1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Atheros AR933X SoC built-in UART driver 4 * 5 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org> 6 * 7 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. 8 */ 9 10 #include <linux/module.h> 11 #include <linux/ioport.h> 12 #include <linux/init.h> 13 #include <linux/console.h> 14 #include <linux/sysrq.h> 15 #include <linux/delay.h> 16 #include <linux/gpio/consumer.h> 17 #include <linux/platform_device.h> 18 #include <linux/of.h> 19 #include <linux/of_platform.h> 20 #include <linux/tty.h> 21 #include <linux/tty_flip.h> 22 #include <linux/serial_core.h> 23 #include <linux/serial.h> 24 #include <linux/slab.h> 25 #include <linux/io.h> 26 #include <linux/irq.h> 27 #include <linux/clk.h> 28 29 #include <asm/div64.h> 30 31 #include <asm/mach-ath79/ar933x_uart.h> 32 33 #include "serial_mctrl_gpio.h" 34 35 #define DRIVER_NAME "ar933x-uart" 36 37 #define AR933X_UART_MAX_SCALE 0xff 38 #define AR933X_UART_MAX_STEP 0xffff 39 40 #define AR933X_UART_MIN_BAUD 300 41 #define AR933X_UART_MAX_BAUD 3000000 42 43 #define AR933X_DUMMY_STATUS_RD 0x01 44 45 static struct uart_driver ar933x_uart_driver; 46 47 struct ar933x_uart_port { 48 struct uart_port port; 49 unsigned int ier; /* shadow Interrupt Enable Register */ 50 unsigned int min_baud; 51 unsigned int max_baud; 52 struct clk *clk; 53 struct mctrl_gpios *gpios; 54 struct gpio_desc *rts_gpiod; 55 }; 56 57 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up, 58 int offset) 59 { 60 return readl(up->port.membase + offset); 61 } 62 63 static inline void ar933x_uart_write(struct ar933x_uart_port *up, 64 int offset, unsigned int value) 65 { 66 writel(value, up->port.membase + offset); 67 } 68 69 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up, 70 unsigned int offset, 71 unsigned int mask, 72 unsigned int val) 73 { 74 unsigned int t; 75 76 t = ar933x_uart_read(up, offset); 77 t &= ~mask; 78 t |= val; 79 ar933x_uart_write(up, offset, t); 80 } 81 82 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up, 83 unsigned int offset, 84 unsigned int val) 85 { 86 ar933x_uart_rmw(up, offset, 0, val); 87 } 88 89 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up, 90 unsigned int offset, 91 unsigned int val) 92 { 93 ar933x_uart_rmw(up, offset, val, 0); 94 } 95 96 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up) 97 { 98 up->ier |= AR933X_UART_INT_TX_EMPTY; 99 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 100 } 101 102 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up) 103 { 104 up->ier &= ~AR933X_UART_INT_TX_EMPTY; 105 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 106 } 107 108 static inline void ar933x_uart_start_rx_interrupt(struct ar933x_uart_port *up) 109 { 110 up->ier |= AR933X_UART_INT_RX_VALID; 111 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 112 } 113 114 static inline void ar933x_uart_stop_rx_interrupt(struct ar933x_uart_port *up) 115 { 116 up->ier &= ~AR933X_UART_INT_RX_VALID; 117 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 118 } 119 120 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch) 121 { 122 unsigned int rdata; 123 124 rdata = ch & AR933X_UART_DATA_TX_RX_MASK; 125 rdata |= AR933X_UART_DATA_TX_CSR; 126 ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata); 127 } 128 129 static unsigned int ar933x_uart_tx_empty(struct uart_port *port) 130 { 131 struct ar933x_uart_port *up = 132 container_of(port, struct ar933x_uart_port, port); 133 unsigned long flags; 134 unsigned int rdata; 135 136 spin_lock_irqsave(&up->port.lock, flags); 137 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 138 spin_unlock_irqrestore(&up->port.lock, flags); 139 140 return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT; 141 } 142 143 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port) 144 { 145 struct ar933x_uart_port *up = 146 container_of(port, struct ar933x_uart_port, port); 147 int ret = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; 