drivers/serial/mrst_max3110.c

   1 /*
   2  *  max3110.c - spi uart protocol driver for Maxim 3110 on Moorestown
   3  *
   4  *  Copyright (C) Intel 2008 Feng Tang <feng.tang@intel.com>
   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/init.h>
  33 #include <linux/console.h>
  34 #include <linux/sysrq.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/tty.h>
  37 #include <linux/tty_flip.h>
  38 #include <linux/serial_core.h>
  39 #include <linux/serial_reg.h>
  40
  41 #include <linux/kthread.h>
  42 #include <linux/delay.h>
  43 #include <asm/atomic.h>
  44 #include <linux/spi/spi.h>
  45 #include <linux/spi/dw_spi.h>
  46
  47 #include "mrst_max3110.h"
  48
  49 #define PR_FMT  "mrst_max3110: "
  50
  51 #define UART_TX_NEEDED 1
  52 #define CON_TX_NEEDED  2
  53 #define BIT_IRQ_PENDING    3
  54
  55 struct uart_max3110 {
  56         struct uart_port port;
  57         struct spi_device *spi;
  58         char *name;
  59
  60         wait_queue_head_t wq;
  61         struct task_struct *main_thread;
  62         struct task_struct *read_thread;
  63         struct mutex thread_mutex;;
  64
  65         u32 baud;
  66         u16 cur_conf;
  67         u8 clock;
  68         u8 parity, word_7bits;
  69
  70         unsigned long uart_flags;
  71
  72         /* console related */
  73         struct circ_buf con_xmit;
  74
  75         /* irq related */
  76         u16 irq;
  77 };
  78
  79 /* global data structure, may need be removed */
  80 struct uart_max3110 *pmax;
  81 static inline void receive_char(struct uart_max3110 *max, u8 ch);
  82 static void receive_chars(struct uart_max3110 *max,
  83                                 unsigned char *str, int len);
  84 static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf);
  85 static void max3110_console_receive(struct uart_max3110 *max);
  86
  87 int max3110_write_then_read(struct uart_max3110 *max,
  88                 const u8 *txbuf, u8 *rxbuf, unsigned len, int always_fast)
  89 {
  90         struct spi_device *spi = max->spi;
  91         struct spi_message      message;
  92         struct spi_transfer     x;
  93         int ret;
  94
  95         if (!txbuf || !rxbuf)
  96                 return -EINVAL;
  97
  98         spi_message_init(&message);
  99         memset(&x, 0, sizeof x);
 100         x.len = len;
 101         x.tx_buf = txbuf;
 102         x.rx_buf = rxbuf;
 103         spi_message_add_tail(&x, &message);
 104
 105         if (always_fast)
 106                 x.speed_hz = 3125000;
 107         else if (max->baud)
 108                 x.speed_hz = max->baud;
 109
 110         /* Do the i/o */
 111         ret = spi_sync(spi, &message);
 112         return ret;
 113 }
 114
 115 /* Write a u16 to the device, and return one u16 read back */
 116 int max3110_out(struct uart_max3110 *max, const u16 out)
 117 {
 118         u16 tmp;
 119         int ret;
 120
 121         ret = max3110_write_then_read(max, (u8 *)&out, (u8 *)&tmp, 2, 1);
 122         if (ret)
 123                 return ret;
 124
 125         /* If some valid data is read back */
 126         if (tmp & MAX3110_READ_DATA_AVAILABLE)
 127                 receive_char(max, (tmp & 0xff));
 128
 129         return ret;
 130 }
 131
 132 #define MAX_READ_LEN    20
 133 /*
 134  * This is usually used to read data from SPIC RX FIFO, which doesn't
 135  * need any delay like flushing character out. It returns how many
 136  * valide bytes are read back
 137  */
 138 static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf)
 139 {
 140         u16 out[MAX_READ_LEN], in[MAX_READ_LEN];
 141         u8 *pbuf, valid_str[MAX_READ_LEN];
 142         int i, j, bytelen;
 143
 144         if (len > MAX_READ_LEN) {
 145                 pr_err(PR_FMT "read len %d is too large\n", len);
 146                 return 0;
 147         }
 148
 149         bytelen = len * 2;
 150         memset(out, 0, bytelen);
