drivers/spi/spi-stmp.c

   1 /*
   2  * Freescale STMP378X SPI master driver
   3  *
   4  * Author: dmitry pervushin <dimka@embeddedalley.com>
   5  *
   6  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   7  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   8  */
   9
  10 /*
  11  * The code contained herein is licensed under the GNU General Public
  12  * License. You may obtain a copy of the GNU General Public License
  13  * Version 2 or later at the following locations:
  14  *
  15  * http://www.opensource.org/licenses/gpl-license.html
  16  * http://www.gnu.org/copyleft/gpl.html
  17  */
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/spi/spi.h>
  23 #include <linux/err.h>
  24 #include <linux/clk.h>
  25 #include <linux/io.h>
  26 #include <linux/dma-mapping.h>
  27 #include <linux/delay.h>
  28
  29 #include <mach/platform.h>
  30 #include <mach/stmp3xxx.h>
  31 #include <mach/dma.h>
  32 #include <mach/regs-ssp.h>
  33 #include <mach/regs-apbh.h>
  34
  35
  36 /* 0 means DMA mode(recommended, default), !0 - PIO mode */
  37 static int pio;
  38 static int clock;
  39
  40 /* default timeout for busy waits is 2 seconds */
  41 #define STMP_SPI_TIMEOUT        (2 * HZ)
  42
  43 struct stmp_spi {
  44         int             id;
  45
  46         void *  __iomem regs;   /* vaddr of the control registers */
  47
  48         int             irq, err_irq;
  49         u32             dma;
  50         struct stmp3xxx_dma_descriptor d;
  51
  52         u32             speed_khz;
  53         u32             saved_timings;
  54         u32             divider;
  55
  56         struct clk      *clk;
  57         struct device   *master_dev;
  58
  59         struct work_struct work;
  60         struct workqueue_struct *workqueue;
  61
  62         /* lock protects queue access */
  63         spinlock_t lock;
  64         struct list_head queue;
  65
  66         struct completion done;
  67 };
  68
  69 #define busy_wait(cond)                                                 \
  70         ({                                                              \
  71         unsigned long end_jiffies = jiffies + STMP_SPI_TIMEOUT;         \
  72         bool succeeded = false;                                         \
  73         do {                                                            \
  74                 if (cond) {                                             \
  75                         succeeded = true;                               \
  76                         break;                                          \
  77                 }                                                       \
  78                 cpu_relax();                                            \
  79         } while (time_before(jiffies, end_jiffies));                    \
  80         succeeded;                                                      \
  81         })
  82
  83 /**
  84  * stmp_spi_init_hw
  85  * Initialize the SSP port
  86  */
  87 static int stmp_spi_init_hw(struct stmp_spi *ss)
  88 {
  89         int err = 0;
  90         void *pins = ss->master_dev->platform_data;
  91
  92         err = stmp3xxx_request_pin_group(pins, dev_name(ss->master_dev));
  93         if (err)
  94                 goto out;
  95
  96         ss->clk = clk_get(NULL, "ssp");
  97         if (IS_ERR(ss->clk)) {
  98                 err = PTR_ERR(ss->clk);
  99                 goto out_free_pins;
 100         }
 101         clk_enable(ss->clk);
 102
 103         stmp3xxx_reset_block(ss->regs, false);
 104         stmp3xxx_dma_reset_channel(ss->dma);
 105
 106         return 0;
 107
 108 out_free_pins:
 109         stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev));
 110 out:
 111         return err;
 112 }
 113
 114 static void stmp_spi_release_hw(struct stmp_spi *ss)
 115 {
 116         void *pins = ss->master_dev->platform_data;
 117
 118         if (ss->clk && !IS_ERR(ss->clk)) {
 119                 clk_disable(ss->clk);
 120                 clk_put(ss->clk);
 121         }
 122         stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev));
 123 }
 124
 125 static int stmp_spi_setup_transfer(struct spi_device *spi,
 126                 struct spi_transfer *t)
 127 {
 128         u8 bits_per_word;
