// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd

   * Author: Addy Ke <addy.ke@rock-chips.com>

   */

  #include <linux/clk.h>

  #include <linux/dmaengine.h>

  #include <linux/interrupt.h>

  #include <linux/module.h>
  #include <linux/of.h>

  #include <linux/pinctrl/consumer.h>

  #include <linux/platform_device.h>

  #include <linux/spi/spi.h>

  #include <linux/pm_runtime.h>

  #include <linux/scatterlist.h>

  
  #define DRIVER_NAME "rockchip-spi"

  #define ROCKCHIP_SPI_CLR_BITS(reg, bits) \
  		writel_relaxed(readl_relaxed(reg) & ~(bits), reg)
  #define ROCKCHIP_SPI_SET_BITS(reg, bits) \
  		writel_relaxed(readl_relaxed(reg) | (bits), reg)

  /* SPI register offsets */
  #define ROCKCHIP_SPI_CTRLR0			0x0000
  #define ROCKCHIP_SPI_CTRLR1			0x0004
  #define ROCKCHIP_SPI_SSIENR			0x0008
  #define ROCKCHIP_SPI_SER			0x000c
  #define ROCKCHIP_SPI_BAUDR			0x0010
  #define ROCKCHIP_SPI_TXFTLR			0x0014
  #define ROCKCHIP_SPI_RXFTLR			0x0018
  #define ROCKCHIP_SPI_TXFLR			0x001c
  #define ROCKCHIP_SPI_RXFLR			0x0020
  #define ROCKCHIP_SPI_SR				0x0024
  #define ROCKCHIP_SPI_IPR			0x0028
  #define ROCKCHIP_SPI_IMR			0x002c
  #define ROCKCHIP_SPI_ISR			0x0030
  #define ROCKCHIP_SPI_RISR			0x0034
  #define ROCKCHIP_SPI_ICR			0x0038
  #define ROCKCHIP_SPI_DMACR			0x003c

  #define ROCKCHIP_SPI_DMATDLR			0x0040
  #define ROCKCHIP_SPI_DMARDLR			0x0044
  #define ROCKCHIP_SPI_VERSION			0x0048

  #define ROCKCHIP_SPI_TXDR			0x0400
  #define ROCKCHIP_SPI_RXDR			0x0800
  
  /* Bit fields in CTRLR0 */
  #define CR0_DFS_OFFSET				0

  #define CR0_DFS_4BIT				0x0
  #define CR0_DFS_8BIT				0x1
  #define CR0_DFS_16BIT				0x2

  
  #define CR0_CFS_OFFSET				2
  
  #define CR0_SCPH_OFFSET				6
  
  #define CR0_SCPOL_OFFSET			7
  
  #define CR0_CSM_OFFSET				8
  #define CR0_CSM_KEEP				0x0
  /* ss_n be high for half sclk_out cycles */
  #define CR0_CSM_HALF				0X1
  /* ss_n be high for one sclk_out cycle */
  #define CR0_CSM_ONE					0x2
  
  /* ss_n to sclk_out delay */
  #define CR0_SSD_OFFSET				10
  /*
   * The period between ss_n active and
   * sclk_out active is half sclk_out cycles
   */
  #define CR0_SSD_HALF				0x0
  /*
   * The period between ss_n active and
   * sclk_out active is one sclk_out cycle
   */
  #define CR0_SSD_ONE					0x1
  
  #define CR0_EM_OFFSET				11
  #define CR0_EM_LITTLE				0x0
  #define CR0_EM_BIG					0x1
  
  #define CR0_FBM_OFFSET				12
  #define CR0_FBM_MSB					0x0
  #define CR0_FBM_LSB					0x1
  
  #define CR0_BHT_OFFSET				13
  #define CR0_BHT_16BIT				0x0
  #define CR0_BHT_8BIT				0x1
  
  #define CR0_RSD_OFFSET				14

  #define CR0_RSD_MAX				0x3

  
  #define CR0_FRF_OFFSET				16
  #define CR0_FRF_SPI					0x0
  #define CR0_FRF_SSP					0x1
  #define CR0_FRF_MICROWIRE			0x2
  
