1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * A FSI master controller, using a simple GPIO bit-banging interface 4 */ 5 6 #include <linux/crc4.h> 7 #include <linux/delay.h> 8 #include <linux/device.h> 9 #include <linux/fsi.h> 10 #include <linux/gpio/consumer.h> 11 #include <linux/io.h> 12 #include <linux/irqflags.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 18 #include "fsi-master.h" 19 20 #define FSI_GPIO_STD_DLY 1 /* Standard pin delay in nS */ 21 #define LAST_ADDR_INVALID 0x1 22 23 struct fsi_master_gpio { 24 struct fsi_master master; 25 struct device *dev; 26 struct mutex cmd_lock; /* mutex for command ordering */ 27 struct gpio_desc *gpio_clk; 28 struct gpio_desc *gpio_data; 29 struct gpio_desc *gpio_trans; /* Voltage translator */ 30 struct gpio_desc *gpio_enable; /* FSI enable */ 31 struct gpio_desc *gpio_mux; /* Mux control */ 32 bool external_mode; 33 bool no_delays; 34 uint32_t last_addr; 35 uint8_t t_send_delay; 36 uint8_t t_echo_delay; 37 }; 38 39 #define CREATE_TRACE_POINTS 40 #include <trace/events/fsi_master_gpio.h> 41 42 #define to_fsi_master_gpio(m) container_of(m, struct fsi_master_gpio, master) 43 44 struct fsi_gpio_msg { 45 uint64_t msg; 46 uint8_t bits; 47 }; 48 49 static void clock_toggle(struct fsi_master_gpio *master, int count) 50 { 51 int i; 52 53 for (i = 0; i < count; i++) { 54 if (!master->no_delays) 55 ndelay(FSI_GPIO_STD_DLY); 56 gpiod_set_value(master->gpio_clk, 0); 57 if (!master->no_delays) 58 ndelay(FSI_GPIO_STD_DLY); 59 gpiod_set_value(master->gpio_clk, 1); 60 } 61 } 62 63 static int sda_clock_in(struct fsi_master_gpio *master) 64 { 65 int in; 66 67 if (!master->no_delays) 68 ndelay(FSI_GPIO_STD_DLY); 69 gpiod_set_value(master->gpio_clk, 0); 70 71 /* Dummy read to feed the synchronizers */ 72 gpiod_get_value(master->gpio_data); 73 74 /* Actual data read */ 75 in = gpiod_get_value(master->gpio_data); 76 if (!master->no_delays) 77 ndelay(FSI_GPIO_STD_DLY); 78 gpiod_set_value(master->gpio_clk, 1); 79 return in ? 1 : 0; 80 } 81 82 static void sda_out(struct fsi_master_gpio *master, int value) 83 { 84 gpiod_set_value(master->gpio_data, value); 85 } 86 87 static void set_sda_input(struct fsi_master_gpio *master) 88 { 89 gpiod_direction_input(master->gpio_data); 90 gpiod_set_value(master->gpio_trans, 0); 91 } 92 93 static void set_sda_output(struct fsi_master_gpio *master, int value) 94 { 95 gpiod_set_value(master->gpio_trans, 1); 96 gpiod_direction_output(master->gpio_data, value); 97 } 98 99 static void clock_zeros(struct fsi_master_gpio *master, int count) 100 { 101 trace_fsi_master_gpio_clock_zeros(master, count); 102 set_sda_output(master, 1); 103 clock_toggle(master, count); 104 } 105 106 static void echo_delay(struct fsi_master_gpio *master) 107 { 108 clock_zeros(master, master->t_echo_delay); 109 } 110 111 112 static void serial_in(struct fsi_master_gpio *master, struct fsi_gpio_msg *msg, 113 uint8_t num_bits) 114 { 115 uint8_t bit, in_bit; 116 117 set_sda_input(master); 118 119 for (bit = 0; bit < num_bits; bit++) { 120 in_bit = sda_clock_in(master); 121 msg->msg <<= 1; 122 msg->msg |= ~in_bit & 0x1; /* Data is active low */ 123 } 124 msg->bits += num_bits; 125 126 trace_fsi_master_gpio_in(master, num_bits, msg->msg); 127 } 128 129 static void serial_out(struct fsi_master_gpio *master, 130 const struct fsi_gpio_msg *cmd) 131 { 132 uint8_t bit; 133 uint64_t msg = ~cmd->msg; /* Data