148 149 mctrl_gpio_get(up->gpios, &ret); 150 151 return ret; 152 } 153 154 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) 155 { 156 struct ar933x_uart_port *up = 157 container_of(port, struct ar933x_uart_port, port); 158 159 mctrl_gpio_set(up->gpios, mctrl); 160 } 161 162 static void ar933x_uart_start_tx(struct uart_port *port) 163 { 164 struct ar933x_uart_port *up = 165 container_of(port, struct ar933x_uart_port, port); 166 167 ar933x_uart_start_tx_interrupt(up); 168 } 169 170 static void ar933x_uart_wait_tx_complete(struct ar933x_uart_port *up) 171 { 172 unsigned int status; 173 unsigned int timeout = 60000; 174 175 /* Wait up to 60ms for the character(s) to be sent. */ 176 do { 177 status = ar933x_uart_read(up, AR933X_UART_CS_REG); 178 if (--timeout == 0) 179 break; 180 udelay(1); 181 } while (status & AR933X_UART_CS_TX_BUSY); 182 183 if (timeout == 0) 184 dev_err(up->port.dev, "waiting for TX timed out\n"); 185 } 186 187 static void ar933x_uart_rx_flush(struct ar933x_uart_port *up) 188 { 189 unsigned int status; 190 191 /* clear RX_VALID interrupt */ 192 ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_RX_VALID); 193 194 /* remove characters from the RX FIFO */ 195 do { 196 ar933x_uart_write(up, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR); 197 status = ar933x_uart_read(up, AR933X_UART_DATA_REG); 198 } while (status & AR933X_UART_DATA_RX_CSR); 199 } 200 201 static void ar933x_uart_stop_tx(struct uart_port *port) 202 { 203 struct ar933x_uart_port *up = 204 container_of(port, struct ar933x_uart_port, port); 205 206 ar933x_uart_stop_tx_interrupt(up); 207 } 208 209 static void ar933x_uart_stop_rx(struct uart_port *port) 210 { 211 struct ar933x_uart_port *up = 212 container_of(port, struct ar933x_uart_port, port); 213 214 ar933x_uart_stop_rx_interrupt(up); 215 } 216 217 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state) 218 { 219 struct ar933x_uart_port *up = 220 container_of(port, struct ar933x_uart_port, port); 221 unsigned long flags; 222 223 spin_lock_irqsave(&up->port.lock, flags); 224 if (break_state == -1) 225 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 226 AR933X_UART_CS_TX_BREAK); 227 else 228 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, 229 AR933X_UART_CS_TX_BREAK); 230 spin_unlock_irqrestore(&up->port.lock, flags); 231 } 232 233 /* 234 * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17)) 235 */ 236 static unsigned long ar933x_uart_get_baud(unsigned int clk, 237 unsigned int scale, 238 unsigned int step) 239 { 240 u64 t; 241 u32 div; 242 243 div = (2 << 16) * (scale + 1); 244 t = clk; 245 t *= step; 246 t += (div / 2); 247 do_div(t, div); 248 249 return t; 250 } 251 252 static void ar933x_uart_get_scale_step(unsigned int clk, 253 unsigned int baud, 254 unsigned int *scale, 255 unsigned int *step) 256 { 257 unsigned int tscale; 258 long min_diff; 259 260 *scale = 0; 261 *step = 0; 262 263 min_diff = baud; 264 for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) { 265 u64 tstep; 266 int diff; 267 268 tstep = baud * (tscale + 1); 269 tstep *= (2 << 16); 270 do_div(tstep, clk); 271 272 if (tstep > AR933X_UART_MAX_STEP) 273 break; 274 275 diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud); 276 if (diff < min_diff) { 277 min_diff = diff; 278 *scale = tscale; 279 *step = tstep; 280 } 281 } 282 } 283 284 static void ar933x_uart_set_termios(struct uart_port *port, 285 struct ktermios *new, 286 const struct ktermios *old) 287 { 288 struct ar933x_uart_port *up = 289 container_of(port, struct ar933x_uart_port, port); 290 unsigned int cs; 291 unsigned long flags; 292 unsigned int baud, scale, step; 293 294 /* Only CS8 is supported */ 295 new->c_cflag &= ~CSIZE; 296 new->c_cflag |= CS8; 297 298 /* Only one stop bit is supported */ 299 new->c_cflag &= ~CSTOPB; 300 301 cs = 0; 302 if (new->c_cflag & PARENB) { 303 if (!