  #define CR0_XFM_OFFSET				18
  #define CR0_XFM_MASK				(0x03 << SPI_XFM_OFFSET)
  #define CR0_XFM_TR					0x0
  #define CR0_XFM_TO					0x1
  #define CR0_XFM_RO					0x2
  
  #define CR0_OPM_OFFSET				20
  #define CR0_OPM_MASTER				0x0
  #define CR0_OPM_SLAVE				0x1
  
  #define CR0_MTM_OFFSET				0x21
  
  /* Bit fields in SER, 2bit */
  #define SER_MASK					0x3

  /* Bit fields in BAUDR */
  #define BAUDR_SCKDV_MIN				2
  #define BAUDR_SCKDV_MAX				65534

  /* Bit fields in SR, 5bit */
  #define SR_MASK						0x1f
  #define SR_BUSY						(1 << 0)
  #define SR_TF_FULL					(1 << 1)
  #define SR_TF_EMPTY					(1 << 2)
  #define SR_RF_EMPTY					(1 << 3)
  #define SR_RF_FULL					(1 << 4)
  
  /* Bit fields in ISR, IMR, ISR, RISR, 5bit */
  #define INT_MASK					0x1f
  #define INT_TF_EMPTY				(1 << 0)
  #define INT_TF_OVERFLOW				(1 << 1)
  #define INT_RF_UNDERFLOW			(1 << 2)
  #define INT_RF_OVERFLOW				(1 << 3)
  #define INT_RF_FULL					(1 << 4)
  
  /* Bit fields in ICR, 4bit */
  #define ICR_MASK					0x0f
  #define ICR_ALL						(1 << 0)
  #define ICR_RF_UNDERFLOW			(1 << 1)
  #define ICR_RF_OVERFLOW				(1 << 2)
  #define ICR_TF_OVERFLOW				(1 << 3)
  
  /* Bit fields in DMACR */
  #define RF_DMA_EN					(1 << 0)
  #define TF_DMA_EN					(1 << 1)

  /* Driver state flags */
  #define RXDMA					(1 << 0)
  #define TXDMA					(1 << 1)

  /* sclk_out: spi master internal logic in rk3x can support 50Mhz */

  #define MAX_SCLK_OUT				50000000U

  /*
   * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However,
   * the controller seems to hang when given 0x10000, so stick with this for now.
   */
  #define ROCKCHIP_SPI_MAX_TRANLEN		0xffff

  #define ROCKCHIP_SPI_MAX_CS_NUM			2

  #define ROCKCHIP_SPI_VER2_TYPE1			0x05EC0002
  #define ROCKCHIP_SPI_VER2_TYPE2			0x00110002

  struct rockchip_spi {
  	struct device *dev;

  
  	struct clk *spiclk;
  	struct clk *apb_pclk;
  
  	void __iomem *regs;

  	dma_addr_t dma_addr_rx;
  	dma_addr_t dma_addr_tx;

  	const void *tx;
  	void *rx;
  	unsigned int tx_left;
  	unsigned int rx_left;

  	atomic_t state;

  	/*depth of the FIFO buffer */
  	u32 fifo_len;

  	/* frequency of spiclk */
  	u32 freq;

  	u8 n_bytes;

  	u8 rsd;

  	bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];

  
  	bool slave_abort;

  };

  static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)

  {

  	writel_relaxed((enable ? 1U : 0U), rs->regs + ROCKCHIP_SPI_SSIENR);

  }

  static inline void wait_for_idle(struct rockchip_spi *rs)
  {
  	unsigned long timeout = jiffies + msecs_to_jiffies(5);
  
  	do {
  		if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY))
  			return;

  	} while (!time_after(jiffies, timeout));

  
  	dev_warn(rs->dev, "spi controller is in busy state!
  ");
  }

  static u32 get_fifo_len(struct rockchip_spi *rs)
  {

  	u32 ver;

  	ver = readl_relaxed(rs->regs + ROCKCHIP_SPI_VERSION);

  	switch (ver) {
  	case ROCKCHIP_SPI_VER2_TYPE1:
  	case ROCKCHIP_SPI_VER2_TYPE2:
  		return 64;
  	default:
  		return 32;
  	}

  }

  static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
  {

  	struct spi_controller *ctlr = spi->controller;
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	bool cs_asserted = !enable;

