diff mbox

[v3,3/7] eSPI: add eSPI controller support

Message ID 1285833646-12006-4-git-send-email-Mingkai.hu@freescale.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Hu Mingkai-B21284 Sept. 30, 2010, 8 a.m. UTC
None
diff mbox

Patch

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 79ad06f..f6888af 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -195,6 +195,15 @@  config SPI_FSL_SPI
 	  MPC83xx platform uses the controller in cpu mode or CPM/QE mode.
 	  MPC8569 uses the controller in QE mode, MPC8610 in cpu mode.
 
+config SPI_FSL_ESPI
+	tristate "Freescale eSPI controller"
+	depends on FSL_SOC
+	select SPI_FSL_LIB
+	help
+	  This enables using the Freescale eSPI controllers in master mode.
+	  From MPC8536, 85xx platform uses the controller, and all P10xx,
+	  P20xx, P30xx,P40xx, P50xx uses this controller.
+
 config SPI_OMAP_UWIRE
 	tristate "OMAP1 MicroWire"
 	depends on ARCH_OMAP1
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 7974c21..833d17e 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -35,6 +35,7 @@  obj-$(CONFIG_SPI_MPC512x_PSC)		+= mpc512x_psc_spi.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= mpc52xx_psc_spi.o
 obj-$(CONFIG_SPI_MPC52xx)		+= mpc52xx_spi.o
 obj-$(CONFIG_SPI_FSL_LIB)		+= spi_fsl_lib.o
+obj-$(CONFIG_SPI_FSL_ESPI)		+= spi_fsl_espi.o
 obj-$(CONFIG_SPI_FSL_SPI)		+= spi_fsl_spi.o
 obj-$(CONFIG_SPI_PPC4xx)		+= spi_ppc4xx.o
 obj-$(CONFIG_SPI_S3C24XX_GPIO)		+= spi_s3c24xx_gpio.o
diff --git a/drivers/spi/spi_fsl_espi.c b/drivers/spi/spi_fsl_espi.c
new file mode 100644
index 0000000..be98148
--- /dev/null
+++ b/drivers/spi/spi_fsl_espi.c
@@ -0,0 +1,642 @@ 
+/*
+ * Freescale eSPI controller driver.
+ *
+ * Copyright 2010 Freescale Semiconductor, Inc.
+ *
+ * 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/module.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/spi/spi.h>
+#include <linux/platform_device.h>
+#include <linux/fsl_devices.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_spi.h>
+#include <sysdev/fsl_soc.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+
+#include "spi_fsl_lib.h"
+
+/* eSPI Controller registers */
+struct fsl_espi_reg {
+	__be32 mode;		/* 0x000 - eSPI mode register */
+	__be32 event;		/* 0x004 - eSPI event register */
+	__be32 mask;		/* 0x008 - eSPI mask register */
+	__be32 command;		/* 0x00c - eSPI command register */
+	__be32 transmit;	/* 0x010 - eSPI transmit FIFO access register*/
+	__be32 receive;		/* 0x014 - eSPI receive FIFO access register*/
+	u8 res[8];		/* 0x018 - 0x01c reserved */
+	__be32 csmode[4];	/* 0x020 - 0x02c eSPI cs mode register */
+};
+
+/* eSPI Controller mode register definitions */
+#define SPMODE_ENABLE		(1 << 31)
+#define SPMODE_LOOP		(1 << 30)
+#define SPMODE_TXTHR(x)		((x) << 8)
+#define SPMODE_RXTHR(x)		((x) << 0)
+
+/* eSPI Controller CS mode register definitions */
+#define CSMODE_CI_INACTIVEHIGH	(1 << 31)
+#define CSMODE_CP_BEGIN_EDGECLK	(1 << 30)
+#define CSMODE_REV		(1 << 29)
+#define CSMODE_DIV16		(1 << 28)
