drivers/spi/spi-tegra20-sflash.c

   1 /*
   2  * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
   3  *
   4  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   5  *
   6  * Author: Laxman Dewangan <ldewangan@nvidia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/clk.h>
  22 #include <linux/completion.h>
  23 #include <linux/delay.h>
  24 #include <linux/err.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/io.h>
  27 #include <linux/kernel.h>
  28 #include <linux/kthread.h>
  29 #include <linux/module.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/pm_runtime.h>
  32 #include <linux/of.h>
  33 #include <linux/of_device.h>
  34 #include <linux/reset.h>
  35 #include <linux/spi/spi.h>
  36
  37 #define SPI_COMMAND                             0x000
  38 #define SPI_GO                                  BIT(30)
  39 #define SPI_M_S                                 BIT(28)
  40 #define SPI_ACTIVE_SCLK_MASK                    (0x3 << 26)
  41 #define SPI_ACTIVE_SCLK_DRIVE_LOW               (0 << 26)
  42 #define SPI_ACTIVE_SCLK_DRIVE_HIGH              (1 << 26)
  43 #define SPI_ACTIVE_SCLK_PULL_LOW                (2 << 26)
  44 #define SPI_ACTIVE_SCLK_PULL_HIGH               (3 << 26)
  45
  46 #define SPI_CK_SDA_FALLING                      (1 << 21)
  47 #define SPI_CK_SDA_RISING                       (0 << 21)
  48 #define SPI_CK_SDA_MASK                         (1 << 21)
  49 #define SPI_ACTIVE_SDA                          (0x3 << 18)
  50 #define SPI_ACTIVE_SDA_DRIVE_LOW                (0 << 18)
  51 #define SPI_ACTIVE_SDA_DRIVE_HIGH               (1 << 18)
  52 #define SPI_ACTIVE_SDA_PULL_LOW                 (2 << 18)
  53 #define SPI_ACTIVE_SDA_PULL_HIGH                (3 << 18)
  54
  55 #define SPI_CS_POL_INVERT                       BIT(16)
  56 #define SPI_TX_EN                               BIT(15)
  57 #define SPI_RX_EN                               BIT(14)
  58 #define SPI_CS_VAL_HIGH                         BIT(13)
  59 #define SPI_CS_VAL_LOW                          0x0
  60 #define SPI_CS_SW                               BIT(12)
  61 #define SPI_CS_HW                               0x0
  62 #define SPI_CS_DELAY_MASK                       (7 << 9)
  63 #define SPI_CS3_EN                              BIT(8)
  64 #define SPI_CS2_EN                              BIT(7)
  65 #define SPI_CS1_EN                              BIT(6)
  66 #define SPI_CS0_EN                              BIT(5)
  67
  68 #define SPI_CS_MASK                     (SPI_CS3_EN | SPI_CS2_EN |      \
  69                                         SPI_CS1_EN | SPI_CS0_EN)
  70 #define SPI_BIT_LENGTH(x)               (((x) & 0x1f) << 0)
  71
  72 #define SPI_MODES                       (SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK)
  73
  74 #define SPI_STATUS                      0x004
  75 #define SPI_BSY                         BIT(31)
  76 #define SPI_RDY                         BIT(30)
  77 #define SPI_TXF_FLUSH                   BIT(29)
  78 #define SPI_RXF_FLUSH                   BIT(28)
  79 #define SPI_RX_UNF                      BIT(27)
  80 #define SPI_TX_OVF                      BIT(26)
  81 #define SPI_RXF_EMPTY                   BIT(25)
  82 #define SPI_RXF_FULL                    BIT(24)
  83 #define SPI_TXF_EMPTY                   BIT(23)
  84 #define SPI_TXF_FULL                    BIT(22)
  85 #define SPI_BLK_CNT(count)              (((count) & 0xffff) + 1)
  86
  87 #define SPI_FIFO_ERROR                  (SPI_RX_UNF | SPI_TX_OVF)
  88 #define SPI_FIFO_EMPTY                  (SPI_TX_EMPTY | SPI_RX_EMPTY)
  89
  90 #define SPI_RX_CMP                      0x8
  91 #define SPI_DMA_CTL                     0x0C
  92 #define SPI_DMA_EN                      BIT(31)
  93 #define SPI_IE_RXC                      BIT(27)
  94 #define SPI_IE_TXC                      BIT(26)
  95 #define SPI_PACKED                      BIT(20)
  96 #define SPI_RX_TRIG_MASK                (0x3 << 18)
  97 #define SPI_RX_TRIG_1W                  (0x0 << 18)
  98 #define SPI_RX_TRIG_4W                  (0x1 << 18)
  99 #define SPI_TX_TRIG_MASK                (0x3 << 16)
