git.oblomov.eu Git - linux-2.6/blob - 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 #include <asm/arch/cpu.h>
  26
  27 #include "atmel_spi.h"
  28
  29 /*
  30  * The core SPI transfer engine just talks to a register bank to set up
  31  * DMA transfers; transfer queue progress is driven by IRQs.  The clock
  32  * framework provides the base clock, subdivided for each spi_device.
  33  *
  34  * Newer controllers, marked with "new_1" flag, have:
  35  *  - CR.LASTXFER
  36  *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
  37  *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
  38  *  - SPI_CSRx.CSAAT
  39  *  - SPI_CSRx.SBCR allows faster clocking
  40  */
  41 struct atmel_spi {
  42         spinlock_t              lock;
  43
  44         void __iomem            *regs;
  45         int                     irq;
  46         struct clk              *clk;
  47         struct platform_device  *pdev;
  48         unsigned                new_1:1;
  49
  50         u8                      stopping;
  51         struct list_head        queue;
  52         struct spi_transfer     *current_transfer;
  53         unsigned long           remaining_bytes;
  54
  55         void                    *buffer;
  56         dma_addr_t              buffer_dma;
  57 };
  58
  59 #define BUFFER_SIZE             PAGE_SIZE
  60 #define INVALID_DMA_ADDRESS     0xffffffff
  61
  62 /*
  63  * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
  64  * they assume that spi slave device state will not change on deselect, so
  65  * that automagic deselection is OK.  Not so!  Workaround uses nCSx pins
  66  * as GPIOs; or newer controllers have CSAAT and friends.
  67  *
  68  * Since the CSAAT functionality is a bit weird on newer controllers
  69  * as well, we use GPIO to control nCSx pins on all controllers.
  70  */
  71
  72 static inline void cs_activate(struct spi_device *spi)
  73 {
  74         unsigned gpio = (unsigned) spi->controller_data;
  75         unsigned active = spi->mode & SPI_CS_HIGH;
  76
  77         dev_dbg(&spi->dev, "activate %u%s\n", gpio, active ? " (high)" : "");
  78         gpio_set_value(gpio, active);
  79 }
  80
  81 static inline void cs_deactivate(struct spi_device *spi)
  82 {
  83         unsigned gpio = (unsigned) spi->controller_data;
  84         unsigned active = spi->mode & SPI_CS_HIGH;
  85
  86         dev_dbg(&spi->dev, "DEactivate %u%s\n", gpio, active ? " (low)" : "");
  87         gpio_set_value(gpio, !active);
  88 }
  89
  90 /*
  91  * Submit next transfer for DMA.
  92  * lock is held, spi irq is blocked
  93  */
  94 static void atmel_spi_next_xfer(struct spi_master *master,
  95                                 struct spi_message *msg)
  96 {
  97         struct atmel_spi        *as = spi_master_get_devdata(master);
  98         struct spi_transfer     *xfer;
  99         u32                     len;
 100         dma_addr_t              tx_dma, rx_dma;
 101
 102         xfer = as->current_transfer;
 103         if (!xfer || as->remaining_bytes == 0) {
 104                 if (xfer)
 105                         xfer = list_entry(xfer->transfer_list.next,
 106                                         struct spi_transfer, transfer_list);
 107                 else
 108                         xfer = list_entry(msg->transfers.next,
 109                                         struct spi_transfer, transfer_list);
 110                 as->remaining_bytes = xfer->len;
 111                 as->current_transfer = xfer;
 112         }
 113
 114         len = as->remaining_bytes;
 115
 116         tx_dma = xfer->tx_dma;
 117         rx_dma = xfer->rx_dma;
 118
 119         /* use scratch buffer only when rx or tx data is unspecified */
 120         if (rx_dma == INVALID_DMA_ADDRESS) {
 121                 rx_dma = as->buffer_dma;
 122                 if (len > BUFFER_SIZE)
 123                         len = BUFFER_SIZE;
 124         }
 125         if (tx_dma == INVALID_DMA_ADDRESS) {
 126                 tx_dma = as->buffer_dma;
 127                 if (len > BUFFER_SIZE)
 128                         len = BUFFER_SIZE;
 129                 memset(as->buffer, 0, len);
 130                 dma_sync_single_for_device(&as->pdev->dev,