 129         u32 hz;
 130         struct stmp_spi *ss = spi_master_get_devdata(spi->master);
 131         u16 rate;
 132
 133         bits_per_word = spi->bits_per_word;
 134         if (t && t->bits_per_word)
 135                 bits_per_word = t->bits_per_word;
 136
 137         /*
 138          * Calculate speed:
 139          *      - by default, use maximum speed from ssp clk
 140          *      - if device overrides it, use it
 141          *      - if transfer specifies other speed, use transfer's one
 142          */
 143         hz = 1000 * ss->speed_khz / ss->divider;
 144         if (spi->max_speed_hz)
 145                 hz = min(hz, spi->max_speed_hz);
 146         if (t && t->speed_hz)
 147                 hz = min(hz, t->speed_hz);
 148
 149         if (hz == 0) {
 150                 dev_err(&spi->dev, "Cannot continue with zero clock\n");
 151                 return -EINVAL;
 152         }
 153
 154         if (bits_per_word != 8) {
 155                 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
 156                         __func__, bits_per_word);
 157                 return -EINVAL;
 158         }
 159
 160         dev_dbg(&spi->dev, "Requested clk rate = %uHz, max = %uHz/%d = %uHz\n",
 161                 hz, ss->speed_khz, ss->divider,
 162                 ss->speed_khz * 1000 / ss->divider);
 163
 164         if (ss->speed_khz * 1000 / ss->divider < hz) {
 165                 dev_err(&spi->dev, "%s, unsupported clock rate %uHz\n",
 166                         __func__, hz);
 167                 return -EINVAL;
 168         }
 169
 170         rate = 1000 * ss->speed_khz/ss->divider/hz;
 171
 172         writel(BF(ss->divider, SSP_TIMING_CLOCK_DIVIDE)         |
 173                BF(rate - 1, SSP_TIMING_CLOCK_RATE),
 174                HW_SSP_TIMING + ss->regs);
 175
 176         writel(BF(1 /* mode SPI */, SSP_CTRL1_SSP_MODE)         |
 177                BF(4 /* 8 bits   */, SSP_CTRL1_WORD_LENGTH)      |
 178                ((spi->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |
 179                ((spi->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0) |
 180                (pio ? 0 : BM_SSP_CTRL1_DMA_ENABLE),
 181                ss->regs + HW_SSP_CTRL1);
 182
 183         return 0;
 184 }
 185
 186 static int stmp_spi_setup(struct spi_device *spi)
 187 {
 188         /* spi_setup() does basic checks,
 189          * stmp_spi_setup_transfer() does more later
 190          */
 191         if (spi->bits_per_word != 8) {
 192                 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
 193                         __func__, spi->bits_per_word);
 194                 return -EINVAL;
 195         }
 196         return 0;
 197 }
 198
 199 static inline u32 stmp_spi_cs(unsigned cs)
 200 {
 201         return  ((cs & 1) ? BM_SSP_CTRL0_WAIT_FOR_CMD : 0) |
 202                 ((cs & 2) ? BM_SSP_CTRL0_WAIT_FOR_IRQ : 0);
 203 }
 204
 205 static int stmp_spi_txrx_dma(struct stmp_spi *ss, int cs,
 206                 unsigned char *buf, dma_addr_t dma_buf, int len,
 207                 int first, int last, bool write)
 208 {
 209         u32 c0 = 0;
 210         dma_addr_t spi_buf_dma = dma_buf;
 211         int status = 0;
 212         enum dma_data_direction dir = write ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
 213
 214         c0 |= (first ? BM_SSP_CTRL0_LOCK_CS : 0);
 215         c0 |= (last ? BM_SSP_CTRL0_IGNORE_CRC : 0);
 216         c0 |= (write ? 0 : BM_SSP_CTRL0_READ);
 217         c0 |= BM_SSP_CTRL0_DATA_XFER;
 218
 219         c0 |= stmp_spi_cs(cs);
 220
 221         c0 |= BF(len, SSP_CTRL0_XFER_COUNT);
 222
 223         if (!dma_buf)
 224                 spi_buf_dma = dma_map_single(ss->master_dev, buf, len, dir);
 225
 226         ss->d.command->cmd =
 227                 BF(len, APBH_CHn_CMD_XFER_COUNT)        |
 228                 BF(1, APBH_CHn_CMD_CMDWORDS)            |
 229                 BM_APBH_CHn_CMD_WAIT4ENDCMD             |
 230                 BM_APBH_CHn_CMD_IRQONCMPLT              |
 231                 BF(write ? BV_APBH_CHn_CMD_COMMAND__DMA_READ :
 232                            BV_APBH_CHn_CMD_COMMAND__DMA_WRITE,
 233                    APBH_CHn_CMD_COMMAND);
 234         ss->d.command->pio_words[0] = c0;
 235         ss->d.command->buf_ptr = spi_buf_dma;
