root/drivers/spi/spi-cadence.c

DEFINITIONS

1. cdns_spi_read
2. cdns_spi_write
3. cdns_spi_init_hw
4. cdns_spi_chipselect
5. cdns_spi_config_clock_mode
6. cdns_spi_config_clock_freq
7. cdns_spi_setup_transfer
8. cdns_spi_fill_tx_fifo
9. cdns_spi_irq
10. cdns_prepare_message
11. cdns_transfer_one
12. cdns_prepare_transfer_hardware
13. cdns_unprepare_transfer_hardware
14. cdns_spi_probe
15. cdns_spi_remove
16. cdns_spi_suspend
17. cdns_spi_resume
18. cnds_runtime_resume
19. cnds_runtime_suspend

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cadence SPI controller driver (master mode only)
   4  *
   5  * Copyright (C) 2008 - 2014 Xilinx, Inc.
   6  *
   7  * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c)
   8  */
   9 
  10 #include <linux/clk.h>
  11 #include <linux/delay.h>
  12 #include <linux/gpio/consumer.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/io.h>
  15 #include <linux/module.h>
  16 #include <linux/of_irq.h>
  17 #include <linux/of_address.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/spi/spi.h>
  21 
  22 /* Name of this driver */
  23 #define CDNS_SPI_NAME           "cdns-spi"
  24 
  25 /* Register offset definitions */
  26 #define CDNS_SPI_CR     0x00 /* Configuration  Register, RW */
  27 #define CDNS_SPI_ISR    0x04 /* Interrupt Status Register, RO */
  28 #define CDNS_SPI_IER    0x08 /* Interrupt Enable Register, WO */
  29 #define CDNS_SPI_IDR    0x0c /* Interrupt Disable Register, WO */
  30 #define CDNS_SPI_IMR    0x10 /* Interrupt Enabled Mask Register, RO */
  31 #define CDNS_SPI_ER     0x14 /* Enable/Disable Register, RW */
  32 #define CDNS_SPI_DR     0x18 /* Delay Register, RW */
  33 #define CDNS_SPI_TXD    0x1C /* Data Transmit Register, WO */
  34 #define CDNS_SPI_RXD    0x20 /* Data Receive Register, RO */
  35 #define CDNS_SPI_SICR   0x24 /* Slave Idle Count Register, RW */
  36 #define CDNS_SPI_THLD   0x28 /* Transmit FIFO Watermark Register,RW */
  37 
  38 #define SPI_AUTOSUSPEND_TIMEOUT         3000
  39 /*
  40  * SPI Configuration Register bit Masks
  41  *
  42  * This register contains various control bits that affect the operation
  43  * of the SPI controller
  44  */
  45 #define CDNS_SPI_CR_MANSTRT     0x00010000 /* Manual TX Start */
  46 #define CDNS_SPI_CR_CPHA                0x00000004 /* Clock Phase Control */
  47 #define CDNS_SPI_CR_CPOL                0x00000002 /* Clock Polarity Control */
  48 #define CDNS_SPI_CR_SSCTRL              0x00003C00 /* Slave Select Mask */
  49 #define CDNS_SPI_CR_PERI_SEL    0x00000200 /* Peripheral Select Decode */
  50 #define CDNS_SPI_CR_BAUD_DIV    0x00000038 /* Baud Rate Divisor Mask */
  51 #define CDNS_SPI_CR_MSTREN              0x00000001 /* Master Enable Mask */
  52 #define CDNS_SPI_CR_MANSTRTEN   0x00008000 /* Manual TX Enable Mask */
  53 #define CDNS_SPI_CR_SSFORCE     0x00004000 /* Manual SS Enable Mask */
  54 #define CDNS_SPI_CR_BAUD_DIV_4  0x00000008 /* Default Baud Div Mask */
  55 #define CDNS_SPI_CR_DEFAULT     (CDNS_SPI_CR_MSTREN | \
  56                                         CDNS_SPI_CR_SSCTRL | \
  57                                         CDNS_SPI_CR_SSFORCE | \
  58                                         CDNS_SPI_CR_BAUD_DIV_4)
  59 
  60 /*
  61  * SPI Configuration Register - Baud rate and slave select
  62  *
  63  * These are the values used in the calculation of baud rate divisor and
  64  * setting the slave select.