 151         memset(in, 0, bytelen);
 152
 153         if (max3110_write_then_read(max, (u8 *)out, (u8 *)in, bytelen, 1))
 154                 return 0;
 155
 156         /* If caller don't provide a buffer, then handle received char */
 157         pbuf = buf ? buf : valid_str;
 158
 159         for (i = 0, j = 0; i < len; i++) {
 160                 if (in[i] & MAX3110_READ_DATA_AVAILABLE)
 161                         pbuf[j++] = (u8)(in[i] & 0xff);
 162         }
 163
 164         if (j && (pbuf == valid_str))
 165                 receive_chars(max, valid_str, j);
 166
 167         return j;
 168 }
 169
 170 static void serial_m3110_con_putchar(struct uart_port *port, int ch)
 171 {
 172         struct uart_max3110 *max =
 173                 container_of(port, struct uart_max3110, port);
 174         struct circ_buf *xmit = &max->con_xmit;
 175
 176         if (uart_circ_chars_free(xmit)) {
 177                 xmit->buf[xmit->head] = (char)ch;
 178                 xmit->head = (xmit->head + 1) & (PAGE_SIZE - 1);
 179         }
 180
 181
 182         if (!test_and_set_bit(CON_TX_NEEDED, &max->uart_flags))
 183                 wake_up_process(max->main_thread);
 184 }
 185
 186 /*
 187  * Print a string to the serial port trying not to disturb
 188  * any possible real use of the port...
 189  *
 190  *      The console_lock must be held when we get here.
 191  */
 192 static void serial_m3110_con_write(struct console *co,
 193                                 const char *s, unsigned int count)
 194 {
 195         if (!pmax)
 196                 return;
 197
 198         uart_console_write(&pmax->port, s, count, serial_m3110_con_putchar);
 199 }
 200
 201 static int __init
 202 serial_m3110_con_setup(struct console *co, char *options)
 203 {
 204         struct uart_max3110 *max = pmax;
 205         int baud = 115200;
 206         int bits = 8;
 207         int parity = 'n';
 208         int flow = 'n';
 209
 210         pr_info(PR_FMT "setting up console\n");
 211
 212         if (!max) {
 213                 pr_err(PR_FMT "pmax is NULL, return");
 214                 return -ENODEV;
 215         }
 216
 217         if (options)
 218                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 219
 220         return uart_set_options(&max->port, co, baud, parity, bits, flow);
 221 }
 222
 223 static struct tty_driver *serial_m3110_con_device(struct console *co,
 224                                                         int *index)
 225 {
 226         struct uart_driver *p = co->data;
 227         *index = co->index;
 228         return p->tty_driver;
 229 }
 230
 231 static struct uart_driver serial_m3110_reg;
 232 static struct console serial_m3110_console = {
 233         .name           = "ttyS",
 234         .write          = serial_m3110_con_write,
 235         .device         = serial_m3110_con_device,
 236         .setup          = serial_m3110_con_setup,
 237         .flags          = CON_PRINTBUFFER,
 238         .index          = -1,
 239         .data           = &serial_m3110_reg,
 240 };
 241
 242 #define MRST_CONSOLE    (&serial_m3110_console)
 243
 244 static unsigned int serial_m3110_tx_empty(struct uart_port *port)
 245 {
 246         return 1;
 247 }
 248
 249 static void serial_m3110_stop_tx(struct uart_port *port)
 250 {
 251         return;
 252 }
 253
 254 /* stop_rx will be called in spin_lock env */
 255 static void serial_m3110_stop_rx(struct uart_port *port)
 256 {
 257         return;
 258 }
 259
 260 #define WORDS_PER_XFER  128
 261 static inline void send_circ_buf(struct uart_max3110 *max,
 262                                 struct circ_buf *xmit)
 263 {
 264         int len, left = 0;
 265         u16 obuf[WORDS_PER_XFER], ibuf[WORDS_PER_XFER];
 266         u8 valid_str[WORDS_PER_XFER];
 267         int i, j;
 268
 269         while (!uart_circ_empty(xmit)) {
