drivers/spi/spi-xlp.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2003-2015 Broadcom Corporation
  * All Rights Reserved
  */
 #include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/spi/spi.h>
 #include <linux/of.h>
 #include <linux/interrupt.h>

 /* SPI Configuration Register */
 #define XLP_SPI_CONFIG			0x00
 #define XLP_SPI_CPHA			BIT(0)
 #define XLP_SPI_CPOL			BIT(1)
 #define XLP_SPI_CS_POL			BIT(2)
 #define XLP_SPI_TXMISO_EN		BIT(3)
 #define XLP_SPI_TXMOSI_EN		BIT(4)
 #define XLP_SPI_RXMISO_EN		BIT(5)
 #define XLP_SPI_CS_LSBFE		BIT(10)
 #define XLP_SPI_RXCAP_EN		BIT(11)

 /* SPI Frequency Divider Register */
 #define XLP_SPI_FDIV			0x04

 /* SPI Command Register */
 #define XLP_SPI_CMD			0x08
 #define XLP_SPI_CMD_IDLE_MASK		0x0
 #define XLP_SPI_CMD_TX_MASK		0x1
 #define XLP_SPI_CMD_RX_MASK		0x2
 #define XLP_SPI_CMD_TXRX_MASK		0x3
 #define XLP_SPI_CMD_CONT		BIT(4)
 #define XLP_SPI_XFR_BITCNT_SHIFT	16

 /* SPI Status Register */
 #define XLP_SPI_STATUS			0x0c
 #define XLP_SPI_XFR_PENDING		BIT(0)
 #define XLP_SPI_XFR_DONE		BIT(1)
 #define XLP_SPI_TX_INT			BIT(2)
 #define XLP_SPI_RX_INT			BIT(3)
 #define XLP_SPI_TX_UF			BIT(4)
 #define XLP_SPI_RX_OF			BIT(5)
 #define XLP_SPI_STAT_MASK		0x3f

 /* SPI Interrupt Enable Register */
 #define XLP_SPI_INTR_EN			0x10
 #define XLP_SPI_INTR_DONE		BIT(0)
 #define XLP_SPI_INTR_TXTH		BIT(1)
 #define XLP_SPI_INTR_RXTH		BIT(2)
 #define XLP_SPI_INTR_TXUF		BIT(3)
 #define XLP_SPI_INTR_RXOF		BIT(4)

 /* SPI FIFO Threshold Register */
 #define XLP_SPI_FIFO_THRESH		0x14

 /* SPI FIFO Word Count Register */
 #define XLP_SPI_FIFO_WCNT		0x18
 #define XLP_SPI_RXFIFO_WCNT_MASK	0xf
 #define XLP_SPI_TXFIFO_WCNT_MASK	0xf0
 #define XLP_SPI_TXFIFO_WCNT_SHIFT	4

 /* SPI Transmit Data FIFO Register */
 #define XLP_SPI_TXDATA_FIFO		0x1c

 /* SPI Receive Data FIFO Register */
 #define XLP_SPI_RXDATA_FIFO		0x20

 /* SPI System Control Register */
 #define XLP_SPI_SYSCTRL			0x100
 #define XLP_SPI_SYS_RESET		BIT(0)
 #define XLP_SPI_SYS_CLKDIS		BIT(1)
 #define XLP_SPI_SYS_PMEN		BIT(8)

 #define SPI_CS_OFFSET			0x40
 #define XLP_SPI_TXRXTH			0x80
 #define XLP_SPI_FIFO_SIZE		8
 #define XLP_SPI_MAX_CS			4
 #define XLP_SPI_DEFAULT_FREQ		133333333
 #define XLP_SPI_FDIV_MIN		4
 #define XLP_SPI_FDIV_MAX		65535
 /*
  * SPI can transfer only 28 bytes properly at a time. So split the
  * transfer into 28 bytes size.
  */
 #define XLP_SPI_XFER_SIZE		28

