drivers/spi/spi_tegra.c

   1 /*
   2  * Driver for Nvidia TEGRA spi controller.
   3  *
   4  * Copyright (C) 2010 Google, Inc.
   5  *
   6  * Author:
   7  *     Erik Gilling <konkers@android.com>
   8  *
   9  * This software is licensed under the terms of the GNU General Public
  10  * License version 2, as published by the Free Software Foundation, and
  11  * may be copied, distributed, and modified under those terms.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/init.h>
  22 #include <linux/err.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/io.h>
  25 #include <linux/dma-mapping.h>
  26 #include <linux/dmapool.h>
  27 #include <linux/clk.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/delay.h>
  30
  31 #include <linux/spi/spi.h>
  32
  33 #include <mach/dma.h>
  34
  35 #define SLINK_COMMAND           0x000
  36 #define   SLINK_BIT_LENGTH(x)           (((x) & 0x1f) << 0)
  37 #define   SLINK_WORD_SIZE(x)            (((x) & 0x1f) << 5)
  38 #define   SLINK_BOTH_EN                 (1 << 10)
  39 #define   SLINK_CS_SW                   (1 << 11)
  40 #define   SLINK_CS_VALUE                (1 << 12)
  41 #define   SLINK_CS_POLARITY             (1 << 13)
  42 #define   SLINK_IDLE_SDA_DRIVE_LOW      (0 << 16)
  43 #define   SLINK_IDLE_SDA_DRIVE_HIGH     (1 << 16)
  44 #define   SLINK_IDLE_SDA_PULL_LOW       (2 << 16)
  45 #define   SLINK_IDLE_SDA_PULL_HIGH      (3 << 16)
  46 #define   SLINK_IDLE_SDA_MASK           (3 << 16)
  47 #define   SLINK_CS_POLARITY1            (1 << 20)
  48 #define   SLINK_CK_SDA                  (1 << 21)
  49 #define   SLINK_CS_POLARITY2            (1 << 22)
  50 #define   SLINK_CS_POLARITY3            (1 << 23)
  51 #define   SLINK_IDLE_SCLK_DRIVE_LOW     (0 << 24)
  52 #define   SLINK_IDLE_SCLK_DRIVE_HIGH    (1 << 24)
  53 #define   SLINK_IDLE_SCLK_PULL_LOW      (2 << 24)
  54 #define   SLINK_IDLE_SCLK_PULL_HIGH     (3 << 24)
  55 #define   SLINK_IDLE_SCLK_MASK          (3 << 24)
  56 #define   SLINK_M_S                     (1 << 28)
  57 #define   SLINK_WAIT                    (1 << 29)
  58 #define   SLINK_GO                      (1 << 30)
  59 #define   SLINK_ENB                     (1 << 31)
  60
  61 #define SLINK_COMMAND2          0x004
  62 #define   SLINK_LSBFE                   (1 << 0)
  63 #define   SLINK_SSOE                    (1 << 1)
  64 #define   SLINK_SPIE                    (1 << 4)
  65 #define   SLINK_BIDIROE                 (1 << 6)
  66 #define   SLINK_MODFEN                  (1 << 7)
  67 #define   SLINK_INT_SIZE(x)             (((x) & 0x1f) << 8)
  68 #define   SLINK_CS_ACTIVE_BETWEEN       (1 << 17)
  69 #define   SLINK_SS_EN_CS(x)             (((x) & 0x3) << 18)
  70 #define   SLINK_SS_SETUP(x)             (((x) & 0x3) << 20)
  71 #define   SLINK_FIFO_REFILLS_0          (0 << 22)
  72 #define   SLINK_FIFO_REFILLS_1          (1 << 22)
  73 #define   SLINK_FIFO_REFILLS_2          (2 << 22)
  74 #define   SLINK_FIFO_REFILLS_3          (3 << 22)
  75 #define   SLINK_FIFO_REFILLS_MASK       (3 << 22)
  76 #define   SLINK_WAIT_PACK_INT(x)        (((x) & 0x7) << 26)
  77 #define   SLINK_SPC0                    (1 << 29)
  78 #define   SLINK_TXEN                    (1 << 30)
  79 #define   SLINK_RXEN                    (1 << 31)
  80
  81 #define SLINK_STATUS            0x008
  82 #define   SLINK_COUNT(val)              (((val) >> 0) & 0x1f)
  83 #define   SLINK_WORD(val)               (((val) >> 5) & 0x1f)
  84 #define   SLINK_BLK_CNT(val)            (((val) >> 0) & 0xffff)