 100 #define SPI_TX_TRIG_1W                  (0x0 << 16)
 101 #define SPI_TX_TRIG_4W                  (0x1 << 16)
 102 #define SPI_DMA_BLK_COUNT(count)        (((count) - 1) & 0xFFFF);
 103
 104 #define SPI_TX_FIFO                     0x10
 105 #define SPI_RX_FIFO                     0x20
 106
 107 #define DATA_DIR_TX                     (1 << 0)
 108 #define DATA_DIR_RX                     (1 << 1)
 109
 110 #define MAX_CHIP_SELECT                 4
 111 #define SPI_FIFO_DEPTH                  4
 112 #define SPI_DMA_TIMEOUT               (msecs_to_jiffies(1000))
 113
 114 struct tegra_sflash_data {
 115         struct device                           *dev;
 116         struct spi_master                       *master;
 117         spinlock_t                              lock;
 118
 119         struct clk                              *clk;
 120         struct reset_control                    *rst;
 121         void __iomem                            *base;
 122         unsigned                                irq;
 123         u32                                     cur_speed;
 124
 125         struct spi_device                       *cur_spi;
 126         unsigned                                cur_pos;
 127         unsigned                                cur_len;
 128         unsigned                                bytes_per_word;
 129         unsigned                                cur_direction;
 130         unsigned                                curr_xfer_words;
 131
 132         unsigned                                cur_rx_pos;
 133         unsigned                                cur_tx_pos;
 134
 135         u32                                     tx_status;
 136         u32                                     rx_status;
 137         u32                                     status_reg;
 138
 139         u32                                     def_command_reg;
 140         u32                                     command_reg;
 141         u32                                     dma_control_reg;
 142
 143         struct completion                       xfer_completion;
 144         struct spi_transfer                     *curr_xfer;
 145 };
 146
 147 static int tegra_sflash_runtime_suspend(struct device *dev);
 148 static int tegra_sflash_runtime_resume(struct device *dev);
 149
 150 static inline u32 tegra_sflash_readl(struct tegra_sflash_data *tsd,
 151                 unsigned long reg)
 152 {
 153         return readl(tsd->base + reg);
 154 }
 155
 156 static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
 157                 u32 val, unsigned long reg)
 158 {
 159         writel(val, tsd->base + reg);
 160 }
 161
 162 static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
 163 {
 164         /* Write 1 to clear status register */
 165         tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS);
 166 }
 167
 168 static unsigned tegra_sflash_calculate_curr_xfer_param(
 169         struct spi_device *spi, struct tegra_sflash_data *tsd,
 170         struct spi_transfer *t)
 171 {
 172         unsigned remain_len = t->len - tsd->cur_pos;
 173         unsigned max_word;
 174
 175         tsd->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
 176         max_word = remain_len / tsd->bytes_per_word;
 177         if (max_word > SPI_FIFO_DEPTH)
 178                 max_word = SPI_FIFO_DEPTH;
 179         tsd->curr_xfer_words = max_word;
 180         return max_word;
 181 }
 182
 183 static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
 184         struct tegra_sflash_data *tsd, struct spi_transfer *t)
 185 {
 186         unsigned nbytes;
 187         u32 status;
 188         unsigned max_n_32bit = tsd->curr_xfer_words;
 189         u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos;
 190
 191         if (max_n_32bit > SPI_FIFO_DEPTH)
 192                 max_n_32bit = SPI_FIFO_DEPTH;
 193         nbytes = max_n_32bit * tsd->bytes_per_word;
 194
 195         status = tegra_sflash_readl(tsd, SPI_STATUS);
 196         while (!(status & SPI_TXF_FULL)) {
 197                 int i;
 198                 u32 x = 0;
 199