 131                                 as->buffer_dma, len, DMA_TO_DEVICE);
 132         }
 133
 134         spi_writel(as, RPR, rx_dma);
 135         spi_writel(as, TPR, tx_dma);
 136
 137         as->remaining_bytes -= len;
 138         if (msg->spi->bits_per_word > 8)
 139                 len >>= 1;
 140
 141         /* REVISIT: when xfer->delay_usecs == 0, the PDC "next transfer"
 142          * mechanism might help avoid the IRQ latency between transfers
 143          *
 144          * We're also waiting for ENDRX before we start the next
 145          * transfer because we need to handle some difficult timing
 146          * issues otherwise. If we wait for ENDTX in one transfer and
 147          * then starts waiting for ENDRX in the next, it's difficult
 148          * to tell the difference between the ENDRX interrupt we're
 149          * actually waiting for and the ENDRX interrupt of the
 150          * previous transfer.
 151          *
 152          * It should be doable, though. Just not now...
 153          */
 154         spi_writel(as, TNCR, 0);
 155         spi_writel(as, RNCR, 0);
 156         spi_writel(as, IER, SPI_BIT(ENDRX) | SPI_BIT(OVRES));
 157
 158         dev_dbg(&msg->spi->dev,
 159                 "  start xfer %p: len %u tx %p/%08x rx %p/%08x imr %03x\n",
 160                 xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
 161                 xfer->rx_buf, xfer->rx_dma, spi_readl(as, IMR));
 162
 163         spi_writel(as, TCR, len);
 164         spi_writel(as, RCR, len);
 165         spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
 166 }
 167
 168 static void atmel_spi_next_message(struct spi_master *master)
 169 {
 170         struct atmel_spi        *as = spi_master_get_devdata(master);
 171         struct spi_message      *msg;
 172         u32                     mr;
 173
 174         BUG_ON(as->current_transfer);
 175
 176         msg = list_entry(as->queue.next, struct spi_message, queue);
 177
 178         /* Select the chip */
 179         mr = spi_readl(as, MR);
 180         mr = SPI_BFINS(PCS, ~(1 << msg->spi->chip_select), mr);
 181         spi_writel(as, MR, mr);
 182         cs_activate(msg->spi);
 183
 184         atmel_spi_next_xfer(master, msg);
 185 }
 186
 187 static void
 188 atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
 189 {
 190         xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
 191         if (xfer->tx_buf)
 192                 xfer->tx_dma = dma_map_single(&as->pdev->dev,
 193                                 (void *) xfer->tx_buf, xfer->len,
 194                                 DMA_TO_DEVICE);
 195         if (xfer->rx_buf)
 196                 xfer->rx_dma = dma_map_single(&as->pdev->dev,
 197                                 xfer->rx_buf, xfer->len,
 198                                 DMA_FROM_DEVICE);
 199 }
 200
 201 static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
 202                                      struct spi_transfer *xfer)
 203 {
 204         if (xfer->tx_dma != INVALID_DMA_ADDRESS)
 205                 dma_unmap_single(master->cdev.dev, xfer->tx_dma,
 206                                  xfer->len, DMA_TO_DEVICE);
 207         if (xfer->rx_dma != INVALID_DMA_ADDRESS)
 208                 dma_unmap_single(master->cdev.dev, xfer->rx_dma,
 209                                  xfer->len, DMA_FROM_DEVICE);
 210 }
 211
 212 static void
 213 atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
 214                    struct spi_message *msg, int status)
 215 {
 216         cs_deactivate(msg->spi);
 217         list_del(&msg->queue);
 218         msg->status = status;
 219
 220         dev_dbg(master->cdev.dev,
 221                 "xfer complete: %u bytes transferred\n",
 222                 msg->actual_length);
 223
 224         spin_unlock(&as->lock);
 225         msg->complete(msg->context);
 226         spin_lock(&as->lock);
 227
 228         as->current_transfer = NULL;
 229
 230         /* continue if needed */
 231         if (list_empty(&as->queue) || as->stopping)
 232                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 233         else
 234                 atmel_spi_next_message(master);
 235 }
 236
 237 static irqreturn_t
 238 atmel_spi_interrupt(int irq, void *dev_id)
