drivers/serial/mrst_max3110.c

   1 /*
   2  *  mrst_max3110.c - spi uart protocol driver for Maxim 3110
   3  *
   4  * Copyright (c) 2008-2010, Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 /*
  21  * Note:
  22  * 1. From Max3110 spec, the Rx FIFO has 8 words, while the Tx FIFO only has
  23  *    1 word. If SPI master controller doesn't support sclk frequency change,
  24  *    then the char need be sent out one by one with some delay
  25  *
  26  * 2. Currently only RX availabe interrrupt is used, no need for waiting TXE
  27  *    interrupt for a low speed UART device
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/ioport.h>
  32 #include <linux/irq.h>
  33 #include <linux/init.h>
  34 #include <linux/console.h>
  35 #include <linux/tty.h>
  36 #include <linux/tty_flip.h>
  37 #include <linux/serial_core.h>
  38 #include <linux/serial_reg.h>
  39
  40 #include <linux/kthread.h>
  41 #include <linux/spi/spi.h>
  42
  43 #include "mrst_max3110.h"
  44
  45 #define PR_FMT  "mrst_max3110: "
  46
  47 #define UART_TX_NEEDED 1
  48 #define CON_TX_NEEDED  2
  49 #define BIT_IRQ_PENDING    3
  50
  51 struct uart_max3110 {
  52         struct uart_port port;
  53         struct spi_device *spi;
  54         char name[24];
  55
  56         wait_queue_head_t wq;
  57         struct task_struct *main_thread;
  58         struct task_struct *read_thread;
  59         struct mutex thread_mutex;;
  60
  61         u32 baud;
  62         u16 cur_conf;
  63         u8 clock;
  64         u8 parity, word_7bits;
  65         u16 irq;
  66
  67         unsigned long uart_flags;
  68
  69         /* console related */
  70         struct circ_buf con_xmit;
  71 };
  72
  73 /* global data structure, may need be removed */
  74 static struct uart_max3110 *pmax;
  75
  76 static void receive_chars(struct uart_max3110 *max,
  77                                 unsigned char *str, int len);
  78 static int max3110_read_multi(struct uart_max3110 *max, u8 *buf);
  79 static void max3110_con_receive(struct uart_max3110 *max);
  80
  81 static int max3110_write_then_read(struct uart_max3110 *max,
  82                 const void *txbuf, void *rxbuf, unsigned len, int always_fast)
  83 {
  84         struct spi_device *spi = max->spi;
  85         struct spi_message      message;
  86         struct spi_transfer     x;
  87         int ret;
  88
  89         spi_message_init(&message);
  90         memset(&x, 0, sizeof x);
  91         x.len = len;
  92         x.tx_buf = txbuf;
  93         x.rx_buf = rxbuf;
  94         spi_message_add_tail(&x, &message);
  95
  96         if (always_fast)
  97                 x.speed_hz = spi->max_speed_hz;
  98         else if (max->baud)
  99                 x.speed_hz = max->baud;
 100
 101         /* Do the i/o */
 102         ret = spi_sync(spi, &message);
 103         return ret;
 104 }
 105
 106 /* Write a 16b word to the device */
 107 static int max3110_out(struct uart_max3110 *max, const u16 out)
 108 {
 109         void *buf;
 110         u16 *obuf, *ibuf;
 111         u8  ch;
 112         int ret;
 113
 114         buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
 115         if (!buf)
 116                 return -ENOMEM;
 117
 118         obuf = buf;
 119         ibuf = buf + 4;
 120         *obuf = out;
 121         ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
 122         if (ret) {
 123                 pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
 124                                 __func__, ret, out);
 125                 goto exit;
 126         }
 127
 128         /* If some valid data is read back */
 129         if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
 130                 ch = *ibuf & 0xff;
 131                 receive_chars(max, &ch, 1);
 132         }
 133
 134 exit:
 135         kfree(buf);
 136         return ret;
 137 }
 138
 139 /*
 140  * This is usually used to read data from SPIC RX FIFO, which doesn't
 141  * need any delay like flushing character out.
