drivers/tty/serial/max3107.c

   1 /*
   2  *  max3107.c - spi uart protocol driver for Maxim 3107
   3  *  Based on max3100.c
   4  *      by Christian Pellegrin <chripell@evolware.org>
   5  *  and max3110.c
   6  *      by Feng Tang <feng.tang@intel.com>
   7  *
   8  *  Copyright (C) Aavamobile 2009
   9  *
  10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or
  15  *  (at your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software
  24  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  *
  26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  27  *
  28  */
  29
  30 #include <linux/delay.h>
  31 #include <linux/device.h>
  32 #include <linux/serial_core.h>
  33 #include <linux/serial.h>
  34 #include <linux/tty.h>
  35 #include <linux/tty_flip.h>
  36 #include <linux/gpio.h>
  37 #include <linux/spi/spi.h>
  38 #include <linux/freezer.h>
  39 #include <linux/module.h>
  40 #include "max3107.h"
  41
  42 static const struct baud_table brg26_ext[] = {
  43         { 300,    MAX3107_BRG26_B300 },
  44         { 600,    MAX3107_BRG26_B600 },
  45         { 1200,   MAX3107_BRG26_B1200 },
  46         { 2400,   MAX3107_BRG26_B2400 },
  47         { 4800,   MAX3107_BRG26_B4800 },
  48         { 9600,   MAX3107_BRG26_B9600 },
  49         { 19200,  MAX3107_BRG26_B19200 },
  50         { 57600,  MAX3107_BRG26_B57600 },
  51         { 115200, MAX3107_BRG26_B115200 },
  52         { 230400, MAX3107_BRG26_B230400 },
  53         { 460800, MAX3107_BRG26_B460800 },
  54         { 921600, MAX3107_BRG26_B921600 },
  55         { 0, 0 }
  56 };
  57
  58 static const struct baud_table brg13_int[] = {
  59         { 300,    MAX3107_BRG13_IB300 },
  60         { 600,    MAX3107_BRG13_IB600 },
  61         { 1200,   MAX3107_BRG13_IB1200 },
  62         { 2400,   MAX3107_BRG13_IB2400 },
  63         { 4800,   MAX3107_BRG13_IB4800 },
  64         { 9600,   MAX3107_BRG13_IB9600 },
  65         { 19200,  MAX3107_BRG13_IB19200 },
  66         { 57600,  MAX3107_BRG13_IB57600 },
  67         { 115200, MAX3107_BRG13_IB115200 },
  68         { 230400, MAX3107_BRG13_IB230400 },
  69         { 460800, MAX3107_BRG13_IB460800 },
  70         { 921600, MAX3107_BRG13_IB921600 },
  71         { 0, 0 }
  72 };
  73
  74 static u32 get_new_brg(int baud, struct max3107_port *s)
  75 {
  76         int i;
  77         const struct baud_table *baud_tbl = s->baud_tbl;
  78
  79         for (i = 0; i < 13; i++) {
  80                 if (baud == baud_tbl[i].baud)
  81                         return baud_tbl[i].new_brg;
  82         }
  83
  84         return 0;
  85 }
  86
  87 /* Perform SPI transfer for write/read of device register(s) */
  88 int max3107_rw(struct max3107_port *s, u8 *tx, u8 *rx, int len)
  89 {
  90         struct spi_message spi_msg;
  91         struct spi_transfer spi_xfer;
  92
  93         /* Initialize SPI ,message */
  94         spi_message_init(&spi_msg);
  95
  96         /* Initialize SPI transfer */
  97         memset(&spi_xfer, 0, sizeof spi_xfer);
  98         spi_xfer.len = len;
  99         spi_xfer.tx_buf = tx;
 100         spi_xfer.rx_buf = rx;
 101         spi_xfer.speed_hz = MAX3107_SPI_SPEED;
 102
 103         /* Add SPI transfer to SPI message */
 104         spi_message_add_tail(&spi_xfer, &spi_msg);
 105
 106 #ifdef DBG_TRACE_SPI_DATA
 107         {
 108                 int i;
 109                 pr_info("tx len %d:\n", spi_xfer.len);
 110                 for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
 111                         pr_info(" %x", ((u8 *)spi_xfer.tx_buf)[i]);
 112                 pr_info("\n");
 113         }
 114 #endif
 115
 116         /* Perform synchronous SPI transfer */
 117         if (spi_sync(s->spi, &spi_msg)) {
 118                 dev_err(&s->spi->dev, "spi_sync failure\n");
 119                 return -EIO;
 120         }
 121
 122 #ifdef DBG_TRACE_SPI_DATA
 123         if (spi_xfer.rx_buf) {
 124                 int i;
 125                 pr_info("rx len %d:\n", spi_xfer.len);
 126                 for (i = 0 ; i < spi_xfer.len && i < 32 ; i++)
 127                         pr_info(" %x", ((u8 *)spi_xfer.rx_buf)[i]);
 128                 pr_info("\n");
 129         }
 130 #endif
 131         return 0;
 132 }
 133 EXPORT_SYMBOL_GPL(max3107_rw);
 134
 135 /* Puts received data to circular buffer */
 136 static void put_data_to_circ_buf(struct max3107_port *s, unsigned char *data,
 137                                         int len)
 138 {
 139         struct uart_port *port = &s->port;
 140         struct tty_struct *tty;
 141
 142         if (!port->state)
 143                 return;
 144
 145         tty = port->state->port.tty;
 146         if (!tty)
 147                 return;
 148
 149         /* Insert received data */
 150         tty_insert_flip_string(tty, data, len);
 151         /* Update RX counter */
 152         port->icount.rx += len;
 153 }
 154
 155 /* Handle data receiving */
 156 static void max3107_handlerx(struct max3107_port *s, u16 rxlvl)
 157 {
 158         int i;
 159         int j;
 160         int len;                                /* SPI transfer buffer length */
 161         u16 *buf;
 162         u8 *valid_str;
 163
 164         if (!s->rx_enabled)
 165                 /* RX is disabled */
 166                 return;
 167
 168         if (rxlvl == 0) {
 169                 /* RX fifo is empty */
 170                 return;
 171         } else if (rxlvl >= MAX3107_RX_FIFO_SIZE) {
 172                 dev_warn(&s->spi->dev, "Possible RX FIFO overrun %d\n", rxlvl);
 173                 /* Ensure sanity of RX level */
 174                 rxlvl = MAX3107_RX_FIFO_SIZE;
 175         }