 239 {
 240         struct spi_master       *master = dev_id;
 241         struct atmel_spi        *as = spi_master_get_devdata(master);
 242         struct spi_message      *msg;
 243         struct spi_transfer     *xfer;
 244         u32                     status, pending, imr;
 245         int                     ret = IRQ_NONE;
 246
 247         spin_lock(&as->lock);
 248
 249         xfer = as->current_transfer;
 250         msg = list_entry(as->queue.next, struct spi_message, queue);
 251
 252         imr = spi_readl(as, IMR);
 253         status = spi_readl(as, SR);
 254         pending = status & imr;
 255
 256         if (pending & SPI_BIT(OVRES)) {
 257                 int timeout;
 258
 259                 ret = IRQ_HANDLED;
 260
 261                 spi_writel(as, IDR, (SPI_BIT(ENDTX) | SPI_BIT(ENDRX)
 262                                      | SPI_BIT(OVRES)));
 263
 264                 /*
 265                  * When we get an overrun, we disregard the current
 266                  * transfer. Data will not be copied back from any
 267                  * bounce buffer and msg->actual_len will not be
 268                  * updated with the last xfer.
 269                  *
 270                  * We will also not process any remaning transfers in
 271                  * the message.
 272                  *
 273                  * First, stop the transfer and unmap the DMA buffers.
 274                  */
 275                 spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 276                 if (!msg->is_dma_mapped)
 277                         atmel_spi_dma_unmap_xfer(master, xfer);
 278
 279                 /* REVISIT: udelay in irq is unfriendly */
 280                 if (xfer->delay_usecs)
 281                         udelay(xfer->delay_usecs);
 282
 283                 dev_warn(master->cdev.dev, "fifo overrun (%u/%u remaining)\n",
 284                          spi_readl(as, TCR), spi_readl(as, RCR));
 285
 286                 /*
 287                  * Clean up DMA registers and make sure the data
 288                  * registers are empty.
 289                  */
 290                 spi_writel(as, RNCR, 0);
 291                 spi_writel(as, TNCR, 0);
 292                 spi_writel(as, RCR, 0);
 293                 spi_writel(as, TCR, 0);
 294                 for (timeout = 1000; timeout; timeout--)
 295                         if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
 296                                 break;
 297                 if (!timeout)
 298                         dev_warn(master->cdev.dev,
 299                                  "timeout waiting for TXEMPTY");
 300                 while (spi_readl(as, SR) & SPI_BIT(RDRF))
 301                         spi_readl(as, RDR);
 302
 303                 /* Clear any overrun happening while cleaning up */
 304                 spi_readl(as, SR);
 305
 306                 atmel_spi_msg_done(master, as, msg, -EIO);
 307         } else if (pending & SPI_BIT(ENDRX)) {
 308                 ret = IRQ_HANDLED;
 309
 310                 spi_writel(as, IDR, pending);
 311
 312                 if (as->remaining_bytes == 0) {
 313                         msg->actual_length += xfer->len;
 314
 315                         if (!msg->is_dma_mapped)
 316                                 atmel_spi_dma_unmap_xfer(master, xfer);
 317
 318                         /* REVISIT: udelay in irq is unfriendly */
 319                         if (xfer->delay_usecs)
 320                                 udelay(xfer->delay_usecs);
 321
 322                         if (msg->transfers.prev == &xfer->transfer_list) {
 323                                 /* report completed message */
 324                                 atmel_spi_msg_done(master, as, msg, 0);
 325                         } else {
 326                                 if (xfer->cs_change) {
 327                                         cs_deactivate(msg->spi);
 328                                         udelay(1);
 329                                         cs_activate(msg->spi);
 330                                 }
 331
 332                                 /*
 333                                  * Not done yet. Submit the next transfer.