 142  *
 143  * Return how many valide bytes are read back
 144  */
 145 static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
 146 {
 147         void *buf;
 148         u16 *obuf, *ibuf;
 149         u8 *pbuf, valid_str[M3110_RX_FIFO_DEPTH];
 150         int i, j, blen;
 151
 152         blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
 153         buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
 154         if (!buf) {
 155                 pr_warning(PR_FMT "%s(): fail to alloc dma buffer\n", __func__);
 156                 return 0;
 157         }
 158
 159         /* tx/rx always have the same length */
 160         obuf = buf;
 161         ibuf = buf + blen;
 162
 163         if (max3110_write_then_read(max, obuf, ibuf, blen, 1)) {
 164                 kfree(buf);
 165                 return 0;
 166         }
 167
 168         /* If caller doesn't provide a buffer, then handle received char */
 169         pbuf = rxbuf ? rxbuf : valid_str;
 170
 171         for (i = 0, j = 0; i < M3110_RX_FIFO_DEPTH; i++) {
 172                 if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
 173                         pbuf[j++] = ibuf[i] & 0xff;
 174         }
 175
 176         if (j && (pbuf == valid_str))
 177                 receive_chars(max, valid_str, j);
 178
 179         kfree(buf);
 180         return j;
 181 }
 182
 183 static void serial_m3110_con_putchar(struct uart_port *port, int ch)
 184 {
 185         struct uart_max3110 *max =
 186                 container_of(port, struct uart_max3110, port);
 187         struct circ_buf *xmit = &max->con_xmit;
 188
 189         if (uart_circ_chars_free(xmit)) {
 190                 xmit->buf[xmit->head] = (char)ch;
 191                 xmit->head = (xmit->head + 1) & (PAGE_SIZE - 1);
 192         }
 193 }
 194
 195 /*
 196  * Print a string to the serial port trying not to disturb
 197  * any possible real use of the port...
 198  *
 199  *      The console_lock must be held when we get here.
 200  */
 201 static void serial_m3110_con_write(struct console *co,
 202                                 const char *s, unsigned int count)
 203 {
 204         if (!pmax)
 205                 return;
 206
 207         uart_console_write(&pmax->port, s, count, serial_m3110_con_putchar);
 208
 209         if (!test_and_set_bit(CON_TX_NEEDED, &pmax->uart_flags))
 210                 wake_up_process(pmax->main_thread);
 211 }
 212
 213 static int __init
 214 serial_m3110_con_setup(struct console *co, char *options)
 215 {
 216         struct uart_max3110 *max = pmax;
 217         int baud = 115200;
 218         int bits = 8;
 219         int parity = 'n';
 220         int flow = 'n';
 221
 222         pr_info(PR_FMT "setting up console\n");
 223
 224         if (co->index == -1)
 225                 co->index = 0;
 226
 227         if (!max) {
 228                 pr_err(PR_FMT "pmax is NULL, return");
 229                 return -ENODEV;
 230         }
 231
 232         if (options)
 233                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 234
 235         return uart_set_options(&max->port, co, baud, parity, bits, flow);
 236 }
 237
 238 static struct tty_driver *serial_m3110_con_device(struct console *co,
 239                                                         int *index)
 240 {
 241         struct uart_driver *p = co->data;
 242         *index = co->index;
 243         return p->tty_driver;
 244 }
 245
 246 static struct uart_driver serial_m3110_reg;
 247 static struct console serial_m3110_console = {
 248         .name           = "ttyS",
 249         .write          = serial_m3110_con_write,
 250         .device         = serial_m3110_con_device,
 251         .setup          = serial_m3110_con_setup,
 252         .flags          = CON_PRINTBUFFER,
 253         .index          = -1,
 254         .data           = &serial_m3110_reg,
 255 };
 256
 257 static unsigned int serial_m3110_tx_empty(struct uart_port *port)
 258 {
 259         return 1;
 260 }
 261
 262 static void serial_m3110_stop_tx(struct uart_port *port)
 263 {
 264         return;
 265 }
 266
 267 /* stop_rx will be called in spin_lock env */
 268 static void serial_m3110_stop_rx(struct uart_port *port)