 270                 left = uart_circ_chars_pending(xmit);
 271                 while (left) {
 272                         len = (left >= WORDS_PER_XFER) ? WORDS_PER_XFER : left;
 273
 274                         memset(obuf, 0, len * 2);
 275                         memset(ibuf, 0, len * 2);
 276                         for (i = 0; i < len; i++) {
 277                                 obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG;
 278                                 xmit->tail = (xmit->tail + 1) &
 279                                                 (UART_XMIT_SIZE - 1);
 280                         }
 281                         max3110_write_then_read(max, (u8 *)obuf,
 282                                                 (u8 *)ibuf, len * 2, 0);
 283
 284                         for (i = 0, j = 0; i < len; i++) {
 285                                 if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
 286                                         valid_str[j++] = (u8)(ibuf[i] & 0xff);
 287                         }
 288
 289                         if (j)
 290                                 receive_chars(max, valid_str, j);
 291
 292                         max->port.icount.tx += len;
 293                         left -= len;
 294                 }
 295         }
 296 }
 297
 298 static void transmit_char(struct uart_max3110 *max)
 299 {
 300         struct uart_port *port = &max->port;
 301         struct circ_buf *xmit = &port->state->xmit;
 302
 303         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 304                 return;
 305
 306         send_circ_buf(max, xmit);
 307
 308         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 309                 uart_write_wakeup(port);
 310
 311         if (uart_circ_empty(xmit))
 312                 serial_m3110_stop_tx(port);
 313 }
 314
 315 /* This will be called by uart_write() and tty_write, can't
 316  * go to sleep */
 317 static void serial_m3110_start_tx(struct uart_port *port)
 318 {
 319         struct uart_max3110 *max =
 320                 container_of(port, struct uart_max3110, port);
 321
 322         if (!test_and_set_bit(UART_TX_NEEDED, &max->uart_flags))
 323                 wake_up_process(max->main_thread);
 324 }
 325
 326 static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
 327 {
 328         struct uart_port *port = &max->port;
 329         struct tty_struct *tty;
 330         int usable;
 331
 332         /* If uart is not opened, just return */
 333         if (!port->state)
 334                 return;
 335
 336         tty = port->state->port.tty;
 337         if (!tty)
 338                 return; /* receive some char before the tty is opened */
 339
 340         while (len) {
 341                 usable = tty_buffer_request_room(tty, len);
 342                 if (usable) {
 343                         tty_insert_flip_string(tty, str, usable);
 344                         str += usable;
 345                         port->icount.rx += usable;
 346                         tty_flip_buffer_push(tty);
 347                 }
 348                 len -= usable;
 349         }
 350 }
 351
 352 static inline void receive_char(struct uart_max3110 *max, u8 ch)
 353 {
 354         receive_chars(max, &ch, 1);
 355 }
 356
 357 static void max3110_console_receive(struct uart_max3110 *max)
 358 {
 359         int loop = 1, num, total = 0;
 360         u8 recv_buf[512], *pbuf;
 361
 362         pbuf = recv_buf;
 363         do {
 364                 num = max3110_read_multi(max, 8, pbuf);
 365
 366                 if (num) {
 367                         loop = 10;
 368                         pbuf += num;
 369                         total += num;
 370
 371                         if (total >= 500) {
 372                                 receive_chars(max, recv_buf, total);
 373                                 pbuf = recv_buf;
 374                                 total = 0;