 struct xlp_spi_priv {
 	struct device		dev;		/* device structure */
 	void __iomem		*base;		/* spi registers base address */
 	const u8		*tx_buf;	/* tx data buffer */
 	u8			*rx_buf;	/* rx data buffer */
 	int			tx_len;		/* tx xfer length */
 	int			rx_len;		/* rx xfer length */
 	int			txerrors;	/* TXFIFO underflow count */
 	int			rxerrors;	/* RXFIFO overflow count */
 	int			cs;		/* slave device chip select */
 	u32			spi_clk;	/* spi clock frequency */
 	bool			cmd_cont;	/* cs active */
 	struct completion	done;		/* completion notification */
 };

 static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
 				int cs, int regoff)
 {
 	return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
 }

 static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
 				int regoff, u32 val)
 {
 	writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
 }

 static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
 				int regoff, u32 val)
 {
 	writel(val, priv->base + regoff);
 }

 /*
  * Setup global SPI_SYSCTRL register for all SPI channels.
  */
 static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
 {
 	int cs;

 	for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
 		xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
 				XLP_SPI_SYS_RESET << cs);
 	xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
 }

 static int xlp_spi_setup(struct spi_device *spi)
 {
 	struct xlp_spi_priv *xspi;
 	u32 fdiv, cfg;
 	int cs;

 	xspi = spi_master_get_devdata(spi->master);
 	cs = spi->chip_select;
 	/*
 	 * The value of fdiv must be between 4 and 65535.
 	 */
 	fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
 	if (fdiv > XLP_SPI_FDIV_MAX)
 		fdiv = XLP_SPI_FDIV_MAX;
 	else if (fdiv < XLP_SPI_FDIV_MIN)
 		fdiv = XLP_SPI_FDIV_MIN;

 	xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
 	xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
 	cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
 	if (spi->mode & SPI_CPHA)
 		cfg |= XLP_SPI_CPHA;
 	else
 		cfg &= ~XLP_SPI_CPHA;
 	if (spi->mode & SPI_CPOL)
 		cfg |= XLP_SPI_CPOL;
 	else
 		cfg &= ~XLP_SPI_CPOL;
 	if (!(spi->mode & SPI_CS_HIGH))
 		cfg |= XLP_SPI_CS_POL;
 	else
 		cfg &= ~XLP_SPI_CS_POL;
 	if (spi->mode & SPI_LSB_FIRST)
 		cfg |= XLP_SPI_CS_LSBFE;
 	else
 		cfg &= ~XLP_SPI_CS_LSBFE;

 	cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN;
 	if (fdiv == 4)
 		cfg |= XLP_SPI_RXCAP_EN;
 	xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);

 	return 0;
 }

 static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
 {
 	u32 rx_data, rxfifo_cnt;
 	int i, j, nbytes;

 	rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
 	rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
 	while (rxfifo_cnt) {
 		rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
 		j = 0;
 		nbytes = min(xspi->rx_len, 4);
 		for (i = nbytes - 1; i >= 0; i--, j++)
 			xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;

 		xspi->rx_len -= nbytes;
 		xspi->rx_buf += nbytes;
 		rxfifo_cnt--;
 	}
 }

 static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
 {
 	u32 tx_data, txfifo_cnt;
 	int i, j, nbytes;

 	txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
 	txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
 	txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
 	while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
 		j = 0;
 		tx_data = 0;
 		nbytes = min(xspi->tx_len, 4);
 		for (i = nbytes - 1; i >= 0; i--, j++)
 			tx_data |= xspi->tx_buf[i] << (j * 8);

 		xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
 		xspi->tx_len -= nbytes;
 		xspi->tx_buf += nbytes;
 		txfifo_cnt++;
 	}
 }

 static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
 {
 	struct xlp_spi_priv *xspi = dev_id;
 	u32 stat;

 	stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
 		XLP_SPI_STAT_MASK;
 	if (!stat)
 		return IRQ_NONE;

 	if (stat & XLP_SPI_TX_INT) {
 		if (xspi->tx_len)
 			xlp_spi_fill_txfifo(xspi);
 		if (stat & XLP_SPI_TX_UF)
 			xspi->txerrors++;
 	}

 	if (stat & XLP_SPI_RX_INT) {
 		if (xspi->rx_len)
 			xlp_spi_read_rxfifo(xspi);
 		if (stat & XLP_SPI_RX_OF)
 			xspi->rxerrors++;
 	}

