230 * Looks up the rotation of a panel in the device tree. The orientation of the 231 * panel is expressed as a property name "rotation" in the device tree. The 232 * rotation in the device tree is counter clockwise. 233 * 234 * Return: 0 when a valid rotation value (0, 90, 180, or 270) is read or the 235 * rotation property doesn't exist. Return a negative error code on failure. 236 */ 237 int drm_of_get_panel_orientation(const struct device_node *np, 238 enum drm_panel_orientation *orientation) 239 { 240 int rotation, ret; 241 242 ret = of_property_read_u32(np, "rotation", &rotation); 243 if (ret == -EINVAL) { 244 /* Don't return an error if there's no rotation property. */ 245 *orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN; 246 return 0; 247 } 248 249 if (ret < 0) 250 return ret; 251 252 if (rotation == 0) 253 *orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL; 254 else if (rotation == 90) 255 *orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP; 256 else if (rotation == 180) 257 *orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP; 258 else if (rotation == 270) 259 *orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP; 260 else 261 return -EINVAL; 262 263 return 0; 264 } 265 EXPORT_SYMBOL_GPL(drm_of_get_panel_orientation); 266 267 /** 268 * drm_of_find_panel_or_bridge - return connected panel or bridge device 269 * @np: device tree node containing encoder output ports 270 * @port: port in the device tree node 271 * @endpoint: endpoint in the device tree node 272 * @panel: pointer to hold returned drm_panel, must not be NULL 273 * @bridge: pointer to hold returned drm_bridge 274 * 275 * Given a DT node's port and endpoint number, find the connected node and 276 * return either the associated struct drm_panel or drm_bridge device. 277 * 278 * This function is deprecated and should not be used in new drivers. Use 279 * of_drm_get_bridge_by_endpoint() instead when not looking for a panel, or 280 * devm_drm_of_get_bridge() otherwise. 281 * 282 * Returns zero if successful, or one of the standard error codes if it fails. 283 */ 284 int drm_of_find_panel_or_bridge(const struct device_node *np, 285 int port, int endpoint, 286 struct drm_panel **panel, 287 struct drm_bridge **bridge) 288 { 289 int ret = -EPROBE_DEFER; 290 struct device_node *remote; 291 292 if (WARN_ON(!panel)) 293 return -EINVAL; 294 295 *panel = NULL; 296 297 /* 298 * of_graph_get_remote_node() produces a noisy error message if port 299 * node isn't found and the absence of the port is a legit case here, 300 * so at first we silently check whether graph presents in the 301 * device-tree node. 302 */ 303 if (!of_graph_is_present(np)) 304 return -ENODEV; 305 306 remote = of_graph_get_remote_node(np, port, endpoint); 307 if (!remote) 308 return -ENODEV; 309 310 *panel = of_drm_find_panel(remote); 311 if (!IS_ERR(*panel)) 312 ret = 0; 313 else 314 *panel = NULL; 315 316 if (bridge) { 317 if (ret) { 318 /* No panel found yet, check for a bridge next. */ 319 *bridge = of_drm_find_bridge(remote); 320 if (*bridge) 321 ret = 0; 322 } else { 323 *bridge = NULL; 324 } 325 326 } 327 328 of_node_put(remote); 329 return ret; 330 } 331 EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge); 332 333 enum drm_of_lvds_pixels { 334 DRM_OF_LVDS_EVEN = BIT(0), 335 DRM_OF_LVDS_ODD = BIT(1), 336 }; 337 338 static int drm_of_lvds_get_port_pixels_type(struct device_node *port_node) 339 { 340 bool even_pixels = 341 of_property_read_bool(port_node, "dual-lvds-even-pixels"); 342 bool odd_pixels = 343 of_property_read_bool(port_node, "dual-lvds-odd-pixels"); 344 345 return (even_pixels ? DRM_OF_LVDS_EVEN : 0) | 346 (odd_pixels ? DRM_OF_LVDS_ODD : 0); 347 } 348 349 static int drm_of_lvds_get_remote_pixels_type( 350 const struct device_node *port_node) 351 { 352 struct device_node *endpoint = NULL; 353 int pixels_type = -EPIPE; 354 355 for_each_child_of_node(port_node, endpoint) { 356 struct device_node *remote_port; 357 int current_pt; 358 359 if (!of_node_name_eq(endpoint, "endpoint")) 360 continue; 361 362 remote_port = of_graph_get_remote_port(endpoint); 363 if (!remote_port) { 364 of_node_put(endpoint); 365 return -EPIPE; 366 } 367 368 current_pt = drm_of_lvds_get_port_pixels_type(remote_port); 369 of_node_put(remote_port); 370 if (pixels_type < 0) 371 pixels_type = current_pt; 372 373 /* 374 * Sanity check, ensure that all remote endpoints have the same 375 * pixel type. We may lift this restriction later if we need to 376 * support multiple sinks with different dual-link 377 * configurations by passing the endpoints explicitly to 378 * drm_of_lvds_get_dual_link_pixel_order(). 379 */ 380 if (!current_pt || pixels_type != current_pt) { 381 of_node_put(endpoint); 382 return -EINVAL; 383 } 384 } 385 386 return pixels_type; 387 } 388 389 static int __drm_of_lvds_get_dual_link_pixel_order(int p1_pt, int p2_pt) 390 { 391 /* 392 * A valid dual-lVDS bus is found when one port is marked with 393 * "dual-lvds-even-pixels", and the other port is marked with 394 * "dual-lvds-odd-pixels", bail out if the markers are not right. 395 */ 396 if (p1_pt + p2_pt != DRM_OF_LVDS_EVEN + DRM_OF_LVDS_ODD) 397 return -EINVAL; 398 399 return p1_pt == DRM_OF_LVDS_EVEN ? 400 DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS : 401 DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS; 402 } 403 404 /** 405 * drm_of_lvds_get_dual_link_pixel_order - Get LVDS dual-link source pixel order 406 * @port1: First DT port node of the Dual-link LVDS source 407 * @port2: Second DT port node of the Dual-link LVDS source 408 * 409 * An LVDS dual-link connection is made of two links, with even pixels 410 * transitting on one link, and odd pixels on the other link. This function 411 * returns, for two ports of an LVDS dual-link source, which port shall transmit 412 * the even and odd pixels, based on the requirements of the connected sink. 413 * 414 * The pixel order is determined from the dual-lvds-even-pixels and 415 * dual-lvds-odd-pixels properties in the sink's DT port nodes. If those 416 * properties are not present, or if their usage is not valid, this function 417 * returns -EINVAL. 418 * 419 * If either port is not connected, this function returns -EPIPE. 420 * 421 * @port1 and @port2 are typically DT sibling nodes, but may have different 422 * parents when, for instance, two separate LVDS encoders carry the even and odd 423 * pixels. 424 * 425 * Return: 426 * * DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS - @port1 carries even pixels and @port2 427 * carries odd pixels 428 * * DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS - @port1 carries odd pixels and @port2 429 * carries even pixels 430 * * -EINVAL - @port1 and @port2 are not connected to a dual-link LVDS sink, or 431 * the sink configuration is invalid 432 * * -EPIPE - when @port1 or @port2 are not connected 433 */ 434 int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1, 435 const struct device_node *port2) 436 { 437 int remote_p1_pt, remote_p2_pt; 438 439 if (!port1 || !port2) 440 return -EINVAL; 441 442 remote_p1_pt = drm_of_lvds_get_remote_pixels_type(port1); 443 if (remote_p1_pt < 0) 444 return remote_p1_pt; 445 446 remote_p2_pt = drm_of_lvds_get_remote_pixels_type(port2); 447 if (remote_p2_pt < 0) 448 return remote_p2_pt; 449 450 return __drm_of_lvds_get_dual_link_pixel_order(remote_p1_pt, remote_p2_pt); 451 } 452 EXPORT_SYMBOL_GPL(drm_of_lvds_get_dual_link_pixel_order); 453 454 /** 455 * drm_of_lvds_get_dual_link_pixel_order_sink - Get LVDS dual-link sink pixel order 456 * @port1: First DT port node of the Dual-link LVDS sink 457 * @port2: Second DT port node of the Dual-link LVDS sink 458 * 459 * An LVDS dual-link connection is made of two links, with even pixels 460 * transitting on one link, and odd pixels on the other link. This function 461 * returns, for two ports of an LVDS dual-link sink, which port shall transmit 462 * the even and odd pixels, based on the requirements of the sink. 463 * 464 * The pixel order is determined from the dual-lvds-even-pixels and 465 * dual-lvds-odd-pixels properties in the sink's DT port nodes. If those 466 * properties are not present, or if their usage is not valid, this function 467 * returns -EINVAL. 