/*
   * drivers/spi/spi-fsl-dspi.c
   *
   * Copyright 2013 Freescale Semiconductor, Inc.
   *
   * Freescale DSPI driver
   * This file contains a driver for the Freescale DSPI
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   */
  
  #include <linux/clk.h>
  #include <linux/delay.h>
  #include <linux/err.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/math64.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/pinctrl/consumer.h>
  #include <linux/platform_device.h>
  #include <linux/pm_runtime.h>
  #include <linux/regmap.h>
  #include <linux/sched.h>
  #include <linux/spi/spi.h>
  #include <linux/spi/spi_bitbang.h>
  #include <linux/time.h>
  
  #define DRIVER_NAME "fsl-dspi"
  
  #define TRAN_STATE_RX_VOID		0x01
  #define TRAN_STATE_TX_VOID		0x02
  #define TRAN_STATE_WORD_ODD_NUM	0x04
  
  #define DSPI_FIFO_SIZE			4
  
  #define SPI_MCR		0x00
  #define SPI_MCR_MASTER		(1 << 31)
  #define SPI_MCR_PCSIS		(0x3F << 16)
  #define SPI_MCR_CLR_TXF	(1 << 11)
  #define SPI_MCR_CLR_RXF	(1 << 10)
  
  #define SPI_TCR			0x08
  #define SPI_TCR_GET_TCNT(x)	(((x) & 0xffff0000) >> 16)
  
  #define SPI_CTAR(x)		(0x0c + (((x) & 0x3) * 4))
  #define SPI_CTAR_FMSZ(x)	(((x) & 0x0000000f) << 27)
  #define SPI_CTAR_CPOL(x)	((x) << 26)
  #define SPI_CTAR_CPHA(x)	((x) << 25)
  #define SPI_CTAR_LSBFE(x)	((x) << 24)
  #define SPI_CTAR_PCSSCK(x)	(((x) & 0x00000003) << 22)
  #define SPI_CTAR_PASC(x)	(((x) & 0x00000003) << 20)
  #define SPI_CTAR_PDT(x)	(((x) & 0x00000003) << 18)
  #define SPI_CTAR_PBR(x)	(((x) & 0x00000003) << 16)
  #define SPI_CTAR_CSSCK(x)	(((x) & 0x0000000f) << 12)
  #define SPI_CTAR_ASC(x)	(((x) & 0x0000000f) << 8)
  #define SPI_CTAR_DT(x)		(((x) & 0x0000000f) << 4)
  #define SPI_CTAR_BR(x)		((x) & 0x0000000f)
  #define SPI_CTAR_SCALE_BITS	0xf
  
  #define SPI_CTAR0_SLAVE	0x0c
  
  #define SPI_SR			0x2c
  #define SPI_SR_EOQF		0x10000000
  #define SPI_SR_TCFQF		0x80000000
  
  #define SPI_RSER		0x30
  #define SPI_RSER_EOQFE		0x10000000
  #define SPI_RSER_TCFQE		0x80000000
  
  #define SPI_PUSHR		0x34
  #define SPI_PUSHR_CONT		(1 << 31)
  #define SPI_PUSHR_CTAS(x)	(((x) & 0x00000003) << 28)
  #define SPI_PUSHR_EOQ		(1 << 27)
  #define SPI_PUSHR_CTCNT	(1 << 26)
  #define SPI_PUSHR_PCS(x)	(((1 << x) & 0x0000003f) << 16)
  #define SPI_PUSHR_TXDATA(x)	((x) & 0x0000ffff)
  
  #define SPI_PUSHR_SLAVE	0x34
  
  #define SPI_POPR		0x38
  #define SPI_POPR_RXDATA(x)	((x) & 0x0000ffff)
  
  #define SPI_TXFR0		0x3c
  #define SPI_TXFR1		0x40
  #define SPI_TXFR2		0x44
  #define SPI_TXFR3		0x48
  #define SPI_RXFR0		0x7c
  #define SPI_RXFR1		0x80
  #define SPI_RXFR2		0x84
  #define SPI_RXFR3		0x88
  