 200                 for (i = 0; nbytes && (i < tsd->bytes_per_word);
 201                                                         i++, nbytes--)
 202                         x |= (u32)(*tx_buf++) << (i * 8);
 203                 tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
 204                 if (!nbytes)
 205                         break;
 206
 207                 status = tegra_sflash_readl(tsd, SPI_STATUS);
 208         }
 209         tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
 210         return max_n_32bit;
 211 }
 212
 213 static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
 214                 struct tegra_sflash_data *tsd, struct spi_transfer *t)
 215 {
 216         u32 status;
 217         unsigned int read_words = 0;
 218         u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos;
 219
 220         status = tegra_sflash_readl(tsd, SPI_STATUS);
 221         while (!(status & SPI_RXF_EMPTY)) {
 222                 int i;
 223                 u32 x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
 224                 for (i = 0; (i < tsd->bytes_per_word); i++)
 225                         *rx_buf++ = (x >> (i*8)) & 0xFF;
 226                 read_words++;
 227                 status = tegra_sflash_readl(tsd, SPI_STATUS);
 228         }
 229         tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
 230         return 0;
 231 }
 232
 233 static int tegra_sflash_start_cpu_based_transfer(
 234                 struct tegra_sflash_data *tsd, struct spi_transfer *t)
 235 {
 236         u32 val = 0;
 237         unsigned cur_words;
 238
 239         if (tsd->cur_direction & DATA_DIR_TX)
 240                 val |= SPI_IE_TXC;
 241
 242         if (tsd->cur_direction & DATA_DIR_RX)
 243                 val |= SPI_IE_RXC;
 244
 245         tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
 246         tsd->dma_control_reg = val;
 247
 248         if (tsd->cur_direction & DATA_DIR_TX)
 249                 cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
 250         else
 251                 cur_words = tsd->curr_xfer_words;
 252         val |= SPI_DMA_BLK_COUNT(cur_words);
 253         tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
 254         tsd->dma_control_reg = val;
 255         val |= SPI_DMA_EN;
 256         tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
 257         return 0;
 258 }
 259
 260 static int tegra_sflash_start_transfer_one(struct spi_device *spi,
 261                 struct spi_transfer *t, bool is_first_of_msg,
 262                 bool is_single_xfer)
 263 {
 264         struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
 265         u32 speed;
 266         u32 command;
 267
 268         speed = t->speed_hz;
 269         if (speed != tsd->cur_speed) {
 270                 clk_set_rate(tsd->clk, speed);
 271                 tsd->cur_speed = speed;
 272         }
 273
 274         tsd->cur_spi = spi;
 275         tsd->cur_pos = 0;
 276         tsd->cur_rx_pos = 0;
 277         tsd->cur_tx_pos = 0;
 278         tsd->curr_xfer = t;
 279         tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
 280         if (is_first_of_msg) {
 281                 command = tsd->def_command_reg;
 282                 command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
 283                 command |= SPI_CS_VAL_HIGH;
 284
 285                 command &= ~SPI_MODES;
 286                 if (spi->mode & SPI_CPHA)
 287                         command |= SPI_CK_SDA_FALLING;
 288
 289                 if (spi->mode & SPI_CPOL)
 290                         command |= SPI_ACTIVE_SCLK_DRIVE_HIGH;
 291                 else
 292                         command |= SPI_ACTIVE_SCLK_DRIVE_LOW;
 293                 command |= SPI_CS0_EN << spi->chip_select;
 294         } else {
 295                 command = tsd->command_reg;
 296                 command &= ~SPI_BIT_LENGTH(~0);
 297                 command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
 298                 command &= ~(SPI_RX_EN | SPI_TX_EN);
 299         }
 300
 301         tsd->cur_direction = 0;
 302         if (t->rx_buf) {
