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, cmd) (VDO((_dp)->alt->svid, 1, 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 u32 header = DP_HEADER(dp, DP_CMD_CONFIGURE); 160 int ret; 161 162 ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data); 163 if (ret) { 164 dev_err(&dp->alt->dev, 165 "unable to put to connector to safe mode\n"); 166 return ret; 167 } 168 169 ret = typec_altmode_vdm(dp->alt, header, &conf, 2); 170 if (ret) { 171 if (DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) 172 dp_altmode_notify(dp); 173 else 174 typec_altmode_notify(dp->alt, TYPEC_STATE_USB, 175 &dp->data); 176 } 177 178 return ret; 179 } 180 181 static void dp_altmode_work(struct work_struct *work) 182 { 183 struct dp_altmode *dp = container_of(work, struct dp_altmode, work); 184 u32 header; 185 u32 vdo; 186 int ret; 187 188 mutex_lock(&dp->lock); 189 190 switch (dp->state) { 191 case DP_STATE_ENTER: 192 ret = typec_altmode_enter(dp->alt, NULL); 193 if (ret) 194 dev_err(&dp->alt->dev, "failed to enter mode\n"); 195 break; 196 case DP_STATE_UPDATE: 197 header = DP_HEADER(dp, DP_CMD_STATUS_UPDATE); 198 vdo = 1; 199 ret = typec_altmode_vdm(dp->alt, header, &vdo, 2); 200 if (ret) 201 dev_err(&dp->alt->dev, 202 "unable to send Status Update command (%d)\n", 203 ret); 204 break; 205 case DP_STATE_CONFIGURE: 206 ret = dp_altmode_configure_vdm(dp, dp->data.conf); 207 if (ret) 208 dev_err(&dp->alt->dev, 209 "unable to send Configure command (%d)\n", ret); 210 break; 211 case DP_STATE_EXIT: 212 if (typec_altmode_exit(dp->alt)) 213 dev_err(&dp->alt->dev, "Exit Mode Failed!\n"); 214 break; 215 default: 216 break; 217 } 218 219 dp->state = DP_STATE_IDLE; 220 221 mutex_unlock(&dp->lock); 222 } 223 224 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo) 225 { 226 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 227 u8 old_state; 228 229 mutex_lock(&dp->lock); 230 231 old_state = dp->state; 232 dp->data.status = vdo; 233 234 if (old_state != DP_STATE_IDLE) 235 dev_warn(&alt->dev, "ATTENTION while processing state %d\n", 236 old_state); 237 238 if (dp_altmode_status_update(dp)) 239 dev_warn(&alt->dev, "%s: status update failed\n", __func__); 240 241 if (dp_altmode_notify(dp)) 242 dev_err(&alt->dev, "%s: notification failed\n", __func__); 243 244 if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE) 245 schedule_work(&dp->work); 246 247 mutex_unlock(&dp->lock); 248 } 249 250 static int dp_altmode_vdm(struct typec_altmode *alt, 251 const u32 hdr, const u32 *vdo, int count) 252 { 253 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 254 int cmd_type = PD_VDO_CMDT(hdr); 255 int cmd = PD_VDO_CMD(hdr); 256 int ret = 0; 257 258 mutex_lock(&dp->lock); 259 260 if (dp->state != DP_STATE_IDLE) { 261 ret = -EBUSY; 262 goto err_unlock; 263 } 264 265 switch (cmd_type) { 266 case CMDT_RSP_ACK: 267 switch (cmd) { 268 case CMD_ENTER_MODE: 269 dp->state = DP_STATE_UPDATE; 270 break; 271 case CMD_EXIT_MODE: 272 dp->data.status = 0; 273 dp->data.conf = 0; 274 break; 275 case DP_CMD_STATUS_UPDATE: 276 dp->data.status = *vdo; 277 ret = dp_altmode_status_update(dp); 278 break; 279 case DP_CMD_CONFIGURE: 280 ret = dp_altmode_configured(dp); 281 break; 282 default: 283 break; 284 } 285 break; 286 case CMDT_RSP_NAK: 287 switch (cmd) { 288 case DP_CMD_CONFIGURE: 289 dp->data.conf = 0; 290 ret = dp_altmode_configured(dp); 291 break; 292 default: 293 break; 294 } 295 break; 296 default: 297 break; 298 } 299 300 if (dp->state != DP_STATE_IDLE) 301 schedule_work(&dp->work); 302 303 err_unlock: 304 