drivers/tty/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 available 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[SPI_NAME_SIZE];
  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         pr_info(PR_FMT "start main thread\n");
 425
 426         do {
 427                 wait_event_interruptible(*wq, max->uart_flags || kthread_should_stop());
 428
 429                 mutex_lock(&max->thread_mutex);
 430
 431                 if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
 432                         max3110_con_receive(max);
 433
 434                 /* first handle console output */
 435                 if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
 436                         send_circ_buf(max, xmit);
 437
 438                 /* handle uart output */
 439                 if (test_and_clear_bit(UART_TX_NEEDED, &max->uart_flags))
 440                         transmit_char(max);
 441
 442                 mutex_unlock(&max->thread_mutex);
 443
 444         } while (!kthread_should_stop());
 445
 446         return ret;
 447 }
 448
 449 static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
 450 {
 451         struct uart_max3110 *max = dev_id;
 452
 453         /* max3110's irq is a falling edge, not level triggered,
 454          * so no need to disable the irq */
 455         if (!test_and_set_bit(BIT_IRQ_PENDING, &max->uart_flags))
 456                 wake_up_process(max->main_thread);
 457
 458         return IRQ_HANDLED;
 459 }
 460
 461 /* if don't use RX IRQ, then need a thread to polling read */
 462 static int max3110_read_thread(void *_max)
 463 {
 464         struct uart_max3110 *max = _max;
 465
 466         pr_info(PR_FMT "start read thread\n");
 467         do {
 468                 /*
 469                  * If can't acquire the mutex, it means the main thread
 470                  * is running which will also perform the rx job
 471                  */
 472                 if (mutex_trylock(&max->thread_mutex)) {
 473                         max3110_con_receive(max);
 474                         mutex_unlock(&max->thread_mutex);
 475                 }
 476
 477                 set_current_state(TASK_INTERRUPTIBLE);
 478                 schedule_timeout(HZ / 20);
 479         } while (!kthread_should_stop());
 480
 481         return 0;
 482 }
 483
 484 static int serial_m3110_startup(struct uart_port *port)
 485 {
 486         struct uart_max3110 *max =
 487                 container_of(port, struct uart_max3110, port);
 488         u16 config = 0;
 489         int ret = 0;
 490
 491         if (port->line != 0) {
 492                 pr_err(PR_FMT "uart port startup failed\n");
 493                 return -1;
 494         }
 495
 496         /* Disable all IRQ and config it to 115200, 8n1 */
 497         config = WC_TAG | WC_FIFO_ENABLE
 498                         | WC_1_STOPBITS
 499                         | WC_8BIT_WORD
 500                         | WC_BAUD_DR2;
 501
 502         /* as we use thread to handle tx/rx, need set low latency */
 503         port->state->port.tty->low_latency = 1;
 504
 505         if (max->irq) {
 506                 max->read_thread = NULL;
 507                 ret = request_irq(max->irq, serial_m3110_irq,
 508                                 IRQ_TYPE_EDGE_FALLING, "max3110", max);
 509                 if (ret) {
 510                         max->irq = 0;
 511                         pr_err(PR_FMT "unable to allocate IRQ, polling\n");
 512                 }  else {
 513                         /* Enable RX IRQ only */
 514                         config |= WC_RXA_IRQ_ENABLE;
 515                 }
 516         }
 517
 518         if (max->irq == 0) {
 519                 /* If IRQ is disabled, start a read thread for input data */
 520                 max->read_thread =
 521                         kthread_run(max3110_read_thread, max, "max3110_read");
 522                 if (IS_ERR(max->read_thread)) {
 523                         ret = PTR_ERR(max->read_thread);
 524                         max->read_thread = NULL;
 525                         pr_err(PR_FMT "Can't create read thread!\n");
 526                         return ret;
 527                 }
 528         }
 529
 530         ret = max3110_out(max, config);