  65  */
  66 
  67 #define CDNS_SPI_BAUD_DIV_MAX           7 /* Baud rate divisor maximum */
  68 #define CDNS_SPI_BAUD_DIV_MIN           1 /* Baud rate divisor minimum */
  69 #define CDNS_SPI_BAUD_DIV_SHIFT         3 /* Baud rate divisor shift in CR */
  70 #define CDNS_SPI_SS_SHIFT               10 /* Slave Select field shift in CR */
  71 #define CDNS_SPI_SS0                    0x1 /* Slave Select zero */
  72 
  73 /*
  74  * SPI Interrupt Registers bit Masks
  75  *
  76  * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
  77  * bit definitions.
  78  */
  79 #define CDNS_SPI_IXR_TXOW       0x00000004 /* SPI TX FIFO Overwater */
  80 #define CDNS_SPI_IXR_MODF       0x00000002 /* SPI Mode Fault */
  81 #define CDNS_SPI_IXR_RXNEMTY 0x00000010 /* SPI RX FIFO Not Empty */
  82 #define CDNS_SPI_IXR_DEFAULT    (CDNS_SPI_IXR_TXOW | \
  83                                         CDNS_SPI_IXR_MODF)
  84 #define CDNS_SPI_IXR_TXFULL     0x00000008 /* SPI TX Full */
  85 #define CDNS_SPI_IXR_ALL        0x0000007F /* SPI all interrupts */
  86 
  87 /*
  88  * SPI Enable Register bit Masks
  89  *
  90  * This register is used to enable or disable the SPI controller
  91  */
  92 #define CDNS_SPI_ER_ENABLE      0x00000001 /* SPI Enable Bit Mask */
  93 #define CDNS_SPI_ER_DISABLE     0x0 /* SPI Disable Bit Mask */
  94 
  95 /* SPI FIFO depth in bytes */
  96 #define CDNS_SPI_FIFO_DEPTH     128
  97 
  98 /* Default number of chip select lines */
  99 #define CDNS_SPI_DEFAULT_NUM_CS         4
 100 
 101 /**
 102  * struct cdns_spi - This definition defines spi driver instance
 103  * @regs:               Virtual address of the SPI controller registers
 104  * @ref_clk:            Pointer to the peripheral clock
 105  * @pclk:               Pointer to the APB clock
 106  * @speed_hz:           Current SPI bus clock speed in Hz
 107  * @txbuf:              Pointer to the TX buffer
 108  * @rxbuf:              Pointer to the RX buffer
 109  * @tx_bytes:           Number of bytes left to transfer
 110  * @rx_bytes:           Number of bytes requested
 111  * @dev_busy:           Device busy flag
 112  * @is_decoded_cs:      Flag for decoder property set or not
 113  */
 114 struct cdns_spi {
 115         void __iomem *regs;
 116         struct clk *ref_clk;
 117         struct clk *pclk;
 118         u32 speed_hz;
 119         const u8 *txbuf;
 120         u8 *rxbuf;
 121         int tx_bytes;
 122         int rx_bytes;
 123         u8 dev_busy;
 124         u32 is_decoded_cs;
 125 };
 126 
 127 /* Macros for the SPI controller read/write */
 128 static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset)
 129 {
 130         return readl_relaxed(xspi->regs + offset);
 131 }
 132 
 133 static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val)
 134 {
 135         writel_relaxed(val, xspi->regs + offset);
 136 }
 137 
 138 /**
 139  * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller
 140  * @xspi:       Pointer to the cdns_spi structure
 141  *
 142  * On reset the SPI controller is configured to be in master mode, baud rate
 143  * divisor is set to 4, threshold value for TX FIFO not full interrupt is set
 144  * to 1 and size of the word to be transferred as 8 bit.
 145  * This function initializes the SPI controller to disable and clear all the
 146  * interrupts, enable manual slave select and manual start, deselect all the
 147  * chip select lines, and enable the SPI controller.