468 * 469 * If either port is not connected, this function returns -EPIPE. 470 * 471 * @port1 and @port2 are typically DT sibling nodes, but may have different 472 * parents when, for instance, two separate LVDS decoders receive the even and 473 * odd pixels. 474 * 475 * Return: 476 * * DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS - @port1 receives even pixels and @port2 477 * receives odd pixels 478 * * DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS - @port1 receives odd pixels and @port2 479 * receives even pixels 480 * * -EINVAL - @port1 or @port2 are NULL 481 * * -EPIPE - when @port1 or @port2 are not connected 482 */ 483 int drm_of_lvds_get_dual_link_pixel_order_sink(struct device_node *port1, 484 struct device_node *port2) 485 { 486 int sink_p1_pt, sink_p2_pt; 487 488 if (!port1 || !port2) 489 return -EINVAL; 490 491 sink_p1_pt = drm_of_lvds_get_port_pixels_type(port1); 492 if (!sink_p1_pt) 493 return -EPIPE; 494 495 sink_p2_pt = drm_of_lvds_get_port_pixels_type(port2); 496 if (!sink_p2_pt) 497 return -EPIPE; 498 499 return __drm_of_lvds_get_dual_link_pixel_order(sink_p1_pt, sink_p2_pt); 500 } 501 EXPORT_SYMBOL_GPL(drm_of_lvds_get_dual_link_pixel_order_sink); 502 503 /** 504 * drm_of_lvds_get_data_mapping - Get LVDS data mapping 505 * @port: DT port node of the LVDS source or sink 506 * 507 * Convert DT "data-mapping" property string value into media bus format value. 508 * 509 * Return: 510 * * MEDIA_BUS_FMT_RGB666_1X7X3_SPWG - data-mapping is "jeida-18" 511 * * MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA - data-mapping is "jeida-24" 512 * * MEDIA_BUS_FMT_RGB101010_1X7X5_JEIDA - data-mapping is "jeida-30" 513 * * MEDIA_BUS_FMT_RGB888_1X7X4_SPWG - data-mapping is "vesa-24" 514 * * MEDIA_BUS_FMT_RGB101010_1X7X5_SPWG - data-mapping is "vesa-30" 515 * * -EINVAL - the "data-mapping" property is unsupported 516 * * -ENODEV - the "data-mapping" property is missing 517 */ 518 int drm_of_lvds_get_data_mapping(const struct device_node *port) 519 { 520 const char *mapping; 521 int ret; 522 523 ret = of_property_read_string(port, "data-mapping", &mapping); 524 if (ret < 0) 525 return -ENODEV; 526 527 if (!strcmp(mapping, "jeida-18")) 528 return MEDIA_BUS_FMT_RGB666_1X7X3_SPWG; 529 if (!strcmp(mapping, "jeida-24")) 530 return MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA; 531 if (!strcmp(mapping, "jeida-30")) 532 return MEDIA_BUS_FMT_RGB101010_1X7X5_JEIDA; 533 if (!strcmp(mapping, "vesa-24")) 534 return MEDIA_BUS_FMT_RGB888_1X7X4_SPWG; 535 if (!strcmp(mapping, "vesa-30")) 536 return MEDIA_BUS_FMT_RGB101010_1X7X5_SPWG; 537 538 return -EINVAL; 539 } 540 EXPORT_SYMBOL_GPL(drm_of_lvds_get_data_mapping); 541 542 /** 543 * drm_of_get_data_lanes_count - Get DSI/(e)DP data lane count 544 * @endpoint: DT endpoint node of the DSI/(e)DP source or sink 545 * @min: minimum supported number of data lanes 546 * @max: maximum supported number of data lanes 547 * 548 * Count DT "data-lanes" property elements and check for validity. 549 * 550 * Return: 551 * * min..max - positive integer count of "data-lanes" elements 552 * * -ve - the "data-lanes" property is missing or invalid 553 * * -EINVAL - the "data-lanes" property is unsupported 554 */ 555 int drm_of_get_data_lanes_count(const struct device_node *endpoint, 556 const unsigned int min, const unsigned int max) 557 { 558 int ret; 559 560 ret = of_property_count_u32_elems(endpoint, "data-lanes"); 561 if (ret < 0) 562 return ret; 563 564 if (ret < min || ret > max) 565 return -EINVAL; 566 567 return ret; 568 } 569 EXPORT_SYMBOL_GPL(drm_of_get_data_lanes_count); 570 571 /** 572 * drm_of_get_data_lanes_count_ep - Get DSI/(e)DP data lane count by endpoint 573 * @port: DT port node of the DSI/(e)DP source or sink 574 * @port_reg: identifier (value of reg property) of the parent port node 575 * @reg: identifier (value of reg property) of the endpoint node 576 * @min: minimum supported number of data lanes 577 * @max: maximum supported number of data lanes 578 * 579 * Count DT "data-lanes" property elements and check for validity. 