  	/* Return immediately for no-op */
  	if (cs_asserted == rs->cs_asserted[spi->chip_select])
  		return;

  	if (cs_asserted) {
  		/* Keep things powered as long as CS is asserted */
  		pm_runtime_get_sync(rs->dev);

  		ROCKCHIP_SPI_SET_BITS(rs->regs + ROCKCHIP_SPI_SER,
  				      BIT(spi->chip_select));
  	} else {
  		ROCKCHIP_SPI_CLR_BITS(rs->regs + ROCKCHIP_SPI_SER,
  				      BIT(spi->chip_select));

  		/* Drop reference from when we first asserted CS */
  		pm_runtime_put(rs->dev);
  	}

  	rs->cs_asserted[spi->chip_select] = cs_asserted;

  }

  static void rockchip_spi_handle_err(struct spi_controller *ctlr,

  				    struct spi_message *msg)

  {

  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	/* stop running spi transfer
  	 * this also flushes both rx and tx fifos

  	 */

  	spi_enable_chip(rs, false);

  	/* make sure all interrupts are masked */
  	writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);

  	if (atomic_read(&rs->state) & TXDMA)

  		dmaengine_terminate_async(ctlr->dma_tx);

  	if (atomic_read(&rs->state) & RXDMA)

  		dmaengine_terminate_async(ctlr->dma_rx);

  }
  
  static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
  {

  	u32 tx_free = rs->fifo_len - readl_relaxed(rs->regs + ROCKCHIP_SPI_TXFLR);
  	u32 words = min(rs->tx_left, tx_free);
  
  	rs->tx_left -= words;
  	for (; words; words--) {
  		u32 txw;

  		if (rs->n_bytes == 1)

  			txw = *(u8 *)rs->tx;

  		else

  			txw = *(u16 *)rs->tx;

  
  		writel_relaxed(txw, rs->regs + ROCKCHIP_SPI_TXDR);
  		rs->tx += rs->n_bytes;
  	}
  }
  
  static void rockchip_spi_pio_reader(struct rockchip_spi *rs)
  {

  	u32 words = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);

  	u32 rx_left = (rs->rx_left > words) ? rs->rx_left - words : 0;

  
  	/* the hardware doesn't allow us to change fifo threshold
  	 * level while spi is enabled, so instead make sure to leave
  	 * enough words in the rx fifo to get the last interrupt
  	 * exactly when all words have been received
  	 */
  	if (rx_left) {
  		u32 ftl = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFTLR) + 1;
  
  		if (rx_left < ftl) {
  			rx_left = ftl;
  			words = rs->rx_left - rx_left;
  		}
  	}
  
  	rs->rx_left = rx_left;
  	for (; words; words--) {
  		u32 rxw = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXDR);
  
  		if (!rs->rx)
  			continue;

  		if (rs->n_bytes == 1)

  			*(u8 *)rs->rx = (u8)rxw;

  		else

  			*(u16 *)rs->rx = (u16)rxw;

  		rs->rx += rs->n_bytes;

  	}

  }

  static irqreturn_t rockchip_spi_isr(int irq, void *dev_id)

  {

  	struct spi_controller *ctlr = dev_id;
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	if (rs->tx_left)
  		rockchip_spi_pio_writer(rs);

  	rockchip_spi_pio_reader(rs);
  	if (!rs->rx_left) {
  		spi_enable_chip(rs, false);
  		writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);

  		spi_finalize_current_transfer(ctlr);

  	}

  	return IRQ_HANDLED;
  }

  static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
  		struct spi_transfer *xfer)
  {
  	rs->tx = xfer->tx_buf;
  	rs->rx = xfer->rx_buf;
  	rs->tx_left = rs->tx ? xfer->len / rs->n_bytes : 0;
  	rs->rx_left = xfer->len / rs->n_bytes;

  	writel_relaxed(INT_RF_FULL, rs->regs + ROCKCHIP_SPI_IMR);
  	spi_enable_chip(rs, true);

  	if (rs->tx_left)
  		rockchip_spi_pio_writer(rs);

  	/* 1 means the transfer is in progress */
  	return 1;