 375                         }
 376                 }
 377         } while (--loop);
 378
 379         if (total)
 380                 receive_chars(max, recv_buf, total);
 381 }
 382
 383 static int max3110_main_thread(void *_max)
 384 {
 385         struct uart_max3110 *max = _max;
 386         wait_queue_head_t *wq = &max->wq;
 387         int ret = 0;
 388         struct circ_buf *xmit = &max->con_xmit;
 389
 390         init_waitqueue_head(wq);
 391         pr_info(PR_FMT "start main thread\n");
 392
 393         do {
 394                 wait_event_interruptible(*wq, max->uart_flags || kthread_should_stop());
 395
 396                 mutex_lock(&max->thread_mutex);
 397
 398                 if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
 399                         max3110_console_receive(max);
 400
 401                 /* first handle console output */
 402                 if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
 403                         send_circ_buf(max, xmit);
 404
 405                 /* handle uart output */
 406                 if (test_and_clear_bit(UART_TX_NEEDED, &max->uart_flags))
 407                         transmit_char(max);
 408
 409                 mutex_unlock(&max->thread_mutex);
 410
 411         } while (!kthread_should_stop());
 412
 413         return ret;
 414 }
 415
 416 #ifdef CONFIG_MRST_MAX3110_IRQ
 417 static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
 418 {
 419         struct uart_max3110 *max = dev_id;
 420
 421         /* max3110's irq is a falling edge, not level triggered,
 422          * so no need to disable the irq */
 423         if (!test_and_set_bit(BIT_IRQ_PENDING, &max->uart_flags))
 424                 wake_up_process(max->main_thread);
 425
 426         return IRQ_HANDLED;
 427 }
 428 #else
 429 /* if don't use RX IRQ, then need a thread to polling read */
 430 static int max3110_read_thread(void *_max)
 431 {
 432         struct uart_max3110 *max = _max;
 433
 434         pr_info(PR_FMT "start read thread\n");
 435         do {
 436                 mutex_lock(&max->thread_mutex);
 437                 max3110_console_receive(max);
 438                 mutex_unlock(&max->thread_mutex);
 439
 440                 set_current_state(TASK_INTERRUPTIBLE);
 441                 schedule_timeout(HZ / 20);
 442         } while (!kthread_should_stop());
 443
 444         return 0;
 445 }
 446 #endif
 447
 448 static int serial_m3110_startup(struct uart_port *port)
 449 {
 450         struct uart_max3110 *max =
 451                 container_of(port, struct uart_max3110, port);
 452         u16 config = 0;
 453         int ret = 0;
 454
 455         if (port->line != 0)
 456                 pr_err(PR_FMT "uart port startup failed\n");
 457
 458         /* firstly disable all IRQ and config it to 115200, 8n1 */
 459         config = WC_TAG | WC_FIFO_ENABLE
 460                         | WC_1_STOPBITS
 461                         | WC_8BIT_WORD
 462                         | WC_BAUD_DR2;
 463         ret = max3110_out(max, config);
 464
 465         /* as we use thread to handle tx/rx, need set low latency */
 466         port->state->port.tty->low_latency = 1;
 467
 468 #ifdef CONFIG_MRST_MAX3110_IRQ
 469         ret = request_irq(max->irq, serial_m3110_irq,
 470                                 IRQ_TYPE_EDGE_FALLING, "max3110", max);
 471         if (ret)
 472                 return ret;
 473
 474         /* enable RX IRQ only */
 475         config |= WC_RXA_IRQ_ENABLE;
 476         max3110_out(max, config);
 477 #else
 478         /* if IRQ is disabled, start a read thread for input data */
 479         max->read_thread =
 480                 kthread_run(max3110_read_thread, max, "max3110_read");
 481 #endif
 482
 483         max->cur_conf = config;
 484         return 0;
 485 }
 486
 487 static void serial_m3110_shutdown(struct uart_port *port)
 488 {