mutex_unlock(&dp->lock); 305 return ret; 306 } 307 308 static int dp_altmode_activate(struct typec_altmode *alt, int activate) 309 { 310 return activate ? typec_altmode_enter(alt, NULL) : 311 typec_altmode_exit(alt); 312 } 313 314 static const struct typec_altmode_ops dp_altmode_ops = { 315 .attention = dp_altmode_attention, 316 .vdm = dp_altmode_vdm, 317 .activate = dp_altmode_activate, 318 }; 319 320 static const char * const configurations[] = { 321 [DP_CONF_USB] = "USB", 322 [DP_CONF_DFP_D] = "source", 323 [DP_CONF_UFP_D] = "sink", 324 }; 325 326 static ssize_t 327 configuration_store(struct device *dev, struct device_attribute *attr, 328 const char *buf, size_t size) 329 { 330 struct dp_altmode *dp = dev_get_drvdata(dev); 331 u32 conf; 332 u32 cap; 333 int con; 334 int ret = 0; 335 336 con = sysfs_match_string(configurations, buf); 337 if (con < 0) 338 return con; 339 340 mutex_lock(&dp->lock); 341 342 if (dp->state != DP_STATE_IDLE) { 343 ret = -EBUSY; 344 goto err_unlock; 345 } 346 347 cap = DP_CAP_CAPABILITY(dp->alt->vdo); 348 349 if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) || 350 (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) { 351 ret = -EINVAL; 352 goto err_unlock; 353 } 354 355 conf = dp->data.conf & ~DP_CONF_DUAL_D; 356 conf |= con; 357 358 if (dp->alt->active) { 359 ret = dp_altmode_configure_vdm(dp, conf); 360 if (ret) 361 goto err_unlock; 362 } 363 364 dp->data.conf = conf; 365 366 err_unlock: 367 mutex_unlock(&dp->lock); 368 369 return ret ? ret : size; 370 } 371 372 static ssize_t configuration_show(struct device *dev, 373 struct device_attribute *attr, char *buf) 374 { 375 struct dp_altmode *dp = dev_get_drvdata(dev); 376 int len; 377 u8 cap; 378 u8 cur; 379 int i; 380 381 mutex_lock(&dp->lock); 382 383 cap = DP_CAP_CAPABILITY(dp->alt->vdo); 384 cur = DP_CONF_CURRENTLY(dp->data.conf); 385 386 len = sprintf(buf, "%s ", cur ? "USB" : "[USB]"); 387 388 for (i = 1; i < ARRAY_SIZE(configurations); i++) { 389 if (i == cur) 390 len += sprintf(buf + len, "[%s] ", configurations[i]); 391 else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) || 392 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D)) 393 len += sprintf(buf + len, "%s ", configurations[i]); 394 } 395 396 mutex_unlock(&dp->lock); 397 398 buf[len - 1] = '\n'; 399 return len; 400 } 401 static DEVICE_ATTR_RW(configuration); 402 403 static const char * const pin_assignments[] = { 404 [DP_PIN_ASSIGN_A] = "A", 405 [DP_PIN_ASSIGN_B] = "B", 406 [DP_PIN_ASSIGN_C] = "C", 407 [DP_PIN_ASSIGN_D] = "D", 408 [DP_PIN_ASSIGN_E] = "E", 409 [DP_PIN_ASSIGN_F] = "F", 410 }; 411 412 static ssize_t 413 pin_assignment_store(struct device *dev, struct device_attribute *attr, 414 const char *buf, size_t size) 415 { 416 struct dp_altmode *dp = dev_get_drvdata(dev); 417 u8 assignments; 418 u32 conf; 419 int ret; 420 421 ret = sysfs_match_string(pin_assignments, buf); 422 if (ret < 0) 423 return ret; 424 425 conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret)); 426 ret = 0; 427 428 mutex_lock(&dp->lock); 429 430 if (conf & dp->data.conf) 431 goto out_unlock; 432 433 if (dp->state != DP_STATE_IDLE) { 434 ret = -EBUSY; 435 goto out_unlock; 436 } 437 438 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D) 439 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo); 440 else 441 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo); 442 443 if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) { 444 ret = -EINVAL; 445 goto out_unlock; 446 } 447 448 conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK; 