drivers/spi/atmel_spi.c

   1 /*
   2  * Driver for Atmel AT32 and AT91 SPI Controllers
   3  *
   4  * Copyright (C) 2006 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/clk.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/delay.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/err.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/spi/spi.h>
  21
  22 #include <asm/io.h>
  23 #include <asm/arch/board.h>
  24 #include <asm/arch/gpio.h>
  25
  26 #ifdef CONFIG_ARCH_AT91
  27 #include <asm/arch/cpu.h>
  28 #endif
  29
  30 #include "atmel_spi.h"
  31
  32 /*
  33  * The core SPI transfer engine just talks to a register bank to set up
  34  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
  35  * framework provides the base clock, subdivided for each spi_device.
  36  *
  37  * Newer controllers, marked with "new_1" flag, have:
  38  *  - CR.LASTXFER
  39  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
  40  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
  41  *  - SPI_CSRx.CSAAT
  42  *  - SPI_CSRx.SBCR allows faster clocking
  43  */
  44 struct atmel_spi {
  45         spinlock_t              lock;
  46
  47         void __iomem            *regs;
  48         int                     irq;
  49         struct clk              *clk;
  50         struct platform_device  *pdev;
  51         unsigned                new_1:1;
  52
  53         u8                      stopping;
  54         struct list_head        queue;
  55         struct spi_transfer     *current_transfer;
  56         unsigned long           remaining_bytes;
  57
  58         void                    *buffer;
  59         dma_addr_t              buffer_dma;
  60 };
  61
  62 #define BUFFER_SIZE             PAGE_SIZE
  63 #define INVALID_DMA_ADDRESS     0xffffffff
  64
  65 /*
  66  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
  67  * they assume that spi slave device state will not change on deselect, so
  68  * that automagic deselection is OK.  Not so!  Workaround uses nCSx pins
  69  * as GPIOs; or newer controllers have CSAAT and friends.
  70  *
  71  * Since the CSAAT functionality is a bit weird on newer controllers
  72  * as well, we use GPIO to control nCSx pins on all controllers.
  73  */
  74
  75 static inline void cs_activate(struct spi_device *spi)
  76 {
  77         unsigned gpio = (unsigned) spi->controller_data;
  78         unsigned active = spi->mode & SPI_CS_HIGH;
  79
  80         dev_dbg(&spi->dev, "activate %u%s\n", gpio, active ? " (high)" : "");
  81         gpio_set_value(gpio, active);
  82 }
  83
  84 static inline void cs_deactivate(struct spi_device *spi)
  85 {
  86         unsigned gpio = (unsigned) spi->controller_data;
  87         unsigned active = spi->mode & SPI_CS_HIGH;
  88
  89         dev_dbg(&spi->dev, "DEactivate %u%s\n", gpio, active ? " (low)" : "");
  90         gpio_set_value(gpio, !active);
  91 }
  92
  93 /*
  94  * Submit next transfer for DMA.