(new->c_cflag & PARODD)) 304 cs |= AR933X_UART_CS_PARITY_EVEN; 305 else 306 cs |= AR933X_UART_CS_PARITY_ODD; 307 } else { 308 cs |= AR933X_UART_CS_PARITY_NONE; 309 } 310 311 /* Mark/space parity is not supported */ 312 new->c_cflag &= ~CMSPAR; 313 314 baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud); 315 ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step); 316 317 /* 318 * Ok, we're now changing the port state. Do it with 319 * interrupts disabled. 320 */ 321 spin_lock_irqsave(&up->port.lock, flags); 322 323 /* disable the UART */ 324 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, 325 AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S); 326 327 /* Update the per-port timeout. */ 328 uart_update_timeout(port, new->c_cflag, baud); 329 330 up->port.ignore_status_mask = 0; 331 332 /* ignore all characters if CREAD is not set */ 333 if ((new->c_cflag & CREAD) == 0) 334 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD; 335 336 ar933x_uart_write(up, AR933X_UART_CLOCK_REG, 337 scale << AR933X_UART_CLOCK_SCALE_S | step); 338 339 /* setup configuration register */ 340 ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs); 341 342 /* enable host interrupt */ 343 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 344 AR933X_UART_CS_HOST_INT_EN); 345 346 /* enable RX and TX ready overide */ 347 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 348 AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE); 349 350 /* reenable the UART */ 351 ar933x_uart_rmw(up, AR933X_UART_CS_REG, 352 AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S, 353 AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S); 354 355 spin_unlock_irqrestore(&up->port.lock, flags); 356 357 if (tty_termios_baud_rate(new)) 358 tty_termios_encode_baud_rate(new, baud, baud); 359 } 360 361 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up) 362 { 363 struct tty_port *port = &up->port.state->port; 364 int max_count = 256; 365 366 do { 367 unsigned int rdata; 368 unsigned char ch; 369 370 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 371 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0) 372 break; 373 374 /* remove the character from the FIFO */ 375 ar933x_uart_write(up, AR933X_UART_DATA_REG, 376 AR933X_UART_DATA_RX_CSR); 377 378 up->port.icount.rx++; 379 ch = rdata & AR933X_UART_DATA_TX_RX_MASK; 380 381 if (uart_handle_sysrq_char(&up->port, ch)) 382 continue; 383 384 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0) 385 tty_insert_flip_char(port, ch, TTY_NORMAL); 386 } while (max_count-- > 0); 387 388 tty_flip_buffer_push(port); 389 } 390 391 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up) 392 { 393 struct circ_buf *xmit = &up->port.state->xmit; 394 struct serial_rs485 *rs485conf = &up->port.rs485; 395 int count; 396 bool half_duplex_send = false; 397 398 if (uart_tx_stopped(&up->port)) 399 return; 400 401 if ((rs485conf->flags & SER_RS485_ENABLED) && 402 (up->port.x_char || !uart_circ_empty(xmit))) { 403 ar933x_uart_stop_rx_interrupt(up); 404 gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_ON_SEND)); 405 half_duplex_send = true; 406 } 407 408 count = up->port.fifosize; 409 do { 410 unsigned int rdata; 411 412 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 413 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0) 414 break; 415 416 if (up->port.x_char) { 417 ar933x_uart_putc(up, up->port.x_char); 418 up->port.icount.tx++; 419 up->port.x_char = 0; 420 continue; 421 } 422 423 if (uart_circ_empty(xmit)) 424 break; 425 426 ar933x_uart_putc(up, xmit->buf[xmit->tail]); 427 428 uart_xmit_advance(&up->port, 1); 429 } while (--count > 0); 430 431 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 432 uart_write_wakeup(&up->port); 433 434 if (!uart_circ_empty(xmit)) { 435 ar933x_uart_start_tx_interrupt(up); 436 } else if (half_duplex_send) { 437 ar933x_uart_wait_tx_complete(up); 438 ar933x_uart_rx_flush(up); 439 ar933x_uart_start_rx_interrupt(up); 440 gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_AFTER_SEND)); 441 } 442 } 443 444 