  }
  
  static void rockchip_spi_dma_rxcb(void *data)
  {

  	struct spi_controller *ctlr = data;
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	int state = atomic_fetch_andnot(RXDMA, &rs->state);

  	if (state & TXDMA && !rs->slave_abort)

  		return;

  	spi_enable_chip(rs, false);

  	spi_finalize_current_transfer(ctlr);

  }
  
  static void rockchip_spi_dma_txcb(void *data)
  {

  	struct spi_controller *ctlr = data;
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	int state = atomic_fetch_andnot(TXDMA, &rs->state);

  	if (state & RXDMA && !rs->slave_abort)

  		return;

  	/* Wait until the FIFO data completely. */
  	wait_for_idle(rs);

  	spi_enable_chip(rs, false);

  	spi_finalize_current_transfer(ctlr);

  }

  static u32 rockchip_spi_calc_burst_size(u32 data_len)
  {
  	u32 i;
  
  	/* burst size: 1, 2, 4, 8 */
  	for (i = 1; i < 8; i <<= 1) {
  		if (data_len & i)
  			break;
  	}
  
  	return i;
  }

  static int rockchip_spi_prepare_dma(struct rockchip_spi *rs,

  		struct spi_controller *ctlr, struct spi_transfer *xfer)

  {

  	struct dma_async_tx_descriptor *rxdesc, *txdesc;

  	atomic_set(&rs->state, 0);

  	rxdesc = NULL;

  	if (xfer->rx_buf) {

  		struct dma_slave_config rxconf = {
  			.direction = DMA_DEV_TO_MEM,

  			.src_addr = rs->dma_addr_rx,

  			.src_addr_width = rs->n_bytes,

  			.src_maxburst = rockchip_spi_calc_burst_size(xfer->len /
  								     rs->n_bytes),

  		};

  		dmaengine_slave_config(ctlr->dma_rx, &rxconf);

  		rxdesc = dmaengine_prep_slave_sg(

  				ctlr->dma_rx,

  				xfer->rx_sg.sgl, xfer->rx_sg.nents,

  				DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);

  		if (!rxdesc)
  			return -EINVAL;

  
  		rxdesc->callback = rockchip_spi_dma_rxcb;

  		rxdesc->callback_param = ctlr;

  	}

  	txdesc = NULL;

  	if (xfer->tx_buf) {

  		struct dma_slave_config txconf = {
  			.direction = DMA_MEM_TO_DEV,

  			.dst_addr = rs->dma_addr_tx,

  			.dst_addr_width = rs->n_bytes,

  			.dst_maxburst = rs->fifo_len / 4,

  		};

  		dmaengine_slave_config(ctlr->dma_tx, &txconf);

  		txdesc = dmaengine_prep_slave_sg(

  				ctlr->dma_tx,

  				xfer->tx_sg.sgl, xfer->tx_sg.nents,

  				DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);

  		if (!txdesc) {
  			if (rxdesc)

  				dmaengine_terminate_sync(ctlr->dma_rx);

  			return -EINVAL;
  		}

  
  		txdesc->callback = rockchip_spi_dma_txcb;

  		txdesc->callback_param = ctlr;

  	}
  
  	/* rx must be started before tx due to spi instinct */

  	if (rxdesc) {

  		atomic_or(RXDMA, &rs->state);

  		dmaengine_submit(rxdesc);

  		dma_async_issue_pending(ctlr->dma_rx);

  	}

  	spi_enable_chip(rs, true);

  	if (txdesc) {

  		atomic_or(TXDMA, &rs->state);

  		dmaengine_submit(txdesc);

  		dma_async_issue_pending(ctlr->dma_tx);

  	}

  	/* 1 means the transfer is in progress */
  	return 1;

  }

  static void rockchip_spi_config(struct rockchip_spi *rs,

  		struct spi_device *spi, struct spi_transfer *xfer,

  		bool use_dma, bool slave_mode)