449 450 /* Only send Configure command if a configuration has been set */ 451 if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) { 452 ret = dp_altmode_configure_vdm(dp, conf); 453 if (ret) 454 goto out_unlock; 455 } 456 457 dp->data.conf = conf; 458 459 out_unlock: 460 mutex_unlock(&dp->lock); 461 462 return ret ? ret : size; 463 } 464 465 static ssize_t pin_assignment_show(struct device *dev, 466 struct device_attribute *attr, char *buf) 467 { 468 struct dp_altmode *dp = dev_get_drvdata(dev); 469 u8 assignments; 470 int len = 0; 471 u8 cur; 472 int i; 473 474 mutex_lock(&dp->lock); 475 476 cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf)); 477 478 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D) 479 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo); 480 else 481 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo); 482 483 for (i = 0; assignments; assignments >>= 1, i++) { 484 if (assignments & 1) { 485 if (i == cur) 486 len += sprintf(buf + len, "[%s] ", 487 pin_assignments[i]); 488 else 489 len += sprintf(buf + len, "%s ", 490 pin_assignments[i]); 491 } 492 } 493 494 mutex_unlock(&dp->lock); 495 496 buf[len - 1] = '\n'; 497 return len; 498 } 499 static DEVICE_ATTR_RW(pin_assignment); 500 501 static struct attribute *dp_altmode_attrs[] = { 502 &dev_attr_configuration.attr, 503 &dev_attr_pin_assignment.attr, 504 NULL 505 }; 506 507 static const struct attribute_group dp_altmode_group = { 508 .name = "displayport", 509 .attrs = dp_altmode_attrs, 510 }; 511 512 int dp_altmode_probe(struct typec_altmode *alt) 513 { 514 const struct typec_altmode *port = typec_altmode_get_partner(alt); 515 struct dp_altmode *dp; 516 int ret; 517 518 /* FIXME: Port can only be DFP_U. */ 519 520 /* Make sure we have compatiple pin configurations */ 521 if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) & 522 DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) && 523 !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) & 524 DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo))) 525 return -ENODEV; 526 527 ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group); 528 if (ret) 529 return ret; 530 531 dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL); 532 if (!dp) 533 return -ENOMEM; 534 535 INIT_WORK(&dp->work, dp_altmode_work); 536 mutex_init(&dp->lock); 537 dp->port = port; 538 dp->alt = alt; 539 540 alt->desc = "DisplayPort"; 541 alt->ops = &dp_altmode_ops; 542 543 typec_altmode_set_drvdata(alt, dp); 544 545 dp->state = DP_STATE_ENTER; 546 schedule_work(&dp->work); 547 548 return 0; 549 } 550 EXPORT_SYMBOL_GPL(dp_altmode_probe); 551 552 void dp_altmode_remove(struct typec_altmode *alt) 553 { 554 struct dp_altmode *dp = typec_altmode_get_drvdata(alt); 555 556 sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group); 557 cancel_work_sync(&dp->work); 558 } 559 EXPORT_SYMBOL_GPL(dp_altmode_remove); 560 561 static const struct typec_device_id dp_typec_id[] = { 562 { USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE }, 563 { }, 564 }; 565 MODULE_DEVICE_TABLE(typec, dp_typec_id); 566 567 static struct typec_altmode_driver dp_altmode_driver = { 568 .id_table = dp_typec_id, 569 .probe = dp_altmode_probe, 570 .remove = dp_altmode_remove, 571 .driver = { 572 .name = "typec_displayport", 573 .owner = THIS_MODULE, 574 }, 575 }; 576 module_typec_altmode_driver(dp_altmode_driver); 577 578 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>"); 579 MODULE_LICENSE("GPL v2"); 580 MODULE_DESCRIPTION("DisplayPort Alternate Mode"); 581