1 /* 2 * Copyright (C) 2013 NVIDIA Corporation 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/delay.h> 11 #include <linux/gpio.h> 12 #include <linux/interrupt.h> 13 #include <linux/io.h> 14 #include <linux/of_gpio.h> 15 #include <linux/platform_device.h> 16 #include <linux/reset.h> 17 #include <linux/regulator/consumer.h> 18 #include <linux/workqueue.h> 19 20 #include <drm/drm_dp_helper.h> 21 #include <drm/drm_panel.h> 22 23 #include "dpaux.h" 24 #include "drm.h" 25 26 static DEFINE_MUTEX(dpaux_lock); 27 static LIST_HEAD(dpaux_list); 28 29 struct tegra_dpaux { 30 struct drm_dp_aux aux; 31 struct device *dev; 32 33 void __iomem *regs; 34 int irq; 35 36 struct tegra_output *output; 37 38 struct reset_control *rst; 39 struct clk *clk_parent; 40 struct clk *clk; 41 42 struct regulator *vdd; 43 44 struct completion complete; 45 struct work_struct work; 46 struct list_head list; 47 }; 48 49 static inline struct tegra_dpaux *to_dpaux(struct drm_dp_aux *aux) 50 { 51 return container_of(aux, struct tegra_dpaux, aux); 52 } 53 54 static inline struct tegra_dpaux *work_to_dpaux(struct work_struct *work) 55 { 56 return container_of(work, struct tegra_dpaux, work); 57 } 58 59 static inline unsigned long tegra_dpaux_readl(struct tegra_dpaux *dpaux, 60 unsigned long offset) 61 { 62 return readl(dpaux->regs + (offset << 2)); 63 } 64 65 static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux, 66 unsigned long value, 67 unsigned long offset) 68 { 69 writel(value, dpaux->regs + (offset << 2)); 70 } 71 72 static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer, 73 size_t size) 74 { 75 unsigned long offset = DPAUX_DP_AUXDATA_WRITE(0); 76 size_t i, j; 77 78 for (i = 0; i < size; i += 4) { 79 size_t num = min_t(size_t, size - i, 4); 80 unsigned long value = 0; 81 82 for (j = 0; j < num; j++) 83 value |= buffer[i + j] << (j * 8); 84 85 tegra_dpaux_writel(dpaux, value, offset++); 86 } 87 } 88 89 static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer, 90 size_t size) 91 { 92 unsigned long offset = DPAUX_DP_AUXDATA_READ(0); 93 size_t i, j; 94 95 for (i = 0; i < size; i += 4) { 96 size_t num = min_t(size_t, size - i, 4); 97 unsigned long value; 98 99 value = tegra_dpaux_readl(dpaux, offset++); 100 101 for (j = 0; j < num; j++) 102 buffer[i + j] = value >> (j * 8); 103 } 104 } 105 106 static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux, 107 struct drm_dp_aux_msg *msg) 108 { 109 unsigned long timeout = msecs_to_jiffies(250); 110 struct tegra_dpaux *dpaux = to_dpaux(aux); 111 unsigned long status; 112 ssize_t ret = 0; 113 u32 value; 114 115 /* Tegra has 4x4 byte DP AUX transmit and receive FIFOs. */ 116 if (msg->size > 16) 117 return -EINVAL; 118 119 /* 120 * Allow zero-sized messages only for I2C, in which case they specify 121 * address-only transactions. 122 */ 123 if (msg->size < 1) { 124 switch (msg->request & ~DP_AUX_I2C_MOT) { 125 case DP_AUX_I2C_WRITE: 126 case DP_AUX_I2C_READ: 127 value = DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY; 128 break; 129 130 default: 131 return -EINVAL; 132 } 133 } else { 134 /* For non-zero-sized messages, set the CMDLEN field. */ 135 value = DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1); 136 } 137 138 switch (msg->request & ~DP_AUX_I2C_MOT) { 139 case DP_AUX_I2C_WRITE: 140 if (msg->request & DP_AUX_I2C_MOT) 141 value |= DPAUX_DP_AUXCTL_CMD_MOT_WR; 142 else 143 value |= DPAUX_DP_AUXCTL_CMD_I2C_WR; 144 145 break; 146 147 case DP_AUX_I2C_READ: 148 if (msg->request & DP_AUX_I2C_MOT) 149 value |= DPAUX_DP_AUXCTL_CMD_MOT_RD; 150 else 151 value |= DPAUX_DP_AUXCTL_CMD_I2C_RD; 152 153 