  {

  	u32 cr0 = CR0_FRF_SPI  << CR0_FRF_OFFSET
  	        | CR0_BHT_8BIT << CR0_BHT_OFFSET
  	        | CR0_SSD_ONE  << CR0_SSD_OFFSET
  	        | CR0_EM_BIG   << CR0_EM_OFFSET;

  	u32 cr1;
  	u32 dmacr = 0;

  	if (slave_mode)
  		cr0 |= CR0_OPM_SLAVE << CR0_OPM_OFFSET;
  	rs->slave_abort = false;

  	cr0 |= rs->rsd << CR0_RSD_OFFSET;

  	cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;

  	if (spi->mode & SPI_LSB_FIRST)
  		cr0 |= CR0_FBM_LSB << CR0_FBM_OFFSET;

  
  	if (xfer->rx_buf && xfer->tx_buf)
  		cr0 |= CR0_XFM_TR << CR0_XFM_OFFSET;
  	else if (xfer->rx_buf)
  		cr0 |= CR0_XFM_RO << CR0_XFM_OFFSET;

  	else if (use_dma)

  		cr0 |= CR0_XFM_TO << CR0_XFM_OFFSET;

  	switch (xfer->bits_per_word) {
  	case 4:
  		cr0 |= CR0_DFS_4BIT << CR0_DFS_OFFSET;
  		cr1 = xfer->len - 1;
  		break;
  	case 8:
  		cr0 |= CR0_DFS_8BIT << CR0_DFS_OFFSET;
  		cr1 = xfer->len - 1;
  		break;
  	case 16:
  		cr0 |= CR0_DFS_16BIT << CR0_DFS_OFFSET;
  		cr1 = xfer->len / 2 - 1;
  		break;
  	default:
  		/* we only whitelist 4, 8 and 16 bit words in

  		 * ctlr->bits_per_word_mask, so this shouldn't

  		 * happen
  		 */
  		unreachable();
  	}

  	if (use_dma) {

  		if (xfer->tx_buf)

  			dmacr |= TF_DMA_EN;

  		if (xfer->rx_buf)

  			dmacr |= RF_DMA_EN;
  	}

  	writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0);

  	writel_relaxed(cr1, rs->regs + ROCKCHIP_SPI_CTRLR1);

  	/* unfortunately setting the fifo threshold level to generate an
  	 * interrupt exactly when the fifo is full doesn't seem to work,
  	 * so we need the strict inequality here
  	 */
  	if (xfer->len < rs->fifo_len)
  		writel_relaxed(xfer->len - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
  	else
  		writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);

  	writel_relaxed(rs->fifo_len / 2, rs->regs + ROCKCHIP_SPI_DMATDLR);

  	writel_relaxed(rockchip_spi_calc_burst_size(xfer->len / rs->n_bytes) - 1,
  		       rs->regs + ROCKCHIP_SPI_DMARDLR);

  	writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);

  	/* the hardware only supports an even clock divisor, so
  	 * round divisor = spiclk / speed up to nearest even number
  	 * so that the resulting speed is <= the requested speed
  	 */
  	writel_relaxed(2 * DIV_ROUND_UP(rs->freq, 2 * xfer->speed_hz),
  			rs->regs + ROCKCHIP_SPI_BAUDR);

  }

  static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
  {
  	return ROCKCHIP_SPI_MAX_TRANLEN;
  }

  static int rockchip_spi_slave_abort(struct spi_controller *ctlr)
  {
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
  
  	rs->slave_abort = true;
  	complete(&ctlr->xfer_completion);
  
  	return 0;
  }

  static int rockchip_spi_transfer_one(

  		struct spi_controller *ctlr,

  		struct spi_device *spi,
  		struct spi_transfer *xfer)
  {

  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	bool use_dma;

  	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&
  		(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY));

  
  	if (!xfer->tx_buf && !xfer->rx_buf) {
  		dev_err(rs->dev, "No buffer for transfer
  ");
  		return -EINVAL;
  	}

  	if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) {
  		dev_err(rs->dev, "Transfer is too long (%d)
  ", xfer->len);
  		return -EINVAL;
  	}

  	rs->n_bytes = xfer->bits_per_word <= 8 ? 1 : 2;

  	use_dma = ctlr->can_dma ? ctlr->can_dma(ctlr, spi, xfer) : false;

  	rockchip_spi_config(rs, spi, xfer, use_dma, ctlr->slave);

  	if (use_dma)

  		return rockchip_spi_prepare_dma(rs, ctlr, xfer);

  	return rockchip_spi_prepare_irq(rs, xfer);