  85 #define   SLINK_MODF                    (1 << 16)
  86 #define   SLINK_RX_UNF                  (1 << 18)
  87 #define   SLINK_TX_OVF                  (1 << 19)
  88 #define   SLINK_TX_FULL                 (1 << 20)
  89 #define   SLINK_TX_EMPTY                (1 << 21)
  90 #define   SLINK_RX_FULL                 (1 << 22)
  91 #define   SLINK_RX_EMPTY                (1 << 23)
  92 #define   SLINK_TX_UNF                  (1 << 24)
  93 #define   SLINK_RX_OVF                  (1 << 25)
  94 #define   SLINK_TX_FLUSH                (1 << 26)
  95 #define   SLINK_RX_FLUSH                (1 << 27)
  96 #define   SLINK_SCLK                    (1 << 28)
  97 #define   SLINK_ERR                     (1 << 29)
  98 #define   SLINK_RDY                     (1 << 30)
  99 #define   SLINK_BSY                     (1 << 31)
 100
 101 #define SLINK_MAS_DATA          0x010
 102 #define SLINK_SLAVE_DATA        0x014
 103
 104 #define SLINK_DMA_CTL           0x018
 105 #define   SLINK_DMA_BLOCK_SIZE(x)       (((x) & 0xffff) << 0)
 106 #define   SLINK_TX_TRIG_1               (0 << 16)
 107 #define   SLINK_TX_TRIG_4               (1 << 16)
 108 #define   SLINK_TX_TRIG_8               (2 << 16)
 109 #define   SLINK_TX_TRIG_16              (3 << 16)
 110 #define   SLINK_TX_TRIG_MASK            (3 << 16)
 111 #define   SLINK_RX_TRIG_1               (0 << 18)
 112 #define   SLINK_RX_TRIG_4               (1 << 18)
 113 #define   SLINK_RX_TRIG_8               (2 << 18)
 114 #define   SLINK_RX_TRIG_16              (3 << 18)
 115 #define   SLINK_RX_TRIG_MASK            (3 << 18)
 116 #define   SLINK_PACKED                  (1 << 20)
 117 #define   SLINK_PACK_SIZE_4             (0 << 21)
 118 #define   SLINK_PACK_SIZE_8             (1 << 21)
 119 #define   SLINK_PACK_SIZE_16            (2 << 21)
 120 #define   SLINK_PACK_SIZE_32            (3 << 21)
 121 #define   SLINK_PACK_SIZE_MASK          (3 << 21)
 122 #define   SLINK_IE_TXC                  (1 << 26)
 123 #define   SLINK_IE_RXC                  (1 << 27)
 124 #define   SLINK_DMA_EN                  (1 << 31)
 125
 126 #define SLINK_STATUS2           0x01c
 127 #define   SLINK_TX_FIFO_EMPTY_COUNT(val)        (((val) & 0x3f) >> 0)
 128 #define   SLINK_RX_FIFO_FULL_COUNT(val)         (((val) & 0x3f) >> 16)
 129
 130 #define SLINK_TX_FIFO           0x100
 131 #define SLINK_RX_FIFO           0x180
 132
 133 static const unsigned long spi_tegra_req_sels[] = {
 134         TEGRA_DMA_REQ_SEL_SL2B1,
 135         TEGRA_DMA_REQ_SEL_SL2B2,
 136         TEGRA_DMA_REQ_SEL_SL2B3,
 137         TEGRA_DMA_REQ_SEL_SL2B4,
 138 };
 139
 140 #define BB_LEN                  32
 141
 142 struct spi_tegra_data {
 143         struct spi_master       *master;
 144         struct platform_device  *pdev;
 145         spinlock_t              lock;
 146
 147         struct clk              *clk;
 148         void __iomem            *base;
 149         unsigned long           phys;
 150
 151         u32                     cur_speed;
 152
 153         struct list_head        queue;
 154         struct spi_transfer     *cur;
 155         unsigned                cur_pos;
 156         unsigned                cur_len;
 157         unsigned                cur_bytes_per_word;
 158
 159         /* The tegra spi controller has a bug which causes the first word
 160          * in PIO transactions to be garbage.  Since packed DMA transactions
 161          * require transfers to be 4 byte aligned we need a bounce buffer
 162          * for the generic case.