  95  * lock is held, spi irq is blocked
  96  */
  97 static void atmel_spi_next_xfer(struct spi_master *master,
  98                                 struct spi_message *msg)
  99 {
 100         struct atmel_spi        *as = spi_master_get_devdata(master);
 101         struct spi_transfer     *xfer;
 102         u32                     len;
 103         dma_addr_t              tx_dma, rx_dma;
 104
 105         xfer = as->current_transfer;
 106         if (!xfer || as->remaining_bytes == 0) {
 107                 if (xfer)
 108                         xfer = list_entry(xfer->transfer_list.next,
 109                                         struct spi_transfer, transfer_list);
 110                 else
 111                         xfer = list_entry(msg->transfers.next,
 112                                         struct spi_transfer, transfer_list);
 113                 as->remaining_bytes = xfer->len;
 114                 as->current_transfer = xfer;
 115         }
 116
 117         len = as->remaining_bytes;
 118
 119         tx_dma = xfer->tx_dma;
 120         rx_dma = xfer->rx_dma;
 121
 122         /* use scratch buffer only when rx or tx data is unspecified */
 123         if (rx_dma == INVALID_DMA_ADDRESS) {
 124                 rx_dma = as->buffer_dma;
 125                 if (len > BUFFER_SIZE)
 126                         len = BUFFER_SIZE;
 127         }
 128         if (tx_dma == INVALID_DMA_ADDRESS) {
 129                 tx_dma = as->buffer_dma;
 130                 if (len > BUFFER_SIZE)
 131                         len = BUFFER_SIZE;
 132                 memset(as->buffer, 0, len);
 133                 dma_sync_single_for_device(&as->pdev->dev,
 134                                 as->buffer_dma, len, DMA_TO_DEVICE);
 135         }
 136
 137         spi_writel(as, RPR, rx_dma);
 138         spi_writel(as, TPR, tx_dma);
 139
 140         as->remaining_bytes -= len;
 141         if (msg->spi->bits_per_word > 8)
 142                 len >>= 1;
 143
 144         /* REVISIT: when xfer->delay_usecs == 0, the PDC "next transfer"
 145          * mechanism might help avoid the IRQ latency between transfers
 146          *
 147          * We're also waiting for ENDRX before we start the next
 148          * transfer because we need to handle some difficult timing
 149          * issues otherwise. If we wait for ENDTX in one transfer and
 150          * then starts waiting for ENDRX in the next, it's difficult
 151          * to tell the difference between the ENDRX interrupt we're
 152          * actually waiting for and the ENDRX interrupt of the
 153          * previous transfer.
 154          *
 155          * It should be doable, though. Just not now...
 156          */
 157         spi_writel(as, TNCR, 0);
 158         spi_writel(as, RNCR, 0);
 159         spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
 160
 161         dev_dbg(&msg->spi->dev,
 162                 "  start xfer %p: len %u tx %p/%08x rx %p/%08x imr %03x\n",
 163                 xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 164                 xfer->rx_buf, xfer->rx_dma, spi_readl(as, IMR));
 165
 166         spi_writel(as, TCR, len);
 167         spi_writel(as, RCR, len);
 168         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 169 }
 170
 171 static void atmel_spi_next_message(struct spi_master *master)
 172 {
 173         struct atmel_spi        *as = spi_master_get_devdata(master);
 174         struct spi_message      *msg;
 175         u32                     mr;
 176
 177         BUG_ON(as->current_transfer);
 178
 179         msg = list_entry(as->queue.next, struct spi_message, queue);
 180
 181         /* Select the chip */
 182         mr = spi_readl(as, MR);
 183         mr = SPI_BFINS(PCS, ~(1 << msg->spi->chip_select), mr);
 184         spi_writel(as, MR, mr);
 185         cs_activate(msg->spi);
 186
 187         atmel_spi_next_xfer(master, msg);
 188 }
 189
 190 static void
 191 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 192 {
 193         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 194         if (xfer->tx_buf)
 195                 xfer->tx_dma = dma_map_single(&as->pdev->dev,
 196                                 (void *) xfer->tx_buf, xfer->len,
 197                                 DMA_TO_DEVICE);
 198         if (xfer->rx_buf)
 199                 xfer->rx_dma = dma_map_single(&as->pdev->dev,
 200                                 xfer->rx_buf, xfer->len,
 201                                 DMA_FROM_DEVICE);
 202 }
 203
 204 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 205                                      struct spi_transfer *xfer)
 206 {
 207         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 208                 dma_unmap_single(master->cdev.dev, xfer->tx_dma,
 209                                  xfer->len, DMA_TO_DEVICE);
 210         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 211                 dma_unmap_single(master->cdev.dev, xfer->rx_dma,
 212                                  xfer->len, DMA_FROM_DEVICE);
 213 }
 214
 215 static void
