drivers/tty/serial/ar933x_uart.c

   1 /*
   2  *  Atheros AR933X SoC built-in UART driver
   3  *
   4  *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify it
   9  *  under the terms of the GNU General Public License version 2 as published
  10  *  by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/ioport.h>
  15 #include <linux/init.h>
  16 #include <linux/console.h>
  17 #include <linux/sysrq.h>
  18 #include <linux/delay.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/of.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/tty.h>
  23 #include <linux/tty_flip.h>
  24 #include <linux/serial_core.h>
  25 #include <linux/serial.h>
  26 #include <linux/slab.h>
  27 #include <linux/io.h>
  28 #include <linux/irq.h>
  29 #include <linux/clk.h>
  30
  31 #include <asm/div64.h>
  32
  33 #include <asm/mach-ath79/ar933x_uart.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 };
  54
  55 static inline bool ar933x_uart_console_enabled(void)
  56 {
  57         return IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);
  58 }
  59
  60 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
  61                                             int offset)
  62 {
  63         return readl(up->port.membase + offset);
  64 }
  65
  66 static inline void ar933x_uart_write(struct ar933x_uart_port *up,
  67                                      int offset, unsigned int value)
  68 {
  69         writel(value, up->port.membase + offset);
  70 }
  71
  72 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
  73                                   unsigned int offset,
  74                                   unsigned int mask,
  75                                   unsigned int val)
  76 {
  77         unsigned int t;
  78
  79         t = ar933x_uart_read(up, offset);
  80         t &= ~mask;
  81         t |= val;
  82         ar933x_uart_write(up, offset, t);
  83 }
  84
  85 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
  86                                        unsigned int offset,
  87                                        unsigned int val)
  88 {
  89         ar933x_uart_rmw(up, offset, 0, val);
  90 }
  91
  92 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
  93                                          unsigned int offset,
  94                                          unsigned int val)
  95 {
  96         ar933x_uart_rmw(up, offset, val, 0);
  97 }
  98
  99 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
 100 {
 101         up->ier |= AR933X_UART_INT_TX_EMPTY;
 102         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 103 }
 104
 105 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
 106 {
 107         up->ier &= ~AR933X_UART_INT_TX_EMPTY;
 108         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 109 }
 110
 111 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
 112 {
 113         unsigned int rdata;
 114
 115         rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
 116         rdata |= AR933X_UART_DATA_TX_CSR;
 117         ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
 118 }
 119
 120 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
 121 {
 122         struct ar933x_uart_port *up =
 123                 container_of(port, struct ar933x_uart_port, port);
 124         unsigned long flags;
 125         unsigned int rdata;
 126
 127         spin_lock_irqsave(&up->port.lock, flags);
 128         rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 129         spin_unlock_irqrestore(&up->port.lock, flags);
 130
 131         return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
 132 }
 133
 134 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
 135 {
 136         return TIOCM_CAR;
 137 }
 138
 139 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 140 {
 141 }
 142
 143 static void ar933x_uart_start_tx(struct uart_port *port)
 144 {
 145         struct ar933x_uart_port *up =
 146                 container_of(port, struct ar933x_uart_port, port);
 147
 148         ar933x_uart_start_tx_interrupt(up);
 149 }
 150
 151 static void ar933x_uart_stop_tx(struct uart_port *port)
 152 {
 153         struct ar933x_uart_port *up =
 154                 container_of(port, struct ar933x_uart_port, port);
 155
 156         ar933x_uart_stop_tx_interrupt(up);
 157 }
 158
 159 static void ar933x_uart_stop_rx(struct uart_port *port)
 160 {
 161         struct ar933x_uart_port *up =
 162                 container_of(port, struct ar933x_uart_port, port);
 163
 164         up->ier &= ~AR933X_UART_INT_RX_VALID;
 165         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 166 }
 167
 168 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
 169 {
 170         struct ar933x_uart_port *up =
 171                 container_of(port, struct ar933x_uart_port, port);
 172         unsigned long flags;
 173
 174         spin_lock_irqsave(&up->port.lock, flags);
 175         if (break_state == -1)
 176                 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 177                                     AR933X_UART_CS_TX_BREAK);
 178         else
 179                 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 180                                       AR933X_UART_CS_TX_BREAK);