 269 {
 270         return;
 271 }
 272
 273 #define WORDS_PER_XFER  128
 274 static void send_circ_buf(struct uart_max3110 *max,
 275                                 struct circ_buf *xmit)
 276 {
 277         void *buf;
 278         u16 *obuf, *ibuf;
 279         u8 valid_str[WORDS_PER_XFER];
 280         int i, j, len, blen, dma_size, left, ret = 0;
 281
 282
 283         dma_size = WORDS_PER_XFER * sizeof(u16) * 2;
 284         buf = kzalloc(dma_size, GFP_KERNEL | GFP_DMA);
 285         if (!buf)
 286                 return;
 287         obuf = buf;
 288         ibuf = buf + dma_size/2;
 289
 290         while (!uart_circ_empty(xmit)) {
 291                 left = uart_circ_chars_pending(xmit);
 292                 while (left) {
 293                         len = min(left, WORDS_PER_XFER);
 294                         blen = len * sizeof(u16);
 295                         memset(ibuf, 0, blen);
 296
 297                         for (i = 0; i < len; i++) {
 298                                 obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG;
 299                                 xmit->tail = (xmit->tail + 1) &
 300                                                 (UART_XMIT_SIZE - 1);
 301                         }
 302
 303                         /* Fail to send msg to console is not very critical */
 304                         ret = max3110_write_then_read(max, obuf, ibuf, blen, 0);
 305                         if (ret)
 306                                 pr_warning(PR_FMT "%s(): get err msg %d\n",
 307                                                 __func__, ret);
 308
 309                         for (i = 0, j = 0; i < len; i++) {
 310                                 if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
 311                                         valid_str[j++] = ibuf[i] & 0xff;
 312                         }
 313
 314                         if (j)
 315                                 receive_chars(max, valid_str, j);
 316
 317                         max->port.icount.tx += len;
 318                         left -= len;
 319                 }
 320         }
 321
 322         kfree(buf);
 323 }
 324
 325 static void transmit_char(struct uart_max3110 *max)
 326 {
 327         struct uart_port *port = &max->port;
 328         struct circ_buf *xmit = &port->state->xmit;
 329
 330         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 331                 return;
 332
 333         send_circ_buf(max, xmit);
 334
 335         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 336                 uart_write_wakeup(port);
 337
 338         if (uart_circ_empty(xmit))
 339                 serial_m3110_stop_tx(port);
 340 }
 341
 342 /*
 343  * This will be called by uart_write() and tty_write, can't
 344  * go to sleep
 345  */
 346 static void serial_m3110_start_tx(struct uart_port *port)
 347 {
 348         struct uart_max3110 *max =
 349                 container_of(port, struct uart_max3110, port);
 350
 351         if (!test_and_set_bit(UART_TX_NEEDED, &max->uart_flags))
 352                 wake_up_process(max->main_thread);
 353 }
 354
 355 static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
 356 {
 357         struct uart_port *port = &max->port;
 358         struct tty_struct *tty;
 359         int usable;
 360
 361         /* If uart is not opened, just return */
 362         if (!port->state)
 363                 return;
 364
 365         tty = port->state->port.tty;
 366         if (!tty)
 367                 return;
 368
 369         while (len) {
 370                 usable = tty_buffer_request_room(tty, len);
 371                 if (usable) {
 372                         tty_insert_flip_string(tty, str, usable);
 373                         str += usable;
 374                         port->icount.rx += usable;
 375                 }
 376                 len -= usable;
 377         }
 378         tty_flip_buffer_push(tty);
 379 }
 380
 381 /*
 382  * This routine will be used in read_thread or RX IRQ handling,
 383  * it will first do one round buffer read(8 words), if there is some
 384  * valid RX data, will try to read 5 more rounds till all data
 385  * is read out.