  #define SPI_FRAME_BITS(bits)	SPI_CTAR_FMSZ((bits) - 1)
  #define SPI_FRAME_BITS_MASK	SPI_CTAR_FMSZ(0xf)
  #define SPI_FRAME_BITS_16	SPI_CTAR_FMSZ(0xf)
  #define SPI_FRAME_BITS_8	SPI_CTAR_FMSZ(0x7)
  
  #define SPI_CS_INIT		0x01
  #define SPI_CS_ASSERT		0x02
  #define SPI_CS_DROP		0x04
  
  #define SPI_TCR_TCNT_MAX	0x10000
  
  struct chip_data {
  	u32 mcr_val;
  	u32 ctar_val;
  	u16 void_write_data;
  };
  
  enum dspi_trans_mode {
  	DSPI_EOQ_MODE = 0,
  	DSPI_TCFQ_MODE,
  };
  
  struct fsl_dspi_devtype_data {
  	enum dspi_trans_mode trans_mode;
  };
  
  static const struct fsl_dspi_devtype_data vf610_data = {
  	.trans_mode = DSPI_EOQ_MODE,
  };
  
  static const struct fsl_dspi_devtype_data ls1021a_v1_data = {
  	.trans_mode = DSPI_TCFQ_MODE,
  };
  
  static const struct fsl_dspi_devtype_data ls2085a_data = {
  	.trans_mode = DSPI_TCFQ_MODE,
  };
  
  struct fsl_dspi {
  	struct spi_master	*master;
  	struct platform_device	*pdev;
  
  	struct regmap		*regmap;
  	int			irq;
  	struct clk		*clk;
  
  	struct spi_transfer	*cur_transfer;
  	struct spi_message	*cur_msg;
  	struct chip_data	*cur_chip;
  	size_t			len;
  	void			*tx;
  	void			*tx_end;
  	void			*rx;
  	void			*rx_end;
  	char			dataflags;
  	u8			cs;
  	u16			void_write_data;
  	u32			cs_change;
  	struct fsl_dspi_devtype_data *devtype_data;
  
  	wait_queue_head_t	waitq;
  	u32			waitflags;
  
  	u32			spi_tcnt;
  };
  
  static inline int is_double_byte_mode(struct fsl_dspi *dspi)
  {
  	unsigned int val;
  
  	regmap_read(dspi->regmap, SPI_CTAR(0), &val);
  
  	return ((val & SPI_FRAME_BITS_MASK) == SPI_FRAME_BITS(8)) ? 0 : 1;
  }
  
  static void hz_to_spi_baud(char *pbr, char *br, int speed_hz,
  		unsigned long clkrate)
  {
  	/* Valid baud rate pre-scaler values */
  	int pbr_tbl[4] = {2, 3, 5, 7};
  	int brs[16] = {	2,	4,	6,	8,
  		16,	32,	64,	128,
  		256,	512,	1024,	2048,
  		4096,	8192,	16384,	32768 };
  	int scale_needed, scale, minscale = INT_MAX;
  	int i, j;
  
  	scale_needed = clkrate / speed_hz;
  	if (clkrate % speed_hz)
  		scale_needed++;
  
  	for (i = 0; i < ARRAY_SIZE(brs); i++)
  		for (j = 0; j < ARRAY_SIZE(pbr_tbl); j++) {
  			scale = brs[i] * pbr_tbl[j];
  			if (scale >= scale_needed) {
  				if (scale < minscale) {
  					minscale = scale;
  					*br = i;
  					*pbr = j;
  				}
  				break;
  			}
  		}
  
  	if (minscale == INT_MAX) {
  		pr_warn("Can not find valid baud rate,speed_hz is %d,clkrate is %ld, we use the max prescaler value.
  ",
  			speed_hz, clkrate);
  		*pbr = ARRAY_SIZE(pbr_tbl) - 1;
  		*br =  ARRAY_SIZE(brs) - 1;
  	}
  }
  