is active low */ 134 uint64_t sda_mask = 0x1ULL << (cmd->bits - 1); 135 uint64_t last_bit = ~0; 136 int next_bit; 137 138 trace_fsi_master_gpio_out(master, cmd->bits, cmd->msg); 139 140 if (!cmd->bits) { 141 dev_warn(master->dev, "trying to output 0 bits\n"); 142 return; 143 } 144 set_sda_output(master, 0); 145 146 /* Send the start bit */ 147 sda_out(master, 0); 148 clock_toggle(master, 1); 149 150 /* Send the message */ 151 for (bit = 0; bit < cmd->bits; bit++) { 152 next_bit = (msg & sda_mask) >> (cmd->bits - 1); 153 if (last_bit ^ next_bit) { 154 sda_out(master, next_bit); 155 last_bit = next_bit; 156 } 157 clock_toggle(master, 1); 158 msg <<= 1; 159 } 160 } 161 162 static void msg_push_bits(struct fsi_gpio_msg *msg, uint64_t data, int bits) 163 { 164 msg->msg <<= bits; 165 msg->msg |= data & ((1ull << bits) - 1); 166 msg->bits += bits; 167 } 168 169 static void msg_push_crc(struct fsi_gpio_msg *msg) 170 { 171 uint8_t crc; 172 int top; 173 174 top = msg->bits & 0x3; 175 176 /* start bit, and any non-aligned top bits */ 177 crc = crc4(0, 1 << top | msg->msg >> (msg->bits - top), top + 1); 178 179 /* aligned bits */ 180 crc = crc4(crc, msg->msg, msg->bits - top); 181 182 msg_push_bits(msg, crc, 4); 183 } 184 185 static bool check_same_address(struct fsi_master_gpio *master, int id, 186 uint32_t addr) 187 { 188 /* this will also handle LAST_ADDR_INVALID */ 189 return master->last_addr == (((id & 0x3) << 21) | (addr & ~0x3)); 190 } 191 192 static bool check_relative_address(struct fsi_master_gpio *master, int id, 193 uint32_t addr, uint32_t *rel_addrp) 194 { 195 uint32_t last_addr = master->last_addr; 196 int32_t rel_addr; 197 198 if (last_addr == LAST_ADDR_INVALID) 199 return false; 200 201 /* We may be in 23-bit addressing mode, which uses the id as the 202 * top two address bits. So, if we're referencing a different ID, 203 * use absolute addresses. 204 */ 205 if (((last_addr >> 21) & 0x3) != id) 206 return false; 207 208 /* remove the top two bits from any 23-bit addressing */ 209 last_addr &= (1 << 21) - 1; 210 211 /* We know that the addresses are limited to 21 bits, so this won't 212 * overflow the signed rel_addr */ 213 rel_addr = addr - last_addr; 214 if (rel_addr > 255 || rel_addr < -256) 215 return false; 216 217 *rel_addrp = (uint32_t)rel_addr; 218 219 return true; 220 } 221 222 static void last_address_update(struct fsi_master_gpio *master, 223 int id, bool valid, uint32_t addr) 224 { 225 if (!valid) 226 master->last_addr = LAST_ADDR_INVALID; 227 else 228 master->last_addr = ((id & 0x3) << 21) | (addr & ~0x3); 229 } 230 231 /* 232 * Encode an Absolute/Relative/Same Address command 233 */ 234 static void build_ar_command(struct fsi_master_gpio *master, 235 struct fsi_gpio_msg *cmd, uint8_t id, 236 uint32_t addr, size_t size, const void *data) 237 { 238 int i, addr_bits, opcode_bits; 239 bool write = !!data; 240 uint8_t ds, opcode; 241 uint32_t rel_addr; 242 243 cmd->bits = 0; 244 cmd->msg = 0; 245 246 /* we have 21 bits of address max */ 247 addr &= ((1 << 21) - 1); 248 249 /* cmd opcodes are variable length - SAME_AR is only two bits */ 250 opcode_bits = 3; 251 252 if (check_same_address(master, id, addr)) { 253 /* we still address the byte offset within the word */ 254 addr_bits = 2; 255 opcode_bits = 2; 256 opcode = FSI_CMD_SAME_AR; 257 trace_fsi_master_gpio_cmd_same_addr(master); 258 259 } else if (check_relative_address(master, id, addr, &rel_addr)) { 260 /* 8 bits plus sign */ 261 addr_bits = 9; 262 addr = rel_addr; 263 opcode = FSI_CMD_REL_AR; 264 trace_fsi_master_gpio_cmd_rel_addr(master, rel_addr); 265 266 } else { 267 addr_bits = 21; 268 opcode = FSI_CMD_ABS_AR; 269 trace_fsi_master_gpio_cmd_abs_addr(master, addr); 270 } 271 272 /* 273 * The read/write size is encoded in the lower bits of the address 274 * (as it must be naturally-aligned), and the following ds bit. 275 * 276 * size addr:1 addr:0 ds 277 * 1 x x 0 278 * 2 x 0 1 279 * 4 0 1 1 280 * 281 */ 282 ds = size > 1 ? 1 : 0; 283 addr &= ~(size - 1); 284 if (size == 4) 285 addr |= 1; 286 287 msg_push_bits(cmd, id, 2); 288 msg_push_bits(cmd, opcode, opcode_bits); 289 msg_push_bits(cmd, write ? 0 : 1, 1); 290 msg_push_bits(cmd, addr, addr_bits); 291 msg_push_bits(cmd, ds, 1); 292 for (i = 0; write && i < size; i++) 293 msg_push_bits(cmd, ((uint8_t *)data)[i], 8); 294 295 msg_push_crc(cmd); 296 } 297 298 static void build_dpoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id) 299 { 300 cmd->bits = 0; 301 cmd->msg = 0; 302 303 msg_push_bits(cmd, slave_id, 2); 304 msg_push_bits(cmd, FSI_CMD_DPOLL, 3); 305 msg_push_crc(cmd); 306 } 307 308 static void build_epoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id) 309 { 310 cmd->bits = 0; 311 cmd->msg = 0; 312 313 msg_push_bits(cmd, slave_id, 2); 314 msg_push_bits(cmd, FSI_CMD_EPOLL, 3); 315 msg_push_crc(cmd); 316 } 317 318 static void build_term_command(struct fsi_gpio_msg *cmd, uint8_t slave_id) 319 { 320 cmd->bits = 0; 321 cmd->msg = 0; 322 323 msg_push_bits(cmd, slave_id, 2); 324 msg_push_bits(cmd, FSI_CMD_TERM, 6); 325 msg_push_crc(cmd); 326 } 327 328 /* 329 * Note: callers rely specifically on this returning -EAGAIN for 330 * a CRC error detected in the response. Use other error code 331 * for other situations. It will be converted to something else 332 * higher up the stack before it reaches userspace. 333 */ 334 static int read_one_response(struct fsi_master_gpio *master, 335 uint8_t data_size, struct fsi_gpio_msg *msgp, uint8_t *tagp) 336 { 337 struct fsi_gpio_msg msg; 338 unsigned long flags; 339 uint32_t crc; 340 uint8_t tag; 341 int i; 342 343 local_irq_save(flags); 344 345 /* wait for the start bit */ 346 for (i = 0; i < FSI_MASTER_MTOE_COUNT; i++) { 347 msg.bits = 0; 348 msg.msg = 0; 349 serial_in(master, &msg, 1); 350 if (msg.msg) 351 break; 352 } 353 if (i == FSI_MASTER_MTOE_COUNT) { 354 dev_dbg(master->dev, 355 "Master time out waiting for response\n"); 356 local_irq_restore(flags); 357 return -ETIMEDOUT; 358 } 359 360 msg.bits = 0; 361 msg.msg = 0; 362 363 /* Read slave ID & response tag */ 364 serial_in(master, &msg, 4); 365 366 tag = msg.msg & 0x3; 367 368 /* If we have an ACK and we're expecting data, clock the data in too */ 369 if (tag == FSI_RESP_ACK && data_size) 370 serial_in(master, &msg, data_size * 8); 371 372 /* read CRC */ 373 serial_in(master, &msg, FSI_CRC_SIZE); 374 375 local_irq_restore(flags); 376 377 /* we have a whole message now; check CRC */ 378 crc = crc4(0, 1, 1); 379 crc = crc4(crc, msg.msg, msg.bits); 380 if (crc) { 381 /* Check if it's all 1's, that probably means the host is off */ 382 if (((~msg.msg) & ((1ull << msg.bits) - 1)) == 0) 383 return -ENODEV; 384 dev_dbg(master->dev, "ERR response CRC msg: 0x%016llx (%d bits)\n", 385 msg.msg, msg.bits); 386 return -EAGAIN; 387 } 388 