 163          */
 164         struct tegra_dma_req    rx_dma_req;
 165         struct tegra_dma_channel *rx_dma;
 166         u32                     *rx_bb;
 167         dma_addr_t              rx_bb_phys;
 168 };
 169
 170
 171 static inline unsigned long spi_tegra_readl(struct spi_tegra_data *tspi,
 172                                             unsigned long reg)
 173 {
 174         return readl(tspi->base + reg);
 175 }
 176
 177 static inline void spi_tegra_writel(struct spi_tegra_data *tspi,
 178                                     unsigned long val,
 179                                     unsigned long reg)
 180 {
 181         writel(val, tspi->base + reg);
 182 }
 183
 184 static void spi_tegra_go(struct spi_tegra_data *tspi)
 185 {
 186         unsigned long val;
 187
 188         wmb();
 189
 190         val = spi_tegra_readl(tspi, SLINK_DMA_CTL);
 191         val &= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN;
 192         val |= SLINK_DMA_BLOCK_SIZE(tspi->rx_dma_req.size / 4 - 1);
 193         spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
 194
 195         tegra_dma_enqueue_req(tspi->rx_dma, &tspi->rx_dma_req);
 196
 197         val |= SLINK_DMA_EN;
 198         spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
 199 }
 200
 201 static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data *tspi,
 202                                   struct spi_transfer *t)
 203 {
 204         unsigned len = min(t->len - tspi->cur_pos, BB_LEN *
 205                            tspi->cur_bytes_per_word);
 206         u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_pos;
 207         int i, j;
 208         unsigned long val;
 209
 210         val = spi_tegra_readl(tspi, SLINK_COMMAND);
 211         val &= ~SLINK_WORD_SIZE(~0);
 212         val |= SLINK_WORD_SIZE(len / tspi->cur_bytes_per_word - 1);
 213         spi_tegra_writel(tspi, val, SLINK_COMMAND);
 214
 215         for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
 216                 val = 0;
 217                 for (j = 0; j < tspi->cur_bytes_per_word; j++)
 218                         val |= tx_buf[i + j] << j * 8;
 219
 220                 spi_tegra_writel(tspi, val, SLINK_TX_FIFO);
 221         }
 222
 223         tspi->rx_dma_req.size = len / tspi->cur_bytes_per_word * 4;
 224
 225         return len;
 226 }
 227
 228 static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data *tspi,
 229                                   struct spi_transfer *t)
 230 {
 231         unsigned len = tspi->cur_len;
 232         u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_pos;
 233         int i, j;
 234         unsigned long val;
 235
 236         for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
 237                 val = tspi->rx_bb[i / tspi->cur_bytes_per_word];
 238                 for (j = 0; j < tspi->cur_bytes_per_word; j++)
 239                         rx_buf[i + j] = (val >> (j * 8)) & 0xff;
 240         }
 241
 242         return len;
 243 }
 244
 245 static void spi_tegra_start_transfer(struct spi_device *spi,
 246                                     struct spi_transfer *t)
 247 {
 248         struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
 249         u32 speed;
 250         u8 bits_per_word;
 251         unsigned long val;
 252
 253         speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
 254         bits_per_word = t->bits_per_word ? t->bits_per_word  :
 255                 spi->bits_per_word;
 256
 257         tspi->cur_bytes_per_word = (bits_per_word - 1) / 8 + 1;
 258
 259         if (speed != tspi->cur_speed)
 260                 clk_set_rate(tspi->clk, speed);
 261
 262         if (tspi->cur_speed == 0)
 263                 clk_enable(tspi->clk);
 264
 265         tspi->cur_speed = speed;
 266
 267         val = spi_tegra_readl(tspi, SLINK_COMMAND2);
 268         val &= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN | SLINK_TXEN;
 269         if (t->rx_buf)
 270                 val |= SLINK_RXEN;
 271         if (t->tx_buf)
 272                 val |= SLINK_TXEN;
 273         val |= SLINK_SS_EN_CS(spi->chip_select);
 274         val |= SLINK_SPIE;
 275         spi_tegra_writel(tspi, val, SLINK_COMMAND2);
 276
 277         val = spi_tegra_readl(tspi, SLINK_COMMAND);
 278         val &= ~SLINK_BIT_LENGTH(~0);
 279         val |= SLINK_BIT_LENGTH(bits_per_word - 1);
 280
 281         /* FIXME: should probably control CS manually so that we can be sure
 282          * it does not go low between transfer and to support delay_usecs
 283          * correctly.