  static void ns_delay_scale(char *psc, char *sc, int delay_ns,
  		unsigned long clkrate)
  {
  	int pscale_tbl[4] = {1, 3, 5, 7};
  	int scale_needed, scale, minscale = INT_MAX;
  	int i, j;
  	u32 remainder;
  
  	scale_needed = div_u64_rem((u64)delay_ns * clkrate, NSEC_PER_SEC,
  			&remainder);
  	if (remainder)
  		scale_needed++;
  
  	for (i = 0; i < ARRAY_SIZE(pscale_tbl); i++)
  		for (j = 0; j <= SPI_CTAR_SCALE_BITS; j++) {
  			scale = pscale_tbl[i] * (2 << j);
  			if (scale >= scale_needed) {
  				if (scale < minscale) {
  					minscale = scale;
  					*psc = i;
  					*sc = j;
  				}
  				break;
  			}
  		}
  
  	if (minscale == INT_MAX) {
  		pr_warn("Cannot find correct scale values for %dns delay at clkrate %ld, using max prescaler value",
  			delay_ns, clkrate);
  		*psc = ARRAY_SIZE(pscale_tbl) - 1;
  		*sc = SPI_CTAR_SCALE_BITS;
  	}
  }
  
  static u32 dspi_data_to_pushr(struct fsl_dspi *dspi, int tx_word)
  {
  	u16 d16;
  
  	if (!(dspi->dataflags & TRAN_STATE_TX_VOID))
  		d16 = tx_word ? *(u16 *)dspi->tx : *(u8 *)dspi->tx;
  	else
  		d16 = dspi->void_write_data;
  
  	dspi->tx += tx_word + 1;
  	dspi->len -= tx_word + 1;
  
  	return	SPI_PUSHR_TXDATA(d16) |
  		SPI_PUSHR_PCS(dspi->cs) |
  		SPI_PUSHR_CTAS(0) |
  		SPI_PUSHR_CONT;
  }
  
  static void dspi_data_from_popr(struct fsl_dspi *dspi, int rx_word)
  {
  	u16 d;
  	unsigned int val;
  
  	regmap_read(dspi->regmap, SPI_POPR, &val);
  	d = SPI_POPR_RXDATA(val);
  
  	if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
  		rx_word ? (*(u16 *)dspi->rx = d) : (*(u8 *)dspi->rx = d);
  
  	dspi->rx += rx_word + 1;
  }
  
  static int dspi_eoq_write(struct fsl_dspi *dspi)
  {
  	int tx_count = 0;
  	int tx_word;
  	u32 dspi_pushr = 0;
  
  	tx_word = is_double_byte_mode(dspi);
  
  	while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
  		/* If we are in word mode, only have a single byte to transfer
  		 * switch to byte mode temporarily.  Will switch back at the
  		 * end of the transfer.
  		 */
  		if (tx_word && (dspi->len == 1)) {
  			dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
  			regmap_update_bits(dspi->regmap, SPI_CTAR(0),
  					SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
  			tx_word = 0;
  		}
  
  		dspi_pushr = dspi_data_to_pushr(dspi, tx_word);
  
  		if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1) {
  			/* last transfer in the transfer */
  			dspi_pushr |= SPI_PUSHR_EOQ;
  			if ((dspi->cs_change) && (!dspi->len))
  				dspi_pushr &= ~SPI_PUSHR_CONT;
  		} else if (tx_word && (dspi->len == 1))
  			dspi_pushr |= SPI_PUSHR_EOQ;
  
  		regmap_write(dspi->regmap, SPI_PUSHR, dspi_pushr);
  
  		tx_count++;
  	}
  
  	return tx_count * (tx_word + 1);
  }
  
  static int dspi_eoq_read(struct fsl_dspi *dspi)
  {
  	int rx_count = 0;
  	int rx_word = is_double_byte_mode(dspi);
  
  	while ((dspi->rx < dspi->rx_end)
  			&& (rx_count < DSPI_FIFO_SIZE)) {
  		if (rx_word && (dspi->rx_end - dspi->rx) == 1)
  			rx_word = 0;
  