 176         if ((s->rxbuf == 0) || (s->rxstr == 0)) {
 177                 dev_warn(&s->spi->dev, "Rx buffer/str isn't ready\n");
 178                 return;
 179         }
 180         buf = s->rxbuf;
 181         valid_str = s->rxstr;
 182         while (rxlvl) {
 183                 pr_debug("rxlvl %d\n", rxlvl);
 184                 /* Clear buffer */
 185                 memset(buf, 0, sizeof(u16) * (MAX3107_RX_FIFO_SIZE + 2));
 186                 len = 0;
 187                 if (s->irqen_reg & MAX3107_IRQ_RXFIFO_BIT) {
 188                         /* First disable RX FIFO interrupt */
 189                         pr_debug("Disabling RX INT\n");
 190                         buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
 191                         s->irqen_reg &= ~MAX3107_IRQ_RXFIFO_BIT;
 192                         buf[0] |= s->irqen_reg;
 193                         len++;
 194                 }
 195                 /* Just increase the length by amount of words in FIFO since
 196                  * buffer was zeroed and SPI transfer of 0x0000 means reading
 197                  * from RX FIFO
 198                  */
 199                 len += rxlvl;
 200                 /* Append RX level query */
 201                 buf[len] = MAX3107_RXFIFOLVL_REG;
 202                 len++;
 203
 204                 /* Perform the SPI transfer */
 205                 if (max3107_rw(s, (u8 *)buf, (u8 *)buf, len * 2)) {
 206                         dev_err(&s->spi->dev, "SPI transfer for RX h failed\n");
 207                         return;
 208                 }
 209
 210                 /* Skip RX FIFO interrupt disabling word if it was added */
 211                 j = ((len - 1) - rxlvl);
 212                 /* Read received words */
 213                 for (i = 0; i < rxlvl; i++, j++)
 214                         valid_str[i] = (u8)buf[j];
 215                 put_data_to_circ_buf(s, valid_str, rxlvl);
 216                 /* Get new RX level */
 217                 rxlvl = (buf[len - 1] & MAX3107_SPI_RX_DATA_MASK);
 218         }
 219
 220         if (s->rx_enabled) {
 221                 /* RX still enabled, re-enable RX FIFO interrupt */
 222                 pr_debug("Enabling RX INT\n");
 223                 buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
 224                 s->irqen_reg |= MAX3107_IRQ_RXFIFO_BIT;
 225                 buf[0] |= s->irqen_reg;
 226                 if (max3107_rw(s, (u8 *)buf, NULL, 2))
 227                         dev_err(&s->spi->dev, "RX FIFO INT enabling failed\n");
 228         }
 229
 230         /* Push the received data to receivers */
 231         if (s->port.state->port.tty)
 232                 tty_flip_buffer_push(s->port.state->port.tty);
 233 }
 234
 235
 236 /* Handle data sending */
 237 static void max3107_handletx(struct max3107_port *s)
 238 {
 239         struct circ_buf *xmit = &s->port.state->xmit;
 240         int i;
 241         unsigned long flags;
 242         int len;                                /* SPI transfer buffer length */
 243         u16 *buf;
 244
 245         if (!s->tx_fifo_empty)
 246                 /* Don't send more data before previous data is sent */
 247                 return;
 248
 249         if (uart_circ_empty(xmit) || uart_tx_stopped(&s->port))
 250                 /* No data to send or TX is stopped */
 251                 return;
 252
 253         if (!s->txbuf) {
 254                 dev_warn(&s->spi->dev, "Txbuf isn't ready\n");
 255                 return;
 256         }
 257         buf = s->txbuf;
 258         /* Get length of data pending in circular buffer */
 259         len = uart_circ_chars_pending(xmit);
 260         if (len) {
 261                 /* Limit to size of TX FIFO */
 262                 if (len > MAX3107_TX_FIFO_SIZE)
 263                         len = MAX3107_TX_FIFO_SIZE;
 264
 265                 pr_debug("txlen %d\n", len);
 266
 267                 /* Update TX counter */
 268                 s->port.icount.tx += len;
 269
 270                 /* TX FIFO will no longer be empty */
 271                 s->tx_fifo_empty = 0;
 272
 273                 i = 0;
 274                 if (s->irqen_reg & MAX3107_IRQ_TXEMPTY_BIT) {
 275                         /* First disable TX empty interrupt */
 276                         pr_debug("Disabling TE INT\n");
 277                         buf[i] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
 278                         s->irqen_reg &= ~MAX3107_IRQ_TXEMPTY_BIT;
 279                         buf[i] |= s->irqen_reg;
 280                         i++;
 281                         len++;
 282                 }
 283                 /* Add data to send */
 284                 spin_lock_irqsave(&s->port.lock, flags);
 285                 for ( ; i < len ; i++) {
 286                         buf[i] = (MAX3107_WRITE_BIT | MAX3107_THR_REG);
 287                         buf[i] |= ((u16)xmit->buf[xmit->tail] &
 288                                                 MAX3107_SPI_TX_DATA_MASK);
 289                         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 290                 }
 291                 spin_unlock_irqrestore(&s->port.lock, flags);
 292                 if (!(s->irqen_reg & MAX3107_IRQ_TXEMPTY_BIT)) {
 293                         /* Enable TX empty interrupt */
 294                         pr_debug("Enabling TE INT\n");
 295                         buf[i] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG);
 296                         s->irqen_reg |= MAX3107_IRQ_TXEMPTY_BIT;
 297                         buf[i] |= s->irqen_reg;
 298                         i++;
 299                         len++;
 300                 }