 284          */
 285         val &= ~SLINK_IDLE_SCLK_MASK & ~SLINK_CK_SDA & ~SLINK_CS_SW;
 286
 287         if (spi->mode & SPI_CPHA)
 288                 val |= SLINK_CK_SDA;
 289
 290         if (spi->mode & SPI_CPOL)
 291                 val |= SLINK_IDLE_SCLK_DRIVE_HIGH;
 292         else
 293                 val |= SLINK_IDLE_SCLK_DRIVE_LOW;
 294
 295         val |= SLINK_M_S;
 296
 297         spi_tegra_writel(tspi, val, SLINK_COMMAND);
 298
 299         spi_tegra_writel(tspi, SLINK_RX_FLUSH | SLINK_TX_FLUSH, SLINK_STATUS);
 300
 301         tspi->cur = t;
 302         tspi->cur_pos = 0;
 303         tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, t);
 304
 305         spi_tegra_go(tspi);
 306 }
 307
 308 static void spi_tegra_start_message(struct spi_device *spi,
 309                                     struct spi_message *m)
 310 {
 311         struct spi_transfer *t;
 312
 313         m->actual_length = 0;
 314         m->status = 0;
 315
 316         t = list_first_entry(&m->transfers, struct spi_transfer, transfer_list);
 317         spi_tegra_start_transfer(spi, t);
 318 }
 319
 320 static void tegra_spi_rx_dma_complete(struct tegra_dma_req *req)
 321 {
 322         struct spi_tegra_data *tspi = req->dev;
 323         unsigned long flags;
 324         struct spi_message *m;
 325         struct spi_device *spi;
 326         int timeout = 0;
 327         unsigned long val;
 328
 329         /* the SPI controller may come back with both the BSY and RDY bits
 330          * set.  In this case we need to wait for the BSY bit to clear so
 331          * that we are sure the DMA is finished.  1000 reads was empirically
 332          * determined to be long enough.
 333          */
 334         while (timeout++ < 1000) {
 335                 if (!(spi_tegra_readl(tspi, SLINK_STATUS) & SLINK_BSY))
 336                         break;
 337         }
 338
 339         spin_lock_irqsave(&tspi->lock, flags);
 340
 341         val = spi_tegra_readl(tspi, SLINK_STATUS);
 342         val |= SLINK_RDY;
 343         spi_tegra_writel(tspi, val, SLINK_STATUS);
 344
 345         m = list_first_entry(&tspi->queue, struct spi_message, queue);
 346
 347         if (timeout >= 1000)
 348                 m->status = -EIO;
 349
 350         spi = m->state;
 351
 352         tspi->cur_pos += spi_tegra_drain_rx_fifo(tspi, tspi->cur);
 353         m->actual_length += tspi->cur_pos;
 354
 355         if (tspi->cur_pos < tspi->cur->len) {
 356                 tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, tspi->cur);
 357                 spi_tegra_go(tspi);
 358         } else if (!list_is_last(&tspi->cur->transfer_list,
 359                                  &m->transfers)) {
 360                 tspi->cur =  list_first_entry(&tspi->cur->transfer_list,
 361                                               struct spi_transfer,
 362                                               transfer_list);
 363                 spi_tegra_start_transfer(spi, tspi->cur);
 364         } else {
 365                 list_del(&m->queue);
 366
 367                 m->complete(m->context);
 368
 369                 if (!list_empty(&tspi->queue)) {
 370                         m = list_first_entry(&tspi->queue, struct spi_message,
 371                                              queue);
 372                         spi = m->state;
 373                         spi_tegra_start_message(spi, m);
 374                 } else {
 375                         clk_disable(tspi->clk);
 376                         tspi->cur_speed = 0;
 377                 }
 378         }
 379
 380         spin_unlock_irqrestore(&tspi->lock, flags);
 381 }
 382
 383 static int spi_tegra_setup(struct spi_device *spi)
 384 {
 385         struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
 386         unsigned long cs_bit;