  }

  static bool rockchip_spi_can_dma(struct spi_controller *ctlr,

  				 struct spi_device *spi,
  				 struct spi_transfer *xfer)

  {

  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	unsigned int bytes_per_word = xfer->bits_per_word <= 8 ? 1 : 2;

  	/* if the numbor of spi words to transfer is less than the fifo
  	 * length we can just fill the fifo and wait for a single irq,
  	 * so don't bother setting up dma
  	 */
  	return xfer->len / bytes_per_word >= rs->fifo_len;

  }
  
  static int rockchip_spi_probe(struct platform_device *pdev)
  {

  	int ret;

  	struct rockchip_spi *rs;

  	struct spi_controller *ctlr;

  	struct resource *mem;

  	struct device_node *np = pdev->dev.of_node;

  	u32 rsd_nsecs;

  	bool slave_mode;
  
  	slave_mode = of_property_read_bool(np, "spi-slave");
  
  	if (slave_mode)
  		ctlr = spi_alloc_slave(&pdev->dev,
  				sizeof(struct rockchip_spi));
  	else
  		ctlr = spi_alloc_master(&pdev->dev,
  				sizeof(struct rockchip_spi));

  	if (!ctlr)

  		return -ENOMEM;

  	platform_set_drvdata(pdev, ctlr);

  	rs = spi_controller_get_devdata(ctlr);

  	ctlr->slave = slave_mode;

  
  	/* Get basic io resource and map it */
  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	rs->regs = devm_ioremap_resource(&pdev->dev, mem);
  	if (IS_ERR(rs->regs)) {

  		ret =  PTR_ERR(rs->regs);

  		goto err_put_ctlr;

  	}
  
  	rs->apb_pclk = devm_clk_get(&pdev->dev, "apb_pclk");
  	if (IS_ERR(rs->apb_pclk)) {
  		dev_err(&pdev->dev, "Failed to get apb_pclk
  ");
  		ret = PTR_ERR(rs->apb_pclk);

  		goto err_put_ctlr;

  	}
  
  	rs->spiclk = devm_clk_get(&pdev->dev, "spiclk");
  	if (IS_ERR(rs->spiclk)) {
  		dev_err(&pdev->dev, "Failed to get spi_pclk
  ");
  		ret = PTR_ERR(rs->spiclk);

  		goto err_put_ctlr;

  	}
  
  	ret = clk_prepare_enable(rs->apb_pclk);

  	if (ret < 0) {

  		dev_err(&pdev->dev, "Failed to enable apb_pclk
  ");

  		goto err_put_ctlr;

  	}
  
  	ret = clk_prepare_enable(rs->spiclk);

  	if (ret < 0) {

  		dev_err(&pdev->dev, "Failed to enable spi_clk
  ");

  		goto err_disable_apbclk;

  	}

  	spi_enable_chip(rs, false);

  	ret = platform_get_irq(pdev, 0);
  	if (ret < 0)
  		goto err_disable_spiclk;
  
  	ret = devm_request_threaded_irq(&pdev->dev, ret, rockchip_spi_isr, NULL,

  			IRQF_ONESHOT, dev_name(&pdev->dev), ctlr);

  	if (ret)
  		goto err_disable_spiclk;

  	rs->dev = &pdev->dev;

  	rs->freq = clk_get_rate(rs->spiclk);

  	if (!of_property_read_u32(pdev->dev.of_node, "rx-sample-delay-ns",

  				  &rsd_nsecs)) {
  		/* rx sample delay is expressed in parent clock cycles (max 3) */
  		u32 rsd = DIV_ROUND_CLOSEST(rsd_nsecs * (rs->freq >> 8),
  				1000000000 >> 8);
  		if (!rsd) {
  			dev_warn(rs->dev, "%u Hz are too slow to express %u ns delay
  ",
  					rs->freq, rsd_nsecs);
  		} else if (rsd > CR0_RSD_MAX) {
  			rsd = CR0_RSD_MAX;
  			dev_warn(rs->dev, "%u Hz are too fast to express %u ns delay, clamping at %u ns
  ",
  					rs->freq, rsd_nsecs,
  					CR0_RSD_MAX * 1000000000U / rs->freq);
  		}
  		rs->rsd = rsd;
  	}

  	rs->fifo_len = get_fifo_len(rs);
  	if (!rs->fifo_len) {
  		dev_err(&pdev->dev, "Failed to get fifo length
  ");

  		ret = -EINVAL;

  		goto err_disable_spiclk;