 301                 if (!s->tx_enabled) {
 302                         /* Enable TX */
 303                         pr_debug("Enable TX\n");
 304                         buf[i] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
 305                         spin_lock_irqsave(&s->data_lock, flags);
 306                         s->mode1_reg &= ~MAX3107_MODE1_TXDIS_BIT;
 307                         buf[i] |= s->mode1_reg;
 308                         spin_unlock_irqrestore(&s->data_lock, flags);
 309                         s->tx_enabled = 1;
 310                         i++;
 311                         len++;
 312                 }
 313
 314                 /* Perform the SPI transfer */
 315                 if (max3107_rw(s, (u8 *)buf, NULL, len*2)) {
 316                         dev_err(&s->spi->dev,
 317                                 "SPI transfer TX handling failed\n");
 318                         return;
 319                 }
 320         }
 321
 322         /* Indicate wake up if circular buffer is getting low on data */
 323         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 324                 uart_write_wakeup(&s->port);
 325
 326 }
 327
 328 /* Handle interrupts
 329  * Also reads and returns current RX FIFO level
 330  */
 331 static u16 handle_interrupt(struct max3107_port *s)
 332 {
 333         u16 buf[4];     /* Buffer for SPI transfers */
 334         u8 irq_status;
 335         u16 rx_level;
 336         unsigned long flags;
 337
 338         /* Read IRQ status register */
 339         buf[0] = MAX3107_IRQSTS_REG;
 340         /* Read status IRQ status register */
 341         buf[1] = MAX3107_STS_IRQSTS_REG;
 342         /* Read LSR IRQ status register */
 343         buf[2] = MAX3107_LSR_IRQSTS_REG;
 344         /* Query RX level */
 345         buf[3] = MAX3107_RXFIFOLVL_REG;
 346
 347         if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 8)) {
 348                 dev_err(&s->spi->dev,
 349                         "SPI transfer for INTR handling failed\n");
 350                 return 0;
 351         }
 352
 353         irq_status = (u8)buf[0];
 354         pr_debug("IRQSTS %x\n", irq_status);
 355         rx_level = (buf[3] & MAX3107_SPI_RX_DATA_MASK);
 356
 357         if (irq_status & MAX3107_IRQ_LSR_BIT) {
 358                 /* LSR interrupt */
 359                 if (buf[2] & MAX3107_LSR_RXTO_BIT)
 360                         /* RX timeout interrupt,
 361                          * handled by normal RX handling
 362                          */
 363                         pr_debug("RX TO INT\n");
 364         }
 365
 366         if (irq_status & MAX3107_IRQ_TXEMPTY_BIT) {
 367                 /* Tx empty interrupt,
 368                  * disable TX and set tx_fifo_empty flag
 369                  */
 370                 pr_debug("TE INT, disabling TX\n");
 371                 buf[0] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
 372                 spin_lock_irqsave(&s->data_lock, flags);
 373                 s->mode1_reg |= MAX3107_MODE1_TXDIS_BIT;
 374                 buf[0] |= s->mode1_reg;
 375                 spin_unlock_irqrestore(&s->data_lock, flags);
 376                 if (max3107_rw(s, (u8 *)buf, NULL, 2))
 377                         dev_err(&s->spi->dev, "SPI transfer TX dis failed\n");
 378                 s->tx_enabled = 0;
 379                 s->tx_fifo_empty = 1;
 380         }
 381
 382         if (irq_status & MAX3107_IRQ_RXFIFO_BIT)
 383                 /* RX FIFO interrupt,
 384                  * handled by normal RX handling
 385                  */
 386                 pr_debug("RFIFO INT\n");
 387
 388         /* Return RX level */
 389         return rx_level;
 390 }
 391
 392 /* Trigger work thread*/
 393 static void max3107_dowork(struct max3107_port *s)
 394 {
 395         if (!work_pending(&s->work) && !freezing(current) && !s->suspended)
 396                 queue_work(s->workqueue, &s->work);
 397         else
 398                 dev_warn(&s->spi->dev, "interrup isn't serviced normally!\n");
 399 }
 400
 401 /* Work thread */
 402 static void max3107_work(struct work_struct *w)
 403 {
 404         struct max3107_port *s = container_of(w, struct max3107_port, work);
 405         u16 rxlvl = 0;
 406         int len;        /* SPI transfer buffer length */
 407         u16 buf[5];     /* Buffer for SPI transfers */
 408         unsigned long flags;
 409
 410         /* Start by reading current RX FIFO level */
 411         buf[0] = MAX3107_RXFIFOLVL_REG;
 412         if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 2)) {
 413                 dev_err(&s->spi->dev, "SPI transfer RX lev failed\n");
 414                 rxlvl = 0;
 415         } else {
 416                 rxlvl = (buf[0] & MAX3107_SPI_RX_DATA_MASK);
 417         }
 418
 419         do {
 420                 pr_debug("rxlvl %d\n", rxlvl);
 421
 422                 /* Handle RX */
 423                 max3107_handlerx(s, rxlvl);
 424                 rxlvl = 0;
 425
 426                 if (s->handle_irq) {
 427                         /* Handle pending interrupts
 428                          * We also get new RX FIFO level since new data may
 429                          * have been received while pushing received data to
 430                          * receivers
 431                          */
 432                         s->handle_irq = 0;
 433                         rxlvl = handle_interrupt(s);
 434                 }
 435
 436                 /* Handle TX */
 437                 max3107_handletx(s);
 438
 439                 /* Handle configuration changes */
 440                 len = 0;