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) 445 { 446 struct ar933x_uart_port *up = dev_id; 447 unsigned int status; 448 449 status = ar933x_uart_read(up, AR933X_UART_CS_REG); 450 if ((status & AR933X_UART_CS_HOST_INT) == 0) 451 return IRQ_NONE; 452 453 spin_lock(&up->port.lock); 454 455 status = ar933x_uart_read(up, AR933X_UART_INT_REG); 456 status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG); 457 458 if (status & AR933X_UART_INT_RX_VALID) { 459 ar933x_uart_write(up, AR933X_UART_INT_REG, 460 AR933X_UART_INT_RX_VALID); 461 ar933x_uart_rx_chars(up); 462 } 463 464 if (status & AR933X_UART_INT_TX_EMPTY) { 465 ar933x_uart_write(up, AR933X_UART_INT_REG, 466 AR933X_UART_INT_TX_EMPTY); 467 ar933x_uart_stop_tx_interrupt(up); 468 ar933x_uart_tx_chars(up); 469 } 470 471 spin_unlock(&up->port.lock); 472 473 return IRQ_HANDLED; 474 } 475 476 static int ar933x_uart_startup(struct uart_port *port) 477 { 478 struct ar933x_uart_port *up = 479 container_of(port, struct ar933x_uart_port, port); 480 unsigned long flags; 481 int ret; 482 483 ret = request_irq(up->port.irq, ar933x_uart_interrupt, 484 up->port.irqflags, dev_name(up->port.dev), up); 485 if (ret) 486 return ret; 487 488 spin_lock_irqsave(&up->port.lock, flags); 489 490 /* Enable HOST interrupts */ 491 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 492 AR933X_UART_CS_HOST_INT_EN); 493 494 /* enable RX and TX ready overide */ 495 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 496 AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE); 497 498 /* Enable RX interrupts */ 499 ar933x_uart_start_rx_interrupt(up); 500 501 spin_unlock_irqrestore(&up->port.lock, flags); 502 503 return 0; 504 } 505 506 static void ar933x_uart_shutdown(struct uart_port *port) 507 { 508 struct ar933x_uart_port *up = 509 container_of(port, struct ar933x_uart_port, port); 510 511 /* Disable all interrupts */ 512 up->ier = 0; 513 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 514 515 /* Disable break condition */ 516 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, 517 AR933X_UART_CS_TX_BREAK); 518 519 free_irq(up->port.irq, up); 520 } 521 522 static const char *ar933x_uart_type(struct uart_port *port) 523 { 524 return (port->type == PORT_AR933X) ? "AR933X UART" : NULL; 525 } 526 527 static void ar933x_uart_release_port(struct uart_port *port) 528 { 529 /* Nothing to release ... */ 530 } 531 532 static int ar933x_uart_request_port(struct uart_port *port) 533 { 534 /* UARTs always present */ 535 return 0; 536 } 537 538 static void ar933x_uart_config_port(struct uart_port *port, int flags) 539 { 540 if (flags & UART_CONFIG_TYPE) 541 port->type = PORT_AR933X; 542 } 543 544 static int ar933x_uart_verify_port(struct uart_port *port, 545 struct serial_struct *ser) 546 { 547 struct ar933x_uart_port *up = 548 container_of(port, struct ar933x_uart_port, port); 549 550 if (ser->type != PORT_UNKNOWN && 551 ser->type != PORT_AR933X) 552 return -EINVAL; 553 554 if (ser->irq < 0 || ser->irq >= NR_IRQS) 555 return -EINVAL; 556 557 if (ser->baud_base < up->min_baud || 558 ser->baud_base > up->max_baud) 559 return -EINVAL; 560 561 return 0; 562 } 563 564 static const struct uart_ops ar933x_uart_ops = { 565 .tx_empty = ar933x_uart_tx_empty, 566 .set_mctrl = ar933x_uart_set_mctrl, 567 .get_mctrl = ar933x_uart_get_mctrl, 568 .stop_tx = ar933x_uart_stop_tx, 569 .start_tx = ar933x_uart_start_tx, 570 .stop_rx = ar933x_uart_stop_rx, 571 .break_ctl = ar933x_uart_break_ctl, 572 .startup = ar933x_uart_startup, 573 .shutdown = ar933x_uart_shutdown, 574 .set_termios = ar933x_uart_set_termios, 575 .type = ar933x_uart_type, 576 .release_port = ar933x_uart_release_port, 577 .request_port = ar933x_uart_request_port, 578 .config_port = ar933x_uart_config_port, 579 .verify_port = ar933x_uart_verify_port, 580 }; 581 582 static int ar933x_config_rs485(struct uart_port *port, struct ktermios *termios, 583 struct serial_rs485 *rs485conf) 584 { 585 struct ar933x_uart_port *up = 586 container_of(port, struct ar933x_uart_port, port); 587 588 if (port->rs485.flags & SER_RS485_ENABLED) 589 gpiod_set_value(up->rts_gpiod, 590 !!