 181         spin_unlock_irqrestore(&up->port.lock, flags);
 182 }
 183
 184 /*
 185  * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
 186  */
 187 static unsigned long ar933x_uart_get_baud(unsigned int clk,
 188                                           unsigned int scale,
 189                                           unsigned int step)
 190 {
 191         u64 t;
 192         u32 div;
 193
 194         div = (2 << 16) * (scale + 1);
 195         t = clk;
 196         t *= step;
 197         t += (div / 2);
 198         do_div(t, div);
 199
 200         return t;
 201 }
 202
 203 static void ar933x_uart_get_scale_step(unsigned int clk,
 204                                        unsigned int baud,
 205                                        unsigned int *scale,
 206                                        unsigned int *step)
 207 {
 208         unsigned int tscale;
 209         long min_diff;
 210
 211         *scale = 0;
 212         *step = 0;
 213
 214         min_diff = baud;
 215         for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
 216                 u64 tstep;
 217                 int diff;
 218
 219                 tstep = baud * (tscale + 1);
 220                 tstep *= (2 << 16);
 221                 do_div(tstep, clk);
 222
 223                 if (tstep > AR933X_UART_MAX_STEP)
 224                         break;
 225
 226                 diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
 227                 if (diff < min_diff) {
 228                         min_diff = diff;
 229                         *scale = tscale;
 230                         *step = tstep;
 231                 }
 232         }
 233 }
 234
 235 static void ar933x_uart_set_termios(struct uart_port *port,
 236                                     struct ktermios *new,
 237                                     struct ktermios *old)
 238 {
 239         struct ar933x_uart_port *up =
 240                 container_of(port, struct ar933x_uart_port, port);
 241         unsigned int cs;
 242         unsigned long flags;
 243         unsigned int baud, scale, step;
 244
 245         /* Only CS8 is supported */
 246         new->c_cflag &= ~CSIZE;
 247         new->c_cflag |= CS8;
 248
 249         /* Only one stop bit is supported */
 250         new->c_cflag &= ~CSTOPB;
 251
 252         cs = 0;
 253         if (new->c_cflag & PARENB) {
 254                 if (!(new->c_cflag & PARODD))
 255                         cs |= AR933X_UART_CS_PARITY_EVEN;
 256                 else
 257                         cs |= AR933X_UART_CS_PARITY_ODD;
 258         } else {
 259                 cs |= AR933X_UART_CS_PARITY_NONE;
 260         }
 261
 262         /* Mark/space parity is not supported */
 263         new->c_cflag &= ~CMSPAR;
 264
 265         baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
 266         ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
 267
 268         /*
 269          * Ok, we're now changing the port state. Do it with
 270          * interrupts disabled.
 271          */
 272         spin_lock_irqsave(&up->port.lock, flags);
 273
 274         /* disable the UART */
 275         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 276                       AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
 277
 278         /* Update the per-port timeout. */
 279         uart_update_timeout(port, new->c_cflag, baud);
 280
 281         up->port.ignore_status_mask = 0;
 282
 283         /* ignore all characters if CREAD is not set */
 284         if ((new->c_cflag & CREAD) == 0)
 285                 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
 286
 287         ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
 288                           scale << AR933X_UART_CLOCK_SCALE_S | step);
 289
 290         /* setup configuration register */
 291         ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
 292
 293         /* enable host interrupt */
 294         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 295                             AR933X_UART_CS_HOST_INT_EN);
 296
 297         /* reenable the UART */
 298         ar933x_uart_rmw(up, AR933X_UART_CS_REG,
 299                         AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
 300                         AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
 301
 302         spin_unlock_irqrestore(&up->port.lock, flags);
 303
 304         if (tty_termios_baud_rate(new))
 305                 tty_termios_encode_baud_rate(new, baud, baud);
 306 }
 307
 308 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
 309 {
 310         struct tty_port *port = &up->port.state->port;
 311         int max_count = 256;
 312
 313         do {
 314                 unsigned int rdata;
 315                 unsigned char ch;
 316
 317                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 318                 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
 319                         break;
 320
 321                 /* remove the character from the FIFO */
 322                 ar933x_uart_write(up, AR933X_UART_DATA_REG,
 323                                   AR933X_UART_DATA_RX_CSR);
 324
 325                 up->port.icount.rx++;