 441                 spin_lock_irqsave(&s->data_lock, flags);
 442                 if (s->mode1_commit) {
 443                         pr_debug("mode1_commit\n");
 444                         buf[len] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
 445                         buf[len++] |= s->mode1_reg;
 446                         s->mode1_commit = 0;
 447                 }
 448                 if (s->lcr_commit) {
 449                         pr_debug("lcr_commit\n");
 450                         buf[len] = (MAX3107_WRITE_BIT | MAX3107_LCR_REG);
 451                         buf[len++] |= s->lcr_reg;
 452                         s->lcr_commit = 0;
 453                 }
 454                 if (s->brg_commit) {
 455                         pr_debug("brg_commit\n");
 456                         buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVMSB_REG);
 457                         buf[len++] |= ((s->brg_cfg >> 16) &
 458                                                 MAX3107_SPI_TX_DATA_MASK);
 459                         buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVLSB_REG);
 460                         buf[len++] |= ((s->brg_cfg >> 8) &
 461                                                 MAX3107_SPI_TX_DATA_MASK);
 462                         buf[len] = (MAX3107_WRITE_BIT | MAX3107_BRGCFG_REG);
 463                         buf[len++] |= ((s->brg_cfg) & 0xff);
 464                         s->brg_commit = 0;
 465                 }
 466                 spin_unlock_irqrestore(&s->data_lock, flags);
 467
 468                 if (len > 0) {
 469                         if (max3107_rw(s, (u8 *)buf, NULL, len * 2))
 470                                 dev_err(&s->spi->dev,
 471                                         "SPI transfer config failed\n");
 472                 }
 473
 474                 /* Reloop if interrupt handling indicated data in RX FIFO */
 475         } while (rxlvl);
 476
 477 }
 478
 479 /* Set sleep mode */
 480 static void max3107_set_sleep(struct max3107_port *s, int mode)
 481 {
 482         u16 buf[1];     /* Buffer for SPI transfer */
 483         unsigned long flags;
 484         pr_debug("enter, mode %d\n", mode);
 485
 486         buf[0] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG);
 487         spin_lock_irqsave(&s->data_lock, flags);
 488         switch (mode) {
 489         case MAX3107_DISABLE_FORCED_SLEEP:
 490                         s->mode1_reg &= ~MAX3107_MODE1_FORCESLEEP_BIT;
 491                         break;
 492         case MAX3107_ENABLE_FORCED_SLEEP:
 493                         s->mode1_reg |= MAX3107_MODE1_FORCESLEEP_BIT;
 494                         break;
 495         case MAX3107_DISABLE_AUTOSLEEP:
 496                         s->mode1_reg &= ~MAX3107_MODE1_AUTOSLEEP_BIT;
 497                         break;
 498         case MAX3107_ENABLE_AUTOSLEEP:
 499                         s->mode1_reg |= MAX3107_MODE1_AUTOSLEEP_BIT;
 500                         break;
 501         default:
 502                 spin_unlock_irqrestore(&s->data_lock, flags);
 503                 dev_warn(&s->spi->dev, "invalid sleep mode\n");
 504                 return;
 505         }
 506         buf[0] |= s->mode1_reg;
 507         spin_unlock_irqrestore(&s->data_lock, flags);
 508
 509         if (max3107_rw(s, (u8 *)buf, NULL, 2))
 510                 dev_err(&s->spi->dev, "SPI transfer sleep mode failed\n");
 511
 512         if (mode == MAX3107_DISABLE_AUTOSLEEP ||
 513                         mode == MAX3107_DISABLE_FORCED_SLEEP)
 514                 msleep(MAX3107_WAKEUP_DELAY);
 515 }
 516
 517 /* Perform full register initialization */
 518 static void max3107_register_init(struct max3107_port *s)
 519 {
 520         u16 buf[11];    /* Buffer for SPI transfers */
 521
 522         /* 1. Configure baud rate, 9600 as default */
 523         s->baud = 9600;
 524         /* the below is default*/
 525         if (s->ext_clk) {
 526                 s->brg_cfg = MAX3107_BRG26_B9600;
 527                 s->baud_tbl = (struct baud_table *)brg26_ext;
 528         } else {
 529                 s->brg_cfg = MAX3107_BRG13_IB9600;
 530                 s->baud_tbl = (struct baud_table *)brg13_int;
 531         }
 532
 533         if (s->pdata->init)
 534                 s->pdata->init(s);
 535
 536         buf[0] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVMSB_REG)
 537                 | ((s->brg_cfg >> 16) & MAX3107_SPI_TX_DATA_MASK);
 538         buf[1] = (MAX3107_WRITE_BIT | MAX3107_BRGDIVLSB_REG)
 539                 | ((s->brg_cfg >> 8) & MAX3107_SPI_TX_DATA_MASK);
 540         buf[2] = (MAX3107_WRITE_BIT | MAX3107_BRGCFG_REG)
 541                 | ((s->brg_cfg) & 0xff);
 542
 543         /* 2. Configure LCR register, 8N1 mode by default */
 544         s->lcr_reg = MAX3107_LCR_WORD_LEN_8;
 545         buf[3] = (MAX3107_WRITE_BIT | MAX3107_LCR_REG)
 546                 | s->lcr_reg;
 547
 548         /* 3. Configure MODE 1 register */
 549         s->mode1_reg = 0;
 550         /* Enable IRQ pin */
 551         s->mode1_reg |= MAX3107_MODE1_IRQSEL_BIT;
 552         /* Disable TX */
 553         s->mode1_reg |= MAX3107_MODE1_TXDIS_BIT;
 554         s->tx_enabled = 0;
 555         /* RX is enabled */
 556         s->rx_enabled = 1;
 557         buf[4] = (MAX3107_WRITE_BIT | MAX3107_MODE1_REG)
 558                 | s->mode1_reg;
 559
 560         /* 4. Configure MODE 2 register */
 561         buf[5] = (MAX3107_WRITE_BIT | MAX3107_MODE2_REG);
 562         if (s->loopback) {
 563                 /* Enable loopback */
 564                 buf[5] |= MAX3107_MODE2_LOOPBACK_BIT;
 565         }
 566         /* Reset FIFOs */
 567         buf[5] |= MAX3107_MODE2_FIFORST_BIT;