  	}

  	pm_runtime_set_active(&pdev->dev);
  	pm_runtime_enable(&pdev->dev);

  	ctlr->auto_runtime_pm = true;
  	ctlr->bus_num = pdev->id;
  	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;

  	if (slave_mode) {
  		ctlr->mode_bits |= SPI_NO_CS;
  		ctlr->slave_abort = rockchip_spi_slave_abort;
  	} else {
  		ctlr->flags = SPI_MASTER_GPIO_SS;

  		ctlr->max_native_cs = ROCKCHIP_SPI_MAX_CS_NUM;
  		/*
  		 * rk spi0 has two native cs, spi1..5 one cs only
  		 * if num-cs is missing in the dts, default to 1
  		 */
  		if (of_property_read_u16(np, "num-cs", &ctlr->num_chipselect))
  			ctlr->num_chipselect = 1;
  		ctlr->use_gpio_descriptors = true;

  	}

  	ctlr->dev.of_node = pdev->dev.of_node;
  	ctlr->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8) | SPI_BPW_MASK(4);
  	ctlr->min_speed_hz = rs->freq / BAUDR_SCKDV_MAX;
  	ctlr->max_speed_hz = min(rs->freq / BAUDR_SCKDV_MIN, MAX_SCLK_OUT);
  
  	ctlr->set_cs = rockchip_spi_set_cs;
  	ctlr->transfer_one = rockchip_spi_transfer_one;
  	ctlr->max_transfer_size = rockchip_spi_max_transfer_size;
  	ctlr->handle_err = rockchip_spi_handle_err;

  
  	ctlr->dma_tx = dma_request_chan(rs->dev, "tx");
  	if (IS_ERR(ctlr->dma_tx)) {

  		/* Check tx to see if we need defer probing driver */

  		if (PTR_ERR(ctlr->dma_tx) == -EPROBE_DEFER) {

  			ret = -EPROBE_DEFER;

  			goto err_disable_pm_runtime;

  		}

  		dev_warn(rs->dev, "Failed to request TX DMA channel
  ");

  		ctlr->dma_tx = NULL;

  	}

  	ctlr->dma_rx = dma_request_chan(rs->dev, "rx");
  	if (IS_ERR(ctlr->dma_rx)) {
  		if (PTR_ERR(ctlr->dma_rx) == -EPROBE_DEFER) {

  			ret = -EPROBE_DEFER;

  			goto err_free_dma_tx;

  		}
  		dev_warn(rs->dev, "Failed to request RX DMA channel
  ");

  		ctlr->dma_rx = NULL;

  	}

  	if (ctlr->dma_tx && ctlr->dma_rx) {

  		rs->dma_addr_tx = mem->start + ROCKCHIP_SPI_TXDR;
  		rs->dma_addr_rx = mem->start + ROCKCHIP_SPI_RXDR;

  		ctlr->can_dma = rockchip_spi_can_dma;

  	}

  	ret = devm_spi_register_controller(&pdev->dev, ctlr);

  	if (ret < 0) {

  		dev_err(&pdev->dev, "Failed to register controller
  ");

  		goto err_free_dma_rx;

  	}

  	return 0;

  err_free_dma_rx:

  	if (ctlr->dma_rx)
  		dma_release_channel(ctlr->dma_rx);

  err_free_dma_tx:

  	if (ctlr->dma_tx)
  		dma_release_channel(ctlr->dma_tx);

  err_disable_pm_runtime:
  	pm_runtime_disable(&pdev->dev);
  err_disable_spiclk:

  	clk_disable_unprepare(rs->spiclk);

  err_disable_apbclk:

  	clk_disable_unprepare(rs->apb_pclk);

  err_put_ctlr:
  	spi_controller_put(ctlr);

  
  	return ret;
  }
  
  static int rockchip_spi_remove(struct platform_device *pdev)
  {

  	struct spi_controller *ctlr = spi_controller_get(platform_get_drvdata(pdev));
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	pm_runtime_get_sync(&pdev->dev);

  
  	clk_disable_unprepare(rs->spiclk);
  	clk_disable_unprepare(rs->apb_pclk);

  	pm_runtime_put_noidle(&pdev->dev);
  	pm_runtime_disable(&pdev->dev);
  	pm_runtime_set_suspended(&pdev->dev);

  	if (ctlr->dma_tx)
  		dma_release_channel(ctlr->dma_tx);
  	if (ctlr->dma_rx)
  		dma_release_channel(ctlr->dma_rx);

  	spi_controller_put(ctlr);