 216 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 217                    struct spi_message *msg, int status)
 218 {
 219         cs_deactivate(msg->spi);
 220         list_del(&msg->queue);
 221         msg->status = status;
 222
 223         dev_dbg(master->cdev.dev,
 224                 "xfer complete: %u bytes transferred\n",
 225                 msg->actual_length);
 226
 227         spin_unlock(&as->lock);
 228         msg->complete(msg->context);
 229         spin_lock(&as->lock);
 230
 231         as->current_transfer = NULL;
 232
 233         /* continue if needed */
 234         if (list_empty(&as->queue) || as->stopping)
 235                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 236         else
 237                 atmel_spi_next_message(master);
 238 }
 239
 240 static irqreturn_t
 241 atmel_spi_interrupt(int irq, void *dev_id)
 242 {
 243         struct spi_master       *master = dev_id;
 244         struct atmel_spi        *as = spi_master_get_devdata(master);
 245         struct spi_message      *msg;
 246         struct spi_transfer     *xfer;
 247         u32                     status, pending, imr;
 248         int                     ret = IRQ_NONE;
 249
 250         spin_lock(&as->lock);
 251
 252         xfer = as->current_transfer;
 253         msg = list_entry(as->queue.next, struct spi_message, queue);
 254
 255         imr = spi_readl(as, IMR);
 256         status = spi_readl(as, SR);
 257         pending = status & imr;
 258
 259         if (pending & SPI_BIT(OVRES)) {
 260                 int timeout;
 261
 262                 ret = IRQ_HANDLED;
 263
 264                 spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
 265                                      | SPI_BIT(OVRES)));
 266
 267                 /*
 268                  * When we get an overrun, we disregard the current
 269                  * transfer. Data will not be copied back from any
 270                  * bounce buffer and msg->actual_len will not be
 271                  * updated with the last xfer.
 272                  *
 273                  * We will also not process any remaning transfers in
 274                  * the message.
 275                  *
 276                  * First, stop the transfer and unmap the DMA buffers.
 277                  */
 278                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 279                 if (!msg->is_dma_mapped)
 280                         atmel_spi_dma_unmap_xfer(master, xfer);
 281
 282                 /* REVISIT: udelay in irq is unfriendly */
 283                 if (xfer->delay_usecs)
 284                         udelay(xfer->delay_usecs);
 285
 286                 dev_warn(master->cdev.dev, "fifo overrun (%u/%u remaining)\n",
 287                          spi_readl(as, TCR), spi_readl(as, RCR));
 288
 289                 /*
 290                  * Clean up DMA registers and make sure the data
 291                  * registers are empty.
 292                  */
 293                 spi_writel(as, RNCR, 0);
 294                 spi_writel(as, TNCR, 0);
 295                 spi_writel(as, RCR, 0);
 296                 spi_writel(as, TCR, 0);
 297                 for (timeout = 1000; timeout; timeout--)
 298                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
 299                                 break;
 300                 if (!timeout)
 301                         dev_warn(master->cdev.dev,
 302                                  "timeout waiting for TXEMPTY");
 303                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
 304                         spi_readl(as, RDR);
 305
 306                 /* Clear any overrun happening while cleaning up */
 307                 spi_readl(as, SR);
 308
 309                 atmel_spi_msg_done(master, as, msg, -EIO);
 310         } else if (pending & SPI_BIT(ENDRX)) {
 311                 ret = IRQ_HANDLED;
 312
 313                 spi_writel(as, IDR, pending);
 314
 315                 if (as->remaining_bytes == 0) {
 316                         msg->actual_length += xfer->len;
 317
 318                         if (!msg->is_dma_mapped)
 319                                 atmel_spi_dma_unmap_xfer(master, xfer);
 320
 321                         /* REVISIT: udelay in irq is unfriendly */
 322                         if (xfer->delay_usecs)
 323                                 udelay(xfer->delay_usecs);
 324
 325                         if (msg->transfers.prev == &xfer->transfer_list) {
 326                                 /* report completed message */
 327                                 atmel_spi_msg_done(master, as, msg, 0);
 328                         } else {
 329                                 if (xfer->cs_change) {
 330                                         cs_deactivate(msg->spi);
 331                                         udelay(1);
 332                                         cs_activate(msg->spi);
 333                                 }
 334
 335                                 /*
 336                                  * Not done yet. Submit the next transfer.