 568         s->tx_fifo_empty = 1;
 569
 570         /* 5. Configure FIFO trigger level register */
 571         buf[6] = (MAX3107_WRITE_BIT | MAX3107_FIFOTRIGLVL_REG);
 572         /* RX FIFO trigger for 16 words, TX FIFO trigger not used */
 573         buf[6] |= (MAX3107_FIFOTRIGLVL_RX(16) | MAX3107_FIFOTRIGLVL_TX(0));
 574
 575         /* 6. Configure flow control levels */
 576         buf[7] = (MAX3107_WRITE_BIT | MAX3107_FLOWLVL_REG);
 577         /* Flow control halt level 96, resume level 48 */
 578         buf[7] |= (MAX3107_FLOWLVL_RES(48) | MAX3107_FLOWLVL_HALT(96));
 579
 580         /* 7. Configure flow control */
 581         buf[8] = (MAX3107_WRITE_BIT | MAX3107_FLOWCTRL_REG);
 582         /* Enable auto CTS and auto RTS flow control */
 583         buf[8] |= (MAX3107_FLOWCTRL_AUTOCTS_BIT | MAX3107_FLOWCTRL_AUTORTS_BIT);
 584
 585         /* 8. Configure RX timeout register */
 586         buf[9] = (MAX3107_WRITE_BIT | MAX3107_RXTO_REG);
 587         /* Timeout after 48 character intervals */
 588         buf[9] |= 0x0030;
 589
 590         /* 9. Configure LSR interrupt enable register */
 591         buf[10] = (MAX3107_WRITE_BIT | MAX3107_LSR_IRQEN_REG);
 592         /* Enable RX timeout interrupt */
 593         buf[10] |= MAX3107_LSR_RXTO_BIT;
 594
 595         /* Perform SPI transfer */
 596         if (max3107_rw(s, (u8 *)buf, NULL, 22))
 597                 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
 598
 599         /* 10. Clear IRQ status register by reading it */
 600         buf[0] = MAX3107_IRQSTS_REG;
 601
 602         /* 11. Configure interrupt enable register */
 603         /* Enable LSR interrupt */
 604         s->irqen_reg = MAX3107_IRQ_LSR_BIT;
 605         /* Enable RX FIFO interrupt */
 606         s->irqen_reg |= MAX3107_IRQ_RXFIFO_BIT;
 607         buf[1] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG)
 608                 | s->irqen_reg;
 609
 610         /* 12. Clear FIFO reset that was set in step 6 */
 611         buf[2] = (MAX3107_WRITE_BIT | MAX3107_MODE2_REG);
 612         if (s->loopback) {
 613                 /* Keep loopback enabled */
 614                 buf[2] |= MAX3107_MODE2_LOOPBACK_BIT;
 615         }
 616
 617         /* Perform SPI transfer */
 618         if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 6))
 619                 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
 620
 621 }
 622
 623 /* IRQ handler */
 624 static irqreturn_t max3107_irq(int irqno, void *dev_id)
 625 {
 626         struct max3107_port *s = dev_id;
 627
 628         if (irqno != s->spi->irq) {
 629                 /* Unexpected IRQ */
 630                 return IRQ_NONE;
 631         }
 632
 633         /* Indicate irq */
 634         s->handle_irq = 1;
 635
 636         /* Trigger work thread */
 637         max3107_dowork(s);
 638
 639         return IRQ_HANDLED;
 640 }
 641
 642 /* HW suspension function
 643  *
 644  * Currently autosleep is used to decrease current consumption, alternative
 645  * approach would be to set the chip to reset mode if UART is not being
 646  * used but that would mess the GPIOs
 647  *
 648  */
 649 void max3107_hw_susp(struct max3107_port *s, int suspend)
 650 {
 651         pr_debug("enter, suspend %d\n", suspend);
 652
 653         if (suspend) {
 654                 /* Suspend requested,
 655                  * enable autosleep to decrease current consumption
 656                  */
 657                 s->suspended = 1;
 658                 max3107_set_sleep(s, MAX3107_ENABLE_AUTOSLEEP);
 659         } else {
 660                 /* Resume requested,
 661                  * disable autosleep
 662                  */
 663                 s->suspended = 0;
 664                 max3107_set_sleep(s, MAX3107_DISABLE_AUTOSLEEP);
 665         }
 666 }
 667 EXPORT_SYMBOL_GPL(max3107_hw_susp);
 668
 669 /* Modem status IRQ enabling */
 670 static void max3107_enable_ms(struct uart_port *port)
 671 {
 672         /* Modem status not supported */
 673 }
 674
 675 /* Data send function */
 676 static void max3107_start_tx(struct uart_port *port)
 677 {
 678         struct max3107_port *s = container_of(port, struct max3107_port, port);
 679
 680         /* Trigger work thread for sending data */
 681         max3107_dowork(s);
 682 }
 683
 684 /* Function for checking that there is no pending transfers */
 685 static unsigned int max3107_tx_empty(struct uart_port *port)
 686 {
 687         struct max3107_port *s = container_of(port, struct max3107_port, port);
 688
 689         pr_debug("returning %d\n",
 690                   (s->tx_fifo_empty && uart_circ_empty(&s->port.state->xmit)));
 691         return s->tx_fifo_empty && uart_circ_empty(&s->port.state->xmit);
 692 }
 693
 694 /* Function for stopping RX */
 695 static void max3107_stop_rx(struct uart_port *port)
 696 {
 697         struct max3107_port *s = container_of(port, struct max3107_port, port);
 698         unsigned long flags;
 699
 700         /* Set RX disabled in MODE 1 register */
 701         spin_lock_irqsave(&s->data_lock, flags);
 702         s->mode1_reg |= MAX3107_MODE1_RXDIS_BIT;
 703         s->mode1_commit = 1;
 704         spin_unlock_irqrestore(&s->data_lock, flags);
 705         /* Set RX disabled */
 706         s->rx_enabled = 0;
 707         /* Trigger work thread for doing the actual configuration change */
 708         max3107_dowork(s);
 709 }
 710
 711 /* Function for returning control pin states */
 712 static unsigned int max3107_get_mctrl(struct uart_port *port)
 713 {
 714         /* DCD and DSR are not wired and CTS/RTS is handled automatically
 715          * so just indicate DSR and CAR asserted