  		dspi_data_from_popr(dspi, rx_word);
  		rx_count++;
  	}
  
  	return rx_count;
  }
  
  static int dspi_tcfq_write(struct fsl_dspi *dspi)
  {
  	int tx_word;
  	u32 dspi_pushr = 0;
  
  	tx_word = is_double_byte_mode(dspi);
  
  	if (tx_word && (dspi->len == 1)) {
  		dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
  		regmap_update_bits(dspi->regmap, SPI_CTAR(0),
  				SPI_FRAME_BITS_MASK, SPI_FRAME_BITS(8));
  		tx_word = 0;
  	}
  
  	dspi_pushr = dspi_data_to_pushr(dspi, tx_word);
  
  	if ((dspi->cs_change) && (!dspi->len))
  		dspi_pushr &= ~SPI_PUSHR_CONT;
  
  	regmap_write(dspi->regmap, SPI_PUSHR, dspi_pushr);
  
  	return tx_word + 1;
  }
  
  static void dspi_tcfq_read(struct fsl_dspi *dspi)
  {
  	int rx_word = is_double_byte_mode(dspi);
  
  	if (rx_word && (dspi->rx_end - dspi->rx) == 1)
  		rx_word = 0;
  
  	dspi_data_from_popr(dspi, rx_word);
  }
  
  static int dspi_transfer_one_message(struct spi_master *master,
  		struct spi_message *message)
  {
  	struct fsl_dspi *dspi = spi_master_get_devdata(master);
  	struct spi_device *spi = message->spi;
  	struct spi_transfer *transfer;
  	int status = 0;
  	enum dspi_trans_mode trans_mode;
  	u32 spi_tcr;
  
  	regmap_read(dspi->regmap, SPI_TCR, &spi_tcr);
  	dspi->spi_tcnt = SPI_TCR_GET_TCNT(spi_tcr);
  
  	message->actual_length = 0;
  
  	list_for_each_entry(transfer, &message->transfers, transfer_list) {
  		dspi->cur_transfer = transfer;
  		dspi->cur_msg = message;
  		dspi->cur_chip = spi_get_ctldata(spi);
  		dspi->cs = spi->chip_select;
  		dspi->cs_change = 0;
  		if (dspi->cur_transfer->transfer_list.next
  				== &dspi->cur_msg->transfers)
  			dspi->cs_change = 1;
  		dspi->void_write_data = dspi->cur_chip->void_write_data;
  
  		dspi->dataflags = 0;
  		dspi->tx = (void *)transfer->tx_buf;
  		dspi->tx_end = dspi->tx + transfer->len;
  		dspi->rx = transfer->rx_buf;
  		dspi->rx_end = dspi->rx + transfer->len;
  		dspi->len = transfer->len;
  
  		if (!dspi->rx)
  			dspi->dataflags |= TRAN_STATE_RX_VOID;
  
  		if (!dspi->tx)
  			dspi->dataflags |= TRAN_STATE_TX_VOID;
  
  		regmap_write(dspi->regmap, SPI_MCR, dspi->cur_chip->mcr_val);
  		regmap_update_bits(dspi->regmap, SPI_MCR,
  				SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF,
  				SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF);
  		regmap_write(dspi->regmap, SPI_CTAR(0),
  				dspi->cur_chip->ctar_val);
  
  		trans_mode = dspi->devtype_data->trans_mode;
  		switch (trans_mode) {
  		case DSPI_EOQ_MODE:
  			regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_EOQFE);
  			dspi_eoq_write(dspi);
  			break;
  		case DSPI_TCFQ_MODE:
  			regmap_write(dspi->regmap, SPI_RSER, SPI_RSER_TCFQE);
  			dspi_tcfq_write(dspi);
  			break;
  		default:
  			dev_err(&dspi->pdev->dev, "unsupported trans_mode %u
  ",
  				trans_mode);
  			status = -EINVAL;
  			goto out;
  		}
  
  		if (wait_event_interruptible(dspi->waitq, dspi->waitflags))
  			dev_err(&dspi->pdev->dev, "wait transfer complete fail!
  ");
  		dspi->waitflags = 0;
  
