drivers/spi/spi-sun6i.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012 - 2014 Allwinner Tech
   4  * Pan Nan <pannan@allwinnertech.com>
   5  *
   6  * Copyright (C) 2014 Maxime Ripard
   7  * Maxime Ripard <maxime.ripard@free-electrons.com>
   8  */
   9
  10 #include <linux/bitfield.h>
  11 #include <linux/clk.h>
  12 #include <linux/delay.h>
  13 #include <linux/device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/reset.h>
  21
  22 #include <linux/spi/spi.h>
  23
  24 #define SUN6I_FIFO_DEPTH                128
  25 #define SUN8I_FIFO_DEPTH                64
  26
  27 #define SUN6I_GBL_CTL_REG               0x04
  28 #define SUN6I_GBL_CTL_BUS_ENABLE                BIT(0)
  29 #define SUN6I_GBL_CTL_MASTER                    BIT(1)
  30 #define SUN6I_GBL_CTL_TP                        BIT(7)
  31 #define SUN6I_GBL_CTL_RST                       BIT(31)
  32
  33 #define SUN6I_TFR_CTL_REG               0x08
  34 #define SUN6I_TFR_CTL_CPHA                      BIT(0)
  35 #define SUN6I_TFR_CTL_CPOL                      BIT(1)
  36 #define SUN6I_TFR_CTL_SPOL                      BIT(2)
  37 #define SUN6I_TFR_CTL_CS_MASK                   0x30
  38 #define SUN6I_TFR_CTL_CS(cs)                    (((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
  39 #define SUN6I_TFR_CTL_CS_MANUAL                 BIT(6)
  40 #define SUN6I_TFR_CTL_CS_LEVEL                  BIT(7)
  41 #define SUN6I_TFR_CTL_DHB                       BIT(8)
  42 #define SUN6I_TFR_CTL_FBS                       BIT(12)
  43 #define SUN6I_TFR_CTL_XCH                       BIT(31)
  44
  45 #define SUN6I_INT_CTL_REG               0x10
  46 #define SUN6I_INT_CTL_RF_RDY                    BIT(0)
  47 #define SUN6I_INT_CTL_TF_ERQ                    BIT(4)
  48 #define SUN6I_INT_CTL_RF_OVF                    BIT(8)
  49 #define SUN6I_INT_CTL_TC                        BIT(12)
  50
  51 #define SUN6I_INT_STA_REG               0x14
  52
  53 #define SUN6I_FIFO_CTL_REG              0x18
  54 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK   0xff
  55 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS   0
  56 #define SUN6I_FIFO_CTL_RF_RST                   BIT(15)
  57 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK   0xff
  58 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS   16
  59 #define SUN6I_FIFO_CTL_TF_RST                   BIT(31)
  60
  61 #define SUN6I_FIFO_STA_REG              0x1c
  62 #define SUN6I_FIFO_STA_RF_CNT_MASK              GENMASK(7, 0)
  63 #define SUN6I_FIFO_STA_TF_CNT_MASK              GENMASK(23, 16)
  64
  65 #define SUN6I_CLK_CTL_REG               0x24
  66 #define SUN6I_CLK_CTL_CDR2_MASK                 0xff
  67 #define SUN6I_CLK_CTL_CDR2(div)                 (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
  68 #define SUN6I_CLK_CTL_CDR1_MASK                 0xf
  69 #define SUN6I_CLK_CTL_CDR1(div)                 (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
  70 #define SUN6I_CLK_CTL_DRS                       BIT(12)
  71
  72 #define SUN6I_MAX_XFER_SIZE             0xffffff
  73
  74 #define SUN6I_BURST_CNT_REG             0x30
  75
  76 #define SUN6I_XMIT_CNT_REG              0x34
  77
  78 #define SUN6I_BURST_CTL_CNT_REG         0x38
  79
  80 #define SUN6I_TXDATA_REG                0x200
  81 #define SUN6I_RXDATA_REG                0x300
  82
  83 struct sun6i_spi {
  84         struct spi_master       *master;
  85         void __iomem            *base_addr;
  86         struct clk              *hclk;
  87         struct clk              *mclk;
  88         struct reset_control    *rstc;
  89
  90         struct completion       done;
  91
  92         const u8                *tx_buf;
  93         u8                      *rx_buf;
  94         int                     len;
  95         unsigned long           fifo_depth;
  96 };
  97
  98 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
  99 {
 100         return readl(sspi->base_addr + reg);
 101 }
 102
 103 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
 104 {
 105         writel(value, sspi->base_addr + reg);
 106 }
 107
 108 static inline u32 sun6i_spi_get_rx_fifo_count(struct sun6i_spi *sspi)