 716          */
 717         return TIOCM_DSR | TIOCM_CAR;
 718 }
 719
 720 /* Function for setting control pin states */
 721 static void max3107_set_mctrl(struct uart_port *port, unsigned int mctrl)
 722 {
 723         /* DCD and DSR are not wired and CTS/RTS is hadnled automatically
 724          * so do nothing
 725          */
 726 }
 727
 728 /* Function for configuring UART parameters */
 729 static void max3107_set_termios(struct uart_port *port,
 730                                 struct ktermios *termios,
 731                                 struct ktermios *old)
 732 {
 733         struct max3107_port *s = container_of(port, struct max3107_port, port);
 734         struct tty_struct *tty;
 735         int baud;
 736         u16 new_lcr = 0;
 737         u32 new_brg = 0;
 738         unsigned long flags;
 739
 740         if (!port->state)
 741                 return;
 742
 743         tty = port->state->port.tty;
 744         if (!tty)
 745                 return;
 746
 747         /* Get new LCR register values */
 748         /* Word size */
 749         if ((termios->c_cflag & CSIZE) == CS7)
 750                 new_lcr |= MAX3107_LCR_WORD_LEN_7;
 751         else
 752                 new_lcr |= MAX3107_LCR_WORD_LEN_8;
 753
 754         /* Parity */
 755         if (termios->c_cflag & PARENB) {
 756                 new_lcr |= MAX3107_LCR_PARITY_BIT;
 757                 if (!(termios->c_cflag & PARODD))
 758                         new_lcr |= MAX3107_LCR_EVENPARITY_BIT;
 759         }
 760
 761         /* Stop bits */
 762         if (termios->c_cflag & CSTOPB) {
 763                 /* 2 stop bits */
 764                 new_lcr |= MAX3107_LCR_STOPLEN_BIT;
 765         }
 766
 767         /* Mask termios capabilities we don't support */
 768         termios->c_cflag &= ~CMSPAR;
 769
 770         /* Set status ignore mask */
 771         s->port.ignore_status_mask = 0;
 772         if (termios->c_iflag & IGNPAR)
 773                 s->port.ignore_status_mask |= MAX3107_ALL_ERRORS;
 774
 775         /* Set low latency to immediately handle pushed data */
 776         s->port.state->port.tty->low_latency = 1;
 777
 778         /* Get new baud rate generator configuration */
 779         baud = tty_get_baud_rate(tty);
 780
 781         spin_lock_irqsave(&s->data_lock, flags);
 782         new_brg = get_new_brg(baud, s);
 783         /* if can't find the corrent config, use previous */
 784         if (!new_brg) {
 785                 baud = s->baud;
 786                 new_brg = s->brg_cfg;
 787         }
 788         spin_unlock_irqrestore(&s->data_lock, flags);
 789         tty_termios_encode_baud_rate(termios, baud, baud);
 790         s->baud = baud;
 791
 792         /* Update timeout according to new baud rate */
 793         uart_update_timeout(port, termios->c_cflag, baud);
 794
 795         spin_lock_irqsave(&s->data_lock, flags);
 796         if (s->lcr_reg != new_lcr) {
 797                 s->lcr_reg = new_lcr;
 798                 s->lcr_commit = 1;
 799         }
 800         if (s->brg_cfg != new_brg) {
 801                 s->brg_cfg = new_brg;
 802                 s->brg_commit = 1;
 803         }
 804         spin_unlock_irqrestore(&s->data_lock, flags);
 805
 806         /* Trigger work thread for doing the actual configuration change */
 807         max3107_dowork(s);
 808 }
 809
 810 /* Port shutdown function */
 811 static void max3107_shutdown(struct uart_port *port)
 812 {
 813         struct max3107_port *s = container_of(port, struct max3107_port, port);
 814
 815         if (s->suspended && s->pdata->hw_suspend)
 816                 s->pdata->hw_suspend(s, 0);
 817
 818         /* Free the interrupt */
 819         free_irq(s->spi->irq, s);
 820
 821         if (s->workqueue) {
 822                 /* Flush and destroy work queue */
 823                 flush_workqueue(s->workqueue);
 824                 destroy_workqueue(s->workqueue);
 825                 s->workqueue = NULL;
 826         }
 827
 828         /* Suspend HW */
 829         if (s->pdata->hw_suspend)
 830                 s->pdata->hw_suspend(s, 1);
 831 }
 832
 833 /* Port startup function */
 834 static int max3107_startup(struct uart_port *port)
 835 {
 836         struct max3107_port *s = container_of(port, struct max3107_port, port);
 837
 838         /* Initialize work queue */
 839         s->workqueue = create_freezable_workqueue("max3107");
 840         if (!s->workqueue) {
 841                 dev_err(&s->spi->dev, "Workqueue creation failed\n");
 842                 return -EBUSY;
 843         }
 844         INIT_WORK(&s->work, max3107_work);
 845
 846         /* Setup IRQ */
 847         if (request_irq(s->spi->irq, max3107_irq, IRQF_TRIGGER_FALLING,
 848                         "max3107", s)) {
 849                 dev_err(&s->spi->dev, "IRQ reguest failed\n");
 850                 destroy_workqueue(s->workqueue);
 851                 s->workqueue = NULL;
 852                 return -EBUSY;
 853         }
 854
 855         /* Resume HW */
 856         if (s->pdata->hw_suspend)
 857                 s->pdata->hw_suspend(s, 0);
 858
 859         /* Init registers */
 860         max3107_register_init(s);
 861
 862         return 0;
 863 }
 864
 865 /* Port type function */
 866 static const char *max3107_type(struct uart_port *port)
 867 {
 868         struct max3107_port *s = container_of(port, struct max3107_port, port);
 869         return s->spi->modalias;
 870 }
 871
 872 /* Port release function */
 873 static void max3107_release_port(struct uart_port *port)
 874 {
 875         /* Do nothing */
 876 }
 877
 878 /* Port request function */
 879 static int max3107_request_port(struct uart_port *port)