  		if (transfer->delay_usecs)
  			udelay(transfer->delay_usecs);
  	}
  
  out:
  	message->status = status;
  	spi_finalize_current_message(master);
  
  	return status;
  }
  
  static int dspi_setup(struct spi_device *spi)
  {
  	struct chip_data *chip;
  	struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
  	u32 cs_sck_delay = 0, sck_cs_delay = 0;
  	unsigned char br = 0, pbr = 0, pcssck = 0, cssck = 0;
  	unsigned char pasc = 0, asc = 0, fmsz = 0;
  	unsigned long clkrate;
  
  	if ((spi->bits_per_word >= 4) && (spi->bits_per_word <= 16)) {
  		fmsz = spi->bits_per_word - 1;
  	} else {
  		pr_err("Invalid wordsize
  ");
  		return -ENODEV;
  	}
  
  	/* Only alloc on first setup */
  	chip = spi_get_ctldata(spi);
  	if (chip == NULL) {
  		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
  		if (!chip)
  			return -ENOMEM;
  	}
  
  	of_property_read_u32(spi->dev.of_node, "fsl,spi-cs-sck-delay",
  			&cs_sck_delay);
  
  	of_property_read_u32(spi->dev.of_node, "fsl,spi-sck-cs-delay",
  			&sck_cs_delay);
  
  	chip->mcr_val = SPI_MCR_MASTER | SPI_MCR_PCSIS |
  		SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF;
  
  	chip->void_write_data = 0;
  
  	clkrate = clk_get_rate(dspi->clk);
  	hz_to_spi_baud(&pbr, &br, spi->max_speed_hz, clkrate);
  
  	/* Set PCS to SCK delay scale values */
  	ns_delay_scale(&pcssck, &cssck, cs_sck_delay, clkrate);
  
  	/* Set After SCK delay scale values */
  	ns_delay_scale(&pasc, &asc, sck_cs_delay, clkrate);
  
  	chip->ctar_val =  SPI_CTAR_FMSZ(fmsz)
  		| SPI_CTAR_CPOL(spi->mode & SPI_CPOL ? 1 : 0)
  		| SPI_CTAR_CPHA(spi->mode & SPI_CPHA ? 1 : 0)
  		| SPI_CTAR_LSBFE(spi->mode & SPI_LSB_FIRST ? 1 : 0)
  		| SPI_CTAR_PCSSCK(pcssck)
  		| SPI_CTAR_CSSCK(cssck)
  		| SPI_CTAR_PASC(pasc)
  		| SPI_CTAR_ASC(asc)
  		| SPI_CTAR_PBR(pbr)
  		| SPI_CTAR_BR(br);
  
  	spi_set_ctldata(spi, chip);
  
  	return 0;
  }
  
  static void dspi_cleanup(struct spi_device *spi)
  {
  	struct chip_data *chip = spi_get_ctldata((struct spi_device *)spi);
  
  	dev_dbg(&spi->dev, "spi_device %u.%u cleanup
  ",
  			spi->master->bus_num, spi->chip_select);
  
  	kfree(chip);
  }
  
  static irqreturn_t dspi_interrupt(int irq, void *dev_id)
  {
  	struct fsl_dspi *dspi = (struct fsl_dspi *)dev_id;
  	struct spi_message *msg = dspi->cur_msg;
  	enum dspi_trans_mode trans_mode;
  	u32 spi_sr, spi_tcr;
  	u32 spi_tcnt, tcnt_diff;
  	int tx_word;
  
  	regmap_read(dspi->regmap, SPI_SR, &spi_sr);
  	regmap_write(dspi->regmap, SPI_SR, spi_sr);
  
  
  	if (spi_sr & (SPI_SR_EOQF | SPI_SR_TCFQF)) {
  		tx_word = is_double_byte_mode(dspi);
  
