1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB Typec-C DisplayPort Alternate Mode driver 4 * 5 * Copyright (C) 2018 Intel Corporation 6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com> 7 * 8 * DisplayPort is trademark of VESA (www.vesa.org) 9 */ 10 11 #include <linux/delay.h> 12 #include <linux/mutex.h> 13 #include <linux/module.h> 14 #include <linux/usb/pd_vdo.h> 15 #include <linux/usb/typec_dp.h> 16 #include "displayport.h" 17 18 #define DP_HEADER(_dp, ver, cmd) (VDO((_dp)->alt->svid, 1, ver, cmd) \ 19 | VDO_OPOS(USB_TYPEC_DP_MODE)) 20 21 enum { 22 DP_CONF_USB, 23 DP_CONF_DFP_D, 24 DP_CONF_UFP_D, 25 DP_CONF_DUAL_D, 26 }; 27 28 /* Pin assignments that use USB3.1 Gen2 signaling to carry DP protocol */ 29 #define DP_PIN_ASSIGN_GEN2_BR_MASK (BIT(DP_PIN_ASSIGN_A) | \ 30 BIT(DP_PIN_ASSIGN_B)) 31 32 /* Pin assignments that use DP v1.3 signaling to carry DP protocol */ 33 #define DP_PIN_ASSIGN_DP_BR_MASK (BIT(DP_PIN_ASSIGN_C) | \ 34 BIT(DP_PIN_ASSIGN_D) | \ 35 BIT(DP_PIN_ASSIGN_E) | \ 36 BIT(DP_PIN_ASSIGN_F)) 37 38 /* DP only pin assignments */ 39 #define DP_PIN_ASSIGN_DP_ONLY_MASK (BIT(DP_PIN_ASSIGN_A) | \ 40 BIT(DP_PIN_ASSIGN_C) | \ 41 BIT(DP_PIN_ASSIGN_E)) 42 43 /* Pin assignments where one channel is for USB */ 44 #define DP_PIN_ASSIGN_MULTI_FUNC_MASK (BIT(DP_PIN_ASSIGN_B) | \ 45 BIT(DP_PIN_ASSIGN_D) | \ 46 BIT(DP_PIN_ASSIGN_F)) 47 48 enum dp_state { 49 DP_STATE_IDLE, 50 DP_STATE_ENTER, 51 DP_STATE_UPDATE, 52 DP_STATE_CONFIGURE, 53 DP_STATE_EXIT, 54 }; 55 56 struct dp_altmode { 57 struct typec_displayport_data data; 58 59 enum dp_state state; 60 61 struct mutex lock; /* device lock */ 62 struct work_struct work; 63 struct typec_altmode *alt; 64 const struct typec_altmode *port; 65 }; 66 67 static int dp_altmode_notify(struct dp_altmode *dp) 68 { 69 u8 state = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf)); 70 71 return typec_altmode_notify(dp->alt, TYPEC_MODAL_STATE(state), 72 &dp->data); 73 } 74 75 static int dp_altmode_configure(struct dp_altmode *dp, u8 con) 76 { 77 u32 conf = DP_CONF_SIGNALING_DP; /* Only DP signaling supported */ 78 u8 pin_assign = 0; 79 80 switch (con) { 81 case DP_STATUS_CON_DISABLED: 82 return 0; 83 case DP_STATUS_CON_DFP_D: 84 conf |= DP_CONF_UFP_U_AS_DFP_D; 85 pin_assign = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo) & 86 DP_CAP_DFP_D_PIN_ASSIGN(dp->port->vdo); 87 break; 88 case DP_STATUS_CON_UFP_D: 89 case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */ 90 conf |= DP_CONF_UFP_U_AS_UFP_D; 91 pin_assign = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo) & 92 DP_CAP_UFP_D_PIN_ASSIGN(dp->port->vdo); 93 break; 94 default: 95 break; 96 } 97 98 /* Determining the initial pin assignment. */ 99 if (!DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) { 100 /* Is USB together with DP preferred */ 101 if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC && 102 pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK) 103 pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK; 104 else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK) 105 pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK; 106 107 if (!pin_assign) 108 return -EINVAL; 109 110 conf |= DP_CONF_SET_PIN_ASSIGN(pin_assign); 111 } 112 113 dp->data.conf = conf; 114 115 return 0; 116 } 117 118 static int dp_altmode_status_update(struct dp_altmode *dp) 119 { 120 bool configured = !!DP_CONF_GET_PIN_ASSIGN(dp->data.conf); 121 u8 con = DP_STATUS_CONNECTION(dp->data.status); 122 int ret = 0; 123 124 if (configured && (dp->data.status & DP_STATUS_SWITCH_TO_USB)) { 125 dp->data.conf = 0; 126 dp->state = DP_STATE_CONFIGURE; 127 } else if (dp->data.status & DP_STATUS_EXIT_DP_MODE) { 128 dp->state = DP_STATE_EXIT; 129 } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) { 130 ret = dp_altmode_configure(dp, con); 131 if (!ret) 132 dp->state = DP_STATE_CONFIGURE; 133 } 134 135 return ret; 136 } 137 138 static int dp_altmode_configured(struct dp_altmode *dp) 139 { 140 int ret; 141 142 sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration"); 143 144 if (!dp->data.conf) 145 return typec_altmode_notify(dp->alt, TYPEC_STATE_USB, 146 &dp->data); 147 148 ret = dp_altmode_notify(dp); 149 if (ret) 150 return ret; 151 152 sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment"); 153 154 return 0; 155 } 156 157 static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf) 158 { 159 int svdm_version = typec_altmode_get_svdm_version(dp->alt); 160 u32 header; 161 int ret; 162 163 if (svdm_version < 0) 164 return svdm_version; 165 166 header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE); 167 ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data); 168 if (ret) { 169 dev_err(&dp->alt->dev, 170 "unable to put to connector to safe mode\n"); 171 return ret; 172 } 173 174 ret = typec_altmode_vdm(dp->alt, header, &conf, 2); 175 if (ret) { 176 if (DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) 177 dp_altmode_notify(dp); 178 else 179 typec_altmode_notify(dp->alt, TYPEC_STATE_USB, 180 &dp->data); 181 } 182 183 return ret; 184 } 185 186 static void dp_altmode_work(struct work_struct *work) 187 { 188 struct dp_altmode *dp = container_of(work, struct dp_altmode, work); 189 int svdm_version; 190 u32 header; 191 u32 vdo; 192 int ret; 193 194 mutex_lock(&dp->lock); 195 196 switch (dp->state) { 197 case DP_STATE_ENTER: 198 ret = typec_altmode_enter(dp->alt, NULL); 199 if (ret && ret != -EBUSY) 200 dev_err(&dp->alt->dev, "failed to enter mode\n"); 201 break; 202 case DP_STATE_UPDATE: 203 svdm_version = typec_altmode_get_svdm_version(dp->alt); 204 if (svdm_version < 0) 205 break; 206 header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE); 207 vdo = 1; 208 ret = typec_altmode_vdm(dp->alt, header, &vdo, 2); 209 if (ret) 210 dev_err(&dp->alt->dev, 211 "unable to send Status Update command (%d)\n", 212 ret); 213 break; 214 case DP_STATE_CONFIGURE: 215 ret = dp_altmode_configure_vdm(dp, dp->data.conf); 216 if (ret) 217 dev_err(&dp->alt->dev, 218 "unable to send Configure command (%d)\n", ret); 219 break; 220 case DP_STATE_EXIT: 221 if (typec_altmode_exit(dp->alt)) 222 dev_err(&dp->alt->dev, "Exit Mode Failed!\n"); 223 break; 224 default: 225 break; 226 } 227 228 dp->state = DP_STATE_IDLE; 229 230 mutex_unlock(&dp->lock); 231 } 232 233 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo) 234 { 235 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 236 u8 old_state; 237 238 mutex_lock(&dp->lock); 239 240 old_state = dp->state; 241 dp->data.status = vdo; 242 243 if (old_state != DP_STATE_IDLE) 244 dev_warn(&alt->dev, "ATTENTION while processing state %d\n", 245 old_state); 246 247 if (dp_altmode_status_update(dp)) 248 dev_warn(&alt->dev, "%s: status update failed\n", __func__); 249 250 if (dp_altmode_notify(dp)) 251 dev_err(&alt->dev, "%s: notification failed\n", __func__); 252 253 if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE) 254 schedule_work(&dp->work); 255 256 mutex_unlock(&dp->lock); 257 } 258 259 static int dp_altmode_vdm(struct typec_altmode *alt, 260 const u32 hdr, const u32 *vdo, int count) 261 { 262 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 263 int cmd_type = PD_VDO_CMDT(hdr); 264 int cmd = PD_VDO_CMD(hdr); 265 int ret = 0; 266 267 mutex_lock(&dp->lock); 268 269 if (dp->state != DP_STATE_IDLE) { 270 ret = -EBUSY; 271 goto err_unlock; 272 } 273 274 switch (cmd_type) { 275 case CMDT_RSP_ACK: 276 switch (cmd) { 277 case CMD_ENTER_MODE: 278 dp->state = DP_STATE_UPDATE; 279 break; 280 case CMD_EXIT_MODE: 281 dp->data.status = 0; 282 dp->data.conf = 0; 283 break; 284 case DP_CMD_STATUS_UPDATE: 