 386  *
 387  * Use stack space as data buffer to save some system load, and chose
 388  * 504 Btyes as a threadhold to do a bulk push to upper tty layer when
 389  * receiving bulk data, a much bigger buffer may cause stack overflow
 390  */
 391 static void max3110_con_receive(struct uart_max3110 *max)
 392 {
 393         int loop = 1, num, total = 0;
 394         u8 recv_buf[512], *pbuf;
 395
 396         pbuf = recv_buf;
 397         do {
 398                 num = max3110_read_multi(max, pbuf);
 399
 400                 if (num) {
 401                         loop = 5;
 402                         pbuf += num;
 403                         total += num;
 404
 405                         if (total >= 504) {
 406                                 receive_chars(max, recv_buf, total);
 407                                 pbuf = recv_buf;
 408                                 total = 0;
 409                         }
 410                 }
 411         } while (--loop);
 412
 413         if (total)
 414                 receive_chars(max, recv_buf, total);
 415 }
 416
 417 static int max3110_main_thread(void *_max)
 418 {
 419         struct uart_max3110 *max = _max;
 420         wait_queue_head_t *wq = &max->wq;
 421         int ret = 0;
 422         struct circ_buf *xmit = &max->con_xmit;
 423
 424         init_waitqueue_head(wq);
 425         pr_info(PR_FMT "start main thread\n");
 426
 427         do {
 428                 wait_event_interruptible(*wq, max->uart_flags || kthread_should_stop());
 429
 430                 mutex_lock(&max->thread_mutex);
 431
 432                 if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
 433                         max3110_con_receive(max);
 434
 435                 /* first handle console output */
 436                 if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
 437                         send_circ_buf(max, xmit);
 438
 439                 /* handle uart output */
 440                 if (test_and_clear_bit(UART_TX_NEEDED, &max->uart_flags))
 441                         transmit_char(max);
 442
 443                 mutex_unlock(&max->thread_mutex);
 444
 445         } while (!kthread_should_stop());
 446
 447         return ret;
 448 }
 449
 450 static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
 451 {
 452         struct uart_max3110 *max = dev_id;
 453
 454         /* max3110's irq is a falling edge, not level triggered,
 455          * so no need to disable the irq */
 456         if (!test_and_set_bit(BIT_IRQ_PENDING, &max->uart_flags))
 457                 wake_up_process(max->main_thread);
 458
 459         return IRQ_HANDLED;
 460 }
 461
 462 /* if don't use RX IRQ, then need a thread to polling read */
 463 static int max3110_read_thread(void *_max)
 464 {
 465         struct uart_max3110 *max = _max;
 466
 467         pr_info(PR_FMT "start read thread\n");
 468         do {
 469                 /*
 470                  * If can't acquire the mutex, it means the main thread
 471                  * is running which will also perform the rx job
 472                  */
 473                 if (mutex_trylock(&max->thread_mutex)) {
 474                         max3110_con_receive(max);
 475                         mutex_unlock(&max->thread_mutex);
 476                 }
 477
 478                 set_current_state(TASK_INTERRUPTIBLE);
 479                 schedule_timeout(HZ / 20);
 480         } while (!kthread_should_stop());
 481
 482         return 0;
 483 }
 484
 485 static int serial_m3110_startup(struct uart_port *port)
 486 {
 487         struct uart_max3110 *max =
 488                 container_of(port, struct uart_max3110, port);
 489         u16 config = 0;
 490         int ret = 0;
 491
 492         if (port->line != 0) {
 493                 pr_err(PR_FMT "uart port startup failed\n");
 494                 return -1;
 495         }
 496
 497         /* Disable all IRQ and config it to 115200, 8n1 */
 498         config = WC_TAG | WC_FIFO_ENABLE
 499                         | WC_1_STOPBITS
 500                         | WC_8BIT_WORD
 501                         | WC_BAUD_DR2;
 502
 503         /* as we use thread to handle tx/rx, need set low latency */
 504         port->state->port.tty->low_latency = 1;
 505
 506         if (max->irq) {
 507                 max->read_thread = NULL;
 508                 ret = request_irq(max->irq, serial_m3110_irq,
 509                                 IRQ_TYPE_EDGE_FALLING, "max3110", max);
 510                 if (ret) {
 511                         max->irq = 0;