 236
 237         stmp3xxx_dma_reset_channel(ss->dma);
 238         stmp3xxx_dma_clear_interrupt(ss->dma);
 239         stmp3xxx_dma_enable_interrupt(ss->dma);
 240         init_completion(&ss->done);
 241         stmp3xxx_dma_go(ss->dma, &ss->d, 1);
 242         wait_for_completion(&ss->done);
 243
 244         if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN))
 245                 status = -ETIMEDOUT;
 246
 247         if (!dma_buf)
 248                 dma_unmap_single(ss->master_dev, spi_buf_dma, len, dir);
 249
 250         return status;
 251 }
 252
 253 static inline void stmp_spi_enable(struct stmp_spi *ss)
 254 {
 255         stmp3xxx_setl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0);
 256         stmp3xxx_clearl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0);
 257 }
 258
 259 static inline void stmp_spi_disable(struct stmp_spi *ss)
 260 {
 261         stmp3xxx_clearl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0);
 262         stmp3xxx_setl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0);
 263 }
 264
 265 static int stmp_spi_txrx_pio(struct stmp_spi *ss, int cs,
 266                 unsigned char *buf, int len,
 267                 bool first, bool last, bool write)
 268 {
 269         if (first)
 270                 stmp_spi_enable(ss);
 271
 272         stmp3xxx_setl(stmp_spi_cs(cs), ss->regs + HW_SSP_CTRL0);
 273
 274         while (len--) {
 275                 if (last && len <= 0)
 276                         stmp_spi_disable(ss);
 277
 278                 stmp3xxx_clearl(BM_SSP_CTRL0_XFER_COUNT,
 279                                 ss->regs + HW_SSP_CTRL0);
 280                 stmp3xxx_setl(1, ss->regs + HW_SSP_CTRL0);
 281
 282                 if (write)
 283                         stmp3xxx_clearl(BM_SSP_CTRL0_READ,
 284                                         ss->regs + HW_SSP_CTRL0);
 285                 else
 286                         stmp3xxx_setl(BM_SSP_CTRL0_READ,
 287                                         ss->regs + HW_SSP_CTRL0);
 288
 289                 /* Run! */
 290                 stmp3xxx_setl(BM_SSP_CTRL0_RUN, ss->regs + HW_SSP_CTRL0);
 291
 292                 if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) &
 293                                 BM_SSP_CTRL0_RUN))
 294                         break;
 295
 296                 if (write)
 297                         writel(*buf, ss->regs + HW_SSP_DATA);
 298
 299                 /* Set TRANSFER */
 300                 stmp3xxx_setl(BM_SSP_CTRL0_DATA_XFER, ss->regs + HW_SSP_CTRL0);
 301
 302                 if (!write) {
 303                         if (busy_wait((readl(ss->regs + HW_SSP_STATUS) &
 304                                         BM_SSP_STATUS_FIFO_EMPTY)))
 305                                 break;
 306                         *buf = readl(ss->regs + HW_SSP_DATA) & 0xFF;
 307                 }
 308
 309                 if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) &
 310                                         BM_SSP_CTRL0_RUN))
 311                         break;
 312
 313                 /* advance to the next byte */
 314                 buf++;
 315         }
 316
 317         return len < 0 ? 0 : -ETIMEDOUT;
 318 }
 319
 320 static int stmp_spi_handle_message(struct stmp_spi *ss, struct spi_message *m)
 321 {
 322         bool first, last;
 323         struct spi_transfer *t, *tmp_t;
 324         int status = 0;
 325         int cs;
 326
 327         cs = m->spi->chip_select;
 328
 329         list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {
 330
 331                 first = (&t->transfer_list == m->transfers.next);
 332                 last = (&t->transfer_list == m->transfers.prev);
 333
 334                 if (first || t->speed_hz || t->bits_per_word)
 335                         stmp_spi_setup_transfer(m->spi, t);
 336
 337                 /* reject "not last" transfers which request to change cs */
 338                 if (t->cs_change && !last) {
 339                         dev_err(&m->spi->dev,
 340                                 "Message with t->cs_change has been skipped\n");
 341                         continue;
 342                 }
 343
 344                 if (t->tx_buf) {
 345                         status = pio ?