 109 {
 110         u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
 111
 112         return FIELD_GET(SUN6I_FIFO_STA_RF_CNT_MASK, reg);
 113 }
 114
 115 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
 116 {
 117         u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
 118
 119         return FIELD_GET(SUN6I_FIFO_STA_TF_CNT_MASK, reg);
 120 }
 121
 122 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
 123 {
 124         u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
 125
 126         reg &= ~mask;
 127         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
 128 }
 129
 130 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi)
 131 {
 132         u32 len;
 133         u8 byte;
 134
 135         /* See how much data is available */
 136         len = sun6i_spi_get_rx_fifo_count(sspi);
 137
 138         while (len--) {
 139                 byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
 140                 if (sspi->rx_buf)
 141                         *sspi->rx_buf++ = byte;
 142         }
 143 }
 144
 145 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi)
 146 {
 147         u32 cnt;
 148         int len;
 149         u8 byte;
 150
 151         /* See how much data we can fit */
 152         cnt = sspi->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
 153
 154         len = min((int)cnt, sspi->len);
 155
 156         while (len--) {
 157                 byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
 158                 writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
 159                 sspi->len--;
 160         }
 161 }
 162
 163 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
 164 {
 165         struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
 166         u32 reg;
 167
 168         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
 169         reg &= ~SUN6I_TFR_CTL_CS_MASK;
 170         reg |= SUN6I_TFR_CTL_CS(spi->chip_select);
 171
 172         if (enable)
 173                 reg |= SUN6I_TFR_CTL_CS_LEVEL;
 174         else
 175                 reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
 176
 177         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
 178 }
 179
 180 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
 181 {
 182         return SUN6I_MAX_XFER_SIZE - 1;
 183 }
 184
 185 static int sun6i_spi_transfer_one(struct spi_master *master,
 186                                   struct spi_device *spi,
 187                                   struct spi_transfer *tfr)
 188 {
 189         struct sun6i_spi *sspi = spi_master_get_devdata(master);
 190         unsigned int mclk_rate, div, div_cdr1, div_cdr2, timeout;
 191         unsigned int start, end, tx_time;
 192         unsigned int trig_level;
 193         unsigned int tx_len = 0, rx_len = 0;
 194         int ret = 0;
 195         u32 reg;
 196
 197         if (tfr->len > SUN6I_MAX_XFER_SIZE)
 198                 return -EINVAL;
 199
 200         reinit_completion(&sspi->done);
 201         sspi->tx_buf = tfr->tx_buf;
 202         sspi->rx_buf = tfr->rx_buf;
 203         sspi->len = tfr->len;
 204
 205         /* Clear pending interrupts */
 206         sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
 207
 208         /* Reset FIFO */
 209         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
 210                         SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
 211
 212         /*
 213          * Setup FIFO interrupt trigger level
 214          * Here we choose 3/4 of the full fifo depth, as it's the hardcoded
 215          * value used in old generation of Allwinner SPI controller.
 216          * (See spi-sun4i.c)
 217          */
 218         trig_level = sspi->fifo_depth / 4 * 3;
 219         sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
 220                         (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
 221                         (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS));
 222
 223         /*
 224          * Setup the transfer control register: Chip Select,
 225          * polarities, etc.