 489         struct uart_max3110 *max =
 490                 container_of(port, struct uart_max3110, port);
 491         u16 config;
 492
 493         if (max->read_thread) {
 494                 kthread_stop(max->read_thread);
 495                 max->read_thread = NULL;
 496         }
 497
 498 #ifdef CONFIG_MRST_MAX3110_IRQ
 499         free_irq(max->irq, max);
 500 #endif
 501
 502         /* Disable interrupts from this port */
 503         config = WC_TAG | WC_SW_SHDI;
 504         max3110_out(max, config);
 505 }
 506
 507 static void serial_m3110_release_port(struct uart_port *port)
 508 {
 509 }
 510
 511 static int serial_m3110_request_port(struct uart_port *port)
 512 {
 513         return 0;
 514 }
 515
 516 static void serial_m3110_config_port(struct uart_port *port, int flags)
 517 {
 518         /* give it fake type */
 519         port->type = PORT_PXA;
 520 }
 521
 522 static int
 523 serial_m3110_verify_port(struct uart_port *port, struct serial_struct *ser)
 524 {
 525         /* we don't want the core code to modify any port params */
 526         return -EINVAL;
 527 }
 528
 529
 530 static const char *serial_m3110_type(struct uart_port *port)
 531 {
 532         struct uart_max3110 *max =
 533                 container_of(port, struct uart_max3110, port);
 534         return max->name;
 535 }
 536
 537 static void
 538 serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 539                        struct ktermios *old)
 540 {
 541         struct uart_max3110 *max =
 542                 container_of(port, struct uart_max3110, port);
 543         unsigned char cval;
 544         unsigned int baud, parity = 0;
 545         int clk_div = -1;
 546         u16 new_conf = max->cur_conf;
 547
 548         switch (termios->c_cflag & CSIZE) {
 549         case CS7:
 550                 cval = UART_LCR_WLEN7;
 551                 new_conf |= WC_7BIT_WORD;
 552                 break;
 553         default:
 554         case CS8:
 555                 cval = UART_LCR_WLEN8;
 556                 new_conf |= WC_8BIT_WORD;
 557                 break;
 558         }
 559
 560         baud = uart_get_baud_rate(port, termios, old, 0, 230400);
 561
 562         /* first calc the div for 1.8MHZ clock case */
 563         switch (baud) {
 564         case 300:
 565                 clk_div = WC_BAUD_DR384;
 566                 break;
 567         case 600:
 568                 clk_div = WC_BAUD_DR192;
 569                 break;
 570         case 1200:
 571                 clk_div = WC_BAUD_DR96;
 572                 break;
 573         case 2400:
 574                 clk_div = WC_BAUD_DR48;
 575                 break;
 576         case 4800:
 577                 clk_div = WC_BAUD_DR24;
 578                 break;
 579         case 9600:
 580                 clk_div = WC_BAUD_DR12;
 581                 break;
 582         case 19200:
 583                 clk_div = WC_BAUD_DR6;
 584                 break;
 585         case 38400:
 586                 clk_div = WC_BAUD_DR3;
 587                 break;
 588         case 57600:
 589                 clk_div = WC_BAUD_DR2;
 590                 break;
 591         case 115200:
 592                 clk_div = WC_BAUD_DR1;
 593                 break;
 594         case 230400:
 595                 if (max->clock & MAX3110_HIGH_CLK)
 596                         break;
 597         default:
 598                 /* pick the previous baud rate */
 599                 baud = max->baud;
 600                 clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
 601                 tty_termios_encode_baud_rate(termios, baud, baud);
 602         }
 603
 604         if (max->clock & MAX3110_HIGH_CLK) {
 605                 clk_div += 1;
 606                 /* high clk version max3110 doesn't support B300 */
 607                 if (baud == 300)
 608                         baud = 600;
 609                 if (baud == 230400)