 346                            stmp_spi_txrx_pio(ss, cs, (void *)t->tx_buf,
 347                                    t->len, first, last, true) :
 348                            stmp_spi_txrx_dma(ss, cs, (void *)t->tx_buf,
 349                                    t->tx_dma, t->len, first, last, true);
 350 #ifdef DEBUG
 351                         if (t->len < 0x10)
 352                                 print_hex_dump_bytes("Tx ",
 353                                         DUMP_PREFIX_OFFSET,
 354                                         t->tx_buf, t->len);
 355                         else
 356                                 pr_debug("Tx: %d bytes\n", t->len);
 357 #endif
 358                 }
 359                 if (t->rx_buf) {
 360                         status = pio ?
 361                            stmp_spi_txrx_pio(ss, cs, t->rx_buf,
 362                                    t->len, first, last, false) :
 363                            stmp_spi_txrx_dma(ss, cs, t->rx_buf,
 364                                    t->rx_dma, t->len, first, last, false);
 365 #ifdef DEBUG
 366                         if (t->len < 0x10)
 367                                 print_hex_dump_bytes("Rx ",
 368                                         DUMP_PREFIX_OFFSET,
 369                                         t->rx_buf, t->len);
 370                         else
 371                                 pr_debug("Rx: %d bytes\n", t->len);
 372 #endif
 373                 }
 374
 375                 if (t->delay_usecs)
 376                         udelay(t->delay_usecs);
 377
 378                 if (status)
 379                         break;
 380
 381         }
 382         return status;
 383 }
 384
 385 /**
 386  * stmp_spi_handle - handle messages from the queue
 387  */
 388 static void stmp_spi_handle(struct work_struct *w)
 389 {
 390         struct stmp_spi *ss = container_of(w, struct stmp_spi, work);
 391         unsigned long flags;
 392         struct spi_message *m;
 393
 394         spin_lock_irqsave(&ss->lock, flags);
 395         while (!list_empty(&ss->queue)) {
 396                 m = list_entry(ss->queue.next, struct spi_message, queue);
 397                 list_del_init(&m->queue);
 398                 spin_unlock_irqrestore(&ss->lock, flags);
 399
 400                 m->status = stmp_spi_handle_message(ss, m);
 401                 m->complete(m->context);
 402
 403                 spin_lock_irqsave(&ss->lock, flags);
 404         }
 405         spin_unlock_irqrestore(&ss->lock, flags);
 406
 407         return;
 408 }
 409
 410 /**
 411  * stmp_spi_transfer - perform message transfer.
 412  * Called indirectly from spi_async, queues all the messages to
 413  * spi_handle_message.
 414  * @spi: spi device
 415  * @m: message to be queued
 416  */
 417 static int stmp_spi_transfer(struct spi_device *spi, struct spi_message *m)
 418 {
 419         struct stmp_spi *ss = spi_master_get_devdata(spi->master);
 420         unsigned long flags;
 421
 422         m->status = -EINPROGRESS;
 423         spin_lock_irqsave(&ss->lock, flags);
 424         list_add_tail(&m->queue, &ss->queue);
 425         queue_work(ss->workqueue, &ss->work);
 426         spin_unlock_irqrestore(&ss->lock, flags);
 427         return 0;
 428 }
 429
 430 static irqreturn_t stmp_spi_irq(int irq, void *dev_id)
 431 {
 432         struct stmp_spi *ss = dev_id;
 433
 434         stmp3xxx_dma_clear_interrupt(ss->dma);
 435         complete(&ss->done);
 436         return IRQ_HANDLED;
 437 }
 438
 439 static irqreturn_t stmp_spi_irq_err(int irq, void *dev_id)
 440 {
 441         struct stmp_spi *ss = dev_id;
 442         u32 c1, st;
 443
 444         c1 = readl(ss->regs + HW_SSP_CTRL1);
 445         st = readl(ss->regs + HW_SSP_STATUS);
 446         dev_err(ss->master_dev, "%s: status = 0x%08X, c1 = 0x%08X\n",
