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 config_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 = (struct ar933x_uart_port *) port;
 123         unsigned long flags;
 124         unsigned int rdata;
 125
 126         spin_lock_irqsave(&up->port.lock, flags);
 127         rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 128         spin_unlock_irqrestore(&up->port.lock, flags);
 129
 130         return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
 131 }
 132
 133 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
 134 {
 135         return TIOCM_CAR;
 136 }
 137
 138 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 139 {
 140 }
 141
 142 static void ar933x_uart_start_tx(struct uart_port *port)
 143 {
 144         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 145
 146         ar933x_uart_start_tx_interrupt(up);
 147 }
 148
 149 static void ar933x_uart_stop_tx(struct uart_port *port)
 150 {
 151         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 152
 153         ar933x_uart_stop_tx_interrupt(up);
 154 }
 155
 156 static void ar933x_uart_stop_rx(struct uart_port *port)
 157 {
 158         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 159
 160         up->ier &= ~AR933X_UART_INT_RX_VALID;
 161         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 162 }
 163
 164 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
 165 {
 166         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 167         unsigned long flags;
 168
 169         spin_lock_irqsave(&up->port.lock, flags);
 170         if (break_state == -1)
 171                 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 172                                     AR933X_UART_CS_TX_BREAK);
 173         else
 174                 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 175                                       AR933X_UART_CS_TX_BREAK);
 176         spin_unlock_irqrestore(&up->port.lock, flags);
 177 }
 178
 179 static void ar933x_uart_enable_ms(struct uart_port *port)
 180 {
 181 }
 182
 183 /*
 184  * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
 185  */
 186 static unsigned long ar933x_uart_get_baud(unsigned int clk,
 187                                           unsigned int scale,
 188                                           unsigned int step)
 189 {
 190         u64 t;
 191         u32 div;
 192
 193         div = (2 << 16) * (scale + 1);
 194         t = clk;
 195         t *= step;
 196         t += (div / 2);
 197         do_div(t, div);
 198
 199         return t;
 200 }
 201
 202 static void ar933x_uart_get_scale_step(unsigned int clk,
 203                                        unsigned int baud,
 204                                        unsigned int *scale,
 205                                        unsigned int *step)
 206 {
 207         unsigned int tscale;
 208         long min_diff;
 209
 210         *scale = 0;
 211         *step = 0;
 212
 213         min_diff = baud;
 214         for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
 215                 u64 tstep;
 216                 int diff;
 217
 218                 tstep = baud * (tscale + 1);
 219                 tstep *= (2 << 16);
 220                 do_div(tstep, clk);
 221
 222                 if (tstep > AR933X_UART_MAX_STEP)
 223                         break;
 224
 225                 diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
 226                 if (diff < min_diff) {
 227                         min_diff = diff;
 228                         *scale = tscale;
 229                         *step = tstep;
 230                 }
 231         }
 232 }
 233
 234 static void ar933x_uart_set_termios(struct uart_port *port,
 235                                     struct ktermios *new,
 236                                     struct ktermios *old)
 237 {
 238         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 239         unsigned int cs;
 240         unsigned long flags;
 241         unsigned int baud, scale, step;
 242
 243         /* Only CS8 is supported */
 244         new->c_cflag &= ~CSIZE;
 245         new->c_cflag |= CS8;
 246
 247         /* Only one stop bit is supported */
 248         new->c_cflag &= ~CSTOPB;
 249
 250         cs = 0;
 251         if (new->c_cflag & PARENB) {
 252                 if (!(new->c_cflag & PARODD))
 253                         cs |= AR933X_UART_CS_PARITY_EVEN;
 254                 else
 255                         cs |= AR933X_UART_CS_PARITY_ODD;
 256         } else {
 257                 cs |= AR933X_UART_CS_PARITY_NONE;
 258         }
 259
 260         /* Mark/space parity is not supported */
 261         new->c_cflag &= ~CMSPAR;
 262
 263         baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
 264         ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
 265
 266         /*
 267          * Ok, we're now changing the port state. Do it with
 268          * interrupts disabled.