285 dp->data.status = *vdo; 286 ret = dp_altmode_status_update(dp); 287 break; 288 case DP_CMD_CONFIGURE: 289 ret = dp_altmode_configured(dp); 290 break; 291 default: 292 break; 293 } 294 break; 295 case CMDT_RSP_NAK: 296 switch (cmd) { 297 case DP_CMD_CONFIGURE: 298 dp->data.conf = 0; 299 ret = dp_altmode_configured(dp); 300 break; 301 default: 302 break; 303 } 304 break; 305 default: 306 break; 307 } 308 309 if (dp->state != DP_STATE_IDLE) 310 schedule_work(&dp->work); 311 312 err_unlock: 313 mutex_unlock(&dp->lock); 314 return ret; 315 } 316 317 static int dp_altmode_activate(struct typec_altmode *alt, int activate) 318 { 319 return activate ? typec_altmode_enter(alt, NULL) : 320 typec_altmode_exit(alt); 321 } 322 323 static const struct typec_altmode_ops dp_altmode_ops = { 324 .attention = dp_altmode_attention, 325 .vdm = dp_altmode_vdm, 326 .activate = dp_altmode_activate, 327 }; 328 329 static const char * const configurations[] = { 330 [DP_CONF_USB] = "USB", 331 [DP_CONF_DFP_D] = "source", 332 [DP_CONF_UFP_D] = "sink", 333 }; 334 335 static ssize_t 336 configuration_store(struct device *dev, struct device_attribute *attr, 337 const char *buf, size_t size) 338 { 339 struct dp_altmode *dp = dev_get_drvdata(dev); 340 u32 conf; 341 u32 cap; 342 int con; 343 int ret = 0; 344 345 con = sysfs_match_string(configurations, buf); 346 if (con < 0) 347 return con; 348 349 mutex_lock(&dp->lock); 350 351 if (dp->state != DP_STATE_IDLE) { 352 ret = -EBUSY; 353 goto err_unlock; 354 } 355 356 cap = DP_CAP_CAPABILITY(dp->alt->vdo); 357 358 if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) || 359 (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) { 360 ret = -EINVAL; 361 goto err_unlock; 362 } 363 364 conf = dp->data.conf & ~DP_CONF_DUAL_D; 365 conf |= con; 366 367 if (dp->alt->active) { 368 ret = dp_altmode_configure_vdm(dp, conf); 369 if (ret) 370 goto err_unlock; 371 } 372 373 dp->data.conf = conf; 374 375 err_unlock: 376 mutex_unlock(&dp->lock); 377 378 return ret ? ret : size; 379 } 380 381 static ssize_t configuration_show(struct device *dev, 382 struct device_attribute *attr, char *buf) 383 { 384 struct dp_altmode *dp = dev_get_drvdata(dev); 385 int len; 386 u8 cap; 387 u8 cur; 388 int i; 389 390 mutex_lock(&dp->lock); 391 392 cap = DP_CAP_CAPABILITY(dp->alt->vdo); 393 cur = DP_CONF_CURRENTLY(dp->data.conf); 394 395 len = sprintf(buf, "%s ", cur ? "USB" : "[USB]"); 396 397 for (i = 1; i < ARRAY_SIZE(configurations); i++) { 398 if (i == cur) 399 len += sprintf(buf + len, "[%s] ", configurations[i]); 400 else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) || 401 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D)) 402 len += sprintf(buf + len, "%s ", configurations[i]); 403 } 404 405 mutex_unlock(&dp->lock); 406 407 buf[len - 1] = '\n'; 408 return len; 409 } 410 static DEVICE_ATTR_RW(configuration); 411 412 static const char * const pin_assignments[] = { 413 [DP_PIN_ASSIGN_A] = "A", 414 [DP_PIN_ASSIGN_B] = "B", 415 [DP_PIN_ASSIGN_C] = "C", 416 [DP_PIN_ASSIGN_D] = "D", 417 [DP_PIN_ASSIGN_E] = "E", 418 [DP_PIN_ASSIGN_F] = "F", 419 }; 420 421 static ssize_t 422 pin_assignment_store(struct device *dev, struct device_attribute *attr, 423 const char *buf, size_t size) 424 { 425 struct dp_altmode *dp = dev_get_drvdata(dev); 426 u8 assignments; 427 u32 conf; 428 int ret; 429 430 ret = sysfs_match_string(pin_assignments, buf); 431 if (ret < 0) 432 return ret; 433 434 conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret)); 435 ret = 0; 436 437 mutex_lock(&dp->lock); 438 439 if (conf & dp->data.conf) 440 goto out_unlock; 441 442 if (dp->state != DP_STATE_IDLE) { 443 ret = -EBUSY; 444 goto out_unlock; 445 } 446 447 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D) 448 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo); 