+#define CSMODE_PM(x)		((x) << 24)
+#define CSMODE_POL_1		(1 << 20)
+#define CSMODE_LEN(x)		((x) << 16)
+#define CSMODE_BEF(x)		((x) << 12)
+#define CSMODE_AFT(x)		((x) << 8)
+#define CSMODE_CG(x)		((x) << 3)
+
+/* Default mode/csmode for eSPI controller */
+#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3))
+#define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
+		| CSMODE_AFT(0) | CSMODE_CG(1))
+
+/* SPIE register values */
+#define	SPIE_NE		0x00000200	/* Not empty */
+#define	SPIE_NF		0x00000100	/* Not full */
+
+/* SPIM register values */
+#define	SPIM_NE		0x00000200	/* Not empty */
+#define	SPIM_NF		0x00000100	/* Not full */
+#define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
+#define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
+
+/* SPCOM register values */
+#define SPCOM_CS(x)		((x) << 30)
+#define SPCOM_TRANLEN(x)	((x) << 0)
+#define	SPCOM_TRANLEN_MAX	0xFFFF	/* Max transaction length */
+
+static void fsl_espi_change_mode(struct spi_device *spi)
+{
+	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
+	struct spi_mpc8xxx_cs *cs = spi->controller_state;
+	struct fsl_espi_reg *reg_base = (struct fsl_espi_reg *)mspi->reg_base;
+	__be32 __iomem *mode;
+	__be32 __iomem *espi_mode = NULL;
+	u32 tmp;
+	unsigned long flags;
+
+	espi_mode = &reg_base->mode;
+	mode = &reg_base->csmode[spi->chip_select];
+
+	/* Turn off IRQs locally to minimize time that SPI is disabled. */
+	local_irq_save(flags);
+
+	/* Turn off SPI unit prior changing mode */
+	tmp = mpc8xxx_spi_read_reg(espi_mode);
+	mpc8xxx_spi_write_reg(espi_mode, tmp & ~SPMODE_ENABLE);
+	mpc8xxx_spi_write_reg(mode, cs->hw_mode);
+	mpc8xxx_spi_write_reg(espi_mode, tmp);
+
+	local_irq_restore(flags);
+}
+
+static u32 fsl_espi_tx_buf_lsb(struct mpc8xxx_spi *mpc8xxx_spi)
+{
+	u32 data;
+	u16 data_h, data_l;
+
+	const u32 *tx = mpc8xxx_spi->tx;
+	if (!tx)
+		return 0;
+
+	data = *tx++ << mpc8xxx_spi->tx_shift;
+	data_l = data & 0xffff;
+	data_h = (data >> 16) & 0xffff;
+	swab16s(&data_l);
+	swab16s(&data_h);
+	data = data_h | data_l;
+
+	mpc8xxx_spi->tx = tx;
+	return data;
+}
+
+static int fsl_espi_setup_transfer(struct spi_device *spi,
+					struct spi_transfer *t)
+{
+	struct mpc8xxx_spi *mpc8xxx_spi;
+	int bits_per_word = 0;
+	u8 pm;
+	u32 hz = 0;
+	struct spi_mpc8xxx_cs	*cs = spi->controller_state;
+
+	mpc8xxx_spi = spi_master_get_devdata(spi->master);
+
+	if (t) {
+		bits_per_word = t->bits_per_word;
+		hz = t->speed_hz;
+	}
+
+	/* spi_transfer level calls that work per-word */
+	if (!bits_per_word)
+		bits_per_word = spi->bits_per_word;
+
+	/* Make sure its a bit width we support [4..16] */
+	if ((bits_per_word < 4) || (bits_per_word > 16))
+		return -EINVAL;
+
+	if (!hz)
+		hz = spi->max_speed_hz;
+
+	cs->rx_shift = 0;
+	cs->tx_shift = 0;
+	cs->get_rx = mpc8xxx_spi_rx_buf_u32;
+	cs->get_tx = mpc8xxx_spi_tx_buf_u32;
+	if (bits_per_word <= 8) {
+		cs->rx_shift = 8 - bits_per_word;
+	} else if (bits_per_word <= 16) {
+		cs->rx_shift = 16 - bits_per_word;