 	/* write status back to clear interrupts */
 	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
 	if (stat & XLP_SPI_XFR_DONE)
 		complete(&xspi->done);

 	return IRQ_HANDLED;
 }

 static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
 			int cmd_cont)
 {
 	u32 cmd = 0;

 	if (xspi->tx_buf)
 		cmd |= XLP_SPI_CMD_TX_MASK;
 	if (xspi->rx_buf)
 		cmd |= XLP_SPI_CMD_RX_MASK;
 	if (cmd_cont)
 		cmd |= XLP_SPI_CMD_CONT;
 	cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
 	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
 }

 static int xlp_spi_xfer_block(struct  xlp_spi_priv *xs,
 		const unsigned char *tx_buf,
 		unsigned char *rx_buf, int xfer_len, int cmd_cont)
 {
 	int timeout;
 	u32 intr_mask = 0;

 	xs->tx_buf = tx_buf;
 	xs->rx_buf = rx_buf;
 	xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
 	xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
 	xs->txerrors = xs->rxerrors = 0;

 	/* fill TXDATA_FIFO, then send the CMD */
 	if (xs->tx_len)
 		xlp_spi_fill_txfifo(xs);

 	xlp_spi_send_cmd(xs, xfer_len, cmd_cont);

 	/*
 	 * We are getting some spurious tx interrupts, so avoid enabling
 	 * tx interrupts when only rx is in process.
 	 * Enable all the interrupts in tx case.
 	 */
 	if (xs->tx_len)
 		intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF |
 				XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;
 	else
 		intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF;

 	intr_mask |= XLP_SPI_INTR_DONE;
 	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);

 	timeout = wait_for_completion_timeout(&xs->done,
 				msecs_to_jiffies(1000));
 	/* Disable interrupts */
 	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
 	if (!timeout) {
 		dev_err(&xs->dev, "xfer timedout!\n");
 		goto out;
 	}
 	if (xs->txerrors || xs->rxerrors)
 		dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
 				xs->rxerrors, xs->txerrors, xfer_len);

 	return xfer_len;
 out:
 	return -ETIMEDOUT;
 }

 static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t)
 {
 	int bytesleft, sz;
 	unsigned char *rx_buf;
 	const unsigned char *tx_buf;

 	tx_buf = t->tx_buf;
 	rx_buf = t->rx_buf;
 	bytesleft = t->len;
 	while (bytesleft) {
 		if (bytesleft > XLP_SPI_XFER_SIZE)
 			sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
 					XLP_SPI_XFER_SIZE, 1);
 		else
 			sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
 					bytesleft, xs->cmd_cont);
 		if (sz < 0)
 			return sz;
 		bytesleft -= sz;
 		if (tx_buf)
 			tx_buf += sz;
 		if (rx_buf)
 			rx_buf += sz;
 	}
 	return bytesleft;
 }

 static int xlp_spi_transfer_one(struct spi_master *master,
 					struct spi_device *spi,
 					struct spi_transfer *t)
 {
 	struct xlp_spi_priv *xspi = spi_master_get_devdata(master);
 	int ret = 0;

 	xspi->cs = spi->chip_select;
 	xspi->dev = spi->dev;

 	if (spi_transfer_is_last(master, t))
 		xspi->cmd_cont = 0;
 	else
 		xspi->cmd_cont = 1;

 	if (xlp_spi_txrx_bufs(xspi, t))
 		ret = -EIO;

 	spi_finalize_current_transfer(master);
 	return ret;
 }

 static int xlp_spi_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct xlp_spi_priv *xspi;
 	struct resource *res;
 	struct clk *clk;
 	int irq, err;

 	xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
 	if (!xspi)
 		return -ENOMEM;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	xspi->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(xspi->base))
 		return PTR_ERR(xspi->base);