 303                 command |= SPI_RX_EN;
 304                 tsd->cur_direction |= DATA_DIR_RX;
 305         }
 306         if (t->tx_buf) {
 307                 command |= SPI_TX_EN;
 308                 tsd->cur_direction |= DATA_DIR_TX;
 309         }
 310         tegra_sflash_writel(tsd, command, SPI_COMMAND);
 311         tsd->command_reg = command;
 312
 313         return tegra_sflash_start_cpu_based_transfer(tsd, t);
 314 }
 315
 316 static int tegra_sflash_transfer_one_message(struct spi_master *master,
 317                         struct spi_message *msg)
 318 {
 319         bool is_first_msg = true;
 320         int single_xfer;
 321         struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
 322         struct spi_transfer *xfer;
 323         struct spi_device *spi = msg->spi;
 324         int ret;
 325
 326         msg->status = 0;
 327         msg->actual_length = 0;
 328         single_xfer = list_is_singular(&msg->transfers);
 329         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 330                 reinit_completion(&tsd->xfer_completion);
 331                 ret = tegra_sflash_start_transfer_one(spi, xfer,
 332                                         is_first_msg, single_xfer);
 333                 if (ret < 0) {
 334                         dev_err(tsd->dev,
 335                                 "spi can not start transfer, err %d\n", ret);
 336                         goto exit;
 337                 }
 338                 is_first_msg = false;
 339                 ret = wait_for_completion_timeout(&tsd->xfer_completion,
 340                                                 SPI_DMA_TIMEOUT);
 341                 if (WARN_ON(ret == 0)) {
 342                         dev_err(tsd->dev,
 343                                 "spi trasfer timeout, err %d\n", ret);
 344                         ret = -EIO;
 345                         goto exit;
 346                 }
 347
 348                 if (tsd->tx_status ||  tsd->rx_status) {
 349                         dev_err(tsd->dev, "Error in Transfer\n");
 350                         ret = -EIO;
 351                         goto exit;
 352                 }
 353                 msg->actual_length += xfer->len;
 354                 if (xfer->cs_change && xfer->delay_usecs) {
 355                         tegra_sflash_writel(tsd, tsd->def_command_reg,
 356                                         SPI_COMMAND);
 357                         udelay(xfer->delay_usecs);
 358                 }
 359         }
 360         ret = 0;
 361 exit:
 362         tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
 363         msg->status = ret;
 364         spi_finalize_current_message(master);
 365         return ret;
 366 }
 367
 368 static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
 369 {
 370         struct spi_transfer *t = tsd->curr_xfer;
 371         unsigned long flags;
 372
 373         spin_lock_irqsave(&tsd->lock, flags);
 374         if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) {
 375                 dev_err(tsd->dev,
 376                         "CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
 377                 dev_err(tsd->dev,
 378                         "CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
 379                                 tsd->dma_control_reg);
 380                 reset_control_assert(tsd->rst);
 381                 udelay(2);
 382                 reset_control_deassert(tsd->rst);
 383                 complete(&tsd->xfer_completion);
 384                 goto exit;
 385         }
 386
 387         if (tsd->cur_direction & DATA_DIR_RX)
 388                 tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
 389
 390         if (tsd->cur_direction & DATA_DIR_TX)
 391                 tsd->cur_pos = tsd->cur_tx_pos;
 392         else
 393                 tsd->cur_pos = tsd->cur_rx_pos;
 394
 395         if (tsd->cur_pos == t->len) {
 396                 complete(&tsd->xfer_completion);
 397                 goto exit;
 398         }
 399
 400         tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