389 if (msgp) 390 *msgp = msg; 391 if (tagp) 392 *tagp = tag; 393 394 return 0; 395 } 396 397 static int issue_term(struct fsi_master_gpio *master, uint8_t slave) 398 { 399 struct fsi_gpio_msg cmd; 400 unsigned long flags; 401 uint8_t tag; 402 int rc; 403 404 build_term_command(&cmd, slave); 405 406 local_irq_save(flags); 407 serial_out(master, &cmd); 408 echo_delay(master); 409 local_irq_restore(flags); 410 411 rc = read_one_response(master, 0, NULL, &tag); 412 if (rc < 0) { 413 dev_err(master->dev, 414 "TERM failed; lost communication with slave\n"); 415 return -EIO; 416 } else if (tag != FSI_RESP_ACK) { 417 dev_err(master->dev, "TERM failed; response %d\n", tag); 418 return -EIO; 419 } 420 421 return 0; 422 } 423 424 static int poll_for_response(struct fsi_master_gpio *master, 425 uint8_t slave, uint8_t size, void *data) 426 { 427 struct fsi_gpio_msg response, cmd; 428 int busy_count = 0, rc, i; 429 unsigned long flags; 430 uint8_t tag; 431 uint8_t *data_byte = data; 432 int crc_err_retries = 0; 433 retry: 434 rc = read_one_response(master, size, &response, &tag); 435 436 /* Handle retries on CRC errors */ 437 if (rc == -EAGAIN) { 438 /* Too many retries ? */ 439 if (crc_err_retries++ > FSI_CRC_ERR_RETRIES) { 440 /* 441 * Pass it up as a -EIO otherwise upper level will retry 442 * the whole command which isn't what we want here. 443 */ 444 rc = -EIO; 445 goto fail; 446 } 447 dev_dbg(master->dev, 448 "CRC error retry %d\n", crc_err_retries); 449 trace_fsi_master_gpio_crc_rsp_error(master); 450 build_epoll_command(&cmd, slave); 451 local_irq_save(flags); 452 clock_zeros(master, FSI_MASTER_EPOLL_CLOCKS); 453 serial_out(master, &cmd); 454 echo_delay(master); 455 local_irq_restore(flags); 456 goto retry; 457 } else if (rc) 458 goto fail; 459 460 switch (tag) { 461 case FSI_RESP_ACK: 462 if (size && data) { 463 uint64_t val = response.msg; 464 /* clear crc & mask */ 465 val >>= 4; 466 val &= (1ull << (size * 8)) - 1; 467 468 for (i = 0; i < size; i++) { 469 data_byte[size-i-1] = val; 470 val >>= 8; 471 } 472 } 473 break; 474 case FSI_RESP_BUSY: 475 /* 476 * Its necessary to clock slave before issuing 477 * d-poll, not indicated in the hardware protocol 478 * spec. < 20 clocks causes slave to hang, 21 ok. 479 */ 480 if (busy_count++ < FSI_MASTER_MAX_BUSY) { 481 build_dpoll_command(&cmd, slave); 482 local_irq_save(flags); 483 clock_zeros(master, FSI_MASTER_DPOLL_CLOCKS); 484 serial_out(master, &cmd); 485 echo_delay(master); 486 local_irq_restore(flags); 487 goto retry; 488 } 489 dev_warn(master->dev, 490 "ERR slave is stuck in busy state, issuing TERM\n"); 491 local_irq_save(flags); 492 clock_zeros(master, FSI_MASTER_DPOLL_CLOCKS); 493 local_irq_restore(flags); 494 issue_term(master, slave); 495 rc = -EIO; 496 break; 497 498 case FSI_RESP_ERRA: 499 dev_dbg(master->dev, "ERRA received: 0x%x\n", (int)response.msg); 500 rc = -EIO; 501 break; 502 case FSI_RESP_ERRC: 503 dev_dbg(master->dev, "ERRC received: 0x%x\n", (int)response.msg); 504 trace_fsi_master_gpio_crc_cmd_error(master); 505 rc = -EAGAIN; 506 break; 507 } 508 509 if (busy_count > 0) 510 trace_fsi_master_gpio_poll_response_busy(master, busy_count); 511 fail: 512 /* 513 * tSendDelay clocks, avoids signal reflections when switching 514 * from receive of response back to send of data. 515 */ 516 local_irq_save(flags); 517 clock_zeros(master, master->t_send_delay); 518 