drivers/spi/spi-nuc900.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2009 Nuvoton technology.
  * Wan ZongShun <mcuos.com@gmail.com>
  */

 #include <linux/module.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
 #include <linux/gpio.h>
 #include <linux/io.h>
 #include <linux/slab.h>

 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>

 #include <linux/platform_data/spi-nuc900.h>

 /* usi registers offset */
 #define USI_CNT		0x00
 #define USI_DIV		0x04
 #define USI_SSR		0x08
 #define USI_RX0		0x10
 #define USI_TX0		0x10

 /* usi register bit */
 #define ENINT		(0x01 << 17)
 #define ENFLG		(0x01 << 16)
 #define SLEEP		(0x0f << 12)
 #define TXNUM		(0x03 << 8)
 #define TXBITLEN	(0x1f << 3)
 #define TXNEG		(0x01 << 2)
 #define RXNEG		(0x01 << 1)
 #define LSB		(0x01 << 10)
 #define SELECTLEV	(0x01 << 2)
 #define SELECTPOL	(0x01 << 31)
 #define SELECTSLAVE	0x01
 #define GOBUSY		0x01

 struct nuc900_spi {
 	struct spi_bitbang	 bitbang;
 	struct completion	 done;
 	void __iomem		*regs;
 	int			 irq;
 	int			 len;
 	int			 count;
 	const unsigned char	*tx;
 	unsigned char		*rx;
 	struct clk		*clk;
 	struct spi_master	*master;
 	struct nuc900_spi_info *pdata;
 	spinlock_t		lock;
 };

 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
 {
 	return spi_master_get_devdata(sdev->master);
 }

 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
 {
 	struct nuc900_spi *hw = to_hw(spi);
 	unsigned int val;
 	unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
 	unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_SSR);

 	if (!cs)
 		val &= ~SELECTLEV;
 	else
 		val |= SELECTLEV;

 	if (!ssr)
 		val &= ~SELECTSLAVE;
 	else
 		val |= SELECTSLAVE;

 	__raw_writel(val, hw->regs + USI_SSR);

 	val = __raw_readl(hw->regs + USI_CNT);

 	if (!cpol)
 		val &= ~SELECTPOL;
 	else
 		val |= SELECTPOL;

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
 {
 	switch (value) {
 	case BITBANG_CS_INACTIVE:
 		nuc900_slave_select(spi, 0);
 		break;

 	case BITBANG_CS_ACTIVE:
 		nuc900_slave_select(spi, 1);
 		break;
 	}
 }

 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;

 	if (txnum)
 		val |= txnum << 0x08;

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);

 }

 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
 							unsigned int txbitlen)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;

 	val |= (txbitlen << 0x03);

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT);

 	val |= GOBUSY;

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
 {
 	return hw->tx ? hw->tx[count] : 0;
 }

 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 {
 	struct nuc900_spi *hw = to_hw(spi);

 	hw->tx = t->tx_buf;
 	hw->rx = t->rx_buf;
 	hw->len = t->len;
 	hw->count = 0;

 	__raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);

 	nuc900_spi_gobusy(hw);

 	wait_for_completion(&hw->done);

 	return hw->count;
 }

 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
 {
 	struct nuc900_spi *hw = dev;
 	unsigned int status;
 	unsigned int count = hw->count;

 	status = __raw_readl(hw->regs + USI_CNT);
 	__raw_writel(status, hw->regs + USI_CNT);

 	if (status & ENFLG) {
 		hw->count++;

 		if (hw->rx)
 			hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
 		count++;

 		if (count < hw->len) {
 			__raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
 			nuc900_spi_gobusy(hw);
 		} else {
 			complete(&hw->done);
 		}

 		return IRQ_HANDLED;
 	}

 	complete(&hw->done);
 	return IRQ_HANDLED;
 }

 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT);

 	if (edge)
 		val |= TXNEG;
 	else
 		val &= ~TXNEG;
 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT);

 	if (edge)
 		val |= RXNEG;
 	else
 		val &= ~RXNEG;
 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT);

 	if (lsb)
 		val |= LSB;
 	else
 		val &= ~LSB;
 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;

 	if (sleep)
 		val |= (sleep << 12);