 337                                  *
 338                                  * FIXME handle protocol options for xfer
 339                                  */
 340                                 atmel_spi_next_xfer(master, msg);
 341                         }
 342                 } else {
 343                         /*
 344                          * Keep going, we still have data to send in
 345                          * the current transfer.
 346                          */
 347                         atmel_spi_next_xfer(master, msg);
 348                 }
 349         }
 350
 351         spin_unlock(&as->lock);
 352
 353         return ret;
 354 }
 355
 356 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 357
 358 static int atmel_spi_setup(struct spi_device *spi)
 359 {
 360         struct atmel_spi        *as;
 361         u32                     scbr, csr;
 362         unsigned int            bits = spi->bits_per_word;
 363         unsigned long           bus_hz, sck_hz;
 364         unsigned int            npcs_pin;
 365         int                     ret;
 366
 367         as = spi_master_get_devdata(spi->master);
 368
 369         if (as->stopping)
 370                 return -ESHUTDOWN;
 371
 372         if (spi->chip_select > spi->master->num_chipselect) {
 373                 dev_dbg(&spi->dev,
 374                                 "setup: invalid chipselect %u (%u defined)\n",
 375                                 spi->chip_select, spi->master->num_chipselect);
 376                 return -EINVAL;
 377         }
 378
 379         if (bits == 0)
 380                 bits = 8;
 381         if (bits < 8 || bits > 16) {
 382                 dev_dbg(&spi->dev,
 383                                 "setup: invalid bits_per_word %u (8 to 16)\n",
 384                                 bits);
 385                 return -EINVAL;
 386         }
 387
 388         if (spi->mode & ~MODEBITS) {
 389                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 390                         spi->mode & ~MODEBITS);
 391                 return -EINVAL;
 392         }
 393
 394         /* speed zero convention is used by some upper layers */
 395         bus_hz = clk_get_rate(as->clk);
 396         if (spi->max_speed_hz) {
 397                 /* assume div32/fdiv/mbz == 0 */
 398                 if (!as->new_1)
 399                         bus_hz /= 2;
 400                 scbr = ((bus_hz + spi->max_speed_hz - 1)
 401                         / spi->max_speed_hz);
 402                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
 403                         dev_dbg(&spi->dev, "setup: %d Hz too slow, scbr %u\n",
 404                                         spi->max_speed_hz, scbr);
 405                         return -EINVAL;
 406                 }
 407         } else
 408                 scbr = 0xff;
 409         sck_hz = bus_hz / scbr;
 410
 411         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
 412         if (spi->mode & SPI_CPOL)
 413                 csr |= SPI_BIT(CPOL);
 414         if (!(spi->mode & SPI_CPHA))
 415                 csr |= SPI_BIT(NCPHA);
 416
 417         /* TODO: DLYBS and DLYBCT */
 418         csr |= SPI_BF(DLYBS, 10);
 419         csr |= SPI_BF(DLYBCT, 10);
 420
 421         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
 422         npcs_pin = (unsigned int)spi->controller_data;
 423         if (!spi->controller_state) {
 424                 ret = gpio_request(npcs_pin, "spi_npcs");
 425                 if (ret)
 426                         return ret;
 427                 spi->controller_state = (void *)npcs_pin;
 428                 gpio_direction_output(npcs_pin);
 429         }
 430
 431         dev_dbg(&spi->dev,
 432                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 433                 sck_hz, bits, spi->mode, spi->chip_select, csr);
 434
 435         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 436
 437         return 0;
 438 }
 439
 440 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
 441 {
 442         struct atmel_spi        *as;
 443         struct spi_transfer     *xfer;