 226          */
 227         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
 228
 229         if (spi->mode & SPI_CPOL)
 230                 reg |= SUN6I_TFR_CTL_CPOL;
 231         else
 232                 reg &= ~SUN6I_TFR_CTL_CPOL;
 233
 234         if (spi->mode & SPI_CPHA)
 235                 reg |= SUN6I_TFR_CTL_CPHA;
 236         else
 237                 reg &= ~SUN6I_TFR_CTL_CPHA;
 238
 239         if (spi->mode & SPI_LSB_FIRST)
 240                 reg |= SUN6I_TFR_CTL_FBS;
 241         else
 242                 reg &= ~SUN6I_TFR_CTL_FBS;
 243
 244         /*
 245          * If it's a TX only transfer, we don't want to fill the RX
 246          * FIFO with bogus data
 247          */
 248         if (sspi->rx_buf) {
 249                 reg &= ~SUN6I_TFR_CTL_DHB;
 250                 rx_len = tfr->len;
 251         } else {
 252                 reg |= SUN6I_TFR_CTL_DHB;
 253         }
 254
 255         /* We want to control the chip select manually */
 256         reg |= SUN6I_TFR_CTL_CS_MANUAL;
 257
 258         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
 259
 260         /* Ensure that we have a parent clock fast enough */
 261         mclk_rate = clk_get_rate(sspi->mclk);
 262         if (mclk_rate < (2 * tfr->speed_hz)) {
 263                 clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
 264                 mclk_rate = clk_get_rate(sspi->mclk);
 265         }
 266
 267         /*
 268          * Setup clock divider.
 269          *
 270          * We have two choices there. Either we can use the clock
 271          * divide rate 1, which is calculated thanks to this formula:
 272          * SPI_CLK = MOD_CLK / (2 ^ cdr)
 273          * Or we can use CDR2, which is calculated with the formula:
 274          * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
 275          * Wether we use the former or the latter is set through the
 276          * DRS bit.
 277          *
 278          * First try CDR2, and if we can't reach the expected
 279          * frequency, fall back to CDR1.
 280          */
 281         div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz);
 282         div_cdr2 = DIV_ROUND_UP(div_cdr1, 2);
 283         if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
 284                 reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS;
 285                 tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2);
 286         } else {
 287                 div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1));
 288                 reg = SUN6I_CLK_CTL_CDR1(div);
 289                 tfr->effective_speed_hz = mclk_rate / (1 << div);
 290         }
 291
 292         sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
 293
 294         /* Setup the transfer now... */
 295         if (sspi->tx_buf)
 296                 tx_len = tfr->len;
 297
 298         /* Setup the counters */
 299         sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, tfr->len);
 300         sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, tx_len);
 301         sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG, tx_len);
 302
 303         /* Fill the TX FIFO */
 304         sun6i_spi_fill_fifo(sspi);
 305
 306         /* Enable the interrupts */
 307         reg = SUN6I_INT_CTL_TC;
 308
 309         if (rx_len > sspi->fifo_depth)
 310                 reg |= SUN6I_INT_CTL_RF_RDY;
 311         if (tx_len > sspi->fifo_depth)
 312                 reg |= SUN6I_INT_CTL_TF_ERQ;
 313
 314         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
 315
 316         /* Start the transfer */
 317         reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
 318         sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
 319
 320         tx_time = max(tfr->len * 8 * 2 / (tfr->speed_hz / 1000), 100U);
 321         start = jiffies;
 322         timeout = wait_for_completion_timeout(&sspi->done,
 323                                               msecs_to_jiffies(tx_time));
 324         end = jiffies;
 325         if (!timeout) {
 326                 dev_warn(&master->dev,
 327                          "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
