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