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_enable_int(struct nuc900_spi *hw)
 {
 	unsigned int val;
 	unsigned long flags;

 	spin_lock_irqsave(&hw->lock, flags);

 	val = __raw_readl(hw->regs + USI_CNT);

 	val |= ENINT;

 	__raw_writel(val, hw->regs + USI_CNT);

 	spin_unlock_irqrestore(&hw->lock, flags);
 }

 static void nuc900_set_divider(struct nuc900_spi *hw)
 {
 	__raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
 }

 static void nuc900_init_spi(struct nuc900_spi *hw)
 {
 	clk_enable(hw->clk);
 	spin_lock_init(&hw->lock);

 	nuc900_tx_edge(hw, hw->pdata->txneg);
 	nuc900_rx_edge(hw, hw->pdata->rxneg);
 	nuc900_send_first(hw, hw->pdata->lsb);
 	nuc900_set_sleep(hw, hw->pdata->sleep);
 	nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
 	nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
 	nuc900_set_divider(hw);
 	nuc900_enable_int(hw);
 }

 static int nuc900_spi_probe(struct platform_device *pdev)
 {
 	struct nuc900_spi *hw;
 	struct spi_master *master;
 	struct resource *res;
 	int err = 0;

 	master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
 	if (master == NULL) {
 		dev_err(&pdev->dev, "No memory for spi_master\n");
 		return -ENOMEM;
 	}

 	hw = spi_master_get_devdata(master);
 	hw->master = master;
 	hw->pdata  = dev_get_platdata(&pdev->dev);

 	if (hw->pdata == NULL) {
 		dev_err(&pdev->dev, "No platform data supplied\n");
 		err = -ENOENT;
 		goto err_pdata;
 	}

 	platform_set_drvdata(pdev, hw);
 	init_completion(&hw->done);

 	master->mode_bits          = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 	if (hw->pdata->lsb)
 		master->mode_bits |= SPI_LSB_FIRST;
 	master->num_chipselect     = hw->pdata->num_cs;
 	master->bus_num            = hw->pdata->bus_num;
 	hw->bitbang.master         = hw->master;
 	hw->bitbang.chipselect     = nuc900_spi_chipsel;
 	hw->bitbang.txrx_bufs      = nuc900_spi_txrx;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	hw->regs = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(hw->regs)) {
 		err = PTR_ERR(hw->regs);
 		goto err_pdata;
 	}

 	hw->irq = platform_get_irq(pdev, 0);
 	if (hw->irq < 0) {
 		dev_err(&pdev->dev, "No IRQ specified\n");
 		err = -ENOENT;
 		goto err_pdata;
 	}

 	err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
 				pdev->name, hw);
 	if (err) {
 		dev_err(&pdev->dev, "Cannot claim IRQ\n");
 		goto err_pdata;
 	}

 	hw->clk = devm_clk_get(&pdev->dev, "spi");
 	if (IS_ERR(hw->clk)) {
 		dev_err(&pdev->dev, "No clock for device\n");
 		err = PTR_ERR(hw->clk);
 		goto err_pdata;
 	}

 	mfp_set_groupg(&pdev->dev, NULL);
 	nuc900_init_spi(hw);

 	err = spi_bitbang_start(&hw->bitbang);
 	if (err) {
 		dev_err(&pdev->dev, "Failed to register SPI master\n");
 		goto err_register;
 	}

 	return 0;

 err_register:
 	clk_disable(hw->clk);
 err_pdata:
 	spi_master_put(hw->master);
 	return err;
 }

 static int nuc900_spi_remove(struct platform_device *dev)
 {
 	struct nuc900_spi *hw = platform_get_drvdata(dev);

 	spi_bitbang_stop(&hw->bitbang);
 	clk_disable(hw->clk);
 	spi_master_put(hw->master);
 	return 0;
 }

 static struct platform_driver nuc900_spi_driver = {
 	.probe		= nuc900_spi_probe,
 	.remove		= nuc900_spi_remove,
 	.driver		= {
 		.name	= "nuc900-spi",
 	},
 };
 module_platform_driver(nuc900_spi_driver);