 334                                  *
 335                                  * FIXME handle protocol options for xfer
 336                                  */
 337                                 atmel_spi_next_xfer(master, msg);
 338                         }
 339                 } else {
 340                         /*
 341                          * Keep going, we still have data to send in
 342                          * the current transfer.
 343                          */
 344                         atmel_spi_next_xfer(master, msg);
 345                 }
 346         }
 347
 348         spin_unlock(&as->lock);
 349
 350         return ret;
 351 }
 352
 353 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 354
 355 static int atmel_spi_setup(struct spi_device *spi)
 356 {
 357         struct atmel_spi        *as;
 358         u32                     scbr, csr;
 359         unsigned int            bits = spi->bits_per_word;
 360         unsigned long           bus_hz, sck_hz;
 361         unsigned int            npcs_pin;
 362         int                     ret;
 363
 364         as = spi_master_get_devdata(spi->master);
 365
 366         if (as->stopping)
 367                 return -ESHUTDOWN;
 368
 369         if (spi->chip_select > spi->master->num_chipselect) {
 370                 dev_dbg(&spi->dev,
 371                                 "setup: invalid chipselect %u (%u defined)\n",
 372                                 spi->chip_select, spi->master->num_chipselect);
 373                 return -EINVAL;
 374         }
 375
 376         if (bits == 0)
 377                 bits = 8;
 378         if (bits < 8 || bits > 16) {
 379                 dev_dbg(&spi->dev,
 380                                 "setup: invalid bits_per_word %u (8 to 16)\n",
 381                                 bits);
 382                 return -EINVAL;
 383         }
 384
 385         if (spi->mode & ~MODEBITS) {
 386                 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 387                         spi->mode & ~MODEBITS);
 388                 return -EINVAL;
 389         }
 390
 391         /* speed zero convention is used by some upper layers */
 392         bus_hz = clk_get_rate(as->clk);
 393         if (spi->max_speed_hz) {
 394                 /* assume div32/fdiv/mbz == 0 */
 395                 if (!as->new_1)
 396                         bus_hz /= 2;
 397                 scbr = ((bus_hz + spi->max_speed_hz - 1)
 398                         / spi->max_speed_hz);
 399                 if (scbr >= (1 << SPI_SCBR_SIZE)) {
 400                         dev_dbg(&spi->dev, "setup: %d Hz too slow, scbr %u\n",
 401                                         spi->max_speed_hz, scbr);
 402                         return -EINVAL;
 403                 }
 404         } else
 405                 scbr = 0xff;
 406         sck_hz = bus_hz / scbr;
 407
 408         csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
 409         if (spi->mode & SPI_CPOL)
 410                 csr |= SPI_BIT(CPOL);
 411         if (!(spi->mode & SPI_CPHA))
 412                 csr |= SPI_BIT(NCPHA);
 413
 414         /* TODO: DLYBS and DLYBCT */
 415         csr |= SPI_BF(DLYBS, 10);
 416         csr |= SPI_BF(DLYBCT, 10);
 417
 418         /* chipselect must have been muxed as GPIO (e.g. in board setup) */
 419         npcs_pin = (unsigned int)spi->controller_data;
 420         if (!spi->controller_state) {
 421                 ret = gpio_request(npcs_pin, "spi_npcs");
 422                 if (ret)
 423                         return ret;
 424                 spi->controller_state = (void *)npcs_pin;
 425                 gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
 426         }
 427
 428         dev_dbg(&spi->dev,
 429                 "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 430                 sck_hz, bits, spi->mode, spi->chip_select, csr);
 431
 432         spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 433
 434         return 0;
 435 }
 436
 437 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
 438 {
 439         struct atmel_spi        *as;
 440         struct spi_transfer     *xfer;