580 * This variant uses endpoint specifier. 581 * 582 * Return: 583 * * min..max - positive integer count of "data-lanes" elements 584 * * -EINVAL - the "data-mapping" property is unsupported 585 * * -ENODEV - the "data-mapping" property is missing 586 */ 587 int drm_of_get_data_lanes_count_ep(const struct device_node *port, 588 int port_reg, int reg, 589 const unsigned int min, 590 const unsigned int max) 591 { 592 struct device_node *endpoint; 593 int ret; 594 595 endpoint = of_graph_get_endpoint_by_regs(port, port_reg, reg); 596 ret = drm_of_get_data_lanes_count(endpoint, min, max); 597 of_node_put(endpoint); 598 599 return ret; 600 } 601 EXPORT_SYMBOL_GPL(drm_of_get_data_lanes_count_ep); 602 603 /** 604 * drm_of_get_data_lanes_count_remote - Get DSI/(e)DP data lane count by endpoint 605 * @port: DT port node of the DSI/(e)DP source or sink 606 * @port_reg: identifier (value of reg property) of the parent port node 607 * @reg: identifier (value of reg property) of the endpoint node 608 * @min: minimum supported number of data lanes 609 * @max: maximum supported number of data lanes 610 * 611 * Count DT "data-lanes" property elements in the remote endpoint and check for 612 * validity. This variant uses endpoint specifier. 613 * 614 * Return: 615 * * min..max - positive integer count of "data-lanes" elements 616 * * -EINVAL - the "data-lanes" property is unsupported 617 * * -ENODEV - the "data-lanes" property is missing 618 */ 619 int drm_of_get_data_lanes_count_remote(const struct device_node *port, 620 int port_reg, int reg, 621 const unsigned int min, 622 const unsigned int max) 623 { 624 struct device_node *endpoint, *remote; 625 int ret; 626 627 endpoint = of_graph_get_endpoint_by_regs(port, port_reg, reg); 628 remote = of_graph_get_remote_endpoint(endpoint); 629 of_node_put(endpoint); 630 ret = drm_of_get_data_lanes_count(remote, min, max); 631 of_node_put(remote); 632 633 return ret; 634 } 635 EXPORT_SYMBOL_GPL(drm_of_get_data_lanes_count_remote); 636 637 #if IS_ENABLED(CONFIG_DRM_MIPI_DSI) 638 639 /** 640 * drm_of_get_dsi_bus - find the DSI bus for a given device 641 * @dev: parent device of display (SPI, I2C) 642 * 643 * Gets parent DSI bus for a DSI device controlled through a bus other 644 * than MIPI-DCS (SPI, I2C, etc.) using the Device Tree. 645 * 646 * This function assumes that the device's port@0 is the DSI input. 647 * 648 * Returns pointer to mipi_dsi_host if successful, -EINVAL if the 649 * request is unsupported, -EPROBE_DEFER if the DSI host is found but 650 * not available, or -ENODEV otherwise. 651 */ 652 struct mipi_dsi_host *drm_of_get_dsi_bus(struct device *dev) 653 { 654 struct mipi_dsi_host *dsi_host; 655 struct device_node *endpoint, *dsi_host_node; 656 657 /* 658 * Get first endpoint child from device. 659 */ 660 endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1); 661 if (!endpoint) 662 return ERR_PTR(-ENODEV); 663 664 /* 665 * Follow the first endpoint to get the DSI host node and then 666 * release the endpoint since we no longer need it. 667 */ 668 dsi_host_node = of_graph_get_remote_port_parent(endpoint); 669 of_node_put(endpoint); 670 if (!dsi_host_node) 671 return ERR_PTR(-ENODEV); 672 673 /* 674 * Get the DSI host from the DSI host node. If we get an error 675 * or the return is null assume we're not ready to probe just 676 * yet. Release the DSI host node since we're done with it. 677 */ 678 dsi_host = of_find_mipi_dsi_host_by_node(dsi_host_node); 679 of_node_put(dsi_host_node); 680 if (IS_ERR_OR_NULL(dsi_host)) 681 return ERR_PTR(-EPROBE_DEFER); 682 683 return dsi_host; 684 } 685 EXPORT_SYMBOL_GPL(drm_of_get_dsi_bus); 686 687 #endif /* CONFIG_DRM_MIPI_DSI */ 688