+		if (spi->mode & SPI_LSB_FIRST)
+			cs->get_tx = fsl_espi_tx_buf_lsb;
+	} else
+		return -EINVAL;
+
+	mpc8xxx_spi->rx_shift = cs->rx_shift;
+	mpc8xxx_spi->tx_shift = cs->tx_shift;
+	mpc8xxx_spi->get_rx = cs->get_rx;
+	mpc8xxx_spi->get_tx = cs->get_tx;
+
+	bits_per_word = bits_per_word - 1;
+
+	/* mask out bits we are going to set */
+	cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16
+				  | CSMODE_PM(0xF));
+
+	cs->hw_mode |= CSMODE_LEN(bits_per_word);
+
+	if ((mpc8xxx_spi->spibrg / hz) > 64) {
+		cs->hw_mode |= CSMODE_DIV16;
+		pm = (mpc8xxx_spi->spibrg - 1) / (hz * 64) + 1;
+
+		WARN_ONCE(pm > 16, "%s: Requested speed is too low: %d Hz. "
+			  "Will use %d Hz instead.\n", dev_name(&spi->dev),
+			  hz, mpc8xxx_spi->spibrg / 1024);
+		if (pm > 16)
+			pm = 16;
+	} else {
+		pm = (mpc8xxx_spi->spibrg - 1) / (hz * 4) + 1;
+	}
+	if (pm)
+		pm--;
+
+	cs->hw_mode |= CSMODE_PM(pm);
+
+	fsl_espi_change_mode(spi);
+	return 0;
+}
+
+int fsl_espi_cpu_bufs(struct mpc8xxx_spi *mspi, struct spi_transfer *t,
+		unsigned int len)
+{
+	u32 word;
+	struct fsl_espi_reg *reg_base = (struct fsl_espi_reg *)mspi->reg_base;
+
+	mspi->count = len;
+
+	/* enable rx ints */
+	mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);
+
+	/* transmit word */
+	word = mspi->get_tx(mspi);
+	mpc8xxx_spi_write_reg(&reg_base->transmit, word);
+
+	return 0;
+}
+
+static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t,
+			    bool is_dma_mapped)
+{
+	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
+	struct fsl_espi_reg *reg_base;
+	unsigned int len = t->len;
+	u8 bits_per_word;
+	int ret;
+
+	reg_base = (struct fsl_espi_reg *)mpc8xxx_spi->reg_base;
+
+	bits_per_word = spi->bits_per_word;
+	if (t->bits_per_word)
+		bits_per_word = t->bits_per_word;
+
+	mpc8xxx_spi->len = t->len;
+	len = roundup(len, 4) / 4;
+
+	mpc8xxx_spi->tx = t->tx_buf;
+	mpc8xxx_spi->rx = t->rx_buf;
+
+	INIT_COMPLETION(mpc8xxx_spi->done);
+
+	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
+	if ((t->len - 1) > SPCOM_TRANLEN_MAX) {
+		dev_err(mpc8xxx_spi->dev, "Transaction length (%d)"
+				" beyond the SPCOM[TRANLEN] field\n", t->len);
+		return -EINVAL;
+	}
+	mpc8xxx_spi_write_reg(&reg_base->command,
+		(SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1)));
+
+	ret = fsl_espi_cpu_bufs(mpc8xxx_spi, t, len);
+	if (ret)
+		return ret;
+
+	wait_for_completion(&mpc8xxx_spi->done);
+
+	/* disable rx ints */
+	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
+
+	return mpc8xxx_spi->count;
+}
+
+static void fsl_espi_do_one_msg(struct spi_message *m)
+{
+	struct spi_device *spi = m->spi;
+	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
+	struct spi_message message;
+	struct spi_transfer *t, *first, trans;
+	u8 *local_buf, *rx_buf = NULL;
+	unsigned int n_tx = 0;
+	unsigned int n_rx = 0;
+	int status = 0;
+	int i = 0;
+
+	spi_message_init(&message);
+	memset(&trans, 0, sizeof(trans));
+
+	first = list_first_entry(&m->transfers, struct spi_transfer,