 401         tegra_sflash_start_cpu_based_transfer(tsd, t);
 402 exit:
 403         spin_unlock_irqrestore(&tsd->lock, flags);
 404         return IRQ_HANDLED;
 405 }
 406
 407 static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
 408 {
 409         struct tegra_sflash_data *tsd = context_data;
 410
 411         tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
 412         if (tsd->cur_direction & DATA_DIR_TX)
 413                 tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
 414
 415         if (tsd->cur_direction & DATA_DIR_RX)
 416                 tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
 417         tegra_sflash_clear_status(tsd);
 418
 419         return handle_cpu_based_xfer(tsd);
 420 }
 421
 422 static const struct of_device_id tegra_sflash_of_match[] = {
 423         { .compatible = "nvidia,tegra20-sflash", },
 424         {}
 425 };
 426 MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
 427
 428 static int tegra_sflash_probe(struct platform_device *pdev)
 429 {
 430         struct spi_master       *master;
 431         struct tegra_sflash_data        *tsd;
 432         struct resource         *r;
 433         int ret;
 434         const struct of_device_id *match;
 435
 436         match = of_match_device(tegra_sflash_of_match, &pdev->dev);
 437         if (!match) {
 438                 dev_err(&pdev->dev, "Error: No device match found\n");
 439                 return -ENODEV;
 440         }
 441
 442         master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
 443         if (!master) {
 444                 dev_err(&pdev->dev, "master allocation failed\n");
 445                 return -ENOMEM;
 446         }
 447
 448         /* the spi->mode bits understood by this driver: */
 449         master->mode_bits = SPI_CPOL | SPI_CPHA;
 450         master->transfer_one_message = tegra_sflash_transfer_one_message;
 451         master->auto_runtime_pm = true;
 452         master->num_chipselect = MAX_CHIP_SELECT;
 453
 454         platform_set_drvdata(pdev, master);
 455         tsd = spi_master_get_devdata(master);
 456         tsd->master = master;
 457         tsd->dev = &pdev->dev;
 458         spin_lock_init(&tsd->lock);
 459
 460         if (of_property_read_u32(tsd->dev->of_node, "spi-max-frequency",
 461                                  &master->max_speed_hz))
 462                 master->max_speed_hz = 25000000; /* 25MHz */
 463
 464         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 465         tsd->base = devm_ioremap_resource(&pdev->dev, r);
 466         if (IS_ERR(tsd->base)) {
 467                 ret = PTR_ERR(tsd->base);
 468                 goto exit_free_master;
 469         }
 470
 471         tsd->irq = platform_get_irq(pdev, 0);
 472         ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
 473                         dev_name(&pdev->dev), tsd);
 474         if (ret < 0) {
 475                 dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
 476                                         tsd->irq);
 477                 goto exit_free_master;
 478         }
 479
 480         tsd->clk = devm_clk_get(&pdev->dev, NULL);
 481         if (IS_ERR(tsd->clk)) {
 482                 dev_err(&pdev->dev, "can not get clock\n");
 483                 ret = PTR_ERR(tsd->clk);
 484                 goto exit_free_irq;
 485         }
 486
 487         tsd->rst = devm_reset_control_get(&pdev->dev, "spi");
 488         if (IS_ERR(tsd->rst)) {
 489                 dev_err(&pdev->dev, "can not get reset\n");
 490                 ret = PTR_ERR(tsd->rst);
 491                 goto exit_free_irq;
 492         }
 493
 494         init_completion(&tsd->xfer_completion);
 495         pm_runtime_enable(&pdev->dev);
 496         if (!pm_runtime_enabled(&pdev->dev)) {
 497                 ret = tegra_sflash_runtime_resume(&pdev->dev);
 498                 if (ret)
 499                         goto exit_pm_disable;
 500         }
 501
 502         ret = pm_runtime_get_sync(&pdev->dev);
 503         if (ret < 0) {
 504                 dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
 505                 goto exit_pm_disable;