 148  */
 149 static void cdns_spi_init_hw(struct cdns_spi *xspi)
 150 {
 151         u32 ctrl_reg = CDNS_SPI_CR_DEFAULT;
 152 
 153         if (xspi->is_decoded_cs)
 154                 ctrl_reg |= CDNS_SPI_CR_PERI_SEL;
 155 
 156         cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
 157         cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_ALL);
 158 
 159         /* Clear the RX FIFO */
 160         while (cdns_spi_read(xspi, CDNS_SPI_ISR) & CDNS_SPI_IXR_RXNEMTY)
 161                 cdns_spi_read(xspi, CDNS_SPI_RXD);
 162 
 163         cdns_spi_write(xspi, CDNS_SPI_ISR, CDNS_SPI_IXR_ALL);
 164         cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
 165         cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
 166 }
 167 
 168 /**
 169  * cdns_spi_chipselect - Select or deselect the chip select line
 170  * @spi:        Pointer to the spi_device structure
 171  * @is_high:    Select(0) or deselect (1) the chip select line
 172  */
 173 static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)
 174 {
 175         struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
 176         u32 ctrl_reg;
 177 
 178         ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
 179 
 180         if (is_high) {
 181                 /* Deselect the slave */
 182                 ctrl_reg |= CDNS_SPI_CR_SSCTRL;
 183         } else {
 184                 /* Select the slave */
 185                 ctrl_reg &= ~CDNS_SPI_CR_SSCTRL;
 186                 if (!(xspi->is_decoded_cs))
 187                         ctrl_reg |= ((~(CDNS_SPI_SS0 << spi->chip_select)) <<
 188                                      CDNS_SPI_SS_SHIFT) &
 189                                      CDNS_SPI_CR_SSCTRL;
 190                 else
 191                         ctrl_reg |= (spi->chip_select << CDNS_SPI_SS_SHIFT) &
 192                                      CDNS_SPI_CR_SSCTRL;
 193         }
 194 
 195         cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
 196 }
 197 
 198 /**
 199  * cdns_spi_config_clock_mode - Sets clock polarity and phase
 200  * @spi:        Pointer to the spi_device structure
 201  *
 202  * Sets the requested clock polarity and phase.
 203  */
 204 static void cdns_spi_config_clock_mode(struct spi_device *spi)
 205 {
 206         struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
 207         u32 ctrl_reg, new_ctrl_reg;
 208 
 209         new_ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
 210         ctrl_reg = new_ctrl_reg;
 211 
 212         /* Set the SPI clock phase and clock polarity */
 213         new_ctrl_reg &= ~(CDNS_SPI_CR_CPHA | CDNS_SPI_CR_CPOL);
 214         if (spi->mode & SPI_CPHA)
 215                 new_ctrl_reg |= CDNS_SPI_CR_CPHA;
 216         if (spi->mode & SPI_CPOL)
 217                 new_ctrl_reg |= CDNS_SPI_CR_CPOL;
 218 
 219         if (new_ctrl_reg != ctrl_reg) {
 220                 /*
 221                  * Just writing the CR register does not seem to apply the clock
 222                  * setting changes. This is problematic when changing the clock
 223                  * polarity as it will cause the SPI slave to see spurious clock
 224                  * transitions. To workaround the issue toggle the ER register.
 225                  */
 226                 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
 227                 cdns_spi_write(xspi, CDNS_SPI_CR, new_ctrl_reg);
 228                 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
 229         }
 230 }
 231 
 232 /**
 233  * cdns_spi_config_clock_freq - Sets clock frequency
 234  * @spi:        Pointer to the spi_device structure
 235  * @transfer:   Pointer to the spi_transfer structure which provides
 236  *              information about next transfer setup parameters
 237  *
 238  * Sets the requested clock frequency.
 239  * Note: If the requested frequency is not an exact match with what can be
 240  * obtained using the prescalar value the driver sets the clock frequency which
 241  * is lower than the requested frequency (maximum lower) for the transfer. If
 242  * the requested frequency is higher or lower than that is supported by the SPI
 243  * controller the driver will set the highest or lowest frequency supported by
 244  * controller.