 269          */
 270         spin_lock_irqsave(&up->port.lock, flags);
 271
 272         /* disable the UART */
 273         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 274                       AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
 275
 276         /* Update the per-port timeout. */
 277         uart_update_timeout(port, new->c_cflag, baud);
 278
 279         up->port.ignore_status_mask = 0;
 280
 281         /* ignore all characters if CREAD is not set */
 282         if ((new->c_cflag & CREAD) == 0)
 283                 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
 284
 285         ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
 286                           scale << AR933X_UART_CLOCK_SCALE_S | step);
 287
 288         /* setup configuration register */
 289         ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
 290
 291         /* enable host interrupt */
 292         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 293                             AR933X_UART_CS_HOST_INT_EN);
 294
 295         /* reenable the UART */
 296         ar933x_uart_rmw(up, AR933X_UART_CS_REG,
 297                         AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
 298                         AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
 299
 300         spin_unlock_irqrestore(&up->port.lock, flags);
 301
 302         if (tty_termios_baud_rate(new))
 303                 tty_termios_encode_baud_rate(new, baud, baud);
 304 }
 305
 306 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
 307 {
 308         struct tty_port *port = &up->port.state->port;
 309         int max_count = 256;
 310
 311         do {
 312                 unsigned int rdata;
 313                 unsigned char ch;
 314
 315                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 316                 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
 317                         break;
 318
 319                 /* remove the character from the FIFO */
 320                 ar933x_uart_write(up, AR933X_UART_DATA_REG,
 321                                   AR933X_UART_DATA_RX_CSR);
 322
 323                 up->port.icount.rx++;
 324                 ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
 325
 326                 if (uart_handle_sysrq_char(&up->port, ch))
 327                         continue;
 328
 329                 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
 330                         tty_insert_flip_char(port, ch, TTY_NORMAL);
 331         } while (max_count-- > 0);
 332
 333         spin_unlock(&up->port.lock);
 334         tty_flip_buffer_push(port);
 335         spin_lock(&up->port.lock);
 336 }
 337
 338 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
 339 {
 340         struct circ_buf *xmit = &up->port.state->xmit;
 341         int count;
 342
 343         if (uart_tx_stopped(&up->port))
 344                 return;
 345
 346         count = up->port.fifosize;
 347         do {
 348                 unsigned int rdata;
 349
 350                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 351                 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
 352                         break;
 353
 354                 if (up->port.x_char) {
 355                         ar933x_uart_putc(up, up->port.x_char);
 356                         up->port.icount.tx++;
 357                         up->port.x_char = 0;
 358                         continue;
 359                 }
 360
 361                 if (uart_circ_empty(xmit))
 362                         break;
 363
 364                 ar933x_uart_putc(up, xmit->buf[xmit->tail]);
 365
 366                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 367                 up->port.icount.tx++;
 368         } while (--count > 0);
 369
 370         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 371                 uart_write_wakeup(&up->port);
 372
 373         if (!uart_circ_empty(xmit))
 374                 ar933x_uart_start_tx_interrupt(up);
 375 }
 376
 377 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
 378 {
 379         struct ar933x_uart_port *up = dev_id;
 380         unsigned int status;
 381
 382         status = ar933x_uart_read(up, AR933X_UART_CS_REG);
 383         if ((status & AR933X_UART_CS_HOST_INT) == 0)
 384                 return IRQ_NONE;
 385
 386         spin_lock(&up->port.lock);
 387
 388         status = ar933x_uart_read(up, AR933X_UART_INT_REG);