 328                          dev_name(&spi->dev), tfr->len, tfr->speed_hz,
 329                          jiffies_to_msecs(end - start), tx_time);
 330                 ret = -ETIMEDOUT;
 331         }
 332
 333         sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
 334
 335         return ret;
 336 }
 337
 338 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
 339 {
 340         struct sun6i_spi *sspi = dev_id;
 341         u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
 342
 343         /* Transfer complete */
 344         if (status & SUN6I_INT_CTL_TC) {
 345                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
 346                 sun6i_spi_drain_fifo(sspi);
 347                 complete(&sspi->done);
 348                 return IRQ_HANDLED;
 349         }
 350
 351         /* Receive FIFO 3/4 full */
 352         if (status & SUN6I_INT_CTL_RF_RDY) {
 353                 sun6i_spi_drain_fifo(sspi);
 354                 /* Only clear the interrupt _after_ draining the FIFO */
 355                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
 356                 return IRQ_HANDLED;
 357         }
 358
 359         /* Transmit FIFO 3/4 empty */
 360         if (status & SUN6I_INT_CTL_TF_ERQ) {
 361                 sun6i_spi_fill_fifo(sspi);
 362
 363                 if (!sspi->len)
 364                         /* nothing left to transmit */
 365                         sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
 366
 367                 /* Only clear the interrupt _after_ re-seeding the FIFO */
 368                 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
 369
 370                 return IRQ_HANDLED;
 371         }
 372
 373         return IRQ_NONE;
 374 }
 375
 376 static int sun6i_spi_runtime_resume(struct device *dev)
 377 {
 378         struct spi_master *master = dev_get_drvdata(dev);
 379         struct sun6i_spi *sspi = spi_master_get_devdata(master);
 380         int ret;
 381
 382         ret = clk_prepare_enable(sspi->hclk);
 383         if (ret) {
 384                 dev_err(dev, "Couldn't enable AHB clock\n");
 385                 goto out;
 386         }
 387
 388         ret = clk_prepare_enable(sspi->mclk);
 389         if (ret) {
 390                 dev_err(dev, "Couldn't enable module clock\n");
 391                 goto err;
 392         }
 393
 394         ret = reset_control_deassert(sspi->rstc);
 395         if (ret) {
 396                 dev_err(dev, "Couldn't deassert the device from reset\n");
 397                 goto err2;
 398         }
 399
 400         sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
 401                         SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
 402
 403         return 0;
 404
 405 err2:
 406         clk_disable_unprepare(sspi->mclk);
 407 err:
 408         clk_disable_unprepare(sspi->hclk);
 409 out:
 410         return ret;
 411 }
 412
 413 static int sun6i_spi_runtime_suspend(struct device *dev)
 414 {
 415         struct spi_master *master = dev_get_drvdata(dev);
 416         struct sun6i_spi *sspi = spi_master_get_devdata(master);
 417
 418         reset_control_assert(sspi->rstc);
 419         clk_disable_unprepare(sspi->mclk);
 420         clk_disable_unprepare(sspi->hclk);
 421
 422         return 0;
 423 }
 424
 425 static int sun6i_spi_probe(struct platform_device *pdev)
 426 {
 427         struct spi_master *master;
 428         struct sun6i_spi *sspi;
 429         int ret = 0, irq;
 430
 431         master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
 432         if (!master) {
 433                 dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
 434                 return -ENOMEM;
 435         }
 436
 437         platform_set_drvdata(pdev, master);
 438         sspi = spi_master_get_devdata(master);
 439
 440         sspi->base_addr = devm_platform_ioremap_resource(pdev, 0);
 441         if (IS_ERR(sspi->base_addr)) {
 442                 ret = PTR_ERR(sspi->base_addr);
 443                 goto err_free_master;
 444         }
 445
 446         irq = platform_get_irq(pdev, 0);
 447         if (irq < 0) {
 448                 ret = -ENXIO;
 449                 goto err_free_master;
 450         }
 451