 447                 __func__, st, c1);
 448         stmp3xxx_clearl(c1 & 0xCCCC0000, ss->regs + HW_SSP_CTRL1);
 449
 450         return IRQ_HANDLED;
 451 }
 452
 453 static int __devinit stmp_spi_probe(struct platform_device *dev)
 454 {
 455         int err = 0;
 456         struct spi_master *master;
 457         struct stmp_spi *ss;
 458         struct resource *r;
 459
 460         master = spi_alloc_master(&dev->dev, sizeof(struct stmp_spi));
 461         if (master == NULL) {
 462                 err = -ENOMEM;
 463                 goto out0;
 464         }
 465         master->flags = SPI_MASTER_HALF_DUPLEX;
 466
 467         ss = spi_master_get_devdata(master);
 468         platform_set_drvdata(dev, master);
 469
 470         /* Get resources(memory, IRQ) associated with the device */
 471         r = platform_get_resource(dev, IORESOURCE_MEM, 0);
 472         if (r == NULL) {
 473                 err = -ENODEV;
 474                 goto out_put_master;
 475         }
 476         ss->regs = ioremap(r->start, resource_size(r));
 477         if (!ss->regs) {
 478                 err = -EINVAL;
 479                 goto out_put_master;
 480         }
 481
 482         ss->master_dev = &dev->dev;
 483         ss->id = dev->id;
 484
 485         INIT_WORK(&ss->work, stmp_spi_handle);
 486         INIT_LIST_HEAD(&ss->queue);
 487         spin_lock_init(&ss->lock);
 488
 489         ss->workqueue = create_singlethread_workqueue(dev_name(&dev->dev));
 490         if (!ss->workqueue) {
 491                 err = -ENXIO;
 492                 goto out_put_master;
 493         }
 494         master->transfer = stmp_spi_transfer;
 495         master->setup = stmp_spi_setup;
 496
 497         /* the spi->mode bits understood by this driver: */
 498         master->mode_bits = SPI_CPOL | SPI_CPHA;
 499
 500         ss->irq = platform_get_irq(dev, 0);
 501         if (ss->irq < 0) {
 502                 err = ss->irq;
 503                 goto out_put_master;
 504         }
 505         ss->err_irq = platform_get_irq(dev, 1);
 506         if (ss->err_irq < 0) {
 507                 err = ss->err_irq;
 508                 goto out_put_master;
 509         }
 510
 511         r = platform_get_resource(dev, IORESOURCE_DMA, 0);
 512         if (r == NULL) {
 513                 err = -ENODEV;
 514                 goto out_put_master;
 515         }
 516
 517         ss->dma = r->start;
 518         err = stmp3xxx_dma_request(ss->dma, &dev->dev, dev_name(&dev->dev));
 519         if (err)
 520                 goto out_put_master;
 521
 522         err = stmp3xxx_dma_allocate_command(ss->dma, &ss->d);
 523         if (err)
 524                 goto out_free_dma;
 525
 526         master->bus_num = dev->id;
 527         master->num_chipselect = 1;
 528
 529         /* SPI controller initializations */
 530         err = stmp_spi_init_hw(ss);
 531         if (err) {
 532                 dev_dbg(&dev->dev, "cannot initialize hardware\n");
 533                 goto out_free_dma_desc;
 534         }
 535
 536         if (clock) {
 537                 dev_info(&dev->dev, "clock rate forced to %d\n", clock);
 538                 clk_set_rate(ss->clk, clock);
 539         }
 540         ss->speed_khz = clk_get_rate(ss->clk);
 541         ss->divider = 2;
 542         dev_info(&dev->dev, "max possible speed %d = %ld/%d kHz\n",
 543                 ss->speed_khz, clk_get_rate(ss->clk), ss->divider);
 544
 545         /* Register for SPI interrupt */
 546         err = request_irq(ss->irq, stmp_spi_irq, 0,
 547                           dev_name(&dev->dev), ss);
 548         if (err) {
 549                 dev_dbg(&dev->dev, "request_irq failed, %d\n", err);
 550                 goto out_release_hw;
 551         }
 552