 880 {
 881         /* Do nothing */
 882         return 0;
 883 }
 884
 885 /* Port config function */
 886 static void max3107_config_port(struct uart_port *port, int flags)
 887 {
 888         struct max3107_port *s = container_of(port, struct max3107_port, port);
 889         s->port.type = PORT_MAX3107;
 890 }
 891
 892 /* Port verify function */
 893 static int max3107_verify_port(struct uart_port *port,
 894                                 struct serial_struct *ser)
 895 {
 896         if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3107)
 897                 return 0;
 898
 899         return -EINVAL;
 900 }
 901
 902 /* Port stop TX function */
 903 static void max3107_stop_tx(struct uart_port *port)
 904 {
 905         /* Do nothing */
 906 }
 907
 908 /* Port break control function */
 909 static void max3107_break_ctl(struct uart_port *port, int break_state)
 910 {
 911         /* We don't support break control, do nothing */
 912 }
 913
 914
 915 /* Port functions */
 916 static struct uart_ops max3107_ops = {
 917         .tx_empty       = max3107_tx_empty,
 918         .set_mctrl      = max3107_set_mctrl,
 919         .get_mctrl      = max3107_get_mctrl,
 920         .stop_tx        = max3107_stop_tx,
 921         .start_tx       = max3107_start_tx,
 922         .stop_rx        = max3107_stop_rx,
 923         .enable_ms      = max3107_enable_ms,
 924         .break_ctl      = max3107_break_ctl,
 925         .startup        = max3107_startup,
 926         .shutdown       = max3107_shutdown,
 927         .set_termios    = max3107_set_termios,
 928         .type           = max3107_type,
 929         .release_port   = max3107_release_port,
 930         .request_port   = max3107_request_port,
 931         .config_port    = max3107_config_port,
 932         .verify_port    = max3107_verify_port,
 933 };
 934
 935 /* UART driver data */
 936 static struct uart_driver max3107_uart_driver = {
 937         .owner          = THIS_MODULE,
 938         .driver_name    = "ttyMAX",
 939         .dev_name       = "ttyMAX",
 940         .nr             = 1,
 941 };
 942
 943 static int driver_registered = 0;
 944
 945
 946
 947 /* 'Generic' platform data */
 948 static struct max3107_plat generic_plat_data = {
 949         .loopback               = 0,
 950         .ext_clk                = 1,
 951         .hw_suspend             = max3107_hw_susp,
 952         .polled_mode            = 0,
 953         .poll_time              = 0,
 954 };
 955
 956
 957 /*******************************************************************/
 958
 959 /**
 960  *      max3107_probe           -       SPI bus probe entry point
 961  *      @spi: the spi device
 962  *
 963  *      SPI wants us to probe this device and if appropriate claim it.
 964  *      Perform any platform specific requirements and then initialise
 965  *      the device.
 966  */
 967
 968 int max3107_probe(struct spi_device *spi, struct max3107_plat *pdata)
 969 {
 970         struct max3107_port *s;
 971         u16 buf[2];     /* Buffer for SPI transfers */
 972         int retval;
 973
 974         pr_info("enter max3107 probe\n");
 975
 976         /* Allocate port structure */
 977         s = kzalloc(sizeof(*s), GFP_KERNEL);
 978         if (!s) {
 979                 pr_err("Allocating port structure failed\n");
 980                 return -ENOMEM;
 981         }
 982
 983         s->pdata = pdata;
 984
 985         /* SPI Rx buffer
 986          * +2 for RX FIFO interrupt
 987          * disabling and RX level query
 988          */
 989         s->rxbuf = kzalloc(sizeof(u16) * (MAX3107_RX_FIFO_SIZE+2), GFP_KERNEL);
 990         if (!s->rxbuf) {
 991                 pr_err("Allocating RX buffer failed\n");
 992                 retval = -ENOMEM;
 993                 goto err_free4;
 994         }
 995         s->rxstr = kzalloc(sizeof(u8) * MAX3107_RX_FIFO_SIZE, GFP_KERNEL);
 996         if (!s->rxstr) {
 997                 pr_err("Allocating RX buffer failed\n");
 998                 retval = -ENOMEM;
 999                 goto err_free3;
1000         }
1001         /* SPI Tx buffer
1002          * SPI transfer buffer
1003          * +3 for TX FIFO empty
1004          * interrupt disabling and
1005          * enabling and TX enabling
1006          */
1007         s->txbuf = kzalloc(sizeof(u16) * MAX3107_TX_FIFO_SIZE + 3, GFP_KERNEL);
1008         if (!s->txbuf) {
1009                 pr_err("Allocating TX buffer failed\n");
1010                 retval = -ENOMEM;
1011                 goto err_free2;
1012         }
1013         /* Initialize shared data lock */
1014         spin_lock_init(&s->data_lock);
1015
1016         /* SPI intializations */
1017         dev_set_drvdata(&spi->dev, s);
1018         spi->mode = SPI_MODE_0;
1019         spi->dev.platform_data = pdata;
1020         spi->bits_per_word = 16;
1021         s->ext_clk = pdata->ext_clk;
1022         s->loopback = pdata->loopback;
1023         spi_setup(spi);
1024         s->spi = spi;
1025
1026         /* Check REV ID to ensure we are talking to what we expect */
1027         buf[0] = MAX3107_REVID_REG;
1028         if (max3107_rw(s, (u8 *)buf, (u8 *)buf, 2)) {
1029                 dev_err(&s->spi->dev, "SPI transfer for REVID read failed\n");
1030                 retval = -EIO;
1031                 goto err_free1;
1032         }
1033         if ((buf[0] & MAX3107_SPI_RX_DATA_MASK) != MAX3107_REVID1 &&
1034                 (buf[0] & MAX3107_SPI_RX_DATA_MASK) != MAX3107_REVID2) {
1035                 dev_err(&s->spi->dev, "REVID %x does not match\n",
1036                                 (buf[0] & MAX3107_SPI_RX_DATA_MASK));
1037                 retval = -ENODEV;