(rs485conf->flags & SER_RS485_RTS_AFTER_SEND)); 591 592 return 0; 593 } 594 595 #ifdef CONFIG_SERIAL_AR933X_CONSOLE 596 static struct ar933x_uart_port * 597 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS]; 598 599 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up) 600 { 601 unsigned int status; 602 unsigned int timeout = 60000; 603 604 /* Wait up to 60ms for the character(s) to be sent. */ 605 do { 606 status = ar933x_uart_read(up, AR933X_UART_DATA_REG); 607 if (--timeout == 0) 608 break; 609 udelay(1); 610 } while ((status & AR933X_UART_DATA_TX_CSR) == 0); 611 } 612 613 static void ar933x_uart_console_putchar(struct uart_port *port, unsigned char ch) 614 { 615 struct ar933x_uart_port *up = 616 container_of(port, struct ar933x_uart_port, port); 617 618 ar933x_uart_wait_xmitr(up); 619 ar933x_uart_putc(up, ch); 620 } 621 622 static void ar933x_uart_console_write(struct console *co, const char *s, 623 unsigned int count) 624 { 625 struct ar933x_uart_port *up = ar933x_console_ports[co->index]; 626 unsigned long flags; 627 unsigned int int_en; 628 int locked = 1; 629 630 local_irq_save(flags); 631 632 if (up->port.sysrq) 633 locked = 0; 634 else if (oops_in_progress) 635 locked = spin_trylock(&up->port.lock); 636 else 637 spin_lock(&up->port.lock); 638 639 /* 640 * First save the IER then disable the interrupts 641 */ 642 int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG); 643 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0); 644 645 uart_console_write(&up->port, s, count, ar933x_uart_console_putchar); 646 647 /* 648 * Finally, wait for transmitter to become empty 649 * and restore the IER 650 */ 651 ar933x_uart_wait_xmitr(up); 652 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en); 653 654 ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); 655 656 if (locked) 657 spin_unlock(&up->port.lock); 658 659 local_irq_restore(flags); 660 } 661 662 static int ar933x_uart_console_setup(struct console *co, char *options) 663 { 664 struct ar933x_uart_port *up; 665 int baud = 115200; 666 int bits = 8; 667 int parity = 'n'; 668 int flow = 'n'; 669 670 if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS) 671 return -EINVAL; 672 673 up = ar933x_console_ports[co->index]; 674 if (!up) 675 return -ENODEV; 676 677 if (options) 678 uart_parse_options(options, &baud, &parity, &bits, &flow); 679 680 return uart_set_options(&up->port, co, baud, parity, bits, flow); 681 } 682 683 static struct console ar933x_uart_console = { 684 .name = "ttyATH", 685 .write = ar933x_uart_console_write, 686 .device = uart_console_device, 687 .setup = ar933x_uart_console_setup, 688 .flags = CON_PRINTBUFFER, 689 .index = -1, 690 .data = &ar933x_uart_driver, 691 }; 692 #endif /* CONFIG_SERIAL_AR933X_CONSOLE */ 693 694 static struct uart_driver ar933x_uart_driver = { 695 .owner = THIS_MODULE, 696 .driver_name = DRIVER_NAME, 697 .dev_name = "ttyATH", 698 .nr = CONFIG_SERIAL_AR933X_NR_UARTS, 699 .cons = NULL, /* filled in runtime */ 700 }; 701 702 static const struct serial_rs485 ar933x_no_rs485 = {}; 703 static const struct serial_rs485 ar933x_rs485_supported = { 704 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND, 705 }; 706 707 static int ar933x_uart_probe(struct platform_device *pdev) 708 { 709 struct ar933x_uart_port *up; 710 struct uart_port *port; 711 struct resource *mem_res; 712 struct device_node *np; 713 unsigned int baud; 714 int id; 715 int ret; 716 int irq; 717 718 np = pdev->dev.of_node; 719 if (IS_ENABLED(CONFIG_OF) && np) { 720 id = of_alias_get_id(np, "serial"); 721 if (id < 0) { 722 dev_err(&pdev->dev, "unable to get alias id, err=%d\n", 723 id); 724 return id; 725 } 726 } else { 727 id = pdev->id; 728 if (id == -1) 729 id = 0; 730 } 731 732 if (id >= CONFIG_SERIAL_AR933X_NR_UARTS) 733 return -EINVAL; 734 735 irq = platform_get_irq(pdev, 