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(&pdev->dev, "no IRQ resource found: %d\n", irq);
 		return irq;
 	}
 	err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
 			pdev->name, xspi);
 	if (err) {
 		dev_err(&pdev->dev, "unable to request irq %d\n", irq);
 		return err;
 	}

 	clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "could not get spi clock\n");
 		return PTR_ERR(clk);
 	}

 	xspi->spi_clk = clk_get_rate(clk);

 	master = spi_alloc_master(&pdev->dev, 0);
 	if (!master) {
 		dev_err(&pdev->dev, "could not alloc master\n");
 		return -ENOMEM;
 	}

 	master->bus_num = 0;
 	master->num_chipselect = XLP_SPI_MAX_CS;
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 	master->setup = xlp_spi_setup;
 	master->transfer_one = xlp_spi_transfer_one;
 	master->dev.of_node = pdev->dev.of_node;

 	init_completion(&xspi->done);
 	spi_master_set_devdata(master, xspi);
 	xlp_spi_sysctl_setup(xspi);

 	/* register spi controller */
 	err = devm_spi_register_master(&pdev->dev, master);
 	if (err) {
 		dev_err(&pdev->dev, "spi register master failed!\n");
 		spi_master_put(master);
 		return err;
 	}

 	return 0;
 }

 #ifdef CONFIG_ACPI
 static const struct acpi_device_id xlp_spi_acpi_match[] = {
 	{ "BRCM900D", 0 },
 	{ "CAV900D",  0 },
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match);
 #endif

 static const struct of_device_id xlp_spi_dt_id[] = {
 	{ .compatible = "netlogic,xlp832-spi" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, xlp_spi_dt_id);

 static struct platform_driver xlp_spi_driver = {
 	.probe	= xlp_spi_probe,
 	.driver = {
 		.name	= "xlp-spi",
 		.of_match_table = xlp_spi_dt_id,
 		.acpi_match_table = ACPI_PTR(xlp_spi_acpi_match),
 	},
 };
 module_platform_driver(xlp_spi_driver);

 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
 MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2003-2015 Broadcom Corporation
	* All Rights Reserved
	*/
	#include <linux/acpi.h>
	#include <linux/clk.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/spi/spi.h>
	#include <linux/of.h>
	#include <linux/interrupt.h>

	/* SPI Configuration Register */
	#define XLP_SPI_CONFIG 0x00
	#define XLP_SPI_CPHA BIT(0)
	#define XLP_SPI_CPOL BIT(1)
	#define XLP_SPI_CS_POL BIT(2)
	#define XLP_SPI_TXMISO_EN BIT(3)
	#define XLP_SPI_TXMOSI_EN BIT(4)
	#define XLP_SPI_RXMISO_EN BIT(5)
	#define XLP_SPI_CS_LSBFE BIT(10)
	#define XLP_SPI_RXCAP_EN BIT(11)

	/* SPI Frequency Divider Register */
	#define XLP_SPI_FDIV 0x04

	/* SPI Command Register */
	#define XLP_SPI_CMD 0x08
	#define XLP_SPI_CMD_IDLE_MASK 0x0
	#define XLP_SPI_CMD_TX_MASK 0x1
	#define XLP_SPI_CMD_RX_MASK 0x2
	#define XLP_SPI_CMD_TXRX_MASK 0x3
	#define XLP_SPI_CMD_CONT BIT(4)
	#define XLP_SPI_XFR_BITCNT_SHIFT 16

	/* SPI Status Register */
	#define XLP_SPI_STATUS 0x0c
	#define XLP_SPI_XFR_PENDING BIT(0)
	#define XLP_SPI_XFR_DONE BIT(1)
	#define XLP_SPI_TX_INT BIT(2)
	#define XLP_SPI_RX_INT BIT(3)
	#define XLP_SPI_TX_UF BIT(4)
	#define XLP_SPI_RX_OF BIT(5)
	#define XLP_SPI_STAT_MASK 0x3f

	/* SPI Interrupt Enable Register */
	#define XLP_SPI_INTR_EN 0x10
	#define XLP_SPI_INTR_DONE BIT(0)
	#define XLP_SPI_INTR_TXTH BIT(1)
	#define XLP_SPI_INTR_RXTH BIT(2)
	#define XLP_SPI_INTR_TXUF BIT(3)
	#define XLP_SPI_INTR_RXOF BIT(4)