local_irq_restore(flags); 519 520 return rc; 521 } 522 523 static int send_request(struct fsi_master_gpio *master, 524 struct fsi_gpio_msg *cmd) 525 { 526 unsigned long flags; 527 528 if (master->external_mode) 529 return -EBUSY; 530 531 local_irq_save(flags); 532 serial_out(master, cmd); 533 echo_delay(master); 534 local_irq_restore(flags); 535 536 return 0; 537 } 538 539 static int fsi_master_gpio_xfer(struct fsi_master_gpio *master, uint8_t slave, 540 struct fsi_gpio_msg *cmd, size_t resp_len, void *resp) 541 { 542 int rc = -EAGAIN, retries = 0; 543 544 while ((retries++) < FSI_CRC_ERR_RETRIES) { 545 rc = send_request(master, cmd); 546 if (rc) 547 break; 548 rc = poll_for_response(master, slave, resp_len, resp); 549 if (rc != -EAGAIN) 550 break; 551 rc = -EIO; 552 dev_warn(master->dev, "ECRC retry %d\n", retries); 553 554 /* Pace it a bit before retry */ 555 msleep(1); 556 } 557 558 return rc; 559 } 560 561 static int fsi_master_gpio_read(struct fsi_master *_master, int link, 562 uint8_t id, uint32_t addr, void *val, size_t size) 563 { 564 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 565 struct fsi_gpio_msg cmd; 566 int rc; 567 568 if (link != 0) 569 return -ENODEV; 570 571 mutex_lock(&master->cmd_lock); 572 build_ar_command(master, &cmd, id, addr, size, NULL); 573 rc = fsi_master_gpio_xfer(master, id, &cmd, size, val); 574 last_address_update(master, id, rc == 0, addr); 575 mutex_unlock(&master->cmd_lock); 576 577 return rc; 578 } 579 580 static int fsi_master_gpio_write(struct fsi_master *_master, int link, 581 uint8_t id, uint32_t addr, const void *val, size_t size) 582 { 583 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 584 struct fsi_gpio_msg cmd; 585 int rc; 586 587 if (link != 0) 588 return -ENODEV; 589 590 mutex_lock(&master->cmd_lock); 591 build_ar_command(master, &cmd, id, addr, size, val); 592 rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL); 593 last_address_update(master, id, rc == 0, addr); 594 mutex_unlock(&master->cmd_lock); 595 596 return rc; 597 } 598 599 static int fsi_master_gpio_term(struct fsi_master *_master, 600 int link, uint8_t id) 601 { 602 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 603 struct fsi_gpio_msg cmd; 604 int rc; 605 606 if (link != 0) 607 return -ENODEV; 608 609 mutex_lock(&master->cmd_lock); 610 build_term_command(&cmd, id); 611 rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL); 612 last_address_update(master, id, false, 0); 613 mutex_unlock(&master->cmd_lock); 614 615 return rc; 616 } 617 618 static int fsi_master_gpio_break(struct fsi_master *_master, int link) 619 { 620 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 621 unsigned long flags; 622 623 if (link != 0) 624 return -ENODEV; 625 626 trace_fsi_master_gpio_break(master); 627 628 mutex_lock(&master->cmd_lock); 629 if (master->external_mode) { 630 mutex_unlock(&master->cmd_lock); 631 return -EBUSY; 632 } 633 634 local_irq_save(flags); 635 636 set_sda_output(master, 1); 637 sda_out(master, 1); 638 clock_toggle(master, FSI_PRE_BREAK_CLOCKS); 639 sda_out(master, 0); 640 clock_toggle(master, FSI_BREAK_CLOCKS); 641 echo_delay(master); 642 sda_out(master, 1); 643 clock_toggle(master, FSI_POST_BREAK_CLOCKS); 644 645 local_irq_restore(flags); 646 647 last_address_update(master, 0, false, 0); 648 mutex_unlock(&master->cmd_lock); 649 650 /* Wait for logic reset to take effect */ 651 udelay(200); 652 653 