break; 154 155 case DP_AUX_I2C_STATUS: 156 if (msg->request & DP_AUX_I2C_MOT) 157 value |= DPAUX_DP_AUXCTL_CMD_MOT_RQ; 158 else 159 value |= DPAUX_DP_AUXCTL_CMD_I2C_RQ; 160 161 break; 162 163 case DP_AUX_NATIVE_WRITE: 164 value |= DPAUX_DP_AUXCTL_CMD_AUX_WR; 165 break; 166 167 case DP_AUX_NATIVE_READ: 168 value |= DPAUX_DP_AUXCTL_CMD_AUX_RD; 169 break; 170 171 default: 172 return -EINVAL; 173 } 174 175 tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR); 176 tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL); 177 178 if ((msg->request & DP_AUX_I2C_READ) == 0) { 179 tegra_dpaux_write_fifo(dpaux, msg->buffer, msg->size); 180 ret = msg->size; 181 } 182 183 /* start transaction */ 184 value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXCTL); 185 value |= DPAUX_DP_AUXCTL_TRANSACTREQ; 186 tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL); 187 188 status = wait_for_completion_timeout(&dpaux->complete, timeout); 189 if (!status) 190 return -ETIMEDOUT; 191 192 /* read status and clear errors */ 193 value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT); 194 tegra_dpaux_writel(dpaux, 0xf00, DPAUX_DP_AUXSTAT); 195 196 if (value & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR) 197 return -ETIMEDOUT; 198 199 if ((value & DPAUX_DP_AUXSTAT_RX_ERROR) || 200 (value & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR) || 201 (value & DPAUX_DP_AUXSTAT_NO_STOP_ERROR)) 202 return -EIO; 203 204 switch ((value & DPAUX_DP_AUXSTAT_REPLY_TYPE_MASK) >> 16) { 205 case 0x00: 206 msg->reply = DP_AUX_NATIVE_REPLY_ACK; 207 break; 208 209 case 0x01: 210 msg->reply = DP_AUX_NATIVE_REPLY_NACK; 211 break; 212 213 case 0x02: 214 msg->reply = DP_AUX_NATIVE_REPLY_DEFER; 215 break; 216 217 case 0x04: 218 msg->reply = DP_AUX_I2C_REPLY_NACK; 219 break; 220 221 case 0x08: 222 msg->reply = DP_AUX_I2C_REPLY_DEFER; 223 break; 224 } 225 226 if ((msg->size > 0) && (msg->reply == DP_AUX_NATIVE_REPLY_ACK)) { 227 if (msg->request & DP_AUX_I2C_READ) { 228 size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK; 229 230 if (WARN_ON(count != msg->size)) 231 count = min_t(size_t, count, msg->size); 232 233 tegra_dpaux_read_fifo(dpaux, msg->buffer, count); 234 ret = count; 235 } 236 } 237 238 return ret; 239 } 240 241 static void tegra_dpaux_hotplug(struct work_struct *work) 242 { 243 struct tegra_dpaux *dpaux = work_to_dpaux(work); 244 245 if (dpaux->output) 246 drm_helper_hpd_irq_event(dpaux->output->connector.dev); 247 } 248 249 static irqreturn_t tegra_dpaux_irq(int irq, void *data) 250 { 251 struct tegra_dpaux *dpaux = data; 252 irqreturn_t ret = IRQ_HANDLED; 253 unsigned long value; 254 255 /* clear interrupts */ 256 value = tegra_dpaux_readl(dpaux, DPAUX_INTR_AUX); 257 tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX); 258 259 if (value & (DPAUX_INTR_PLUG_EVENT | DPAUX_INTR_UNPLUG_EVENT)) 260 schedule_work(&dpaux->work); 261 262 if (value & DPAUX_INTR_IRQ_EVENT) { 263 /* TODO: handle this */ 264 } 265 266 if (value & DPAUX_INTR_AUX_DONE) 267 complete(&dpaux->complete); 268 269 return ret; 270 } 271 272 static int tegra_dpaux_probe(struct platform_device *pdev) 273 { 274 struct tegra_dpaux *dpaux; 275 struct resource *regs; 276 unsigned long value; 277 int err; 278 279 dpaux = devm_kzalloc(&pdev->dev, sizeof(*dpaux), GFP_KERNEL); 280 if (!dpaux) 281 return -ENOMEM; 282 283 INIT_WORK(&dpaux->work, tegra_dpaux_hotplug); 284 init_completion(&dpaux->complete); 285 INIT_LIST_HEAD(&dpaux->list); 286 dpaux->dev = &pdev->dev; 287 288 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 289 dpaux->regs = devm_ioremap_resource(&pdev->dev, regs); 290 