 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
 MODULE_DESCRIPTION("nuc900 spi driver!");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:nuc900-spi");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2009 Nuvoton technology.
	* Wan ZongShun <mcuos.com@gmail.com>
	*/

	#include <linux/module.h>
	#include <linux/spinlock.h>
	#include <linux/interrupt.h>
	#include <linux/delay.h>
	#include <linux/errno.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/platform_device.h>
	#include <linux/gpio.h>
	#include <linux/io.h>
	#include <linux/slab.h>

	#include <linux/spi/spi.h>
	#include <linux/spi/spi_bitbang.h>

	#include <linux/platform_data/spi-nuc900.h>

	/* usi registers offset */
	#define USI_CNT 0x00
	#define USI_DIV 0x04
	#define USI_SSR 0x08
	#define USI_RX0 0x10
	#define USI_TX0 0x10

	/* usi register bit */
	#define ENINT (0x01 << 17)
	#define ENFLG (0x01 << 16)
	#define SLEEP (0x0f << 12)
	#define TXNUM (0x03 << 8)
	#define TXBITLEN (0x1f << 3)
	#define TXNEG (0x01 << 2)
	#define RXNEG (0x01 << 1)
	#define LSB (0x01 << 10)
	#define SELECTLEV (0x01 << 2)
	#define SELECTPOL (0x01 << 31)
	#define SELECTSLAVE 0x01
	#define GOBUSY 0x01

	struct nuc900_spi {
	struct spi_bitbang bitbang;
	struct completion done;
	void __iomem *regs;
	int irq;
	int len;
	int count;
	const unsigned char *tx;
	unsigned char *rx;
	struct clk *clk;
	struct spi_master *master;
	struct nuc900_spi_info *pdata;
	spinlock_t lock;
	};

	static inline struct nuc900_spi to_hw(struct spi_device sdev)
	{
	return spi_master_get_devdata(sdev->master);
	}

	static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
	{
	struct nuc900_spi *hw = to_hw(spi);
	unsigned int val;
	unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
	unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_SSR);

	if (!cs)
	val &= ~SELECTLEV;
	else
	val \|= SELECTLEV;

	if (!ssr)
	val &= ~SELECTSLAVE;
	else
	val \|= SELECTSLAVE;

	__raw_writel(val, hw->regs + USI_SSR);

	val = __raw_readl(hw->regs + USI_CNT);

	if (!cpol)
	val &= ~SELECTPOL;
	else
	val \|= SELECTPOL;

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_spi_chipsel(struct spi_device *spi, int value)
	{
	switch (value) {
	case BITBANG_CS_INACTIVE:
	nuc900_slave_select(spi, 0);
	break;

	case BITBANG_CS_ACTIVE:
	nuc900_slave_select(spi, 1);
	break;
	}
	}

	static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;

	if (txnum)
	val \|= txnum << 0x08;

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);

	}

	static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
	unsigned int txbitlen)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;

	val \|= (txbitlen << 0x03);

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_spi_gobusy(struct nuc900_spi *hw)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT);

	val \|= GOBUSY;

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
	{
	return hw->tx ? hw->tx[count] : 0;
	}

	static int nuc900_spi_txrx(struct spi_device spi, struct spi_transfer t)
	{
	struct nuc900_spi *hw = to_hw(spi);

	hw->tx = t->tx_buf;
	hw->rx = t->rx_buf;
	hw->len = t->len;
	hw->count = 0;

	__raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);

	nuc900_spi_gobusy(hw);

	wait_for_completion(&hw->done);

	return hw->count;
	}

	static irqreturn_t nuc900_spi_irq(int irq, void *dev)
	{
	struct nuc900_spi *hw = dev;
	unsigned int status;
	unsigned int count = hw->count;

	status = __raw_readl(hw->regs + USI_CNT);
	__raw_writel(status, hw->regs + USI_CNT);

	if (status & ENFLG) {
	hw->count++;

	if (hw->rx)
	hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
	count++;

	if (count < hw->len) {
	__raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
	nuc900_spi_gobusy(hw);
	} else {
	complete(&hw->done);
	}

	return IRQ_HANDLED;
	}

	complete(&hw->done);
	return IRQ_HANDLED;
	}

	static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT);

	if (edge)
	val \|= TXNEG;
	else
	val &= ~TXNEG;
	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT);

	if (edge)
	val \|= RXNEG;
	else
	val &= ~RXNEG;
	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT);

	if (lsb)
	val \|= LSB;
	else
	val &= ~LSB;
	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;

	if (sleep)
	val \|= (sleep << 12);