return 0; 654 } 655 656 static void fsi_master_gpio_init(struct fsi_master_gpio *master) 657 { 658 unsigned long flags; 659 660 gpiod_direction_output(master->gpio_mux, 1); 661 gpiod_direction_output(master->gpio_trans, 1); 662 gpiod_direction_output(master->gpio_enable, 1); 663 gpiod_direction_output(master->gpio_clk, 1); 664 gpiod_direction_output(master->gpio_data, 1); 665 666 /* todo: evaluate if clocks can be reduced */ 667 local_irq_save(flags); 668 clock_zeros(master, FSI_INIT_CLOCKS); 669 local_irq_restore(flags); 670 } 671 672 static void fsi_master_gpio_init_external(struct fsi_master_gpio *master) 673 { 674 gpiod_direction_output(master->gpio_mux, 0); 675 gpiod_direction_output(master->gpio_trans, 0); 676 gpiod_direction_output(master->gpio_enable, 1); 677 gpiod_direction_input(master->gpio_clk); 678 gpiod_direction_input(master->gpio_data); 679 } 680 681 static int fsi_master_gpio_link_enable(struct fsi_master *_master, int link, 682 bool enable) 683 { 684 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 685 int rc = -EBUSY; 686 687 if (link != 0) 688 return -ENODEV; 689 690 mutex_lock(&master->cmd_lock); 691 if (!master->external_mode) { 692 gpiod_set_value(master->gpio_enable, enable ? 1 : 0); 693 rc = 0; 694 } 695 mutex_unlock(&master->cmd_lock); 696 697 return rc; 698 } 699 700 static int fsi_master_gpio_link_config(struct fsi_master *_master, int link, 701 u8 t_send_delay, u8 t_echo_delay) 702 { 703 struct fsi_master_gpio *master = to_fsi_master_gpio(_master); 704 705 if (link != 0) 706 return -ENODEV; 707 708 mutex_lock(&master->cmd_lock); 709 master->t_send_delay = t_send_delay; 710 master->t_echo_delay = t_echo_delay; 711 mutex_unlock(&master->cmd_lock); 712 713 return 0; 714 } 715 716 static ssize_t external_mode_show(struct device *dev, 717 struct device_attribute *attr, char *buf) 718 { 719 struct fsi_master_gpio *master = dev_get_drvdata(dev); 720 721 return snprintf(buf, PAGE_SIZE - 1, "%u\n", 722 master->external_mode ? 1 : 0); 723 } 724 725 static ssize_t external_mode_store(struct device *dev, 726 struct device_attribute *attr, const char *buf, size_t count) 727 { 728 struct fsi_master_gpio *master = dev_get_drvdata(dev); 729 unsigned long val; 730 bool external_mode; 731 int err; 732 733 err = kstrtoul(buf, 0, &val); 734 if (err) 735 return err; 736 737 external_mode = !!val; 738 739 mutex_lock(&master->cmd_lock); 740 741 if (external_mode == master->external_mode) { 742 mutex_unlock(&master->cmd_lock); 743 return count; 744 } 745 746 master->external_mode = external_mode; 747 if (master->external_mode) 748 fsi_master_gpio_init_external(master); 749 else 750 fsi_master_gpio_init(master); 751 752 mutex_unlock(&master->cmd_lock); 753 754 fsi_master_rescan(&master->master); 755 756 return count; 757 } 758 759 static DEVICE_ATTR(external_mode, 0664, 760 external_mode_show, external_mode_store); 761 762 static void fsi_master_gpio_release(struct device *dev) 763 { 764 struct fsi_master_gpio *master = to_fsi_master_gpio(dev_to_fsi_master(dev)); 765 766 of_node_put(dev_of_node(master->dev)); 767 768 kfree(master); 769 } 770 771 static int fsi_master_gpio_probe(struct platform_device *pdev) 772 { 773 struct fsi_master_gpio *master; 774 struct gpio_desc *gpio; 775 int rc; 776 777 master = kzalloc(sizeof(*master), GFP_KERNEL); 778 if (!master) 779 return -ENOMEM; 780 781 master->dev = &pdev->dev; 782 