 326                 ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
 327
 328                 if (uart_handle_sysrq_char(&up->port, ch))
 329                         continue;
 330
 331                 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
 332                         tty_insert_flip_char(port, ch, TTY_NORMAL);
 333         } while (max_count-- > 0);
 334
 335         spin_unlock(&up->port.lock);
 336         tty_flip_buffer_push(port);
 337         spin_lock(&up->port.lock);
 338 }
 339
 340 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
 341 {
 342         struct circ_buf *xmit = &up->port.state->xmit;
 343         int count;
 344
 345         if (uart_tx_stopped(&up->port))
 346                 return;
 347
 348         count = up->port.fifosize;
 349         do {
 350                 unsigned int rdata;
 351
 352                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 353                 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
 354                         break;
 355
 356                 if (up->port.x_char) {
 357                         ar933x_uart_putc(up, up->port.x_char);
 358                         up->port.icount.tx++;
 359                         up->port.x_char = 0;
 360                         continue;
 361                 }
 362
 363                 if (uart_circ_empty(xmit))
 364                         break;
 365
 366                 ar933x_uart_putc(up, xmit->buf[xmit->tail]);
 367
 368                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 369                 up->port.icount.tx++;
 370         } while (--count > 0);
 371
 372         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 373                 uart_write_wakeup(&up->port);
 374
 375         if (!uart_circ_empty(xmit))
 376                 ar933x_uart_start_tx_interrupt(up);
 377 }
 378
 379 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
 380 {
 381         struct ar933x_uart_port *up = dev_id;
 382         unsigned int status;
 383
 384         status = ar933x_uart_read(up, AR933X_UART_CS_REG);
 385         if ((status & AR933X_UART_CS_HOST_INT) == 0)
 386                 return IRQ_NONE;
 387
 388         spin_lock(&up->port.lock);
 389
 390         status = ar933x_uart_read(up, AR933X_UART_INT_REG);
 391         status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 392
 393         if (status & AR933X_UART_INT_RX_VALID) {
 394                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 395                                   AR933X_UART_INT_RX_VALID);
 396                 ar933x_uart_rx_chars(up);
 397         }
 398
 399         if (status & AR933X_UART_INT_TX_EMPTY) {
 400                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 401                                   AR933X_UART_INT_TX_EMPTY);
 402                 ar933x_uart_stop_tx_interrupt(up);
 403                 ar933x_uart_tx_chars(up);
 404         }
 405
 406         spin_unlock(&up->port.lock);
 407
 408         return IRQ_HANDLED;
 409 }
 410
 411 static int ar933x_uart_startup(struct uart_port *port)
 412 {
 413         struct ar933x_uart_port *up =
 414                 container_of(port, struct ar933x_uart_port, port);
 415         unsigned long flags;
 416         int ret;
 417
 418         ret = request_irq(up->port.irq, ar933x_uart_interrupt,
 419                           up->port.irqflags, dev_name(up->port.dev), up);
 420         if (ret)
 421                 return ret;
 422
 423         spin_lock_irqsave(&up->port.lock, flags);
 424
 425         /* Enable HOST interrupts */
 426         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 427                             AR933X_UART_CS_HOST_INT_EN);
 428
 429         /* Enable RX interrupts */
 430         up->ier = AR933X_UART_INT_RX_VALID;
 431         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 432
 433         spin_unlock_irqrestore(&up->port.lock, flags);
 434
 435         return 0;
 436 }
 437
 438 static void ar933x_uart_shutdown(struct uart_port *port)
 439 {
 440         struct ar933x_uart_port *up =
 441                 container_of(port, struct ar933x_uart_port, port);
 442
 443         /* Disable all interrupts */
 444         up->ier = 0;
 445         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 446
 447         /* Disable break condition */
 448         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 449                               AR933X_UART_CS_TX_BREAK);
 450
 451         free_irq(up->port.irq, up);
 452 }
 453
 454 static const char *ar933x_uart_type(struct uart_port *port)
 455 {
 456         return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
 457 }
 458
 459 static void ar933x_uart_release_port(struct uart_port *port)
 460 {
 461         /* Nothing to release ... */
 462 }
 463
 464 static int ar933x_uart_request_port(struct uart_port *port)
 465 {
 466         /* UARTs always present */
 467         return 0;
 468 }
 469
 470 static void ar933x_uart_config_port(struct uart_port *port, int flags)
 471 {
 472         if (flags & UART_CONFIG_TYPE)
 473                 port->type = PORT_AR933X;
 474 }
 475
 476 static int ar933x_uart_verify_port(struct uart_port *port,
 477                                    struct serial_struct *ser)