 506         }
 507
 508         /* Reset controller */
 509         reset_control_assert(tsd->rst);
 510         udelay(2);
 511         reset_control_deassert(tsd->rst);
 512
 513         tsd->def_command_reg  = SPI_M_S | SPI_CS_SW;
 514         tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
 515         pm_runtime_put(&pdev->dev);
 516
 517         master->dev.of_node = pdev->dev.of_node;
 518         ret = devm_spi_register_master(&pdev->dev, master);
 519         if (ret < 0) {
 520                 dev_err(&pdev->dev, "can not register to master err %d\n", ret);
 521                 goto exit_pm_disable;
 522         }
 523         return ret;
 524
 525 exit_pm_disable:
 526         pm_runtime_disable(&pdev->dev);
 527         if (!pm_runtime_status_suspended(&pdev->dev))
 528                 tegra_sflash_runtime_suspend(&pdev->dev);
 529 exit_free_irq:
 530         free_irq(tsd->irq, tsd);
 531 exit_free_master:
 532         spi_master_put(master);
 533         return ret;
 534 }
 535
 536 static int tegra_sflash_remove(struct platform_device *pdev)
 537 {
 538         struct spi_master *master = platform_get_drvdata(pdev);
 539         struct tegra_sflash_data        *tsd = spi_master_get_devdata(master);
 540
 541         free_irq(tsd->irq, tsd);
 542
 543         pm_runtime_disable(&pdev->dev);
 544         if (!pm_runtime_status_suspended(&pdev->dev))
 545                 tegra_sflash_runtime_suspend(&pdev->dev);
 546
 547         return 0;
 548 }
 549
 550 #ifdef CONFIG_PM_SLEEP
 551 static int tegra_sflash_suspend(struct device *dev)
 552 {
 553         struct spi_master *master = dev_get_drvdata(dev);
 554
 555         return spi_master_suspend(master);
 556 }
 557
 558 static int tegra_sflash_resume(struct device *dev)
 559 {
 560         struct spi_master *master = dev_get_drvdata(dev);
 561         struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
 562         int ret;
 563
 564         ret = pm_runtime_get_sync(dev);
 565         if (ret < 0) {
 566                 dev_err(dev, "pm runtime failed, e = %d\n", ret);
 567                 return ret;
 568         }
 569         tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
 570         pm_runtime_put(dev);
 571
 572         return spi_master_resume(master);
 573 }
 574 #endif
 575
 576 static int tegra_sflash_runtime_suspend(struct device *dev)
 577 {
 578         struct spi_master *master = dev_get_drvdata(dev);
 579         struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
 580
 581         /* Flush all write which are in PPSB queue by reading back */
 582         tegra_sflash_readl(tsd, SPI_COMMAND);
 583
 584         clk_disable_unprepare(tsd->clk);
 585         return 0;
 586 }
 587
 588 static int tegra_sflash_runtime_resume(struct device *dev)
 589 {
 590         struct spi_master *master = dev_get_drvdata(dev);
 591         struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
 592         int ret;
 593
 594         ret = clk_prepare_enable(tsd->clk);
 595         if (ret < 0) {
 596                 dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
 597                 return ret;
 598         }
 599         return 0;
 600 }
 601
 602 static const struct dev_pm_ops slink_pm_ops = {
 603         SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
 604                 tegra_sflash_runtime_resume, NULL)
 605         SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
 606 };
 607 static struct platform_driver tegra_sflash_driver = {
 608         .driver = {
 609                 .name           = "spi-tegra-sflash",
 610                 .owner          = THIS_MODULE,
 611                 .pm             = &slink_pm_ops,
 612                 .of_match_table = tegra_sflash_of_match,
 613         },
 614         .probe =        tegra_sflash_probe,
 615         .remove =       tegra_sflash_remove,
 616 };
 617 module_platform_driver(tegra_sflash_driver);
 618
 619 MODULE_ALIAS("platform:spi-tegra-sflash");
 620 MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
 621 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 622 MODULE_LICENSE("GPL v2");