if (IS_ERR(dpaux->regs)) 291 return PTR_ERR(dpaux->regs); 292 293 dpaux->irq = platform_get_irq(pdev, 0); 294 if (dpaux->irq < 0) { 295 dev_err(&pdev->dev, "failed to get IRQ\n"); 296 return -ENXIO; 297 } 298 299 dpaux->rst = devm_reset_control_get(&pdev->dev, "dpaux"); 300 if (IS_ERR(dpaux->rst)) 301 return PTR_ERR(dpaux->rst); 302 303 dpaux->clk = devm_clk_get(&pdev->dev, NULL); 304 if (IS_ERR(dpaux->clk)) 305 return PTR_ERR(dpaux->clk); 306 307 err = clk_prepare_enable(dpaux->clk); 308 if (err < 0) 309 return err; 310 311 reset_control_deassert(dpaux->rst); 312 313 dpaux->clk_parent = devm_clk_get(&pdev->dev, "parent"); 314 if (IS_ERR(dpaux->clk_parent)) 315 return PTR_ERR(dpaux->clk_parent); 316 317 err = clk_prepare_enable(dpaux->clk_parent); 318 if (err < 0) 319 return err; 320 321 err = clk_set_rate(dpaux->clk_parent, 270000000); 322 if (err < 0) { 323 dev_err(&pdev->dev, "failed to set clock to 270 MHz: %d\n", 324 err); 325 return err; 326 } 327 328 dpaux->vdd = devm_regulator_get(&pdev->dev, "vdd"); 329 if (IS_ERR(dpaux->vdd)) 330 return PTR_ERR(dpaux->vdd); 331 332 err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0, 333 dev_name(dpaux->dev), dpaux); 334 if (err < 0) { 335 dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n", 336 dpaux->irq, err); 337 return err; 338 } 339 340 dpaux->aux.transfer = tegra_dpaux_transfer; 341 dpaux->aux.dev = &pdev->dev; 342 343 err = drm_dp_aux_register(&dpaux->aux); 344 if (err < 0) 345 return err; 346 347 /* enable and clear all interrupts */ 348 value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT | 349 DPAUX_INTR_UNPLUG_EVENT | DPAUX_INTR_PLUG_EVENT; 350 tegra_dpaux_writel(dpaux, value, DPAUX_INTR_EN_AUX); 351 tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX); 352 353 mutex_lock(&dpaux_lock); 354 list_add_tail(&dpaux->list, &dpaux_list); 355 mutex_unlock(&dpaux_lock); 356 357 platform_set_drvdata(pdev, dpaux); 358 359 return 0; 360 } 361 362 static int tegra_dpaux_remove(struct platform_device *pdev) 363 { 364 struct tegra_dpaux *dpaux = platform_get_drvdata(pdev); 365 366 drm_dp_aux_unregister(&dpaux->aux); 367 368 mutex_lock(&dpaux_lock); 369 list_del(&dpaux->list); 370 mutex_unlock(&dpaux_lock); 371 372 cancel_work_sync(&dpaux->work); 373 374 clk_disable_unprepare(dpaux->clk_parent); 375 reset_control_assert(dpaux->rst); 376 clk_disable_unprepare(dpaux->clk); 377 378 return 0; 379 } 380 381 static const struct of_device_id tegra_dpaux_of_match[] = { 382 { .compatible = "nvidia,tegra124-dpaux", }, 383 { }, 384 }; 385 MODULE_DEVICE_TABLE(of, tegra_dpaux_of_match); 386 387 struct platform_driver tegra_dpaux_driver = { 388 .driver = { 389 .name = "tegra-dpaux", 390 .of_match_table = tegra_dpaux_of_match, 391 }, 392 .probe = tegra_dpaux_probe, 393 .remove = tegra_dpaux_remove, 394 }; 395 396 struct tegra_dpaux *tegra_dpaux_find_by_of_node(struct device_node *np) 397 { 398 struct tegra_dpaux *dpaux; 399 400 mutex_lock(&dpaux_lock); 401 402 list_for_each_entry(dpaux, &dpaux_list, list) 403 if (np == dpaux->dev->of_node) { 404 mutex_unlock(&dpaux_lock); 405 return dpaux; 406 } 407 408 mutex_unlock(&dpaux_lock); 409 410 return NULL; 411 } 412 413 int tegra_dpaux_attach(struct tegra_dpaux *dpaux, struct tegra_output *output) 414 { 415 unsigned long timeout; 416 int err; 417 418 output->connector.polled = DRM_CONNECTOR_POLL_HPD; 419 dpaux->output = output; 420 421 err = regulator_enable(dpaux->vdd); 422 if (err < 0) 423 return err; 424 425 timeout = jiffies + msecs_to_jiffies(250); 426 427 while (time_before(jiffies, timeout)) { 428 enum drm_connector_status status; 429 430 status = tegra_dpaux_detect(dpaux); 431 if (status == connector_status_connected) 432 return 0; 433 434 usleep_range(1000, 2000); 435 } 436 437 return -ETIMEDOUT; 438 } 439 440 int tegra_dpaux_detach(struct tegra_dpaux *dpaux) 441 { 442 unsigned long timeout; 443 int err; 444 445 err = regulator_disable(dpaux->vdd); 446 if (err < 0) 447 return err; 448 449 timeout = jiffies + msecs_to_jiffies(250); 450 451 while (time_before(jiffies, timeout)) { 452 enum drm_connector_status status; 453 454 status = tegra_dpaux_detect(dpaux); 455 if (status == connector_status_disconnected) { 456 dpaux->output = NULL; 457 return 0; 458 } 459 460 usleep_range(1000, 2000); 461 } 462 463 return -ETIMEDOUT; 464 } 465 466 enum drm_connector_status tegra_dpaux_detect(struct tegra_dpaux *dpaux) 467 { 468 unsigned long value; 469 470 value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT); 471 472 if (value & DPAUX_DP_AUXSTAT_HPD_STATUS) 473 return connector_status_connected; 474 475 return connector_status_disconnected; 476 } 477 478 int tegra_dpaux_enable(struct tegra_dpaux *dpaux) 479 { 480 unsigned long value; 481 482 value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) | 483 DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) | 484 DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) | 485 DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV | 486 DPAUX_HYBRID_PADCTL_MODE_AUX; 487 tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL); 488 489 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); 490 value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; 491 tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); 492 493 return 0; 494 } 495 496 int tegra_dpaux_disable(struct tegra_dpaux *dpaux) 497 { 498 unsigned long value; 499 500 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE); 501 value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN; 502 tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE); 503 504 return 0; 505 } 506 507 int tegra_dpaux_prepare(struct tegra_dpaux *dpaux, u8 encoding) 508 { 509 int err; 510 511 err = drm_dp_dpcd_writeb(&dpaux->aux, DP_MAIN_LINK_CHANNEL_CODING_SET, 512 encoding); 513 if (err < 0) 514 return err; 515 516 return 0; 517 } 518 519 int tegra_dpaux_train(struct tegra_dpaux *dpaux, struct drm_dp_link *link, 520 u8 pattern) 521 { 522 u8 tp = pattern & DP_TRAINING_PATTERN_MASK; 523 u8 status[DP_LINK_STATUS_SIZE], values[4]; 524 unsigned int i; 525 int err; 526 527 err = drm_dp_dpcd_writeb(&dpaux->aux, DP_TRAINING_PATTERN_SET, pattern); 528 if (err < 0) 529 return err; 530 531 if (tp == DP_TRAINING_PATTERN_DISABLE) 532 return 0; 533 534 for (i = 0; i < link->num_lanes; i++) 535 values[i] = DP_TRAIN_MAX_PRE_EMPHASIS_REACHED | 536 DP_TRAIN_PRE_EMPH_LEVEL_0 | 537 DP_TRAIN_MAX_SWING_REACHED | 538 DP_TRAIN_VOLTAGE_SWING_LEVEL_0; 539 540 err = drm_dp_dpcd_write(&dpaux->aux, DP_TRAINING_LANE0_SET, values, 541 link->num_lanes); 542 if (err < 0) 543 return err; 544 545 usleep_range(500, 1000); 546 547 err = drm_dp_dpcd_read_link_status(&dpaux->aux, status); 548 if (err < 0) 549 return err; 550 551 switch (tp) { 552 case DP_TRAINING_PATTERN_1: 553 if (!drm_dp_clock_recovery_ok(status, link->num_lanes)) 554 return -EAGAIN; 555 556 break; 557 558 case DP_TRAINING_PATTERN_2: 559 if (!drm_dp_channel_eq_ok(status, link->num_lanes)) 560 return -EAGAIN; 561 562 break; 563 564 default: 565 dev_err(dpaux->dev, "unsupported training pattern %u\n", tp); 566 return -EINVAL; 567 } 568 569 err = drm_dp_dpcd_writeb(&dpaux->aux, DP_EDP_CONFIGURATION_SET, 0); 570 if (err < 0) 571 return err; 572 573 return 0; 574 } 575