 389         status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 390
 391         if (status & AR933X_UART_INT_RX_VALID) {
 392                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 393                                   AR933X_UART_INT_RX_VALID);
 394                 ar933x_uart_rx_chars(up);
 395         }
 396
 397         if (status & AR933X_UART_INT_TX_EMPTY) {
 398                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 399                                   AR933X_UART_INT_TX_EMPTY);
 400                 ar933x_uart_stop_tx_interrupt(up);
 401                 ar933x_uart_tx_chars(up);
 402         }
 403
 404         spin_unlock(&up->port.lock);
 405
 406         return IRQ_HANDLED;
 407 }
 408
 409 static int ar933x_uart_startup(struct uart_port *port)
 410 {
 411         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 412         unsigned long flags;
 413         int ret;
 414
 415         ret = request_irq(up->port.irq, ar933x_uart_interrupt,
 416                           up->port.irqflags, dev_name(up->port.dev), up);
 417         if (ret)
 418                 return ret;
 419
 420         spin_lock_irqsave(&up->port.lock, flags);
 421
 422         /* Enable HOST interrupts */
 423         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 424                             AR933X_UART_CS_HOST_INT_EN);
 425
 426         /* Enable RX interrupts */
 427         up->ier = AR933X_UART_INT_RX_VALID;
 428         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 429
 430         spin_unlock_irqrestore(&up->port.lock, flags);
 431
 432         return 0;
 433 }
 434
 435 static void ar933x_uart_shutdown(struct uart_port *port)
 436 {
 437         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 438
 439         /* Disable all interrupts */
 440         up->ier = 0;
 441         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 442
 443         /* Disable break condition */
 444         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 445                               AR933X_UART_CS_TX_BREAK);
 446
 447         free_irq(up->port.irq, up);
 448 }
 449
 450 static const char *ar933x_uart_type(struct uart_port *port)
 451 {
 452         return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
 453 }
 454
 455 static void ar933x_uart_release_port(struct uart_port *port)
 456 {
 457         /* Nothing to release ... */
 458 }
 459
 460 static int ar933x_uart_request_port(struct uart_port *port)
 461 {
 462         /* UARTs always present */
 463         return 0;
 464 }
 465
 466 static void ar933x_uart_config_port(struct uart_port *port, int flags)
 467 {
 468         if (flags & UART_CONFIG_TYPE)
 469                 port->type = PORT_AR933X;
 470 }
 471
 472 static int ar933x_uart_verify_port(struct uart_port *port,
 473                                    struct serial_struct *ser)
 474 {
 475         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 476
 477         if (ser->type != PORT_UNKNOWN &&
 478             ser->type != PORT_AR933X)
 479                 return -EINVAL;
 480
 481         if (ser->irq < 0 || ser->irq >= NR_IRQS)
 482                 return -EINVAL;
 483
 484         if (ser->baud_base < up->min_baud ||
 485             ser->baud_base > up->max_baud)
 486                 return -EINVAL;
 487
 488         return 0;
 489 }
 490
 491 static struct uart_ops ar933x_uart_ops = {
 492         .tx_empty       = ar933x_uart_tx_empty,
 493         .set_mctrl      = ar933x_uart_set_mctrl,
 494         .get_mctrl      = ar933x_uart_get_mctrl,
 495         .stop_tx        = ar933x_uart_stop_tx,
 496         .start_tx       = ar933x_uart_start_tx,
 497         .stop_rx        = ar933x_uart_stop_rx,
 498         .enable_ms      = ar933x_uart_enable_ms,
 499         .break_ctl      = ar933x_uart_break_ctl,
 500         .startup        = ar933x_uart_startup,
 501         .shutdown       = ar933x_uart_shutdown,
 502         .set_termios    = ar933x_uart_set_termios,
 503         .type           = ar933x_uart_type,
 504         .release_port   = ar933x_uart_release_port,
 505         .request_port   = ar933x_uart_request_port,
 506         .config_port    = ar933x_uart_config_port,
 507         .verify_port    = ar933x_uart_verify_port,
 508 };
 509
 510 static struct ar933x_uart_port *
 511 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
 512
 513 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