 441         unsigned long           flags;
 442         struct device           *controller = spi->master->cdev.dev;
 443
 444         as = spi_master_get_devdata(spi->master);
 445
 446         dev_dbg(controller, "new message %p submitted for %s\n",
 447                         msg, spi->dev.bus_id);
 448
 449         if (unlikely(list_empty(&msg->transfers)
 450                         || !spi->max_speed_hz))
 451                 return -EINVAL;
 452
 453         if (as->stopping)
 454                 return -ESHUTDOWN;
 455
 456         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 457                 if (!(xfer->tx_buf || xfer->rx_buf)) {
 458                         dev_dbg(&spi->dev, "missing rx or tx buf\n");
 459                         return -EINVAL;
 460                 }
 461
 462                 /* FIXME implement these protocol options!! */
 463                 if (xfer->bits_per_word || xfer->speed_hz) {
 464                         dev_dbg(&spi->dev, "no protocol options yet\n");
 465                         return -ENOPROTOOPT;
 466                 }
 467         }
 468
 469         /* scrub dcache "early" */
 470         if (!msg->is_dma_mapped) {
 471                 list_for_each_entry(xfer, &msg->transfers, transfer_list)
 472                         atmel_spi_dma_map_xfer(as, xfer);
 473         }
 474
 475         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 476                 dev_dbg(controller,
 477                         "  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
 478                         xfer, xfer->len,
 479                         xfer->tx_buf, xfer->tx_dma,
 480                         xfer->rx_buf, xfer->rx_dma);
 481         }
 482
 483         msg->status = -EINPROGRESS;
 484         msg->actual_length = 0;
 485
 486         spin_lock_irqsave(&as->lock, flags);
 487         list_add_tail(&msg->queue, &as->queue);
 488         if (!as->current_transfer)
 489                 atmel_spi_next_message(spi->master);
 490         spin_unlock_irqrestore(&as->lock, flags);
 491
 492         return 0;
 493 }
 494
 495 static void atmel_spi_cleanup(struct spi_device *spi)
 496 {
 497         if (spi->controller_state)
 498                 gpio_free((unsigned int)spi->controller_data);
 499 }
 500
 501 /*-------------------------------------------------------------------------*/
 502
 503 static int __init atmel_spi_probe(struct platform_device *pdev)
 504 {
 505         struct resource         *regs;
 506         int                     irq;
 507         struct clk              *clk;
 508         int                     ret;
 509         struct spi_master       *master;
 510         struct atmel_spi        *as;
 511
 512         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 513         if (!regs)
 514                 return -ENXIO;
 515
 516         irq = platform_get_irq(pdev, 0);
 517         if (irq < 0)
 518                 return irq;
 519
 520         clk = clk_get(&pdev->dev, "spi_clk");
 521         if (IS_ERR(clk))
 522                 return PTR_ERR(clk);
 523
 524         /* setup spi core then atmel-specific driver state */
 525         ret = -ENOMEM;
 526         master = spi_alloc_master(&pdev->dev, sizeof *as);
 527         if (!master)
 528                 goto out_free;
 529
 530         master->bus_num = pdev->id;
 531         master->num_chipselect = 4;
 532         master->setup = atmel_spi_setup;
 533         master->transfer = atmel_spi_transfer;
 534         master->cleanup = atmel_spi_cleanup;
 535         platform_set_drvdata(pdev, master);
 536
 537         as = spi_master_get_devdata(master);
 538
 539         as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
 540                                         &as->buffer_dma, GFP_KERNEL);
 541         if (!as->buffer)
 542                 goto out_free;
 543
 544         spin_lock_init(&as->lock);
 545         INIT_LIST_HEAD(&as->queue);
 546         as->pdev = pdev;
 547         as->regs = ioremap(regs->start, (regs->end - regs->start) + 1);
 548         if (!as->regs)
 549                 goto out_free_buffer;
 550         as->irq = irq;
 551         as->clk = clk;