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_enable_int(struct nuc900_spi *hw)
	{
	unsigned int val;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	val = __raw_readl(hw->regs + USI_CNT);

	val \|= ENINT;

	__raw_writel(val, hw->regs + USI_CNT);

	spin_unlock_irqrestore(&hw->lock, flags);
	}

	static void nuc900_set_divider(struct nuc900_spi *hw)
	{
	__raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
	}

	static void nuc900_init_spi(struct nuc900_spi *hw)
	{
	clk_enable(hw->clk);
	spin_lock_init(&hw->lock);

	nuc900_tx_edge(hw, hw->pdata->txneg);
	nuc900_rx_edge(hw, hw->pdata->rxneg);
	nuc900_send_first(hw, hw->pdata->lsb);
	nuc900_set_sleep(hw, hw->pdata->sleep);
	nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
	nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
	nuc900_set_divider(hw);
	nuc900_enable_int(hw);
	}

	static int nuc900_spi_probe(struct platform_device *pdev)
	{
	struct nuc900_spi *hw;
	struct spi_master *master;
	struct resource *res;
	int err = 0;

	master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
	if (master == NULL) {
	dev_err(&pdev->dev, "No memory for spi_master\n");
	return -ENOMEM;
	}

	hw = spi_master_get_devdata(master);
	hw->master = master;
	hw->pdata = dev_get_platdata(&pdev->dev);

	if (hw->pdata == NULL) {
	dev_err(&pdev->dev, "No platform data supplied\n");
	err = -ENOENT;
	goto err_pdata;
	}

	platform_set_drvdata(pdev, hw);
	init_completion(&hw->done);

	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH;
	if (hw->pdata->lsb)
	master->mode_bits \|= SPI_LSB_FIRST;
	master->num_chipselect = hw->pdata->num_cs;
	master->bus_num = hw->pdata->bus_num;
	hw->bitbang.master = hw->master;
	hw->bitbang.chipselect = nuc900_spi_chipsel;
	hw->bitbang.txrx_bufs = nuc900_spi_txrx;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	hw->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(hw->regs)) {
	err = PTR_ERR(hw->regs);
	goto err_pdata;
	}

	hw->irq = platform_get_irq(pdev, 0);
	if (hw->irq < 0) {
	dev_err(&pdev->dev, "No IRQ specified\n");
	err = -ENOENT;
	goto err_pdata;
	}

	err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
	pdev->name, hw);
	if (err) {
	dev_err(&pdev->dev, "Cannot claim IRQ\n");
	goto err_pdata;
	}

	hw->clk = devm_clk_get(&pdev->dev, "spi");
	if (IS_ERR(hw->clk)) {
	dev_err(&pdev->dev, "No clock for device\n");
	err = PTR_ERR(hw->clk);
	goto err_pdata;
	}

	mfp_set_groupg(&pdev->dev, NULL);
	nuc900_init_spi(hw);

	err = spi_bitbang_start(&hw->bitbang);
	if (err) {
	dev_err(&pdev->dev, "Failed to register SPI master\n");
	goto err_register;
	}

	return 0;

	err_register:
	clk_disable(hw->clk);
	err_pdata:
	spi_master_put(hw->master);
	return err;
	}

	static int nuc900_spi_remove(struct platform_device *dev)
	{
	struct nuc900_spi *hw = platform_get_drvdata(dev);

	spi_bitbang_stop(&hw->bitbang);
	clk_disable(hw->clk);
	spi_master_put(hw->master);
	return 0;
	}

	static struct platform_driver nuc900_spi_driver = {
	.probe = nuc900_spi_probe,
	.remove = nuc900_spi_remove,
	.driver = {
	.name = "nuc900-spi",
	},
	};
	module_platform_driver(nuc900_spi_driver);

	MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
	MODULE_DESCRIPTION("nuc900 spi driver!");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:nuc900-spi");