 387         unsigned long val;
 388         unsigned long flags;
 389
 390         dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
 391                 spi->bits_per_word,
 392                 spi->mode & SPI_CPOL ? "" : "~",
 393                 spi->mode & SPI_CPHA ? "" : "~",
 394                 spi->max_speed_hz);
 395
 396
 397         switch (spi->chip_select) {
 398         case 0:
 399                 cs_bit = SLINK_CS_POLARITY;
 400                 break;
 401
 402         case 1:
 403                 cs_bit = SLINK_CS_POLARITY1;
 404                 break;
 405
 406         case 2:
 407                 cs_bit = SLINK_CS_POLARITY2;
 408                 break;
 409
 410         case 4:
 411                 cs_bit = SLINK_CS_POLARITY3;
 412                 break;
 413
 414         default:
 415                 return -EINVAL;
 416         }
 417
 418         spin_lock_irqsave(&tspi->lock, flags);
 419
 420         val = spi_tegra_readl(tspi, SLINK_COMMAND);
 421         if (spi->mode & SPI_CS_HIGH)
 422                 val |= cs_bit;
 423         else
 424                 val &= ~cs_bit;
 425         spi_tegra_writel(tspi, val, SLINK_COMMAND);
 426
 427         spin_unlock_irqrestore(&tspi->lock, flags);
 428
 429         return 0;
 430 }
 431
 432 static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m)
 433 {
 434         struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
 435         struct spi_transfer *t;
 436         unsigned long flags;
 437         int was_empty;
 438
 439         if (list_empty(&m->transfers) || !m->complete)
 440                 return -EINVAL;
 441
 442         list_for_each_entry(t, &m->transfers, transfer_list) {
 443                 if (t->bits_per_word < 0 || t->bits_per_word > 32)
 444                         return -EINVAL;
 445
 446                 if (t->len == 0)
 447                         return -EINVAL;
 448
 449                 if (!t->rx_buf && !t->tx_buf)
 450                         return -EINVAL;
 451         }
 452
 453         m->state = spi;
 454
 455         spin_lock_irqsave(&tspi->lock, flags);
 456         was_empty = list_empty(&tspi->queue);
 457         list_add_tail(&m->queue, &tspi->queue);
 458
 459         if (was_empty)
 460                 spi_tegra_start_message(spi, m);
 461
 462         spin_unlock_irqrestore(&tspi->lock, flags);
 463
 464         return 0;
 465 }
 466
 467 static int __init spi_tegra_probe(struct platform_device *pdev)
 468 {
 469         struct spi_master       *master;
 470         struct spi_tegra_data   *tspi;
 471         struct resource         *r;
 472         int ret;
 473
 474         master = spi_alloc_master(&pdev->dev, sizeof *tspi);
 475         if (master == NULL) {
 476                 dev_err(&pdev->dev, "master allocation failed\n");
 477                 return -ENOMEM;
 478         }
 479
 480         /* the spi->mode bits understood by this driver: */
 481         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 482
 483         master->bus_num = pdev->id;
 484
 485         master->setup = spi_tegra_setup;
 486         master->transfer = spi_tegra_transfer;
 487         master->num_chipselect = 4;
 488
 489         dev_set_drvdata(&pdev->dev, master);
 490         tspi = spi_master_get_devdata(master);
 491         tspi->master = master;
 492         tspi->pdev = pdev;
 493         spin_lock_init(&tspi->lock);
 494
 495         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 496         if (r == NULL) {
 497                 ret = -ENODEV;
 498                 goto err0;
 499         }
 500
 501         if (!request_mem_region(r->start, (r->end - r->start) + 1,
 502                                 dev_name(&pdev->dev))) {
 503                 ret = -EBUSY;
 504                 goto err0;
 505         }
 506