 245  */
 246 static void cdns_spi_config_clock_freq(struct spi_device *spi,
 247                                        struct spi_transfer *transfer)
 248 {
 249         struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
 250         u32 ctrl_reg, baud_rate_val;
 251         unsigned long frequency;
 252 
 253         frequency = clk_get_rate(xspi->ref_clk);
 254 
 255         ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
 256 
 257         /* Set the clock frequency */
 258         if (xspi->speed_hz != transfer->speed_hz) {
 259                 /* first valid value is 1 */
 260                 baud_rate_val = CDNS_SPI_BAUD_DIV_MIN;
 261                 while ((baud_rate_val < CDNS_SPI_BAUD_DIV_MAX) &&
 262                        (frequency / (2 << baud_rate_val)) > transfer->speed_hz)
 263                         baud_rate_val++;
 264 
 265                 ctrl_reg &= ~CDNS_SPI_CR_BAUD_DIV;
 266                 ctrl_reg |= baud_rate_val << CDNS_SPI_BAUD_DIV_SHIFT;
 267 
 268                 xspi->speed_hz = frequency / (2 << baud_rate_val);
 269         }
 270         cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
 271 }
 272 
 273 /**
 274  * cdns_spi_setup_transfer - Configure SPI controller for specified transfer
 275  * @spi:        Pointer to the spi_device structure
 276  * @transfer:   Pointer to the spi_transfer structure which provides
 277  *              information about next transfer setup parameters
 278  *
 279  * Sets the operational mode of SPI controller for the next SPI transfer and
 280  * sets the requested clock frequency.
 281  *
 282  * Return:      Always 0
 283  */
 284 static int cdns_spi_setup_transfer(struct spi_device *spi,
 285                                    struct spi_transfer *transfer)
 286 {
 287         struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
 288 
 289         cdns_spi_config_clock_freq(spi, transfer);
 290 
 291         dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n",
 292                 __func__, spi->mode, spi->bits_per_word,
 293                 xspi->speed_hz);
 294 
 295         return 0;
 296 }
 297 
 298 /**
 299  * cdns_spi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible
 300  * @xspi:       Pointer to the cdns_spi structure
 301  */
 302 static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi)
 303 {
 304         unsigned long trans_cnt = 0;
 305 
 306         while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) &&
 307                (xspi->tx_bytes > 0)) {
 308 
 309                 /* When xspi in busy condition, bytes may send failed,
 310                  * then spi control did't work thoroughly, add one byte delay
 311                  */
 312                 if (cdns_spi_read(xspi, CDNS_SPI_ISR) &
 313                     CDNS_SPI_IXR_TXFULL)
 314                         udelay(10);
 315 
 316                 if (xspi->txbuf)
 317                         cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);
 318                 else
 319                         cdns_spi_write(xspi, CDNS_SPI_TXD, 0);
 320 
 321                 xspi->tx_bytes--;
 322                 trans_cnt++;
 323         }
 324 }
 325 
 326 /**
 327  * cdns_spi_irq - Interrupt service routine of the SPI controller
 328  * @irq:        IRQ number
 329  * @dev_id:     Pointer to the xspi structure
 330  *
 331  * This function handles TX empty and Mode Fault interrupts only.
 332  * On TX empty interrupt this function reads the received data from RX FIFO and
 333  * fills the TX FIFO if there is any data remaining to be transferred.
 334  * On Mode Fault interrupt this function indicates that transfer is completed,
 335  * the SPI subsystem will identify the error as the remaining bytes to be
 336  * transferred is non-zero.
 337  *
 338  * Return:      IRQ_HANDLED when handled; IRQ_NONE otherwise.