  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int rockchip_spi_suspend(struct device *dev)
  {

  	int ret;

  	struct spi_controller *ctlr = dev_get_drvdata(dev);

  	ret = spi_controller_suspend(ctlr);

  	if (ret < 0)

  		return ret;

  	ret = pm_runtime_force_suspend(dev);
  	if (ret < 0)
  		return ret;

  	pinctrl_pm_select_sleep_state(dev);

  	return 0;

  }
  
  static int rockchip_spi_resume(struct device *dev)
  {

  	int ret;

  	struct spi_controller *ctlr = dev_get_drvdata(dev);
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  	pinctrl_pm_select_default_state(dev);

  	ret = pm_runtime_force_resume(dev);
  	if (ret < 0)
  		return ret;

  	ret = spi_controller_resume(ctlr);

  	if (ret < 0) {
  		clk_disable_unprepare(rs->spiclk);
  		clk_disable_unprepare(rs->apb_pclk);
  	}

  	return 0;

  }
  #endif /* CONFIG_PM_SLEEP */

  #ifdef CONFIG_PM

  static int rockchip_spi_runtime_suspend(struct device *dev)
  {

  	struct spi_controller *ctlr = dev_get_drvdata(dev);
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  
  	clk_disable_unprepare(rs->spiclk);
  	clk_disable_unprepare(rs->apb_pclk);
  
  	return 0;
  }
  
  static int rockchip_spi_runtime_resume(struct device *dev)
  {
  	int ret;

  	struct spi_controller *ctlr = dev_get_drvdata(dev);
  	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);

  
  	ret = clk_prepare_enable(rs->apb_pclk);

  	if (ret < 0)

  		return ret;
  
  	ret = clk_prepare_enable(rs->spiclk);

  	if (ret < 0)

  		clk_disable_unprepare(rs->apb_pclk);

  	return 0;

  }

  #endif /* CONFIG_PM */

  
  static const struct dev_pm_ops rockchip_spi_pm = {
  	SET_SYSTEM_SLEEP_PM_OPS(rockchip_spi_suspend, rockchip_spi_resume)
  	SET_RUNTIME_PM_OPS(rockchip_spi_runtime_suspend,
  			   rockchip_spi_runtime_resume, NULL)
  };
  
  static const struct of_device_id rockchip_spi_dt_match[] = {

  	{ .compatible = "rockchip,px30-spi", },

  	{ .compatible = "rockchip,rk3036-spi", },

  	{ .compatible = "rockchip,rk3066-spi", },

  	{ .compatible = "rockchip,rk3188-spi", },

  	{ .compatible = "rockchip,rk3228-spi", },

  	{ .compatible = "rockchip,rk3288-spi", },

  	{ .compatible = "rockchip,rk3308-spi", },
  	{ .compatible = "rockchip,rk3328-spi", },

  	{ .compatible = "rockchip,rk3368-spi", },

  	{ .compatible = "rockchip,rk3399-spi", },

  	{ .compatible = "rockchip,rv1108-spi", },

  	{ },
  };
  MODULE_DEVICE_TABLE(of, rockchip_spi_dt_match);
  
  static struct platform_driver rockchip_spi_driver = {
  	.driver = {
  		.name	= DRIVER_NAME,

  		.pm = &rockchip_spi_pm,
  		.of_match_table = of_match_ptr(rockchip_spi_dt_match),
  	},
  	.probe = rockchip_spi_probe,
  	.remove = rockchip_spi_remove,
  };
  
  module_platform_driver(rockchip_spi_driver);

  MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");

  MODULE_DESCRIPTION("ROCKCHIP SPI Controller Driver");
  MODULE_LICENSE("GPL v2");