 514 {
 515         unsigned int status;
 516         unsigned int timeout = 60000;
 517
 518         /* Wait up to 60ms for the character(s) to be sent. */
 519         do {
 520                 status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 521                 if (--timeout == 0)
 522                         break;
 523                 udelay(1);
 524         } while ((status & AR933X_UART_DATA_TX_CSR) == 0);
 525 }
 526
 527 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
 528 {
 529         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 530
 531         ar933x_uart_wait_xmitr(up);
 532         ar933x_uart_putc(up, ch);
 533 }
 534
 535 static void ar933x_uart_console_write(struct console *co, const char *s,
 536                                       unsigned int count)
 537 {
 538         struct ar933x_uart_port *up = ar933x_console_ports[co->index];
 539         unsigned long flags;
 540         unsigned int int_en;
 541         int locked = 1;
 542
 543         local_irq_save(flags);
 544
 545         if (up->port.sysrq)
 546                 locked = 0;
 547         else if (oops_in_progress)
 548                 locked = spin_trylock(&up->port.lock);
 549         else
 550                 spin_lock(&up->port.lock);
 551
 552         /*
 553          * First save the IER then disable the interrupts
 554          */
 555         int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 556         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
 557
 558         uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
 559
 560         /*
 561          * Finally, wait for transmitter to become empty
 562          * and restore the IER
 563          */
 564         ar933x_uart_wait_xmitr(up);
 565         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
 566
 567         ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
 568
 569         if (locked)
 570                 spin_unlock(&up->port.lock);
 571
 572         local_irq_restore(flags);
 573 }
 574
 575 static int ar933x_uart_console_setup(struct console *co, char *options)
 576 {
 577         struct ar933x_uart_port *up;
 578         int baud = 115200;
 579         int bits = 8;
 580         int parity = 'n';
 581         int flow = 'n';
 582
 583         if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
 584                 return -EINVAL;
 585
 586         up = ar933x_console_ports[co->index];
 587         if (!up)
 588                 return -ENODEV;
 589
 590         if (options)
 591                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 592
 593         return uart_set_options(&up->port, co, baud, parity, bits, flow);
 594 }
 595
 596 static struct console ar933x_uart_console = {
 597         .name           = "ttyATH",
 598         .write          = ar933x_uart_console_write,
 599         .device         = uart_console_device,
 600         .setup          = ar933x_uart_console_setup,
 601         .flags          = CON_PRINTBUFFER,
 602         .index          = -1,
 603         .data           = &ar933x_uart_driver,
 604 };
 605
 606 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
 607 {
 608         if (!ar933x_uart_console_enabled())
 609                 return;
 610
 611         ar933x_console_ports[up->port.line] = up;
 612 }
 613
 614 static struct uart_driver ar933x_uart_driver = {
 615         .owner          = THIS_MODULE,
 616         .driver_name    = DRIVER_NAME,
 617         .dev_name       = "ttyATH",
 618         .nr             = CONFIG_SERIAL_AR933X_NR_UARTS,
 619         .cons           = NULL, /* filled in runtime */
 620 };
 621
 622 static int ar933x_uart_probe(struct platform_device *pdev)
 623 {
 624         struct ar933x_uart_port *up;
 625         struct uart_port *port;
 626         struct resource *mem_res;
 627         struct resource *irq_res;
 628         struct device_node *np;
 629         unsigned int baud;
 630         int id;
 631         int ret;
 632
 633         np = pdev->dev.of_node;
 634         if (config_enabled(CONFIG_OF) && np) {
 635                 id = of_alias_get_id(np, "serial");
 636                 if (id < 0) {
 637                         dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
 638                                 id);
 639                         return id;
 640                 }
 641         } else {
 642                 id = pdev->id;
 643                 if (id == -1)
 644                         id = 0;