 507         tspi->phys = r->start;
 508         tspi->base = ioremap(r->start, r->end - r->start + 1);
 509         if (!tspi->base) {
 510                 dev_err(&pdev->dev, "can't ioremap iomem\n");
 511                 ret = -ENOMEM;
 512                 goto err1;
 513         }
 514
 515         tspi->clk = clk_get(&pdev->dev, NULL);
 516         if (IS_ERR(tspi->clk)) {
 517                 dev_err(&pdev->dev, "can not get clock\n");
 518                 ret = PTR_ERR(tspi->clk);
 519                 goto err2;
 520         }
 521
 522         INIT_LIST_HEAD(&tspi->queue);
 523
 524         tspi->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT);
 525         if (!tspi->rx_dma) {
 526                 dev_err(&pdev->dev, "can not allocate rx dma channel\n");
 527                 ret = -ENODEV;
 528                 goto err3;
 529         }
 530
 531         tspi->rx_bb = dma_alloc_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
 532                                          &tspi->rx_bb_phys, GFP_KERNEL);
 533         if (!tspi->rx_bb) {
 534                 dev_err(&pdev->dev, "can not allocate rx bounce buffer\n");
 535                 ret = -ENOMEM;
 536                 goto err4;
 537         }
 538
 539         tspi->rx_dma_req.complete = tegra_spi_rx_dma_complete;
 540         tspi->rx_dma_req.to_memory = 1;
 541         tspi->rx_dma_req.dest_addr = tspi->rx_bb_phys;
 542         tspi->rx_dma_req.dest_bus_width = 32;
 543         tspi->rx_dma_req.source_addr = tspi->phys + SLINK_RX_FIFO;
 544         tspi->rx_dma_req.source_bus_width = 32;
 545         tspi->rx_dma_req.source_wrap = 4;
 546         tspi->rx_dma_req.req_sel = spi_tegra_req_sels[pdev->id];
 547         tspi->rx_dma_req.dev = tspi;
 548
 549         ret = spi_register_master(master);
 550
 551         if (ret < 0)
 552                 goto err5;
 553
 554         return ret;
 555
 556 err5:
 557         dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
 558                           tspi->rx_bb, tspi->rx_bb_phys);
 559 err4:
 560         tegra_dma_free_channel(tspi->rx_dma);
 561 err3:
 562         clk_put(tspi->clk);
 563 err2:
 564         iounmap(tspi->base);
 565 err1:
 566         release_mem_region(r->start, (r->end - r->start) + 1);
 567 err0:
 568         spi_master_put(master);
 569         return ret;
 570 }
 571
 572 static int __devexit spi_tegra_remove(struct platform_device *pdev)
 573 {
 574         struct spi_master       *master;
 575         struct spi_tegra_data   *tspi;
 576         struct resource         *r;
 577
 578         master = dev_get_drvdata(&pdev->dev);
 579         tspi = spi_master_get_devdata(master);
 580
 581         spi_unregister_master(master);
 582         tegra_dma_free_channel(tspi->rx_dma);
 583
 584         dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
 585                           tspi->rx_bb, tspi->rx_bb_phys);
 586
 587         clk_put(tspi->clk);
 588         iounmap(tspi->base);
 589
 590         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 591         release_mem_region(r->start, (r->end - r->start) + 1);
 592
 593         return 0;
 594 }
 595
 596 MODULE_ALIAS("platform:spi_tegra");
 597
 598 static struct platform_driver spi_tegra_driver = {
 599         .driver = {
 600                 .name =         "spi_tegra",
 601                 .owner =        THIS_MODULE,
 602         },
 603         .remove =       __devexit_p(spi_tegra_remove),
 604 };
 605
 606 static int __init spi_tegra_init(void)
 607 {
 608         return platform_driver_probe(&spi_tegra_driver, spi_tegra_probe);
 609 }
 610 module_init(spi_tegra_init);
 611
 612 static void __exit spi_tegra_exit(void)
 613 {
 614         platform_driver_unregister(&spi_tegra_driver);
 615 }
 616 module_exit(spi_tegra_exit);
 617
 618 MODULE_LICENSE("GPL");