	/* SPI FIFO Threshold Register */
	#define XLP_SPI_FIFO_THRESH 0x14

	/* SPI FIFO Word Count Register */
	#define XLP_SPI_FIFO_WCNT 0x18
	#define XLP_SPI_RXFIFO_WCNT_MASK 0xf
	#define XLP_SPI_TXFIFO_WCNT_MASK 0xf0
	#define XLP_SPI_TXFIFO_WCNT_SHIFT 4

	/* SPI Transmit Data FIFO Register */
	#define XLP_SPI_TXDATA_FIFO 0x1c

	/* SPI Receive Data FIFO Register */
	#define XLP_SPI_RXDATA_FIFO 0x20

	/* SPI System Control Register */
	#define XLP_SPI_SYSCTRL 0x100
	#define XLP_SPI_SYS_RESET BIT(0)
	#define XLP_SPI_SYS_CLKDIS BIT(1)
	#define XLP_SPI_SYS_PMEN BIT(8)

	#define SPI_CS_OFFSET 0x40
	#define XLP_SPI_TXRXTH 0x80
	#define XLP_SPI_FIFO_SIZE 8
	#define XLP_SPI_MAX_CS 4
	#define XLP_SPI_DEFAULT_FREQ 133333333
	#define XLP_SPI_FDIV_MIN 4
	#define XLP_SPI_FDIV_MAX 65535
	/*
	* SPI can transfer only 28 bytes properly at a time. So split the
	* transfer into 28 bytes size.
	*/
	#define XLP_SPI_XFER_SIZE 28

	struct xlp_spi_priv {
	struct device dev; /* device structure */
	void __iomem base; / spi registers base address */
	const u8 tx_buf; / tx data buffer */
	u8 rx_buf; / rx data buffer */
	int tx_len; /* tx xfer length */
	int rx_len; /* rx xfer length */
	int txerrors; /* TXFIFO underflow count */
	int rxerrors; /* RXFIFO overflow count */
	int cs; /* slave device chip select */
	u32 spi_clk; /* spi clock frequency */
	bool cmd_cont; /* cs active */
	struct completion done; /* completion notification */
	};

	static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv,
	int cs, int regoff)
	{
	return readl(priv->base + regoff + cs * SPI_CS_OFFSET);
	}

	static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs,
	int regoff, u32 val)
	{
	writel(val, priv->base + regoff + cs * SPI_CS_OFFSET);
	}

	static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv,
	int regoff, u32 val)
	{
	writel(val, priv->base + regoff);
	}

	/*
	* Setup global SPI_SYSCTRL register for all SPI channels.
	*/
	static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi)
	{
	int cs;

	for (cs = 0; cs < XLP_SPI_MAX_CS; cs++)
	xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL,
	XLP_SPI_SYS_RESET << cs);
	xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN);
	}

	static int xlp_spi_setup(struct spi_device *spi)
	{
	struct xlp_spi_priv *xspi;
	u32 fdiv, cfg;
	int cs;

	xspi = spi_master_get_devdata(spi->master);
	cs = spi->chip_select;
	/*
	* The value of fdiv must be between 4 and 65535.
	*/
	fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz);
	if (fdiv > XLP_SPI_FDIV_MAX)
	fdiv = XLP_SPI_FDIV_MAX;
	else if (fdiv < XLP_SPI_FDIV_MIN)
	fdiv = XLP_SPI_FDIV_MIN;

	xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv);
	xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH);
	cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG);
	if (spi->mode & SPI_CPHA)
	cfg \|= XLP_SPI_CPHA;
	else
	cfg &= ~XLP_SPI_CPHA;
	if (spi->mode & SPI_CPOL)
	cfg \|= XLP_SPI_CPOL;
	else
	cfg &= ~XLP_SPI_CPOL;
	if (!(spi->mode & SPI_CS_HIGH))
	cfg \|= XLP_SPI_CS_POL;
	else
	cfg &= ~XLP_SPI_CS_POL;
	if (spi->mode & SPI_LSB_FIRST)
	cfg \|= XLP_SPI_CS_LSBFE;
	else
	cfg &= ~XLP_SPI_CS_LSBFE;