 552         if (!cpu_is_at91rm9200())
 553                 as->new_1 = 1;
 554
 555         ret = request_irq(irq, atmel_spi_interrupt, 0,
 556                         pdev->dev.bus_id, master);
 557         if (ret)
 558                 goto out_unmap_regs;
 559
 560         /* Initialize the hardware */
 561         clk_enable(clk);
 562         spi_writel(as, CR, SPI_BIT(SWRST));
 563         spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
 564         spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
 565         spi_writel(as, CR, SPI_BIT(SPIEN));
 566
 567         /* go! */
 568         dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
 569                         (unsigned long)regs->start, irq);
 570
 571         ret = spi_register_master(master);
 572         if (ret)
 573                 goto out_reset_hw;
 574
 575         return 0;
 576
 577 out_reset_hw:
 578         spi_writel(as, CR, SPI_BIT(SWRST));
 579         clk_disable(clk);
 580         free_irq(irq, master);
 581 out_unmap_regs:
 582         iounmap(as->regs);
 583 out_free_buffer:
 584         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 585                         as->buffer_dma);
 586 out_free:
 587         clk_put(clk);
 588         spi_master_put(master);
 589         return ret;
 590 }
 591
 592 static int __exit atmel_spi_remove(struct platform_device *pdev)
 593 {
 594         struct spi_master       *master = platform_get_drvdata(pdev);
 595         struct atmel_spi        *as = spi_master_get_devdata(master);
 596         struct spi_message      *msg;
 597
 598         /* reset the hardware and block queue progress */
 599         spin_lock_irq(&as->lock);
 600         as->stopping = 1;
 601         spi_writel(as, CR, SPI_BIT(SWRST));
 602         spi_readl(as, SR);
 603         spin_unlock_irq(&as->lock);
 604
 605         /* Terminate remaining queued transfers */
 606         list_for_each_entry(msg, &as->queue, queue) {
 607                 /* REVISIT unmapping the dma is a NOP on ARM and AVR32
 608                  * but we shouldn't depend on that...
 609                  */
 610                 msg->status = -ESHUTDOWN;
 611                 msg->complete(msg->context);
 612         }
 613
 614         dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
 615                         as->buffer_dma);
 616
 617         clk_disable(as->clk);
 618         clk_put(as->clk);
 619         free_irq(as->irq, master);
 620         iounmap(as->regs);
 621
 622         spi_unregister_master(master);
 623
 624         return 0;
 625 }
 626
 627 #ifdef  CONFIG_PM
 628
 629 static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
 630 {
 631         struct spi_master       *master = platform_get_drvdata(pdev);
 632         struct atmel_spi        *as = spi_master_get_devdata(master);
 633
 634         clk_disable(as->clk);
 635         return 0;
 636 }
 637
 638 static int atmel_spi_resume(struct platform_device *pdev)
 639 {
 640         struct spi_master       *master = platform_get_drvdata(pdev);
 641         struct atmel_spi        *as = spi_master_get_devdata(master);
 642
 643         clk_enable(as->clk);
 644         return 0;
 645 }
 646
 647 #else
 648 #define atmel_spi_suspend       NULL
 649 #define atmel_spi_resume        NULL
 650 #endif
 651
 652
 653 static struct platform_driver atmel_spi_driver = {
 654         .driver         = {
 655                 .name   = "atmel_spi",
 656                 .owner  = THIS_MODULE,
 657         },
 658         .suspend        = atmel_spi_suspend,
 659         .resume         = atmel_spi_resume,
 660         .remove         = __exit_p(atmel_spi_remove),
 661 };
 662
 663 static int __init atmel_spi_init(void)
 664 {
 665         return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe);
 666 }
 667 module_init(atmel_spi_init);
 668
 669 static void __exit atmel_spi_exit(void)
 670 {
 671         platform_driver_unregister(&atmel_spi_driver);
 672 }
 673 module_exit(atmel_spi_exit);
 674
 675 MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
 676 MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
 677 MODULE_LICENSE("GPL");