 531         if (ret) {
 532                 if (max->irq)
 533                         free_irq(max->irq, max);
 534                 if (max->read_thread)
 535                         kthread_stop(max->read_thread);
 536                 max->read_thread = NULL;
 537                 return ret;
 538         }
 539
 540         max->cur_conf = config;
 541         return 0;
 542 }
 543
 544 static void serial_m3110_shutdown(struct uart_port *port)
 545 {
 546         struct uart_max3110 *max =
 547                 container_of(port, struct uart_max3110, port);
 548         u16 config;
 549
 550         if (max->read_thread) {
 551                 kthread_stop(max->read_thread);
 552                 max->read_thread = NULL;
 553         }
 554
 555         if (max->irq)
 556                 free_irq(max->irq, max);
 557
 558         /* Disable interrupts from this port */
 559         config = WC_TAG | WC_SW_SHDI;
 560         max3110_out(max, config);
 561 }
 562
 563 static void serial_m3110_release_port(struct uart_port *port)
 564 {
 565 }
 566
 567 static int serial_m3110_request_port(struct uart_port *port)
 568 {
 569         return 0;
 570 }
 571
 572 static void serial_m3110_config_port(struct uart_port *port, int flags)
 573 {
 574         port->type = PORT_MAX3100;
 575 }
 576
 577 static int
 578 serial_m3110_verify_port(struct uart_port *port, struct serial_struct *ser)
 579 {
 580         /* we don't want the core code to modify any port params */
 581         return -EINVAL;
 582 }
 583
 584
 585 static const char *serial_m3110_type(struct uart_port *port)
 586 {
 587         struct uart_max3110 *max =
 588                 container_of(port, struct uart_max3110, port);
 589         return max->name;
 590 }
 591
 592 static void
 593 serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 594                        struct ktermios *old)
 595 {
 596         struct uart_max3110 *max =
 597                 container_of(port, struct uart_max3110, port);
 598         unsigned char cval;
 599         unsigned int baud, parity = 0;
 600         int clk_div = -1;
 601         u16 new_conf = max->cur_conf;
 602
 603         switch (termios->c_cflag & CSIZE) {
 604         case CS7:
 605                 cval = UART_LCR_WLEN7;
 606                 new_conf |= WC_7BIT_WORD;
 607                 break;
 608         default:
 609                 /* We only support CS7 & CS8 */
 610                 termios->c_cflag &= ~CSIZE;
 611                 termios->c_cflag |= CS8;
 612         case CS8:
 613                 cval = UART_LCR_WLEN8;
 614                 new_conf |= WC_8BIT_WORD;
 615                 break;
 616         }
 617
 618         baud = uart_get_baud_rate(port, termios, old, 0, 230400);
 619
 620         /* First calc the div for 1.8MHZ clock case */
 621         switch (baud) {
 622         case 300:
 623                 clk_div = WC_BAUD_DR384;
 624                 break;
 625         case 600:
 626                 clk_div = WC_BAUD_DR192;
 627                 break;
 628         case 1200:
 629                 clk_div = WC_BAUD_DR96;
 630                 break;
 631         case 2400:
 632                 clk_div = WC_BAUD_DR48;
 633                 break;
 634         case 4800:
 635                 clk_div = WC_BAUD_DR24;
 636                 break;
 637         case 9600:
 638                 clk_div = WC_BAUD_DR12;
 639                 break;
 640         case 19200:
 641                 clk_div = WC_BAUD_DR6;
 642                 break;
 643         case 38400:
 644                 clk_div = WC_BAUD_DR3;
 645                 break;
 646         case 57600:
 647                 clk_div = WC_BAUD_DR2;
 648                 break;
 649         case 115200:
 650                 clk_div = WC_BAUD_DR1;
 651                 break;
 652         case 230400:
 653                 if (max->clock & MAX3110_HIGH_CLK)
 654                         break;
 655         default:
 656                 /* Pick the previous baud rate */
 657                 baud = max->baud;
 658                 clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
 659                 tty_termios_encode_baud_rate(termios, baud, baud);
 660         }
 661
 662         if (max->clock & MAX3110_HIGH_CLK) {
 663                 clk_div += 1;