 339  */
 340 static irqreturn_t cdns_spi_irq(int irq, void *dev_id)
 341 {
 342         struct spi_master *master = dev_id;
 343         struct cdns_spi *xspi = spi_master_get_devdata(master);
 344         u32 intr_status, status;
 345 
 346         status = IRQ_NONE;
 347         intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR);
 348         cdns_spi_write(xspi, CDNS_SPI_ISR, intr_status);
 349 
 350         if (intr_status & CDNS_SPI_IXR_MODF) {
 351                 /* Indicate that transfer is completed, the SPI subsystem will
 352                  * identify the error as the remaining bytes to be
 353                  * transferred is non-zero
 354                  */
 355                 cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_DEFAULT);
 356                 spi_finalize_current_transfer(master);
 357                 status = IRQ_HANDLED;
 358         } else if (intr_status & CDNS_SPI_IXR_TXOW) {
 359                 unsigned long trans_cnt;
 360 
 361                 trans_cnt = xspi->rx_bytes - xspi->tx_bytes;
 362 
 363                 /* Read out the data from the RX FIFO */
 364                 while (trans_cnt) {
 365                         u8 data;
 366 
 367                         data = cdns_spi_read(xspi, CDNS_SPI_RXD);
 368                         if (xspi->rxbuf)
 369                                 *xspi->rxbuf++ = data;
 370 
 371                         xspi->rx_bytes--;
 372                         trans_cnt--;
 373                 }
 374 
 375                 if (xspi->tx_bytes) {
 376                         /* There is more data to send */
 377                         cdns_spi_fill_tx_fifo(xspi);
 378                 } else {
 379                         /* Transfer is completed */
 380                         cdns_spi_write(xspi, CDNS_SPI_IDR,
 381                                        CDNS_SPI_IXR_DEFAULT);
 382                         spi_finalize_current_transfer(master);
 383                 }
 384                 status = IRQ_HANDLED;
 385         }
 386 
 387         return status;
 388 }
 389 
 390 static int cdns_prepare_message(struct spi_master *master,
 391                                 struct spi_message *msg)
 392 {
 393         cdns_spi_config_clock_mode(msg->spi);
 394         return 0;
 395 }
 396 
 397 /**
 398  * cdns_transfer_one - Initiates the SPI transfer
 399  * @master:     Pointer to spi_master structure
 400  * @spi:        Pointer to the spi_device structure
 401  * @transfer:   Pointer to the spi_transfer structure which provides
 402  *              information about next transfer parameters
 403  *
 404  * This function fills the TX FIFO, starts the SPI transfer and
 405  * returns a positive transfer count so that core will wait for completion.
 406  *
 407  * Return:      Number of bytes transferred in the last transfer
 408  */
 409 static int cdns_transfer_one(struct spi_master *master,
 410                              struct spi_device *spi,
 411                              struct spi_transfer *transfer)
 412 {
 413         struct cdns_spi *xspi = spi_master_get_devdata(master);
 414 
 415         xspi->txbuf = transfer->tx_buf;
 416         xspi->rxbuf = transfer->rx_buf;
 417         xspi->tx_bytes = transfer->len;
 418         xspi->rx_bytes = transfer->len;
 419 
 420         cdns_spi_setup_transfer(spi, transfer);
 421 
 422         cdns_spi_fill_tx_fifo(xspi);
 423 
 424         cdns_spi_write(xspi, CDNS_SPI_IER, CDNS_SPI_IXR_DEFAULT);
 425         return transfer->len;
 426 }
 427 
 428 /**
 429  * cdns_prepare_transfer_hardware - Prepares hardware for transfer.
 430  * @master:     Pointer to the spi_master structure which provides
 431  *              information about the controller.
 432  *
 433  * This function enables SPI master controller.
 434  *
 435  * Return:      0 always
 436  */
 437 static int cdns_prepare_transfer_hardware(struct spi_master *master)
 438 {
 439         struct cdns_spi *xspi = spi_master_get_devdata(master);
 440 
 441         cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
 442 
 443         return 0;
 444 }
 445 
 446 /**
 447  * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer
 448  * @master:     Pointer to the spi_master structure which provides
 449  *              information about the controller.
 450  *
 451  * This function disables the SPI master controller.
 452  *
 453  * Return:      0 always
 454  */
 455 static int cdns_unprepare_transfer_hardware(struct spi_master *master)
 456 {
 457         struct cdns_spi *xspi = spi_master_get_devdata(master);
 458 
 459         cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
 460 
 461         return 0;
 462 }
 463 
 464 /**
 465  * cdns_spi_probe - Probe method for the SPI driver
 466  * @pdev:       Pointer to the platform_device structure
 467  *
 468  * This function initializes the driver data structures and the hardware.