 478 {
 479         struct ar933x_uart_port *up =
 480                 container_of(port, struct ar933x_uart_port, port);
 481
 482         if (ser->type != PORT_UNKNOWN &&
 483             ser->type != PORT_AR933X)
 484                 return -EINVAL;
 485
 486         if (ser->irq < 0 || ser->irq >= NR_IRQS)
 487                 return -EINVAL;
 488
 489         if (ser->baud_base < up->min_baud ||
 490             ser->baud_base > up->max_baud)
 491                 return -EINVAL;
 492
 493         return 0;
 494 }
 495
 496 static struct uart_ops ar933x_uart_ops = {
 497         .tx_empty       = ar933x_uart_tx_empty,
 498         .set_mctrl      = ar933x_uart_set_mctrl,
 499         .get_mctrl      = ar933x_uart_get_mctrl,
 500         .stop_tx        = ar933x_uart_stop_tx,
 501         .start_tx       = ar933x_uart_start_tx,
 502         .stop_rx        = ar933x_uart_stop_rx,
 503         .break_ctl      = ar933x_uart_break_ctl,
 504         .startup        = ar933x_uart_startup,
 505         .shutdown       = ar933x_uart_shutdown,
 506         .set_termios    = ar933x_uart_set_termios,
 507         .type           = ar933x_uart_type,
 508         .release_port   = ar933x_uart_release_port,
 509         .request_port   = ar933x_uart_request_port,
 510         .config_port    = ar933x_uart_config_port,
 511         .verify_port    = ar933x_uart_verify_port,
 512 };
 513
 514 static struct ar933x_uart_port *
 515 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
 516
 517 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
 518 {
 519         unsigned int status;
 520         unsigned int timeout = 60000;
 521
 522         /* Wait up to 60ms for the character(s) to be sent. */
 523         do {
 524                 status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 525                 if (--timeout == 0)
 526                         break;
 527                 udelay(1);
 528         } while ((status & AR933X_UART_DATA_TX_CSR) == 0);
 529 }
 530
 531 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
 532 {
 533         struct ar933x_uart_port *up =
 534                 container_of(port, struct ar933x_uart_port, port);
 535
 536         ar933x_uart_wait_xmitr(up);
 537         ar933x_uart_putc(up, ch);
 538 }
 539
 540 static void ar933x_uart_console_write(struct console *co, const char *s,
 541                                       unsigned int count)
 542 {
 543         struct ar933x_uart_port *up = ar933x_console_ports[co->index];
 544         unsigned long flags;
 545         unsigned int int_en;
 546         int locked = 1;
 547
 548         local_irq_save(flags);
 549
 550         if (up->port.sysrq)
 551                 locked = 0;
 552         else if (oops_in_progress)
 553                 locked = spin_trylock(&up->port.lock);
 554         else
 555                 spin_lock(&up->port.lock);
 556
 557         /*
 558          * First save the IER then disable the interrupts
 559          */
 560         int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 561         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
 562
 563         uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
 564
 565         /*
 566          * Finally, wait for transmitter to become empty
 567          * and restore the IER
 568          */
 569         ar933x_uart_wait_xmitr(up);
 570         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
 571
 572         ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
 573
 574         if (locked)
 575                 spin_unlock(&up->port.lock);
 576
 577         local_irq_restore(flags);
 578 }
 579
 580 static int ar933x_uart_console_setup(struct console *co, char *options)
 581 {
 582         struct ar933x_uart_port *up;
 583         int baud = 115200;
 584         int bits = 8;
 585         int parity = 'n';
 586         int flow = 'n';
 587
 588         if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
 589                 return -EINVAL;
 590
 591         up = ar933x_console_ports[co->index];
 592         if (!up)
 593                 return -ENODEV;
 594
 595         if (options)
 596                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 597
 598         return uart_set_options(&up->port, co, baud, parity, bits, flow);
 599 }
 600
 601 static struct console ar933x_uart_console = {
 602         .name           = "ttyATH",
 603         .write          = ar933x_uart_console_write,
 604         .device         = uart_console_device,
 605         .setup          = ar933x_uart_console_setup,
 606         .flags          = CON_PRINTBUFFER,
 607         .index          = -1,
 608         .data           = &ar933x_uart_driver,
 609 };
 610
 611 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
 612 {
 613         if (!ar933x_uart_console_enabled())
 614                 return;
 615
 616         ar933x_console_ports[up->port.line] = up;
 617 }
 618
 619 static struct uart_driver ar933x_uart_driver = {
 620         .owner          = THIS_MODULE,
 621         .driver_name    = DRIVER_NAME,
 622         .dev_name       = "ttyATH",
 623         .nr             = CONFIG_SERIAL_AR933X_NR_UARTS,
 624         .cons           = NULL, /* filled in runtime */
 625 };