 664                 /* High clk version max3110 doesn't support B300 */
 665                 if (baud == 300) {
 666                         baud = 600;
 667                         clk_div = WC_BAUD_DR384;
 668                 }
 669                 if (baud == 230400)
 670                         clk_div = WC_BAUD_DR1;
 671                 tty_termios_encode_baud_rate(termios, baud, baud);
 672         }
 673
 674         new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
 675
 676         if (unlikely(termios->c_cflag & CMSPAR))
 677                 termios->c_cflag &= ~CMSPAR;
 678
 679         if (termios->c_cflag & CSTOPB)
 680                 new_conf |= WC_2_STOPBITS;
 681         else
 682                 new_conf &= ~WC_2_STOPBITS;
 683
 684         if (termios->c_cflag & PARENB) {
 685                 new_conf |= WC_PARITY_ENABLE;
 686                 parity |= UART_LCR_PARITY;
 687         } else
 688                 new_conf &= ~WC_PARITY_ENABLE;
 689
 690         if (!(termios->c_cflag & PARODD))
 691                 parity |= UART_LCR_EPAR;
 692         max->parity = parity;
 693
 694         uart_update_timeout(port, termios->c_cflag, baud);
 695
 696         new_conf |= WC_TAG;
 697         if (new_conf != max->cur_conf) {
 698                 if (!max3110_out(max, new_conf)) {
 699                         max->cur_conf = new_conf;
 700                         max->baud = baud;
 701                 }
 702         }
 703 }
 704
 705 /* Don't handle hw handshaking */
 706 static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
 707 {
 708         return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
 709 }
 710
 711 static void serial_m3110_set_mctrl(struct uart_port *port, unsigned int mctrl)
 712 {
 713 }
 714
 715 static void serial_m3110_break_ctl(struct uart_port *port, int break_state)
 716 {
 717 }
 718
 719 static void serial_m3110_pm(struct uart_port *port, unsigned int state,
 720                         unsigned int oldstate)
 721 {
 722 }
 723
 724 static void serial_m3110_enable_ms(struct uart_port *port)
 725 {
 726 }
 727
 728 struct uart_ops serial_m3110_ops = {
 729         .tx_empty       = serial_m3110_tx_empty,
 730         .set_mctrl      = serial_m3110_set_mctrl,
 731         .get_mctrl      = serial_m3110_get_mctrl,
 732         .stop_tx        = serial_m3110_stop_tx,
 733         .start_tx       = serial_m3110_start_tx,
 734         .stop_rx        = serial_m3110_stop_rx,
 735         .enable_ms      = serial_m3110_enable_ms,
 736         .break_ctl      = serial_m3110_break_ctl,
 737         .startup        = serial_m3110_startup,
 738         .shutdown       = serial_m3110_shutdown,
 739         .set_termios    = serial_m3110_set_termios,
 740         .pm             = serial_m3110_pm,
 741         .type           = serial_m3110_type,
 742         .release_port   = serial_m3110_release_port,
 743         .request_port   = serial_m3110_request_port,
 744         .config_port    = serial_m3110_config_port,
 745         .verify_port    = serial_m3110_verify_port,
 746 };
 747
 748 static struct uart_driver serial_m3110_reg = {
 749         .owner          = THIS_MODULE,
 750         .driver_name    = "MRST serial",
 751         .dev_name       = "ttyS",
 752         .major          = TTY_MAJOR,
 753         .minor          = 64,
 754         .nr             = 1,
 755         .cons           = &serial_m3110_console,
 756 };
 757
 758 #ifdef CONFIG_PM
 759 static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
 760 {
 761         struct uart_max3110 *max = spi_get_drvdata(spi);
 762
 763         disable_irq(max->irq);
 764         uart_suspend_port(&serial_m3110_reg, &max->port);
 765         max3110_out(max, max->cur_conf | WC_SW_SHDI);
 766         return 0;
 767 }
 768
 769 static int serial_m3110_resume(struct spi_device *spi)
 770 {
 771         struct uart_max3110 *max = spi_get_drvdata(spi);
 772
 773         max3110_out(max, max->cur_conf);
 774         uart_resume_port(&serial_m3110_reg, &max->port);
 775         enable_irq(max->irq);
 776         return 0;
 777 }
 778 #else
 779 #define serial_m3110_suspend    NULL
 780 #define serial_m3110_resume     NULL
 781 #endif
 782
 783 static int __devinit serial_m3110_probe(struct spi_device *spi)
 784 {