  		regmap_read(dspi->regmap, SPI_TCR, &spi_tcr);
  		spi_tcnt = SPI_TCR_GET_TCNT(spi_tcr);
  		/*
  		 * The width of SPI Transfer Counter in SPI_TCR is 16bits,
  		 * so the max couner is 65535. When the counter reach 65535,
  		 * it will wrap around, counter reset to zero.
  		 * spi_tcnt my be less than dspi->spi_tcnt, it means the
  		 * counter already wrapped around.
  		 * SPI Transfer Counter is a counter of transmitted frames.
  		 * The size of frame maybe two bytes.
  		 */
  		tcnt_diff = ((spi_tcnt + SPI_TCR_TCNT_MAX) - dspi->spi_tcnt)
  			% SPI_TCR_TCNT_MAX;
  		tcnt_diff *= (tx_word + 1);
  		if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM)
  			tcnt_diff--;
  
  		msg->actual_length += tcnt_diff;
  
  		dspi->spi_tcnt = spi_tcnt;
  
  		trans_mode = dspi->devtype_data->trans_mode;
  		switch (trans_mode) {
  		case DSPI_EOQ_MODE:
  			dspi_eoq_read(dspi);
  			break;
  		case DSPI_TCFQ_MODE:
  			dspi_tcfq_read(dspi);
  			break;
  		default:
  			dev_err(&dspi->pdev->dev, "unsupported trans_mode %u
  ",
  				trans_mode);
  				return IRQ_HANDLED;
  		}
  
  		if (!dspi->len) {
  			if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM) {
  				regmap_update_bits(dspi->regmap,
  						   SPI_CTAR(0),
  						   SPI_FRAME_BITS_MASK,
  						   SPI_FRAME_BITS(16));
  				dspi->dataflags &= ~TRAN_STATE_WORD_ODD_NUM;
  			}
  
  			dspi->waitflags = 1;
  			wake_up_interruptible(&dspi->waitq);
  		} else {
  			switch (trans_mode) {
  			case DSPI_EOQ_MODE:
  				dspi_eoq_write(dspi);
  				break;
  			case DSPI_TCFQ_MODE:
  				dspi_tcfq_write(dspi);
  				break;
  			default:
  				dev_err(&dspi->pdev->dev,
  					"unsupported trans_mode %u
  ",
  					trans_mode);
  			}
  		}
  	}
  
  	return IRQ_HANDLED;
  }
  
  static const struct of_device_id fsl_dspi_dt_ids[] = {
  	{ .compatible = "fsl,vf610-dspi", .data = (void *)&vf610_data, },
  	{ .compatible = "fsl,ls1021a-v1.0-dspi",
  		.data = (void *)&ls1021a_v1_data, },
  	{ .compatible = "fsl,ls2085a-dspi", .data = (void *)&ls2085a_data, },
  	{ /* sentinel */ }
  };
  MODULE_DEVICE_TABLE(of, fsl_dspi_dt_ids);
  
  #ifdef CONFIG_PM_SLEEP
  static int dspi_suspend(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct fsl_dspi *dspi = spi_master_get_devdata(master);
  
  	spi_master_suspend(master);
  	clk_disable_unprepare(dspi->clk);
  
  	pinctrl_pm_select_sleep_state(dev);
  
  	return 0;
  }
  
  static int dspi_resume(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct fsl_dspi *dspi = spi_master_get_devdata(master);
  
  	pinctrl_pm_select_default_state(dev);
  
  	clk_prepare_enable(dspi->clk);
  	spi_master_resume(master);
  
  	return 0;
  }
  #endif /* CONFIG_PM_SLEEP */
  
  static SIMPLE_DEV_PM_OPS(dspi_pm, dspi_suspend, dspi_resume);
  
  static const struct regmap_config dspi_regmap_config = {
  	.reg_bits = 32,
  	.val_bits = 32,
  	.reg_stride = 4,
  	.max_register = 0x88,
  };
  
  static int dspi_probe(struct platform_device *pdev)
  {
  	struct device_node *np = pdev->dev.of_node;
  	struct spi_master *master;
  	struct fsl_dspi *dspi;
  	struct resource *res;
  	void __iomem *base;
  	int ret = 0, cs_num, bus_num;
  	const struct of_device_id *of_id =
  			of_match_device(fsl_dspi_dt_ids, &pdev->dev);
  