 512                         pr_err(PR_FMT "unable to allocate IRQ, polling\n");
 513                 }  else {
 514                         /* Enable RX IRQ only */
 515                         config |= WC_RXA_IRQ_ENABLE;
 516                 }
 517         }
 518
 519         if (max->irq == 0) {
 520                 /* If IRQ is disabled, start a read thread for input data */
 521                 max->read_thread =
 522                         kthread_run(max3110_read_thread, max, "max3110_read");
 523                 if (IS_ERR(max->read_thread)) {
 524                         ret = PTR_ERR(max->read_thread);
 525                         max->read_thread = NULL;
 526                         pr_err(PR_FMT "Can't create read thread!\n");
 527                         return ret;
 528                 }
 529         }
 530
 531         ret = max3110_out(max, config);
 532         if (ret) {
 533                 if (max->irq)
 534                         free_irq(max->irq, max);
 535                 if (max->read_thread)
 536                         kthread_stop(max->read_thread);
 537                 max->read_thread = NULL;
 538                 return ret;
 539         }
 540
 541         max->cur_conf = config;
 542         return 0;
 543 }
 544
 545 static void serial_m3110_shutdown(struct uart_port *port)
 546 {
 547         struct uart_max3110 *max =
 548                 container_of(port, struct uart_max3110, port);
 549         u16 config;
 550
 551         if (max->read_thread) {
 552                 kthread_stop(max->read_thread);
 553                 max->read_thread = NULL;
 554         }
 555
 556         if (max->irq)
 557                 free_irq(max->irq, max);
 558
 559         /* Disable interrupts from this port */
 560         config = WC_TAG | WC_SW_SHDI;
 561         max3110_out(max, config);
 562 }
 563
 564 static void serial_m3110_release_port(struct uart_port *port)
 565 {
 566 }
 567
 568 static int serial_m3110_request_port(struct uart_port *port)
 569 {
 570         return 0;
 571 }
 572
 573 static void serial_m3110_config_port(struct uart_port *port, int flags)
 574 {
 575         port->type = PORT_MAX3100;
 576 }
 577
 578 static int
 579 serial_m3110_verify_port(struct uart_port *port, struct serial_struct *ser)
 580 {
 581         /* we don't want the core code to modify any port params */
 582         return -EINVAL;
 583 }
 584
 585
 586 static const char *serial_m3110_type(struct uart_port *port)
 587 {
 588         struct uart_max3110 *max =
 589                 container_of(port, struct uart_max3110, port);
 590         return max->name;
 591 }
 592
 593 static void
 594 serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 595                        struct ktermios *old)
 596 {
 597         struct uart_max3110 *max =
 598                 container_of(port, struct uart_max3110, port);
 599         unsigned char cval;
 600         unsigned int baud, parity = 0;
 601         int clk_div = -1;
 602         u16 new_conf = max->cur_conf;
 603
 604         switch (termios->c_cflag & CSIZE) {
 605         case CS7:
 606                 cval = UART_LCR_WLEN7;
 607                 new_conf |= WC_7BIT_WORD;
 608                 break;
 609         default:
 610                 /* We only support CS7 & CS8 */
 611                 termios->c_cflag &= ~CSIZE;
 612                 termios->c_cflag |= CS8;
 613         case CS8:
 614                 cval = UART_LCR_WLEN8;
 615                 new_conf |= WC_8BIT_WORD;
 616                 break;
 617         }
 618
 619         baud = uart_get_baud_rate(port, termios, old, 0, 230400);
 620
 621         /* First calc the div for 1.8MHZ clock case */
 622         switch (baud) {
 623         case 300:
 624                 clk_div = WC_BAUD_DR384;
 625                 break;
 626         case 600:
 627                 clk_div = WC_BAUD_DR192;
 628                 break;
 629         case 1200:
 630                 clk_div = WC_BAUD_DR96;
 631                 break;
 632         case 2400:
 633                 clk_div = WC_BAUD_DR48;
 634                 break;
 635         case 4800:
 636                 clk_div = WC_BAUD_DR24;
 637                 break;
 638         case 9600:
 639                 clk_div = WC_BAUD_DR12;
 640                 break;
 641         case 19200:
 642                 clk_div = WC_BAUD_DR6;
 643                 break;
 644         case 38400:
 645                 clk_div = WC_BAUD_DR3;
 646                 break;
 647         case 57600:
 648                 clk_div = WC_BAUD_DR2;