 553         /* ..and shared interrupt for all SSP controllers */
 554         err = request_irq(ss->err_irq, stmp_spi_irq_err, IRQF_SHARED,
 555                           dev_name(&dev->dev), ss);
 556         if (err) {
 557                 dev_dbg(&dev->dev, "request_irq(error) failed, %d\n", err);
 558                 goto out_free_irq;
 559         }
 560
 561         err = spi_register_master(master);
 562         if (err) {
 563                 dev_dbg(&dev->dev, "cannot register spi master, %d\n", err);
 564                 goto out_free_irq_2;
 565         }
 566         dev_info(&dev->dev, "at (mapped) 0x%08X, irq=%d, bus %d, %s mode\n",
 567                         (u32)ss->regs, ss->irq, master->bus_num,
 568                         pio ? "PIO" : "DMA");
 569         return 0;
 570
 571 out_free_irq_2:
 572         free_irq(ss->err_irq, ss);
 573 out_free_irq:
 574         free_irq(ss->irq, ss);
 575 out_free_dma_desc:
 576         stmp3xxx_dma_free_command(ss->dma, &ss->d);
 577 out_free_dma:
 578         stmp3xxx_dma_release(ss->dma);
 579 out_release_hw:
 580         stmp_spi_release_hw(ss);
 581 out_put_master:
 582         if (ss->workqueue)
 583                 destroy_workqueue(ss->workqueue);
 584         if (ss->regs)
 585                 iounmap(ss->regs);
 586         platform_set_drvdata(dev, NULL);
 587         spi_master_put(master);
 588 out0:
 589         return err;
 590 }
 591
 592 static int __devexit stmp_spi_remove(struct platform_device *dev)
 593 {
 594         struct stmp_spi *ss;
 595         struct spi_master *master;
 596
 597         master = platform_get_drvdata(dev);
 598         if (master == NULL)
 599                 goto out0;
 600         ss = spi_master_get_devdata(master);
 601
 602         spi_unregister_master(master);
 603
 604         free_irq(ss->err_irq, ss);
 605         free_irq(ss->irq, ss);
 606         stmp3xxx_dma_free_command(ss->dma, &ss->d);
 607         stmp3xxx_dma_release(ss->dma);
 608         stmp_spi_release_hw(ss);
 609         destroy_workqueue(ss->workqueue);
 610         iounmap(ss->regs);
 611         spi_master_put(master);
 612         platform_set_drvdata(dev, NULL);
 613 out0:
 614         return 0;
 615 }
 616
 617 #ifdef CONFIG_PM
 618 static int stmp_spi_suspend(struct platform_device *pdev, pm_message_t pmsg)
 619 {
 620         struct stmp_spi *ss;
 621         struct spi_master *master;
 622
 623         master = platform_get_drvdata(pdev);
 624         ss = spi_master_get_devdata(master);
 625
 626         ss->saved_timings = readl(HW_SSP_TIMING + ss->regs);
 627         clk_disable(ss->clk);
 628
 629         return 0;
 630 }
 631
 632 static int stmp_spi_resume(struct platform_device *pdev)
 633 {
 634         struct stmp_spi *ss;
 635         struct spi_master *master;
 636
 637         master = platform_get_drvdata(pdev);
 638         ss = spi_master_get_devdata(master);
 639
 640         clk_enable(ss->clk);
 641         stmp3xxx_reset_block(ss->regs, false);
 642         writel(ss->saved_timings, ss->regs + HW_SSP_TIMING);
 643
 644         return 0;
 645 }
 646
 647 #else
 648 #define stmp_spi_suspend NULL
 649 #define stmp_spi_resume  NULL
 650 #endif
 651
 652 static struct platform_driver stmp_spi_driver = {
 653         .probe  = stmp_spi_probe,
 654         .remove = __devexit_p(stmp_spi_remove),
 655         .driver = {
 656                 .name = "stmp3xxx_ssp",
 657                 .owner = THIS_MODULE,
 658         },
 659         .suspend = stmp_spi_suspend,
 660         .resume  = stmp_spi_resume,
 661 };
 662 module_platform_driver(stmp_spi_driver);
 663
 664 module_param(pio, int, S_IRUGO);
 665 module_param(clock, int, S_IRUGO);
 666 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com>");
 667 MODULE_DESCRIPTION("STMP3xxx SPI/SSP driver");
 668 MODULE_LICENSE("GPL");