  	master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi));
  	if (!master)
  		return -ENOMEM;
  
  	dspi = spi_master_get_devdata(master);
  	dspi->pdev = pdev;
  	dspi->master = master;
  
  	master->transfer = NULL;
  	master->setup = dspi_setup;
  	master->transfer_one_message = dspi_transfer_one_message;
  	master->dev.of_node = pdev->dev.of_node;
  
  	master->cleanup = dspi_cleanup;
  	master->mode_bits = SPI_CPOL | SPI_CPHA;
  	master->bits_per_word_mask = SPI_BPW_MASK(4) | SPI_BPW_MASK(8) |
  					SPI_BPW_MASK(16);
  
  	ret = of_property_read_u32(np, "spi-num-chipselects", &cs_num);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "can't get spi-num-chipselects
  ");
  		goto out_master_put;
  	}
  	master->num_chipselect = cs_num;
  
  	ret = of_property_read_u32(np, "bus-num", &bus_num);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "can't get bus-num
  ");
  		goto out_master_put;
  	}
  	master->bus_num = bus_num;
  
  	dspi->devtype_data = (struct fsl_dspi_devtype_data *)of_id->data;
  	if (!dspi->devtype_data) {
  		dev_err(&pdev->dev, "can't get devtype_data
  ");
  		ret = -EFAULT;
  		goto out_master_put;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(base)) {
  		ret = PTR_ERR(base);
  		goto out_master_put;
  	}
  
  	dspi->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
  						&dspi_regmap_config);
  	if (IS_ERR(dspi->regmap)) {
  		dev_err(&pdev->dev, "failed to init regmap: %ld
  ",
  				PTR_ERR(dspi->regmap));
  		return PTR_ERR(dspi->regmap);
  	}
  
  	dspi->irq = platform_get_irq(pdev, 0);
  	if (dspi->irq < 0) {
  		dev_err(&pdev->dev, "can't get platform irq
  ");
  		ret = dspi->irq;
  		goto out_master_put;
  	}
  
  	ret = devm_request_irq(&pdev->dev, dspi->irq, dspi_interrupt, 0,
  			pdev->name, dspi);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Unable to attach DSPI interrupt
  ");
  		goto out_master_put;
  	}
  
  	dspi->clk = devm_clk_get(&pdev->dev, "dspi");
  	if (IS_ERR(dspi->clk)) {
  		ret = PTR_ERR(dspi->clk);
  		dev_err(&pdev->dev, "unable to get clock
  ");
  		goto out_master_put;
  	}
  	clk_prepare_enable(dspi->clk);
  
  	init_waitqueue_head(&dspi->waitq);
  	platform_set_drvdata(pdev, master);
  
  	ret = spi_register_master(master);
  	if (ret != 0) {
  		dev_err(&pdev->dev, "Problem registering DSPI master
  ");
  		goto out_clk_put;
  	}
  
  	return ret;
  
  out_clk_put:
  	clk_disable_unprepare(dspi->clk);
  out_master_put:
  	spi_master_put(master);
  
  	return ret;
  }
  
  static int dspi_remove(struct platform_device *pdev)
  {
  	struct spi_master *master = platform_get_drvdata(pdev);
  	struct fsl_dspi *dspi = spi_master_get_devdata(master);
  
  	/* Disconnect from the SPI framework */
  	clk_disable_unprepare(dspi->clk);
  	spi_unregister_master(dspi->master);
  
  	return 0;
  }
  
  static struct platform_driver fsl_dspi_driver = {
  	.driver.name    = DRIVER_NAME,
  	.driver.of_match_table = fsl_dspi_dt_ids,
  	.driver.owner   = THIS_MODULE,
  	.driver.pm = &dspi_pm,
  	.probe          = dspi_probe,
  	.remove		= dspi_remove,
  };
  module_platform_driver(fsl_dspi_driver);
  
  MODULE_DESCRIPTION("Freescale DSPI Controller Driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:" DRIVER_NAME);