 649                 break;
 650         case 115200:
 651                 clk_div = WC_BAUD_DR1;
 652                 break;
 653         case 230400:
 654                 if (max->clock & MAX3110_HIGH_CLK)
 655                         break;
 656         default:
 657                 /* Pick the previous baud rate */
 658                 baud = max->baud;
 659                 clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
 660                 tty_termios_encode_baud_rate(termios, baud, baud);
 661         }
 662
 663         if (max->clock & MAX3110_HIGH_CLK) {
 664                 clk_div += 1;
 665                 /* High clk version max3110 doesn't support B300 */
 666                 if (baud == 300) {
 667                         baud = 600;
 668                         clk_div = WC_BAUD_DR384;
 669                 }
 670                 if (baud == 230400)
 671                         clk_div = WC_BAUD_DR1;
 672                 tty_termios_encode_baud_rate(termios, baud, baud);
 673         }
 674
 675         new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
 676
 677         if (unlikely(termios->c_cflag & CMSPAR))
 678                 termios->c_cflag &= ~CMSPAR;
 679
 680         if (termios->c_cflag & CSTOPB)
 681                 new_conf |= WC_2_STOPBITS;
 682         else
 683                 new_conf &= ~WC_2_STOPBITS;
 684
 685         if (termios->c_cflag & PARENB) {
 686                 new_conf |= WC_PARITY_ENABLE;
 687                 parity |= UART_LCR_PARITY;
 688         } else
 689                 new_conf &= ~WC_PARITY_ENABLE;
 690
 691         if (!(termios->c_cflag & PARODD))
 692                 parity |= UART_LCR_EPAR;
 693         max->parity = parity;
 694
 695         uart_update_timeout(port, termios->c_cflag, baud);
 696
 697         new_conf |= WC_TAG;
 698         if (new_conf != max->cur_conf) {
 699                 if (!max3110_out(max, new_conf)) {
 700                         max->cur_conf = new_conf;
 701                         max->baud = baud;
 702                 }
 703         }
 704 }
 705
 706 /* Don't handle hw handshaking */
 707 static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
 708 {
 709         return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
 710 }
 711
 712 static void serial_m3110_set_mctrl(struct uart_port *port, unsigned int mctrl)
 713 {
 714 }
 715
 716 static void serial_m3110_break_ctl(struct uart_port *port, int break_state)
 717 {
 718 }
 719
 720 static void serial_m3110_pm(struct uart_port *port, unsigned int state,
 721                         unsigned int oldstate)
 722 {
 723 }
 724
 725 static void serial_m3110_enable_ms(struct uart_port *port)
 726 {
 727 }
 728
 729 struct uart_ops serial_m3110_ops = {
 730         .tx_empty       = serial_m3110_tx_empty,
 731         .set_mctrl      = serial_m3110_set_mctrl,
 732         .get_mctrl      = serial_m3110_get_mctrl,
 733         .stop_tx        = serial_m3110_stop_tx,
 734         .start_tx       = serial_m3110_start_tx,
 735         .stop_rx        = serial_m3110_stop_rx,
 736         .enable_ms      = serial_m3110_enable_ms,
 737         .break_ctl      = serial_m3110_break_ctl,
 738         .startup        = serial_m3110_startup,
 739         .shutdown       = serial_m3110_shutdown,
 740         .set_termios    = serial_m3110_set_termios,
 741         .pm             = serial_m3110_pm,
 742         .type           = serial_m3110_type,
 743         .release_port   = serial_m3110_release_port,
 744         .request_port   = serial_m3110_request_port,
 745         .config_port    = serial_m3110_config_port,
 746         .verify_port    = serial_m3110_verify_port,
 747 };
 748
 749 static struct uart_driver serial_m3110_reg = {
 750         .owner          = THIS_MODULE,
 751         .driver_name    = "MRST serial",
 752         .dev_name       = "ttyS",
 753         .major          = TTY_MAJOR,
 754         .minor          = 64,
 755         .nr             = 1,
 756         .cons           = &serial_m3110_console,
 757 };
 758
 759 #ifdef CONFIG_PM
 760 static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
 761 {
 762         struct uart_max3110 *max = spi_get_drvdata(spi);
 763
 764         disable_irq(max->irq);
 765         uart_suspend_port(&serial_m3110_reg, &max->port);
 766         max3110_out(max, max->cur_conf | WC_SW_SHDI);
 767         return 0;
 768 }
 769
 770 static int serial_m3110_resume(struct spi_device *spi)
 771 {
 772         struct uart_max3110 *max = spi_get_drvdata(spi);
 773
 774         max3110_out(max, max->cur_conf);