1038                 goto err_free1;
1039         }
1040
1041         /* Disable all interrupts */
1042         buf[0] = (MAX3107_WRITE_BIT | MAX3107_IRQEN_REG | 0x0000);
1043         buf[0] |= 0x0000;
1044
1045         /* Configure clock source */
1046         buf[1] = (MAX3107_WRITE_BIT | MAX3107_CLKSRC_REG);
1047         if (s->ext_clk) {
1048                 /* External clock */
1049                 buf[1] |= MAX3107_CLKSRC_EXTCLK_BIT;
1050         }
1051
1052         /* PLL bypass ON */
1053         buf[1] |= MAX3107_CLKSRC_PLLBYP_BIT;
1054
1055         /* Perform SPI transfer */
1056         if (max3107_rw(s, (u8 *)buf, NULL, 4)) {
1057                 dev_err(&s->spi->dev, "SPI transfer for init failed\n");
1058                 retval = -EIO;
1059                 goto err_free1;
1060         }
1061
1062         /* Register UART driver */
1063         if (!driver_registered) {
1064                 retval = uart_register_driver(&max3107_uart_driver);
1065                 if (retval) {
1066                         dev_err(&s->spi->dev, "Registering UART driver failed\n");
1067                         goto err_free1;
1068                 }
1069                 driver_registered = 1;
1070         }
1071
1072         /* Initialize UART port data */
1073         s->port.fifosize = 128;
1074         s->port.ops = &max3107_ops;
1075         s->port.line = 0;
1076         s->port.dev = &spi->dev;
1077         s->port.uartclk = 9600;
1078         s->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
1079         s->port.irq = s->spi->irq;
1080         s->port.type = PORT_MAX3107;
1081
1082         /* Add UART port */
1083         retval = uart_add_one_port(&max3107_uart_driver, &s->port);
1084         if (retval < 0) {
1085                 dev_err(&s->spi->dev, "Adding UART port failed\n");
1086                 goto err_free1;
1087         }
1088
1089         if (pdata->configure) {
1090                 retval = pdata->configure(s);
1091                 if (retval < 0)
1092                         goto err_free1;
1093         }
1094
1095         /* Go to suspend mode */
1096         if (pdata->hw_suspend)
1097                 pdata->hw_suspend(s, 1);
1098
1099         return 0;
1100
1101 err_free1:
1102         kfree(s->txbuf);
1103 err_free2:
1104         kfree(s->rxstr);
1105 err_free3:
1106         kfree(s->rxbuf);
1107 err_free4:
1108         kfree(s);
1109         return retval;
1110 }
1111 EXPORT_SYMBOL_GPL(max3107_probe);
1112
1113 /* Driver remove function */
1114 int max3107_remove(struct spi_device *spi)
1115 {
1116         struct max3107_port *s = dev_get_drvdata(&spi->dev);
1117
1118         pr_info("enter max3107 remove\n");
1119
1120         /* Remove port */
1121         if (uart_remove_one_port(&max3107_uart_driver, &s->port))
1122                 dev_warn(&s->spi->dev, "Removing UART port failed\n");
1123
1124
1125         /* Free TxRx buffer */
1126         kfree(s->rxbuf);
1127         kfree(s->rxstr);
1128         kfree(s->txbuf);
1129
1130         /* Free port structure */
1131         kfree(s);
1132
1133         return 0;
1134 }
1135 EXPORT_SYMBOL_GPL(max3107_remove);
1136
1137 /* Driver suspend function */
1138 int max3107_suspend(struct spi_device *spi, pm_message_t state)
1139 {
1140 #ifdef CONFIG_PM
1141         struct max3107_port *s = dev_get_drvdata(&spi->dev);
1142
1143         pr_debug("enter suspend\n");
1144
1145         /* Suspend UART port */
1146         uart_suspend_port(&max3107_uart_driver, &s->port);
1147
1148         /* Go to suspend mode */
1149         if (s->pdata->hw_suspend)
1150                 s->pdata->hw_suspend(s, 1);
1151 #endif  /* CONFIG_PM */
1152         return 0;
1153 }
1154 EXPORT_SYMBOL_GPL(max3107_suspend);
1155
1156 /* Driver resume function */
1157 int max3107_resume(struct spi_device *spi)
1158 {
1159 #ifdef CONFIG_PM
1160         struct max3107_port *s = dev_get_drvdata(&spi->dev);
1161
1162         pr_debug("enter resume\n");
1163
1164         /* Resume from suspend */
1165         if (s->pdata->hw_suspend)
1166                 s->pdata->hw_suspend(s, 0);
1167
1168         /* Resume UART port */
1169         uart_resume_port(&max3107_uart_driver, &s->port);
1170 #endif  /* CONFIG_PM */
1171         return 0;
1172 }
1173 EXPORT_SYMBOL_GPL(max3107_resume);
1174
1175 static int max3107_probe_generic(struct spi_device *spi)
1176 {
1177         return max3107_probe(spi, &generic_plat_data);
1178 }
1179
1180 /* Spi driver data */
1181 static struct spi_driver max3107_driver = {
1182         .driver = {
1183                 .name           = "max3107",
1184                 .bus            = &spi_bus_type,
1185                 .owner          = THIS_MODULE,
1186         },
1187         .probe          = max3107_probe_generic,
1188         .remove         = __devexit_p(max3107_remove),
1189         .suspend        = max3107_suspend,
1190         .resume         = max3107_resume,
1191 };
1192
1193 /* Driver init function */
1194 static int __init max3107_init(void)
1195 {
1196         pr_info("enter max3107 init\n");
1197         return spi_register_driver(&max3107_driver);
1198 }
1199
1200 /* Driver exit function */
1201 static void __exit max3107_exit(void)
1202 {
1203         pr_info("enter max3107 exit\n");
1204         /* Unregister UART driver */
1205         if (driver_registered)
1206                 uart_unregister_driver(&max3107_uart_driver);
1207         spi_unregister_driver(&max3107_driver);
1208 }
1209
1210 module_init(max3107_init);
1211 module_exit(max3107_exit);
1212
1213 MODULE_DESCRIPTION("MAX3107 driver");
1214 MODULE_AUTHOR("Aavamobile");
1215 MODULE_ALIAS("spi:max3107");
1216 MODULE_LICENSE("GPL v2");