+			transfer_list);
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if ((first->bits_per_word != t->bits_per_word) ||
+			(first->speed_hz != t->speed_hz)) {
+			status = -EINVAL;
+			dev_err(mspi->dev, "bits_per_word/speed_hz should be"
+					" same for the same SPI transfer\n");
+			return;
+		}
+
+		trans.speed_hz = t->speed_hz;
+		trans.bits_per_word = t->bits_per_word;
+		trans.delay_usecs = max(first->delay_usecs, t->delay_usecs);
+
+		if (t->tx_buf)
+			n_tx += t->len;
+
+		if (t->rx_buf) {
+			n_rx += t->len;
+			rx_buf = t->rx_buf;
+		}
+	}
+
+	local_buf = kzalloc(n_tx * 2 + roundup(n_rx + n_tx, 4), GFP_KERNEL);
+	if (!local_buf) {
+		status = -ENOMEM;
+		return;
+	}
+
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if (t->tx_buf) {
+			memcpy(local_buf + i, t->tx_buf, t->len);
+			i += t->len;
+		}
+	}
+
+	trans.len = n_tx + n_rx;
+	trans.tx_buf = local_buf;
+	trans.rx_buf = local_buf + n_tx;
+	spi_message_add_tail(&trans, &message);
+
+	list_for_each_entry(t, &message.transfers, transfer_list) {
+		if (t->bits_per_word || t->speed_hz) {
+			status = -EINVAL;
+
+			status = fsl_espi_setup_transfer(spi, t);
+			if (status < 0)
+				break;
+		}
+
+		if (t->len)
+			status = fsl_espi_bufs(spi, t, 0);
+		if (status) {
+			status = -EMSGSIZE;
+			break;
+		}
+		m->actual_length += t->len;
+
+		if (rx_buf)
+			memcpy(rx_buf, t->rx_buf + n_tx, n_rx);
+
+		if (t->delay_usecs)
+			udelay(t->delay_usecs);
+	}
+
+	m->status = status;
+	m->complete(m->context);
+
+	fsl_espi_setup_transfer(spi, NULL);
+	kfree(local_buf);
+}
+
+static int fsl_espi_setup(struct spi_device *spi)
+{
+	struct mpc8xxx_spi *mpc8xxx_spi;
+	struct fsl_espi_reg *reg_base;
+	int retval;
+	u32 hw_mode;
+	u32 loop_mode;
+	struct spi_mpc8xxx_cs	*cs = spi->controller_state;
+
+	if (!spi->max_speed_hz)
+		return -EINVAL;
+
+	if (!cs) {
+		cs = kzalloc(sizeof *cs, GFP_KERNEL);
+		if (!cs)
+			return -ENOMEM;
+		spi->controller_state = cs;
+	}
+
+	mpc8xxx_spi = spi_master_get_devdata(spi->master);
+	reg_base = (struct fsl_espi_reg *)mpc8xxx_spi->reg_base;
+
+	hw_mode = cs->hw_mode; /* Save orginal settings */
+	cs->hw_mode = mpc8xxx_spi_read_reg(
+			&reg_base->csmode[spi->chip_select]);
+	/* mask out bits we are going to set */
+	cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
+			 | CSMODE_REV);
+
+	if (spi->mode & SPI_CPHA)
+		cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
+	if (spi->mode & SPI_CPOL)
+		cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
+	if (!(spi->mode & SPI_LSB_FIRST))
+		cs->hw_mode |= CSMODE_REV;
+
+	/* Handle the loop mode */
+	loop_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
+	loop_mode &= ~SPMODE_LOOP;
+	if (spi->mode & SPI_LOOP)
+		loop_mode |= SPMODE_LOOP;
+	mpc8xxx_spi_write_reg(&reg_base->mode, loop_mode);
+
+	retval = fsl_espi_setup_transfer(spi, NULL);
+	if (retval < 0) {
+		cs->hw_mode = hw_mode; /* Restore settings */
+		return retval;
+	}
+	return 0;
+}
+
+static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