 444         unsigned long           flags;
 445         struct device           *controller = spi->master->cdev.dev;
 446
 447         as = spi_master_get_devdata(spi->master);
 448
 449         dev_dbg(controller, "new message %p submitted for %s\n",
 450                         msg, spi->dev.bus_id);
 451
 452         if (unlikely(list_empty(&msg->transfers)
 453                         || !spi->max_speed_hz))
 454                 return -EINVAL;
 455
 456         if (as->stopping)
 457                 return -ESHUTDOWN;
 458
 459         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 460                 if (!(xfer->tx_buf || xfer->rx_buf)) {
 461                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
 462                         return -EINVAL;
 463                 }
 464
 465                 /* FIXME implement these protocol options!! */
 466                 if (xfer->bits_per_word || xfer->speed_hz) {
 467                         dev_dbg(&spi->dev, "no protocol options yet\n");
 468                         return -ENOPROTOOPT;
 469                 }
 470         }
 471
 472         /* scrub dcache "early" */
 473         if (!msg->is_dma_mapped) {
 474                 list_for_each_entry(xfer, &msg->transfers, transfer_list)
 475                         atmel_spi_dma_map_xfer(as, xfer);
 476         }
 477
 478         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 479                 dev_dbg(controller,
 480                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 481                         xfer, xfer->len,
 482                         xfer->tx_buf, xfer->tx_dma,
 483                         xfer->rx_buf, xfer->rx_dma);
 484         }
 485
 486         msg->status = -EINPROGRESS;
 487         msg->actual_length = 0;
 488
 489         spin_lock_irqsave(&as->lock, flags);
 490         list_add_tail(&msg->queue, &as->queue);
 491         if (!as->current_transfer)
 492                 atmel_spi_next_message(spi->master);
 493         spin_unlock_irqrestore(&as->lock, flags);
 494
 495         return 0;
 496 }
 497
 498 static void atmel_spi_cleanup(struct spi_device *spi)
 499 {
 500         if (spi->controller_state)
 501                 gpio_free((unsigned int)spi->controller_data);
 502 }
 503
 504 /*-------------------------------------------------------------------------*/
 505
 506 static int __init atmel_spi_probe(struct platform_device *pdev)
 507 {
 508         struct resource         *regs;
 509         int                     irq;
 510         struct clk              *clk;
 511         int                     ret;
 512         struct spi_master       *master;
 513         struct atmel_spi        *as;
 514
 515         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 516         if (!regs)
 517                 return -ENXIO;
 518
 519         irq = platform_get_irq(pdev, 0);
 520         if (irq < 0)
 521                 return irq;
 522
 523         clk = clk_get(&pdev->dev, "spi_clk");
 524         if (IS_ERR(clk))
 525                 return PTR_ERR(clk);
 526
 527         /* setup spi core then atmel-specific driver state */
 528         ret = -ENOMEM;
 529         master = spi_alloc_master(&pdev->dev, sizeof *as);
 530         if (!master)
 531                 goto out_free;
 532
 533         master->bus_num = pdev->id;
 534         master->num_chipselect = 4;
 535         master->setup = atmel_spi_setup;
 536         master->transfer = atmel_spi_transfer;
 537         master->cleanup = atmel_spi_cleanup;
 538         platform_set_drvdata(pdev, master);
 539
 540         as = spi_master_get_devdata(master);
 541
 542         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
 543                                         &as->buffer_dma, GFP_KERNEL);
 544         if (!as->buffer)
 545                 goto out_free;
 546
 547         spin_lock_init(&as->lock);
 548         INIT_LIST_HEAD(&as->queue);
 549         as->pdev = pdev;
 550         as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
 551         if (!as->regs)
 552                 goto out_free_buffer;
 553         as->irq = irq;
 554         as->clk = clk;
 555 #ifdef CONFIG_ARCH_AT91