 645         }
 646
 647         if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
 648                 return -EINVAL;
 649
 650         irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 651         if (!irq_res) {
 652                 dev_err(&pdev->dev, "no IRQ resource\n");
 653                 return -EINVAL;
 654         }
 655
 656         up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
 657                           GFP_KERNEL);
 658         if (!up)
 659                 return -ENOMEM;
 660
 661         up->clk = devm_clk_get(&pdev->dev, "uart");
 662         if (IS_ERR(up->clk)) {
 663                 dev_err(&pdev->dev, "unable to get UART clock\n");
 664                 return PTR_ERR(up->clk);
 665         }
 666
 667         port = &up->port;
 668
 669         mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 670         port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
 671         if (IS_ERR(port->membase))
 672                 return PTR_ERR(port->membase);
 673
 674         ret = clk_prepare_enable(up->clk);
 675         if (ret)
 676                 return ret;
 677
 678         port->uartclk = clk_get_rate(up->clk);
 679         if (!port->uartclk) {
 680                 ret = -EINVAL;
 681                 goto err_disable_clk;
 682         }
 683
 684         port->mapbase = mem_res->start;
 685         port->line = id;
 686         port->irq = irq_res->start;
 687         port->dev = &pdev->dev;
 688         port->type = PORT_AR933X;
 689         port->iotype = UPIO_MEM32;
 690
 691         port->regshift = 2;
 692         port->fifosize = AR933X_UART_FIFO_SIZE;
 693         port->ops = &ar933x_uart_ops;
 694
 695         baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
 696         up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
 697
 698         baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
 699         up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
 700
 701         ar933x_uart_add_console_port(up);
 702
 703         ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
 704         if (ret)
 705                 goto err_disable_clk;
 706
 707         platform_set_drvdata(pdev, up);
 708         return 0;
 709
 710 err_disable_clk:
 711         clk_disable_unprepare(up->clk);
 712         return ret;
 713 }
 714
 715 static int ar933x_uart_remove(struct platform_device *pdev)
 716 {
 717         struct ar933x_uart_port *up;
 718
 719         up = platform_get_drvdata(pdev);
 720
 721         if (up) {
 722                 uart_remove_one_port(&ar933x_uart_driver, &up->port);
 723                 clk_disable_unprepare(up->clk);
 724         }
 725
 726         return 0;
 727 }
 728
 729 #ifdef CONFIG_OF
 730 static const struct of_device_id ar933x_uart_of_ids[] = {
 731         { .compatible = "qca,ar9330-uart" },
 732         {},
 733 };
 734 MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
 735 #endif
 736
 737 static struct platform_driver ar933x_uart_platform_driver = {
 738         .probe          = ar933x_uart_probe,
 739         .remove         = ar933x_uart_remove,
 740         .driver         = {
 741                 .name           = DRIVER_NAME,
 742                 .owner          = THIS_MODULE,
 743                 .of_match_table = of_match_ptr(ar933x_uart_of_ids),
 744         },
 745 };
 746
 747 static int __init ar933x_uart_init(void)
 748 {
 749         int ret;
 750
 751         if (ar933x_uart_console_enabled())
 752                 ar933x_uart_driver.cons = &ar933x_uart_console;
 753
 754         ret = uart_register_driver(&ar933x_uart_driver);
 755         if (ret)
 756                 goto err_out;
 757
 758         ret = platform_driver_register(&ar933x_uart_platform_driver);
 759         if (ret)
 760                 goto err_unregister_uart_driver;
 761
 762         return 0;
 763
 764 err_unregister_uart_driver:
 765         uart_unregister_driver(&ar933x_uart_driver);
 766 err_out:
 767         return ret;
 768 }
 769
 770 static void __exit ar933x_uart_exit(void)
 771 {
 772         platform_driver_unregister(&ar933x_uart_platform_driver);
 773         uart_unregister_driver(&ar933x_uart_driver);
 774 }
 775
 776 module_init(ar933x_uart_init);
 777 module_exit(ar933x_uart_exit);
 778
 779 MODULE_DESCRIPTION("Atheros AR933X UART driver");
 780 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 781 MODULE_LICENSE("GPL v2");
 782 MODULE_ALIAS("platform:" DRIVER_NAME);