 785         struct uart_max3110 *max;
 786         void *buffer;
 787         u16 res;
 788         int ret = 0;
 789
 790         max = kzalloc(sizeof(*max), GFP_KERNEL);
 791         if (!max)
 792                 return -ENOMEM;
 793
 794         /* Set spi info */
 795         spi->bits_per_word = 16;
 796         max->clock = MAX3110_HIGH_CLK;
 797
 798         spi_setup(spi);
 799
 800         max->port.type = PORT_MAX3100;
 801         max->port.fifosize = 2;         /* Only have 16b buffer */
 802         max->port.ops = &serial_m3110_ops;
 803         max->port.line = 0;
 804         max->port.dev = &spi->dev;
 805         max->port.uartclk = 115200;
 806
 807         max->spi = spi;
 808         strcpy(max->name, spi->modalias);
 809         max->irq = (u16)spi->irq;
 810
 811         mutex_init(&max->thread_mutex);
 812
 813         max->word_7bits = 0;
 814         max->parity = 0;
 815         max->baud = 0;
 816
 817         max->cur_conf = 0;
 818         max->uart_flags = 0;
 819
 820         /* Check if reading configuration register returns something sane */
 821
 822         res = RC_TAG;
 823         ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0);
 824         if (ret < 0 || res == 0 || res == 0xffff) {
 825                 dev_dbg(&spi->dev, "MAX3111 deemed not present (conf reg %04x)",
 826                                                                         res);
 827                 ret = -ENODEV;
 828                 goto err_get_page;
 829         }
 830
 831         buffer = (void *)__get_free_page(GFP_KERNEL);
 832         if (!buffer) {
 833                 ret = -ENOMEM;
 834                 goto err_get_page;
 835         }
 836         max->con_xmit.buf = buffer;
 837         max->con_xmit.head = 0;
 838         max->con_xmit.tail = 0;
 839
 840         init_waitqueue_head(&max->wq);
 841
 842         max->main_thread = kthread_run(max3110_main_thread,
 843                                         max, "max3110_main");
 844         if (IS_ERR(max->main_thread)) {
 845                 ret = PTR_ERR(max->main_thread);
 846                 goto err_kthread;
 847         }
 848
 849         spi_set_drvdata(spi, max);
 850         pmax = max;
 851
 852         /* Give membase a psudo value to pass serial_core's check */
 853         max->port.membase = (void *)0xff110000;
 854         uart_add_one_port(&serial_m3110_reg, &max->port);
 855
 856         return 0;
 857
 858 err_kthread:
 859         free_page((unsigned long)buffer);
 860 err_get_page:
 861         kfree(max);
 862         return ret;
 863 }
 864
 865 static int __devexit serial_m3110_remove(struct spi_device *dev)
 866 {
 867         struct uart_max3110 *max = spi_get_drvdata(dev);
 868
 869         if (!max)
 870                 return 0;
 871
 872         uart_remove_one_port(&serial_m3110_reg, &max->port);
 873
 874         free_page((unsigned long)max->con_xmit.buf);
 875
 876         if (max->main_thread)
 877                 kthread_stop(max->main_thread);
 878
 879         kfree(max);
 880         return 0;
 881 }
 882
 883 static struct spi_driver uart_max3110_driver = {
 884         .driver = {
 885                         .name   = "spi_max3111",
 886                         .bus    = &spi_bus_type,
 887                         .owner  = THIS_MODULE,
 888         },
 889         .probe          = serial_m3110_probe,
 890         .remove         = __devexit_p(serial_m3110_remove),
 891         .suspend        = serial_m3110_suspend,
 892         .resume         = serial_m3110_resume,
 893 };
 894
 895 static int __init serial_m3110_init(void)
 896 {
 897         int ret = 0;
 898
 899         ret = uart_register_driver(&serial_m3110_reg);
 900         if (ret)
 901                 return ret;
 902
 903         ret = spi_register_driver(&uart_max3110_driver);
 904         if (ret)
 905                 uart_unregister_driver(&serial_m3110_reg);
 906
 907         return ret;
 908 }
 909
 910 static void __exit serial_m3110_exit(void)
 911 {
 912         spi_unregister_driver(&uart_max3110_driver);
 913         uart_unregister_driver(&serial_m3110_reg);
 914 }
 915
 916 module_init(serial_m3110_init);
 917 module_exit(serial_m3110_exit);
 918
 919 MODULE_LICENSE("GPL v2");
 920 MODULE_ALIAS("max3110-uart");