 556         if (!cpu_is_at91rm9200())
 557                 as->new_1 = 1;
 558 #endif
 559
 560         ret = request_irq(irq, atmel_spi_interrupt, 0,
 561                         pdev->dev.bus_id, master);
 562         if (ret)
 563                 goto out_unmap_regs;
 564
 565         /* Initialize the hardware */
 566         clk_enable(clk);
 567         spi_writel(as, CR, SPI_BIT(SWRST));
 568         spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
 569         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 570         spi_writel(as, CR, SPI_BIT(SPIEN));
 571
 572         /* go! */
 573         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
 574                         (unsigned long)regs->start, irq);
 575
 576         ret = spi_register_master(master);
 577         if (ret)
 578                 goto out_reset_hw;
 579
 580         return 0;
 581
 582 out_reset_hw:
 583         spi_writel(as, CR, SPI_BIT(SWRST));
 584         clk_disable(clk);
 585         free_irq(irq, master);
 586 out_unmap_regs:
 587         iounmap(as->regs);
 588 out_free_buffer:
 589         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 590                         as->buffer_dma);
 591 out_free:
 592         clk_put(clk);
 593         spi_master_put(master);
 594         return ret;
 595 }
 596
 597 static int __exit atmel_spi_remove(struct platform_device *pdev)
 598 {
 599         struct spi_master       *master = platform_get_drvdata(pdev);
 600         struct atmel_spi        *as = spi_master_get_devdata(master);
 601         struct spi_message      *msg;
 602
 603         /* reset the hardware and block queue progress */
 604         spin_lock_irq(&as->lock);
 605         as->stopping = 1;
 606         spi_writel(as, CR, SPI_BIT(SWRST));
 607         spi_readl(as, SR);
 608         spin_unlock_irq(&as->lock);
 609
 610         /* Terminate remaining queued transfers */
 611         list_for_each_entry(msg, &as->queue, queue) {
 612                 /* REVISIT unmapping the dma is a NOP on ARM and AVR32
 613                  * but we shouldn't depend on that...
 614                  */
 615                 msg->status = -ESHUTDOWN;
 616                 msg->complete(msg->context);
 617         }
 618
 619         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 620                         as->buffer_dma);
 621
 622         clk_disable(as->clk);
 623         clk_put(as->clk);
 624         free_irq(as->irq, master);
 625         iounmap(as->regs);
 626
 627         spi_unregister_master(master);
 628
 629         return 0;
 630 }
 631
 632 #ifdef  CONFIG_PM
 633
 634 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 635 {
 636         struct spi_master       *master = platform_get_drvdata(pdev);
 637         struct atmel_spi        *as = spi_master_get_devdata(master);
 638
 639         clk_disable(as->clk);
 640         return 0;
 641 }
 642
 643 static int atmel_spi_resume(struct platform_device *pdev)
 644 {
 645         struct spi_master       *master = platform_get_drvdata(pdev);
 646         struct atmel_spi        *as = spi_master_get_devdata(master);
 647
 648         clk_enable(as->clk);
 649         return 0;
 650 }
 651
 652 #else
 653 #define atmel_spi_suspend       NULL
 654 #define atmel_spi_resume        NULL
 655 #endif
 656
 657
 658 static struct platform_driver atmel_spi_driver = {
 659         .driver         = {
 660                 .name   = "atmel_spi",
 661                 .owner  = THIS_MODULE,
 662         },
 663         .suspend        = atmel_spi_suspend,
 664         .resume         = atmel_spi_resume,
 665         .remove         = __exit_p(atmel_spi_remove),
 666 };
 667
 668 static int __init atmel_spi_init(void)
 669 {
 670         return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
 671 }
 672 module_init(atmel_spi_init);
 673
 674 static void __exit atmel_spi_exit(void)
 675 {
 676         platform_driver_unregister(&atmel_spi_driver);
 677 }
 678 module_exit(atmel_spi_exit);
 679
 680 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
 681 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 682 MODULE_LICENSE("GPL");