0); 736 if (irq < 0) 737 return irq; 738 739 up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port), 740 GFP_KERNEL); 741 if (!up) 742 return -ENOMEM; 743 744 up->clk = devm_clk_get(&pdev->dev, "uart"); 745 if (IS_ERR(up->clk)) { 746 dev_err(&pdev->dev, "unable to get UART clock\n"); 747 return PTR_ERR(up->clk); 748 } 749 750 port = &up->port; 751 752 port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &mem_res); 753 if (IS_ERR(port->membase)) 754 return PTR_ERR(port->membase); 755 756 ret = clk_prepare_enable(up->clk); 757 if (ret) 758 return ret; 759 760 port->uartclk = clk_get_rate(up->clk); 761 if (!port->uartclk) { 762 ret = -EINVAL; 763 goto err_disable_clk; 764 } 765 766 port->mapbase = mem_res->start; 767 port->line = id; 768 port->irq = irq; 769 port->dev = &pdev->dev; 770 port->type = PORT_AR933X; 771 port->iotype = UPIO_MEM32; 772 773 port->regshift = 2; 774 port->fifosize = AR933X_UART_FIFO_SIZE; 775 port->ops = &ar933x_uart_ops; 776 port->rs485_config = ar933x_config_rs485; 777 port->rs485_supported = ar933x_rs485_supported; 778 779 baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1); 780 up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD); 781 782 baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP); 783 up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD); 784 785 ret = uart_get_rs485_mode(port); 786 if (ret) 787 goto err_disable_clk; 788 789 up->gpios = mctrl_gpio_init(port, 0); 790 if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS) { 791 ret = PTR_ERR(up->gpios); 792 goto err_disable_clk; 793 } 794 795 up->rts_gpiod = mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS); 796 797 if (!up->rts_gpiod) { 798 port->rs485_supported = ar933x_no_rs485; 799 if (port->rs485.flags & SER_RS485_ENABLED) { 800 dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n"); 801 port->rs485.flags &= ~SER_RS485_ENABLED; 802 } 803 } 804 805 #ifdef CONFIG_SERIAL_AR933X_CONSOLE 806 ar933x_console_ports[up->port.line] = up; 807 #endif 808 809 ret = uart_add_one_port(&ar933x_uart_driver, &up->port); 810 if (ret) 811 goto err_disable_clk; 812 813 platform_set_drvdata(pdev, up); 814 return 0; 815 816 err_disable_clk: 817 clk_disable_unprepare(up->clk); 818 return ret; 819 } 820 821 static int ar933x_uart_remove(struct platform_device *pdev) 822 { 823 struct ar933x_uart_port *up; 824 825 up = platform_get_drvdata(pdev); 826 827 if (up) { 828 uart_remove_one_port(&ar933x_uart_driver, &up->port); 829 clk_disable_unprepare(up->clk); 830 } 831 832 return 0; 833 } 834 835 #ifdef CONFIG_OF 836 static const struct of_device_id ar933x_uart_of_ids[] = { 837 { .compatible = "qca,ar9330-uart" }, 838 {}, 839 }; 840 MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids); 841 #endif 842 843 static struct platform_driver ar933x_uart_platform_driver = { 844 .probe = ar933x_uart_probe, 845 .remove = ar933x_uart_remove, 846 .driver = { 847 .name = DRIVER_NAME, 848 .of_match_table = of_match_ptr(ar933x_uart_of_ids), 849 }, 850 }; 851 852 static int __init ar933x_uart_init(void) 853 { 854 int ret; 855 856 #ifdef CONFIG_SERIAL_AR933X_CONSOLE 857 ar933x_uart_driver.cons = &ar933x_uart_console; 858 #endif 859 860 ret = uart_register_driver(&ar933x_uart_driver); 861 if (ret) 862 goto err_out; 863 864 ret = platform_driver_register(&ar933x_uart_platform_driver); 865 if (ret) 866 goto err_unregister_uart_driver; 867 868 return 0; 869 870 err_unregister_uart_driver: 871 uart_unregister_driver(&ar933x_uart_driver); 872 err_out: 873 return ret; 874 } 875 876 static void __exit ar933x_uart_exit(void) 877 { 878 platform_driver_unregister(&ar933x_uart_platform_driver); 879 uart_unregister_driver(&ar933x_uart_driver); 880 } 881 882 module_init(ar933x_uart_init); 883 module_exit(ar933x_uart_exit); 884 885 MODULE_DESCRIPTION("Atheros AR933X UART driver"); 886 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); 887 MODULE_LICENSE("GPL v2"); 888 MODULE_ALIAS("platform:" DRIVER_NAME); 889