	cfg \|= XLP_SPI_TXMOSI_EN \| XLP_SPI_RXMISO_EN;
	if (fdiv == 4)
	cfg \|= XLP_SPI_RXCAP_EN;
	xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg);

	return 0;
	}

	static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi)
	{
	u32 rx_data, rxfifo_cnt;
	int i, j, nbytes;

	rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
	rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK;
	while (rxfifo_cnt) {
	rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO);
	j = 0;
	nbytes = min(xspi->rx_len, 4);
	for (i = nbytes - 1; i >= 0; i--, j++)
	xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff;

	xspi->rx_len -= nbytes;
	xspi->rx_buf += nbytes;
	rxfifo_cnt--;
	}
	}

	static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi)
	{
	u32 tx_data, txfifo_cnt;
	int i, j, nbytes;

	txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT);
	txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK;
	txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT;
	while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) {
	j = 0;
	tx_data = 0;
	nbytes = min(xspi->tx_len, 4);
	for (i = nbytes - 1; i >= 0; i--, j++)
	tx_data \|= xspi->tx_buf[i] << (j * 8);

	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data);
	xspi->tx_len -= nbytes;
	xspi->tx_buf += nbytes;
	txfifo_cnt++;
	}
	}

	static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id)
	{
	struct xlp_spi_priv *xspi = dev_id;
	u32 stat;

	stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) &
	XLP_SPI_STAT_MASK;
	if (!stat)
	return IRQ_NONE;

	if (stat & XLP_SPI_TX_INT) {
	if (xspi->tx_len)
	xlp_spi_fill_txfifo(xspi);
	if (stat & XLP_SPI_TX_UF)
	xspi->txerrors++;
	}

	if (stat & XLP_SPI_RX_INT) {
	if (xspi->rx_len)
	xlp_spi_read_rxfifo(xspi);
	if (stat & XLP_SPI_RX_OF)
	xspi->rxerrors++;
	}

	/* write status back to clear interrupts */
	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat);
	if (stat & XLP_SPI_XFR_DONE)
	complete(&xspi->done);

	return IRQ_HANDLED;
	}

	static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len,
	int cmd_cont)
	{
	u32 cmd = 0;

	if (xspi->tx_buf)
	cmd \|= XLP_SPI_CMD_TX_MASK;
	if (xspi->rx_buf)
	cmd \|= XLP_SPI_CMD_RX_MASK;
	if (cmd_cont)
	cmd \|= XLP_SPI_CMD_CONT;
	cmd \|= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT);
	xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd);
	}

	static int xlp_spi_xfer_block(struct xlp_spi_priv *xs,
	const unsigned char *tx_buf,
	unsigned char *rx_buf, int xfer_len, int cmd_cont)
	{
	int timeout;
	u32 intr_mask = 0;

	xs->tx_buf = tx_buf;
	xs->rx_buf = rx_buf;
	xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len;
	xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len;
	xs->txerrors = xs->rxerrors = 0;

	/* fill TXDATA_FIFO, then send the CMD */
	if (xs->tx_len)
	xlp_spi_fill_txfifo(xs);

	xlp_spi_send_cmd(xs, xfer_len, cmd_cont);

	/*
	* We are getting some spurious tx interrupts, so avoid enabling
	* tx interrupts when only rx is in process.
	* Enable all the interrupts in tx case.
	*/
	if (xs->tx_len)
	intr_mask \|= XLP_SPI_INTR_TXTH \| XLP_SPI_INTR_TXUF \|
	XLP_SPI_INTR_RXTH \| XLP_SPI_INTR_RXOF;
	else
	intr_mask \|= XLP_SPI_INTR_RXTH \| XLP_SPI_INTR_RXOF;

	intr_mask \|= XLP_SPI_INTR_DONE;
	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask);

	timeout = wait_for_completion_timeout(&xs->done,
	msecs_to_jiffies(1000));
	/* Disable interrupts */
	xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0);
	if (!timeout) {
	dev_err(&xs->dev, "xfer timedout!\n");
	goto out;
	}
	if (xs->txerrors \|\| xs->rxerrors)
	dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n",
	xs->rxerrors, xs->txerrors, xfer_len);