master->master.dev.parent = master->dev; 783 master->master.dev.of_node = of_node_get(dev_of_node(master->dev)); 784 master->master.dev.release = fsi_master_gpio_release; 785 master->last_addr = LAST_ADDR_INVALID; 786 787 gpio = devm_gpiod_get(&pdev->dev, "clock", 0); 788 if (IS_ERR(gpio)) { 789 dev_err(&pdev->dev, "failed to get clock gpio\n"); 790 rc = PTR_ERR(gpio); 791 goto err_free; 792 } 793 master->gpio_clk = gpio; 794 795 gpio = devm_gpiod_get(&pdev->dev, "data", 0); 796 if (IS_ERR(gpio)) { 797 dev_err(&pdev->dev, "failed to get data gpio\n"); 798 rc = PTR_ERR(gpio); 799 goto err_free; 800 } 801 master->gpio_data = gpio; 802 803 /* Optional GPIOs */ 804 gpio = devm_gpiod_get_optional(&pdev->dev, "trans", 0); 805 if (IS_ERR(gpio)) { 806 dev_err(&pdev->dev, "failed to get trans gpio\n"); 807 rc = PTR_ERR(gpio); 808 goto err_free; 809 } 810 master->gpio_trans = gpio; 811 812 gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 0); 813 if (IS_ERR(gpio)) { 814 dev_err(&pdev->dev, "failed to get enable gpio\n"); 815 rc = PTR_ERR(gpio); 816 goto err_free; 817 } 818 master->gpio_enable = gpio; 819 820 gpio = devm_gpiod_get_optional(&pdev->dev, "mux", 0); 821 if (IS_ERR(gpio)) { 822 dev_err(&pdev->dev, "failed to get mux gpio\n"); 823 rc = PTR_ERR(gpio); 824 goto err_free; 825 } 826 master->gpio_mux = gpio; 827 828 /* 829 * Check if GPIO block is slow enought that no extra delays 830 * are necessary. This improves performance on ast2500 by 831 * an order of magnitude. 832 */ 833 master->no_delays = device_property_present(&pdev->dev, "no-gpio-delays"); 834 835 /* Default FSI command delays */ 836 master->t_send_delay = FSI_SEND_DELAY_CLOCKS; 837 master->t_echo_delay = FSI_ECHO_DELAY_CLOCKS; 838 839 master->master.n_links = 1; 840 master->master.flags = FSI_MASTER_FLAG_SWCLOCK; 841 master->master.read = fsi_master_gpio_read; 842 master->master.write = fsi_master_gpio_write; 843 master->master.term = fsi_master_gpio_term; 844 master->master.send_break = fsi_master_gpio_break; 845 master->master.link_enable = fsi_master_gpio_link_enable; 846 master->master.link_config = fsi_master_gpio_link_config; 847 platform_set_drvdata(pdev, master); 848 mutex_init(&master->cmd_lock); 849 850 fsi_master_gpio_init(master); 851 852 rc = device_create_file(&pdev->dev, &dev_attr_external_mode); 853 if (rc) 854 goto err_free; 855 856 rc = fsi_master_register(&master->master); 857 if (rc) { 858 device_remove_file(&pdev->dev, &dev_attr_external_mode); 859 put_device(&master->master.dev); 860 return rc; 861 } 862 return 0; 863 err_free: 864 kfree(master); 865 return rc; 866 } 867 868 869 870 static int fsi_master_gpio_remove(struct platform_device *pdev) 871 { 872 struct fsi_master_gpio *master = platform_get_drvdata(pdev); 873 874 device_remove_file(&pdev->dev, &dev_attr_external_mode); 875 876 fsi_master_unregister(&master->master); 877 878 return 0; 879 } 880 881 static const struct of_device_id fsi_master_gpio_match[] = { 882 { .compatible = "fsi-master-gpio" }, 883 { }, 884 }; 885 MODULE_DEVICE_TABLE(of, fsi_master_gpio_match); 886 887 static struct platform_driver fsi_master_gpio_driver = { 888 .driver = { 889 .name = "fsi-master-gpio", 890 .of_match_table = fsi_master_gpio_match, 891 }, 892 .probe = fsi_master_gpio_probe, 893 .remove = fsi_master_gpio_remove, 894 }; 895 896 module_platform_driver(fsi_master_gpio_driver); 897 MODULE_LICENSE("GPL"); 898