+{
+	struct fsl_espi_reg *reg_base = (struct fsl_espi_reg *)mspi->reg_base;
+
+	/* We need handle RX first */
+	if (events & SPIE_NE) {
+		u32 rx_data;
+
+		/* Spin until RX is done */
+		while (SPIE_RXCNT(events) < min(4, mspi->len)) {
+			cpu_relax();
+			events = mpc8xxx_spi_read_reg(&reg_base->event);
+		}
+		mspi->len -= 4;
+
+		rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
+
+		if (mspi->rx)
+			mspi->get_rx(rx_data, mspi);
+	}
+
+	if ((events & SPIE_NF) == 0)
+		/* spin until TX is done */
+		while (((events = mpc8xxx_spi_read_reg(&reg_base->event))
+					& SPIE_NF) == 0)
+			cpu_relax();
+
+	/* Clear the events */
+	mpc8xxx_spi_write_reg(&reg_base->event, events);
+
+	mspi->count -= 1;
+	if (mspi->count) {
+		u32 word = mspi->get_tx(mspi);
+
+		mpc8xxx_spi_write_reg(&reg_base->transmit, word);
+	} else {
+		complete(&mspi->done);
+	}
+}
+
+static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
+{
+	struct mpc8xxx_spi *mspi = context_data;
+	struct fsl_espi_reg *reg_base = (struct fsl_espi_reg *)mspi->reg_base;
+	irqreturn_t ret = IRQ_NONE;
+	u32 events;
+
+	/* Get interrupt events(tx/rx) */
+	events = mpc8xxx_spi_read_reg(&reg_base->event);
+	if (events)
+		ret = IRQ_HANDLED;
+
+	dev_dbg(mspi->dev, "%s: events %x\n", __func__, events);
+
+	fsl_espi_cpu_irq(mspi, events);
+
+	return ret;
+}
+
+static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
+{
+	iounmap(mspi->reg_base);
+}
+
+static struct spi_master * __devinit fsl_espi_probe(struct device *dev,
+		struct resource *mem, unsigned int irq)
+{
+	struct fsl_spi_platform_data *pdata = dev->platform_data;
+	struct spi_master *master;
+	struct mpc8xxx_spi *mpc8xxx_spi;
+	struct fsl_espi_reg *reg_base;
+	u32 regval;
+	int i, ret = 0;
+
+	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
+	if (master == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	dev_set_drvdata(dev, master);
+
+	ret = mpc8xxx_spi_probe(dev, mem, irq);
+	if (ret)
+		goto err_probe;
+
+	master->setup = fsl_espi_setup;
+
+	mpc8xxx_spi = spi_master_get_devdata(master);
+	mpc8xxx_spi->spi_do_one_msg = fsl_espi_do_one_msg;
+	mpc8xxx_spi->spi_remove = fsl_espi_remove;
+
+	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
+	if (mpc8xxx_spi->reg_base == NULL) {
+		ret = -ENOMEM;
+		goto err_probe;
+	}
+
+	reg_base = (struct fsl_espi_reg *)mpc8xxx_spi->reg_base;
+
+	/* Register for SPI Interrupt */
+	ret = request_irq(mpc8xxx_spi->irq, fsl_espi_irq,
+			  0, "fsl_espi", mpc8xxx_spi);
+
+	if (ret != 0)
+		goto free_irq;
+
+	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
+		mpc8xxx_spi->rx_shift = 16;
+		mpc8xxx_spi->tx_shift = 24;
+	}
+
+	/* SPI controller initializations */
+	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
+	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
+	mpc8xxx_spi_write_reg(&reg_base->command, 0);
+	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);
+
+	/* Init eSPI CS mode register */
+	for (i = 0; i < pdata->max_chipselect; i++)