 610                         clk_div = WC_BAUD_DR1;
 611                 tty_termios_encode_baud_rate(termios, baud, baud);
 612         }
 613
 614         new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
 615         if (termios->c_cflag & CSTOPB)
 616                 new_conf |= WC_2_STOPBITS;
 617         else
 618                 new_conf &= ~WC_2_STOPBITS;
 619
 620         if (termios->c_cflag & PARENB) {
 621                 new_conf |= WC_PARITY_ENABLE;
 622                 parity |= UART_LCR_PARITY;
 623         } else
 624                 new_conf &= ~WC_PARITY_ENABLE;
 625
 626         if (!(termios->c_cflag & PARODD))
 627                 parity |= UART_LCR_EPAR;
 628         max->parity = parity;
 629
 630         uart_update_timeout(port, termios->c_cflag, baud);
 631
 632         new_conf |= WC_TAG;
 633         if (new_conf != max->cur_conf) {
 634                 max3110_out(max, new_conf);
 635                 max->cur_conf = new_conf;
 636                 max->baud = baud;
 637         }
 638 }
 639
 640 /* don't handle hw handshaking */
 641 static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
 642 {
 643         return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
 644 }
 645
 646 static void serial_m3110_set_mctrl(struct uart_port *port, unsigned int mctrl)
 647 {
 648 }
 649
 650 static void serial_m3110_break_ctl(struct uart_port *port, int break_state)
 651 {
 652 }
 653
 654 static void serial_m3110_pm(struct uart_port *port, unsigned int state,
 655                         unsigned int oldstate)
 656 {
 657 }
 658
 659 static void serial_m3110_enable_ms(struct uart_port *port)
 660 {
 661 }
 662
 663 struct uart_ops serial_m3110_ops = {
 664         .tx_empty       = serial_m3110_tx_empty,
 665         .set_mctrl      = serial_m3110_set_mctrl,
 666         .get_mctrl      = serial_m3110_get_mctrl,
 667         .stop_tx        = serial_m3110_stop_tx,
 668         .start_tx       = serial_m3110_start_tx,
 669         .stop_rx        = serial_m3110_stop_rx,
 670         .enable_ms      = serial_m3110_enable_ms,
 671         .break_ctl      = serial_m3110_break_ctl,
 672         .startup        = serial_m3110_startup,
 673         .shutdown       = serial_m3110_shutdown,
 674         .set_termios    = serial_m3110_set_termios,     /* must have */
 675         .pm             = serial_m3110_pm,
 676         .type           = serial_m3110_type,
 677         .release_port   = serial_m3110_release_port,
 678         .request_port   = serial_m3110_request_port,
 679         .config_port    = serial_m3110_config_port,
 680         .verify_port    = serial_m3110_verify_port,
 681 };
 682
 683 static struct uart_driver serial_m3110_reg = {
 684         .owner          = THIS_MODULE,
 685         .driver_name    = "MRST serial",
 686         .dev_name       = "ttyS",
 687         .major          = TTY_MAJOR,
 688         .minor          = 64,
 689         .nr             = 1,
 690         .cons           = MRST_CONSOLE,
 691 };
 692
 693 static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
 694 {
 695         return 0;
 696 }
 697
 698 static int serial_m3110_resume(struct spi_device *spi)
 699 {
 700         return 0;
 701 }
 702
 703 static struct dw_spi_chip spi0_uart = {
 704         .poll_mode = 1,
 705         .enable_dma = 0,
 706         .type = SPI_FRF_SPI,
 707 };
 708
 709 static int serial_m3110_probe(struct spi_device *spi)
 710 {
 711         struct uart_max3110 *max;
 712         int ret;
 713         unsigned char *buffer;
 714         u16 res;
 715         max = kzalloc(sizeof(*max), GFP_KERNEL);
 716         if (!max)
 717                 return -ENOMEM;
 718
 719         /* set spi info */
 720         spi->mode = SPI_MODE_0;
 721         spi->bits_per_word = 16;
 722         max->clock = MAX3110_HIGH_CLK;
 723         spi->controller_data = &spi0_uart;
 724