449 else 450 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo); 451 452 if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) { 453 ret = -EINVAL; 454 goto out_unlock; 455 } 456 457 conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK; 458 459 /* Only send Configure command if a configuration has been set */ 460 if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) { 461 ret = dp_altmode_configure_vdm(dp, conf); 462 if (ret) 463 goto out_unlock; 464 } 465 466 dp->data.conf = conf; 467 468 out_unlock: 469 mutex_unlock(&dp->lock); 470 471 return ret ? ret : size; 472 } 473 474 static ssize_t pin_assignment_show(struct device *dev, 475 struct device_attribute *attr, char *buf) 476 { 477 struct dp_altmode *dp = dev_get_drvdata(dev); 478 u8 assignments; 479 int len = 0; 480 u8 cur; 481 int i; 482 483 mutex_lock(&dp->lock); 484 485 cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf)); 486 487 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D) 488 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo); 489 else 490 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo); 491 492 for (i = 0; assignments; assignments >>= 1, i++) { 493 if (assignments & 1) { 494 if (i == cur) 495 len += sprintf(buf + len, "[%s] ", 496 pin_assignments[i]); 497 else 498 len += sprintf(buf + len, "%s ", 499 pin_assignments[i]); 500 } 501 } 502 503 mutex_unlock(&dp->lock); 504 505 buf[len - 1] = '\n'; 506 return len; 507 } 508 static DEVICE_ATTR_RW(pin_assignment); 509 510 static struct attribute *dp_altmode_attrs[] = { 511 &dev_attr_configuration.attr, 512 &dev_attr_pin_assignment.attr, 513 NULL 514 }; 515 516 static const struct attribute_group dp_altmode_group = { 517 .name = "displayport", 518 .attrs = dp_altmode_attrs, 519 }; 520 521 int dp_altmode_probe(struct typec_altmode *alt) 522 { 523 const struct typec_altmode *port = typec_altmode_get_partner(alt); 524 struct dp_altmode *dp; 525 int ret; 526 527 /* FIXME: Port can only be DFP_U. */ 528 529 /* Make sure we have compatiple pin configurations */ 530 if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) & 531 DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) && 532 !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) & 533 DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo))) 534 return -ENODEV; 535 536 ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group); 537 if (ret) 538 return ret; 539 540 dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL); 541 if (!dp) 542 return -ENOMEM; 543 544 INIT_WORK(&dp->work, dp_altmode_work); 545 mutex_init(&dp->lock); 546 dp->port = port; 547 dp->alt = alt; 548 549 alt->desc = "DisplayPort"; 550 alt->ops = &dp_altmode_ops; 551 552 typec_altmode_set_drvdata(alt, dp); 553 554 dp->state = DP_STATE_ENTER; 555 schedule_work(&dp->work); 556 557 return 0; 558 } 559 EXPORT_SYMBOL_GPL(dp_altmode_probe); 560 561 void dp_altmode_remove(struct typec_altmode *alt) 562 { 563 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 564 565 sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group); 566 cancel_work_sync(&dp->work); 567 } 568 EXPORT_SYMBOL_GPL(dp_altmode_remove); 569 570 static const struct typec_device_id dp_typec_id[] = { 571 { USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE }, 572 { }, 573 }; 574 MODULE_DEVICE_TABLE(typec, dp_typec_id); 575 576 static struct typec_altmode_driver dp_altmode_driver = { 577 .id_table = dp_typec_id, 578 .probe = dp_altmode_probe, 579 .remove = dp_altmode_remove, 580 .driver = { 581 .name = "typec_displayport", 582 .owner = THIS_MODULE, 583 }, 584 }; 585 module_typec_altmode_driver(dp_altmode_driver); 586 587 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>"); 588 MODULE_LICENSE("GPL v2"); 589 MODULE_DESCRIPTION("DisplayPort Alternate Mode"); 590