+		mpc8xxx_spi_write_reg(&reg_base->csmode[i], CSMODE_INIT_VAL);
+
+	/* Enable SPI interface */
+	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
+
+	mpc8xxx_spi_write_reg(&reg_base->mode, regval);
+
+	ret = spi_register_master(master);
+	if (ret < 0)
+		goto unreg_master;
+
+	dev_info(dev, "at 0x%p (irq = %d)\n", reg_base, mpc8xxx_spi->irq);
+
+	return master;
+
+unreg_master:
+	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
+free_irq:
+	iounmap(mpc8xxx_spi->reg_base);
+err_probe:
+	spi_master_put(master);
+err:
+	return ERR_PTR(ret);
+}
+
+static int of_fsl_espi_get_chipselects(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct fsl_spi_platform_data *pdata = dev->platform_data;
+	const u32 *prop;
+	int len;
+
+	prop = of_get_property(np, "fsl,espi-num-chipselects", &len);
+	if (!prop || len < sizeof(*prop)) {
+		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
+		return -EINVAL;
+	}
+
+	pdata->max_chipselect = *prop;
+	pdata->cs_control = NULL;
+
+	return 0;
+}
+
+static int __devinit of_fsl_espi_probe(struct platform_device *ofdev,
+					const struct of_device_id *ofid)
+{
+	struct device *dev = &ofdev->dev;
+	struct device_node *np = ofdev->dev.of_node;
+	struct spi_master *master;
+	struct resource mem;
+	struct resource irq;
+	int ret = -ENOMEM;
+
+	ret = of_mpc8xxx_spi_probe(ofdev, ofid);
+	if (ret)
+		return ret;
+
+	ret = of_fsl_espi_get_chipselects(dev);
+	if (ret)
+		goto err;
+
+	ret = of_address_to_resource(np, 0, &mem);
+	if (ret)
+		goto err;
+
+	ret = of_irq_to_resource(np, 0, &irq);
+	if (!ret) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	master = fsl_espi_probe(dev, &mem, irq.start);
+	if (IS_ERR(master)) {
+		ret = PTR_ERR(master);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	return ret;
+}
+
+static int __devexit of_fsl_espi_remove(struct platform_device *dev)
+{
+	int ret;
+
+	ret = mpc8xxx_spi_remove(&dev->dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id of_fsl_espi_match[] = {
+	{ .compatible = "fsl,mpc8536-espi" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
+
+static struct of_platform_driver fsl_espi_driver = {
+	.driver = {
+		.name = "fsl_espi",
+		.owner = THIS_MODULE,
+		.of_match_table = of_fsl_espi_match,
+	},
+	.probe		= of_fsl_espi_probe,
+	.remove		= __devexit_p(of_fsl_espi_remove),
+};
+
+static int __init fsl_espi_init(void)
+{
+	return of_register_platform_driver(&fsl_espi_driver);
+}
+module_init(fsl_espi_init);
+
+static void __exit fsl_espi_exit(void)
+{
+	of_unregister_platform_driver(&fsl_espi_driver);
+}
+module_exit(fsl_espi_exit);
+
+MODULE_AUTHOR("Mingkai Hu");
+MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/spi/spi_fsl_lib.h b/drivers/spi/spi_fsl_lib.h
index 6ae8949..9c81498 100644
--- a/drivers/spi/spi_fsl_lib.h
+++ b/drivers/spi/spi_fsl_lib.h
@@ -26,6 +26,7 @@  struct mpc8xxx_spi {
 	/* rx & tx bufs from the spi_transfer */
 	const void *tx;
 	void *rx;
+	int len;
 
 	int subblock;
 	struct spi_pram __iomem *pram;