 469  *
 470  * Return:      0 on success and error value on error
 471  */
 472 static int cdns_spi_probe(struct platform_device *pdev)
 473 {
 474         int ret = 0, irq;
 475         struct spi_master *master;
 476         struct cdns_spi *xspi;
 477         u32 num_cs;
 478 
 479         master = spi_alloc_master(&pdev->dev, sizeof(*xspi));
 480         if (!master)
 481                 return -ENOMEM;
 482 
 483         xspi = spi_master_get_devdata(master);
 484         master->dev.of_node = pdev->dev.of_node;
 485         platform_set_drvdata(pdev, master);
 486 
 487         xspi->regs = devm_platform_ioremap_resource(pdev, 0);
 488         if (IS_ERR(xspi->regs)) {
 489                 ret = PTR_ERR(xspi->regs);
 490                 goto remove_master;
 491         }
 492 
 493         xspi->pclk = devm_clk_get(&pdev->dev, "pclk");
 494         if (IS_ERR(xspi->pclk)) {
 495                 dev_err(&pdev->dev, "pclk clock not found.\n");
 496                 ret = PTR_ERR(xspi->pclk);
 497                 goto remove_master;
 498         }
 499 
 500         xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");
 501         if (IS_ERR(xspi->ref_clk)) {
 502                 dev_err(&pdev->dev, "ref_clk clock not found.\n");
 503                 ret = PTR_ERR(xspi->ref_clk);
 504                 goto remove_master;
 505         }
 506 
 507         ret = clk_prepare_enable(xspi->pclk);
 508         if (ret) {
 509                 dev_err(&pdev->dev, "Unable to enable APB clock.\n");
 510                 goto remove_master;
 511         }
 512 
 513         ret = clk_prepare_enable(xspi->ref_clk);
 514         if (ret) {
 515                 dev_err(&pdev->dev, "Unable to enable device clock.\n");
 516                 goto clk_dis_apb;
 517         }
 518 
 519         ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
 520         if (ret < 0)
 521                 master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;
 522         else
 523                 master->num_chipselect = num_cs;
 524 
 525         ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs",
 526                                    &xspi->is_decoded_cs);
 527         if (ret < 0)
 528                 xspi->is_decoded_cs = 0;
 529 
 530         /* SPI controller initializations */
 531         cdns_spi_init_hw(xspi);
 532 
 533         pm_runtime_set_active(&pdev->dev);
 534         pm_runtime_enable(&pdev->dev);
 535         pm_runtime_use_autosuspend(&pdev->dev);
 536         pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
 537 
 538         irq = platform_get_irq(pdev, 0);
 539         if (irq <= 0) {
 540                 ret = -ENXIO;
 541                 goto clk_dis_all;
 542         }
 543 
 544         ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq,
 545                                0, pdev->name, master);
 546         if (ret != 0) {
 547                 ret = -ENXIO;
 548                 dev_err(&pdev->dev, "request_irq failed\n");
 549                 goto clk_dis_all;
 550         }
 551 
 552         master->use_gpio_descriptors = true;
 553         master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;
 554         master->prepare_message = cdns_prepare_message;
 555         master->transfer_one = cdns_transfer_one;
 556         master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
 557         master->set_cs = cdns_spi_chipselect;
 558         master->auto_runtime_pm = true;
 559         master->mode_bits = SPI_CPOL | SPI_CPHA;
 560 
 561         /* Set to default valid value */
 562         master->max_speed_hz = clk_get_rate(xspi->ref_clk) / 4;
 563         xspi->speed_hz = master->max_speed_hz;
 564 
 565         master->bits_per_word_mask = SPI_BPW_MASK(8);
 566 
 567         ret = spi_register_master(master);
 568         if (ret) {
 569                 dev_err(&pdev->dev, "spi_register_master failed\n");
 570                 goto clk_dis_all;
 571         }
 572 
 573         return ret;
 574 
 575 clk_dis_all:
 576         pm_runtime_set_suspended(&pdev->dev);
 577         pm_runtime_disable(&pdev->dev);
 578         clk_disable_unprepare(xspi->ref_clk);
 579 clk_dis_apb:
 580         clk_disable_unprepare(xspi->pclk);
 581 remove_master:
 582         spi_master_put(master);
 583         return ret;
 584 }
 585 
 586 /**
 587  * cdns_spi_remove - Remove method for the SPI driver
 588  * @pdev:       Pointer to the platform_device structure
 589  *
 590  * This function is called if a device is physically removed from the system or
 591  * if the driver module is being unloaded. It frees all resources allocated to
 592  * the device.