	return xfer_len;
	out:
	return -ETIMEDOUT;
	}

	static int xlp_spi_txrx_bufs(struct xlp_spi_priv xs, struct spi_transfer t)
	{
	int bytesleft, sz;
	unsigned char *rx_buf;
	const unsigned char *tx_buf;

	tx_buf = t->tx_buf;
	rx_buf = t->rx_buf;
	bytesleft = t->len;
	while (bytesleft) {
	if (bytesleft > XLP_SPI_XFER_SIZE)
	sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
	XLP_SPI_XFER_SIZE, 1);
	else
	sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf,
	bytesleft, xs->cmd_cont);
	if (sz < 0)
	return sz;
	bytesleft -= sz;
	if (tx_buf)
	tx_buf += sz;
	if (rx_buf)
	rx_buf += sz;
	}
	return bytesleft;
	}

	static int xlp_spi_transfer_one(struct spi_master *master,
	struct spi_device *spi,
	struct spi_transfer *t)
	{
	struct xlp_spi_priv *xspi = spi_master_get_devdata(master);
	int ret = 0;

	xspi->cs = spi->chip_select;
	xspi->dev = spi->dev;

	if (spi_transfer_is_last(master, t))
	xspi->cmd_cont = 0;
	else
	xspi->cmd_cont = 1;

	if (xlp_spi_txrx_bufs(xspi, t))
	ret = -EIO;

	spi_finalize_current_transfer(master);
	return ret;
	}

	static int xlp_spi_probe(struct platform_device *pdev)
	{
	struct spi_master *master;
	struct xlp_spi_priv *xspi;
	struct resource *res;
	struct clk *clk;
	int irq, err;

	xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL);
	if (!xspi)
	return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	xspi->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(xspi->base))
	return PTR_ERR(xspi->base);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
	dev_err(&pdev->dev, "no IRQ resource found: %d\n", irq);
	return irq;
	}
	err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0,
	pdev->name, xspi);
	if (err) {
	dev_err(&pdev->dev, "unable to request irq %d\n", irq);
	return err;
	}

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
	dev_err(&pdev->dev, "could not get spi clock\n");
	return PTR_ERR(clk);
	}

	xspi->spi_clk = clk_get_rate(clk);

	master = spi_alloc_master(&pdev->dev, 0);
	if (!master) {
	dev_err(&pdev->dev, "could not alloc master\n");
	return -ENOMEM;
	}

	master->bus_num = 0;
	master->num_chipselect = XLP_SPI_MAX_CS;
	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH;
	master->setup = xlp_spi_setup;
	master->transfer_one = xlp_spi_transfer_one;
	master->dev.of_node = pdev->dev.of_node;

	init_completion(&xspi->done);
	spi_master_set_devdata(master, xspi);
	xlp_spi_sysctl_setup(xspi);

	/* register spi controller */
	err = devm_spi_register_master(&pdev->dev, master);
	if (err) {
	dev_err(&pdev->dev, "spi register master failed!\n");
	spi_master_put(master);
	return err;
	}

	return 0;
	}

	#ifdef CONFIG_ACPI
	static const struct acpi_device_id xlp_spi_acpi_match[] = {
	{ "BRCM900D", 0 },
	{ "CAV900D", 0 },
	{ },
	};
	MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match);
	#endif

	static const struct of_device_id xlp_spi_dt_id[] = {
	{ .compatible = "netlogic,xlp832-spi" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, xlp_spi_dt_id);

	static struct platform_driver xlp_spi_driver = {
	.probe = xlp_spi_probe,
	.driver = {
	.name = "xlp-spi",
	.of_match_table = xlp_spi_dt_id,
	.acpi_match_table = ACPI_PTR(xlp_spi_acpi_match),
	},
	};
	module_platform_driver(xlp_spi_driver);

	MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
	MODULE_DESCRIPTION("Netlogic XLP SPI controller driver");
	MODULE_LICENSE("GPL v2");