 452         ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
 453                                0, "sun6i-spi", sspi);
 454         if (ret) {
 455                 dev_err(&pdev->dev, "Cannot request IRQ\n");
 456                 goto err_free_master;
 457         }
 458
 459         sspi->master = master;
 460         sspi->fifo_depth = (unsigned long)of_device_get_match_data(&pdev->dev);
 461
 462         master->max_speed_hz = 100 * 1000 * 1000;
 463         master->min_speed_hz = 3 * 1000;
 464         master->use_gpio_descriptors = true;
 465         master->set_cs = sun6i_spi_set_cs;
 466         master->transfer_one = sun6i_spi_transfer_one;
 467         master->num_chipselect = 4;
 468         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
 469         master->bits_per_word_mask = SPI_BPW_MASK(8);
 470         master->dev.of_node = pdev->dev.of_node;
 471         master->auto_runtime_pm = true;
 472         master->max_transfer_size = sun6i_spi_max_transfer_size;
 473
 474         sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
 475         if (IS_ERR(sspi->hclk)) {
 476                 dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
 477                 ret = PTR_ERR(sspi->hclk);
 478                 goto err_free_master;
 479         }
 480
 481         sspi->mclk = devm_clk_get(&pdev->dev, "mod");
 482         if (IS_ERR(sspi->mclk)) {
 483                 dev_err(&pdev->dev, "Unable to acquire module clock\n");
 484                 ret = PTR_ERR(sspi->mclk);
 485                 goto err_free_master;
 486         }
 487
 488         init_completion(&sspi->done);
 489
 490         sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 491         if (IS_ERR(sspi->rstc)) {
 492                 dev_err(&pdev->dev, "Couldn't get reset controller\n");
 493                 ret = PTR_ERR(sspi->rstc);
 494                 goto err_free_master;
 495         }
 496
 497         /*
 498          * This wake-up/shutdown pattern is to be able to have the
 499          * device woken up, even if runtime_pm is disabled
 500          */
 501         ret = sun6i_spi_runtime_resume(&pdev->dev);
 502         if (ret) {
 503                 dev_err(&pdev->dev, "Couldn't resume the device\n");
 504                 goto err_free_master;
 505         }
 506
 507         pm_runtime_set_active(&pdev->dev);
 508         pm_runtime_enable(&pdev->dev);
 509         pm_runtime_idle(&pdev->dev);
 510
 511         ret = devm_spi_register_master(&pdev->dev, master);
 512         if (ret) {
 513                 dev_err(&pdev->dev, "cannot register SPI master\n");
 514                 goto err_pm_disable;
 515         }
 516
 517         return 0;
 518
 519 err_pm_disable:
 520         pm_runtime_disable(&pdev->dev);
 521         sun6i_spi_runtime_suspend(&pdev->dev);
 522 err_free_master:
 523         spi_master_put(master);
 524         return ret;
 525 }
 526
 527 static int sun6i_spi_remove(struct platform_device *pdev)
 528 {
 529         pm_runtime_force_suspend(&pdev->dev);
 530
 531         return 0;
 532 }
 533
 534 static const struct of_device_id sun6i_spi_match[] = {
 535         { .compatible = "allwinner,sun6i-a31-spi", .data = (void *)SUN6I_FIFO_DEPTH },
 536         { .compatible = "allwinner,sun8i-h3-spi",  .data = (void *)SUN8I_FIFO_DEPTH },
 537         {}
 538 };
 539 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
 540
 541 static const struct dev_pm_ops sun6i_spi_pm_ops = {
 542         .runtime_resume         = sun6i_spi_runtime_resume,
 543         .runtime_suspend        = sun6i_spi_runtime_suspend,
 544 };
 545
 546 static struct platform_driver sun6i_spi_driver = {
 547         .probe  = sun6i_spi_probe,
 548         .remove = sun6i_spi_remove,
 549         .driver = {
 550                 .name           = "sun6i-spi",
 551                 .of_match_table = sun6i_spi_match,
 552                 .pm             = &sun6i_spi_pm_ops,
 553         },
 554 };
 555 module_platform_driver(sun6i_spi_driver);
 556
 557 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
 558 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 559 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
 560 MODULE_LICENSE("GPL");