 593  *
 594  * Return:      0 on success and error value on error
 595  */
 596 static int cdns_spi_remove(struct platform_device *pdev)
 597 {
 598         struct spi_master *master = platform_get_drvdata(pdev);
 599         struct cdns_spi *xspi = spi_master_get_devdata(master);
 600 
 601         cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
 602 
 603         clk_disable_unprepare(xspi->ref_clk);
 604         clk_disable_unprepare(xspi->pclk);
 605         pm_runtime_set_suspended(&pdev->dev);
 606         pm_runtime_disable(&pdev->dev);
 607 
 608         spi_unregister_master(master);
 609 
 610         return 0;
 611 }
 612 
 613 /**
 614  * cdns_spi_suspend - Suspend method for the SPI driver
 615  * @dev:        Address of the platform_device structure
 616  *
 617  * This function disables the SPI controller and
 618  * changes the driver state to "suspend"
 619  *
 620  * Return:      0 on success and error value on error
 621  */
 622 static int __maybe_unused cdns_spi_suspend(struct device *dev)
 623 {
 624         struct spi_master *master = dev_get_drvdata(dev);
 625 
 626         return spi_master_suspend(master);
 627 }
 628 
 629 /**
 630  * cdns_spi_resume - Resume method for the SPI driver
 631  * @dev:        Address of the platform_device structure
 632  *
 633  * This function changes the driver state to "ready"
 634  *
 635  * Return:      0 on success and error value on error
 636  */
 637 static int __maybe_unused cdns_spi_resume(struct device *dev)
 638 {
 639         struct spi_master *master = dev_get_drvdata(dev);
 640         struct cdns_spi *xspi = spi_master_get_devdata(master);
 641 
 642         cdns_spi_init_hw(xspi);
 643         return spi_master_resume(master);
 644 }
 645 
 646 /**
 647  * cdns_spi_runtime_resume - Runtime resume method for the SPI driver
 648  * @dev:        Address of the platform_device structure
 649  *
 650  * This function enables the clocks
 651  *
 652  * Return:      0 on success and error value on error
 653  */
 654 static int __maybe_unused cnds_runtime_resume(struct device *dev)
 655 {
 656         struct spi_master *master = dev_get_drvdata(dev);
 657         struct cdns_spi *xspi = spi_master_get_devdata(master);
 658         int ret;
 659 
 660         ret = clk_prepare_enable(xspi->pclk);
 661         if (ret) {
 662                 dev_err(dev, "Cannot enable APB clock.\n");
 663                 return ret;
 664         }
 665 
 666         ret = clk_prepare_enable(xspi->ref_clk);
 667         if (ret) {
 668                 dev_err(dev, "Cannot enable device clock.\n");
 669                 clk_disable_unprepare(xspi->pclk);
 670                 return ret;
 671         }
 672         return 0;
 673 }
 674 
 675 /**
 676  * cdns_spi_runtime_suspend - Runtime suspend method for the SPI driver
 677  * @dev:        Address of the platform_device structure
 678  *
 679  * This function disables the clocks
 680  *
 681  * Return:      Always 0
 682  */
 683 static int __maybe_unused cnds_runtime_suspend(struct device *dev)
 684 {
 685         struct spi_master *master = dev_get_drvdata(dev);
 686         struct cdns_spi *xspi = spi_master_get_devdata(master);
 687 
 688         clk_disable_unprepare(xspi->ref_clk);
 689         clk_disable_unprepare(xspi->pclk);
 690 
 691         return 0;
 692 }
 693 
 694 static const struct dev_pm_ops cdns_spi_dev_pm_ops = {
 695         SET_RUNTIME_PM_OPS(cnds_runtime_suspend,
 696                            cnds_runtime_resume, NULL)
 697         SET_SYSTEM_SLEEP_PM_OPS(cdns_spi_suspend, cdns_spi_resume)
 698 };
 699 
 700 static const struct of_device_id cdns_spi_of_match[] = {
 701         { .compatible = "xlnx,zynq-spi-r1p6" },
 702         { .compatible = "cdns,spi-r1p6" },
 703         { /* end of table */ }
 704 };
 705 MODULE_DEVICE_TABLE(of, cdns_spi_of_match);
 706 
 707 /* cdns_spi_driver - This structure defines the SPI subsystem platform driver */
 708 static struct platform_driver cdns_spi_driver = {
 709         .probe  = cdns_spi_probe,
 710         .remove = cdns_spi_remove,
 711         .driver = {
 712                 .name = CDNS_SPI_NAME,
 713                 .of_match_table = cdns_spi_of_match,
 714                 .pm = &cdns_spi_dev_pm_ops,
 715         },
 716 };
 717 
 718 module_platform_driver(cdns_spi_driver);
 719 
 720 MODULE_AUTHOR("Xilinx, Inc.");
 721 MODULE_DESCRIPTION("Cadence SPI driver");
 722 MODULE_LICENSE("GPL");