 725         spi_setup(spi);
 726
 727         max->port.type = PORT_PXA;      /* need apply for a max3110 type */
 728         max->port.fifosize = 2;         /* only have 16b buffer */
 729         max->port.ops = &serial_m3110_ops;
 730         max->port.line = 0;
 731         max->port.dev = &spi->dev;
 732         max->port.uartclk = 115200;
 733
 734         max->spi = spi;
 735         max->name = spi->modalias;      /* use spi name as the name */
 736         max->irq = (u16)spi->irq;
 737
 738         mutex_init(&max->thread_mutex);
 739
 740         max->word_7bits = 0;
 741         max->parity = 0;
 742         max->baud = 0;
 743
 744         max->cur_conf = 0;
 745         max->uart_flags = 0;
 746
 747         /* Check if reading configuration register returns something sane */
 748
 749         res = RC_TAG;
 750         ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0);
 751         if (ret < 0 || res == 0 || res == 0xffff) {
 752                 printk(KERN_ERR "MAX3111 deemed not present (conf reg %04x)",
 753                                                                         res);
 754                 ret = -ENODEV;
 755                 goto err_get_page;
 756         }
 757         buffer = (unsigned char *)__get_free_page(GFP_KERNEL);
 758         if (!buffer) {
 759                 ret = -ENOMEM;
 760                 goto err_get_page;
 761         }
 762         max->con_xmit.buf = (unsigned char *)buffer;
 763         max->con_xmit.head = max->con_xmit.tail = 0;
 764
 765         max->main_thread = kthread_run(max3110_main_thread,
 766                                         max, "max3110_main");
 767         if (IS_ERR(max->main_thread)) {
 768                 ret = PTR_ERR(max->main_thread);
 769                 goto err_kthread;
 770         }
 771
 772         pmax = max;
 773         /* give membase a psudo value to pass serial_core's check */
 774         max->port.membase = (void *)0xff110000;
 775         uart_add_one_port(&serial_m3110_reg, &max->port);
 776
 777         return 0;
 778
 779 err_kthread:
 780         free_page((unsigned long)buffer);
 781 err_get_page:
 782         pmax = NULL;
 783         kfree(max);
 784         return ret;
 785 }
 786
 787 static int max3110_remove(struct spi_device *dev)
 788 {
 789         struct uart_max3110 *max = pmax;
 790
 791         if (!pmax)
 792                 return 0;
 793
 794         pmax = NULL;
 795         uart_remove_one_port(&serial_m3110_reg, &max->port);
 796
 797         free_page((unsigned long)max->con_xmit.buf);
 798
 799         if (max->main_thread)
 800                 kthread_stop(max->main_thread);
 801
 802         kfree(max);
 803         return 0;
 804 }
 805
 806 static struct spi_driver uart_max3110_driver = {
 807         .driver = {
 808                         .name   = "spi_max3111",
 809                         .bus    = &spi_bus_type,
 810                         .owner  = THIS_MODULE,
 811         },
 812         .probe          = serial_m3110_probe,
 813         .remove         = __devexit_p(max3110_remove),
 814         .suspend        = serial_m3110_suspend,
 815         .resume         = serial_m3110_resume,
 816 };
 817
 818
 819 int __init serial_m3110_init(void)
 820 {
 821         int ret = 0;
 822
 823         ret = uart_register_driver(&serial_m3110_reg);
 824         if (ret)
 825                 return ret;
 826
 827         ret = spi_register_driver(&uart_max3110_driver);
 828         if (ret)
 829                 uart_unregister_driver(&serial_m3110_reg);
 830
 831         return ret;
 832 }
 833
 834 void __exit serial_m3110_exit(void)
 835 {
 836         spi_unregister_driver(&uart_max3110_driver);
 837         uart_unregister_driver(&serial_m3110_reg);
 838 }
 839
 840 module_init(serial_m3110_init);
 841 module_exit(serial_m3110_exit);
 842
 843 MODULE_LICENSE("GPL");
 844 MODULE_ALIAS("max3110-uart");