 775         uart_resume_port(&serial_m3110_reg, &max->port);
 776         enable_irq(max->irq);
 777         return 0;
 778 }
 779 #else
 780 #define serial_m3110_suspend    NULL
 781 #define serial_m3110_resume     NULL
 782 #endif
 783
 784 static int __devinit serial_m3110_probe(struct spi_device *spi)
 785 {
 786         struct uart_max3110 *max;
 787         void *buffer;
 788         u16 res;
 789         int ret = 0;
 790
 791         max = kzalloc(sizeof(*max), GFP_KERNEL);
 792         if (!max)
 793                 return -ENOMEM;
 794
 795         /* Set spi info */
 796         spi->bits_per_word = 16;
 797         max->clock = MAX3110_HIGH_CLK;
 798
 799         spi_setup(spi);
 800
 801         max->port.type = PORT_MAX3100;
 802         max->port.fifosize = 2;         /* Only have 16b buffer */
 803         max->port.ops = &serial_m3110_ops;
 804         max->port.line = 0;
 805         max->port.dev = &spi->dev;
 806         max->port.uartclk = 115200;
 807
 808         max->spi = spi;
 809         strcpy(max->name, spi->modalias);
 810         max->irq = (u16)spi->irq;
 811
 812         mutex_init(&max->thread_mutex);
 813
 814         max->word_7bits = 0;
 815         max->parity = 0;
 816         max->baud = 0;
 817
 818         max->cur_conf = 0;
 819         max->uart_flags = 0;
 820
 821         /* Check if reading configuration register returns something sane */
 822
 823         res = RC_TAG;
 824         ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0);
 825         if (ret < 0 || res == 0 || res == 0xffff) {
 826                 printk(KERN_ERR "MAX3111 deemed not present (conf reg %04x)",
 827                                                                         res);
 828                 ret = -ENODEV;
 829                 goto err_get_page;
 830         }
 831
 832         buffer = (void *)__get_free_page(GFP_KERNEL);
 833         if (!buffer) {
 834                 ret = -ENOMEM;
 835                 goto err_get_page;
 836         }
 837         max->con_xmit.buf = buffer;
 838         max->con_xmit.head = 0;
 839         max->con_xmit.tail = 0;
 840
 841         max->main_thread = kthread_run(max3110_main_thread,
 842                                         max, "max3110_main");
 843         if (IS_ERR(max->main_thread)) {
 844                 ret = PTR_ERR(max->main_thread);
 845                 goto err_kthread;
 846         }
 847
 848         spi_set_drvdata(spi, max);
 849         pmax = max;
 850
 851         /* Give membase a psudo value to pass serial_core's check */
 852         max->port.membase = (void *)0xff110000;
 853         uart_add_one_port(&serial_m3110_reg, &max->port);
 854
 855         return 0;
 856
 857 err_kthread:
 858         free_page((unsigned long)buffer);
 859 err_get_page:
 860         kfree(max);
 861         return ret;
 862 }
 863
 864 static int __devexit serial_m3110_remove(struct spi_device *dev)
 865 {
 866         struct uart_max3110 *max = spi_get_drvdata(dev);
 867
 868         if (!max)
 869                 return 0;
 870
 871         uart_remove_one_port(&serial_m3110_reg, &max->port);
 872
 873         free_page((unsigned long)max->con_xmit.buf);
 874
 875         if (max->main_thread)
 876                 kthread_stop(max->main_thread);
 877
 878         kfree(max);
 879         return 0;
 880 }
 881
 882 static struct spi_driver uart_max3110_driver = {
 883         .driver = {
 884                         .name   = "spi_max3111",
 885                         .bus    = &spi_bus_type,
 886                         .owner  = THIS_MODULE,
 887         },
 888         .probe          = serial_m3110_probe,
 889         .remove         = __devexit_p(serial_m3110_remove),
 890         .suspend        = serial_m3110_suspend,
 891         .resume         = serial_m3110_resume,
 892 };
 893
 894 static int __init serial_m3110_init(void)
 895 {
 896         int ret = 0;
 897
 898         ret = uart_register_driver(&serial_m3110_reg);
 899         if (ret)
 900                 return ret;
 901
 902         ret = spi_register_driver(&uart_max3110_driver);
 903         if (ret)
 904                 uart_unregister_driver(&serial_m3110_reg);
 905
 906         return ret;
 907 }
 908
 909 static void __exit serial_m3110_exit(void)
 910 {
 911         spi_unregister_driver(&uart_max3110_driver);
 912         uart_unregister_driver(&serial_m3110_reg);
 913 }
 914
 915 module_init(serial_m3110_init);
 916 module_exit(serial_m3110_exit);
 917
 918 MODULE_LICENSE("GPL v2");
 919 MODULE_ALIAS("max3110-uart");