 626
 627 static int ar933x_uart_probe(struct platform_device *pdev)
 628 {
 629         struct ar933x_uart_port *up;
 630         struct uart_port *port;
 631         struct resource *mem_res;
 632         struct resource *irq_res;
 633         struct device_node *np;
 634         unsigned int baud;
 635         int id;
 636         int ret;
 637
 638         np = pdev->dev.of_node;
 639         if (IS_ENABLED(CONFIG_OF) && np) {
 640                 id = of_alias_get_id(np, "serial");
 641                 if (id < 0) {
 642                         dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
 643                                 id);
 644                         return id;
 645                 }
 646         } else {
 647                 id = pdev->id;
 648                 if (id == -1)
 649                         id = 0;
 650         }
 651
 652         if (id >= CONFIG_SERIAL_AR933X_NR_UARTS)
 653                 return -EINVAL;
 654
 655         irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 656         if (!irq_res) {
 657                 dev_err(&pdev->dev, "no IRQ resource\n");
 658                 return -EINVAL;
 659         }
 660
 661         up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
 662                           GFP_KERNEL);
 663         if (!up)
 664                 return -ENOMEM;
 665
 666         up->clk = devm_clk_get(&pdev->dev, "uart");
 667         if (IS_ERR(up->clk)) {
 668                 dev_err(&pdev->dev, "unable to get UART clock\n");
 669                 return PTR_ERR(up->clk);
 670         }
 671
 672         port = &up->port;
 673
 674         mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 675         port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
 676         if (IS_ERR(port->membase))
 677                 return PTR_ERR(port->membase);
 678
 679         ret = clk_prepare_enable(up->clk);
 680         if (ret)
 681                 return ret;
 682
 683         port->uartclk = clk_get_rate(up->clk);
 684         if (!port->uartclk) {
 685                 ret = -EINVAL;
 686                 goto err_disable_clk;
 687         }
 688
 689         port->mapbase = mem_res->start;
 690         port->line = id;
 691         port->irq = irq_res->start;
 692         port->dev = &pdev->dev;
 693         port->type = PORT_AR933X;
 694         port->iotype = UPIO_MEM32;
 695
 696         port->regshift = 2;
 697         port->fifosize = AR933X_UART_FIFO_SIZE;
 698         port->ops = &ar933x_uart_ops;
 699
 700         baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
 701         up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
 702
 703         baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
 704         up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
 705
 706         ar933x_uart_add_console_port(up);
 707
 708         ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
 709         if (ret)
 710                 goto err_disable_clk;
 711
 712         platform_set_drvdata(pdev, up);
 713         return 0;
 714
 715 err_disable_clk:
 716         clk_disable_unprepare(up->clk);
 717         return ret;
 718 }
 719
 720 static int ar933x_uart_remove(struct platform_device *pdev)
 721 {
 722         struct ar933x_uart_port *up;
 723
 724         up = platform_get_drvdata(pdev);
 725
 726         if (up) {
 727                 uart_remove_one_port(&ar933x_uart_driver, &up->port);
 728                 clk_disable_unprepare(up->clk);
 729         }
 730
 731         return 0;
 732 }
 733
 734 #ifdef CONFIG_OF
 735 static const struct of_device_id ar933x_uart_of_ids[] = {
 736         { .compatible = "qca,ar9330-uart" },
 737         {},
 738 };
 739 MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
 740 #endif
 741
 742 static struct platform_driver ar933x_uart_platform_driver = {
 743         .probe          = ar933x_uart_probe,
 744         .remove         = ar933x_uart_remove,
 745         .driver         = {
 746                 .name           = DRIVER_NAME,
 747                 .of_match_table = of_match_ptr(ar933x_uart_of_ids),
 748         },
 749 };
 750
 751 static int __init ar933x_uart_init(void)
 752 {
 753         int ret;
 754
 755         if (ar933x_uart_console_enabled())
 756                 ar933x_uart_driver.cons = &ar933x_uart_console;
 757
 758         ret = uart_register_driver(&ar933x_uart_driver);
 759         if (ret)
 760                 goto err_out;
 761
 762         ret = platform_driver_register(&ar933x_uart_platform_driver);
 763         if (ret)
 764                 goto err_unregister_uart_driver;
 765
 766         return 0;
 767
 768 err_unregister_uart_driver:
 769         uart_unregister_driver(&ar933x_uart_driver);
 770 err_out:
 771         return ret;
 772 }
 773
 774 static void __exit ar933x_uart_exit(void)
 775 {
 776         platform_driver_unregister(&ar933x_uart_platform_driver);
 777         uart_unregister_driver(&ar933x_uart_driver);
 778 }
 779
 780 module_init(ar933x_uart_init);
 781 module_exit(ar933x_uart_exit);
 782
 783 MODULE_DESCRIPTION("Atheros AR933X UART driver");
 784 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 785 MODULE_LICENSE("GPL v2");
 786 MODULE_ALIAS("platform:" DRIVER_NAME);