1 files changed, 844 insertions, 0 deletions

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
new file mode 100644
index 0000000000..ea647ee94d
--- /dev/null
+++ b/drivers/spi/spi-fsl-espi.c
@@ -0,0 +1,844 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Freescale eSPI controller driver.
+ *
+ * Copyright 2010 Freescale Semiconductor, Inc.
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/fsl_devices.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/pm_runtime.h>
+#include <sysdev/fsl_soc.h>
+
+/* eSPI Controller registers */
+#define ESPI_SPMODE	0x00	/* eSPI mode register */
+#define ESPI_SPIE	0x04	/* eSPI event register */
+#define ESPI_SPIM	0x08	/* eSPI mask register */
+#define ESPI_SPCOM	0x0c	/* eSPI command register */
+#define ESPI_SPITF	0x10	/* eSPI transmit FIFO access register*/
+#define ESPI_SPIRF	0x14	/* eSPI receive FIFO access register*/
+#define ESPI_SPMODE0	0x20	/* eSPI cs0 mode register */
+
+#define ESPI_SPMODEx(x)	(ESPI_SPMODE0 + (x) * 4)
+
+/* eSPI Controller mode register definitions */
+#define SPMODE_ENABLE		BIT(31)
+#define SPMODE_LOOP		BIT(30)
+#define SPMODE_TXTHR(x)		((x) << 8)
+#define SPMODE_RXTHR(x)		((x) << 0)
+
+/* eSPI Controller CS mode register definitions */
+#define CSMODE_CI_INACTIVEHIGH	BIT(31)
+#define CSMODE_CP_BEGIN_EDGECLK	BIT(30)
+#define CSMODE_REV		BIT(29)
+#define CSMODE_DIV16		BIT(28)
+#define CSMODE_PM(x)		((x) << 24)
+#define CSMODE_POL_1		BIT(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)
+
+#define FSL_ESPI_FIFO_SIZE	32
+#define FSL_ESPI_RXTHR		15
+
+/* Default mode/csmode for eSPI controller */
+#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(FSL_ESPI_RXTHR))
+#define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
+		| CSMODE_AFT(0) | CSMODE_CG(1))
+
+/* SPIE register values */
+#define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
+#define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
+#define	SPIE_TXE		BIT(15)	/* TX FIFO empty */
+#define	SPIE_DON		BIT(14)	/* TX done */
+#define	SPIE_RXT		BIT(13)	/* RX FIFO threshold */
+#define	SPIE_RXF		BIT(12)	/* RX FIFO full */
+#define	SPIE_TXT		BIT(11)	/* TX FIFO threshold*/
+#define	SPIE_RNE		BIT(9)	/* RX FIFO not empty */
+#define	SPIE_TNF		BIT(8)	/* TX FIFO not full */
+
+/* SPIM register values */
+#define	SPIM_TXE		BIT(15)	/* TX FIFO empty */
+#define	SPIM_DON		BIT(14)	/* TX done */
+#define	SPIM_RXT		BIT(13)	/* RX FIFO threshold */
+#define	SPIM_RXF		BIT(12)	/* RX FIFO full */
+#define	SPIM_TXT		BIT(11)	/* TX FIFO threshold*/
+#define	SPIM_RNE		BIT(9)	/* RX FIFO not empty */
+#define	SPIM_TNF		BIT(8)	/* TX FIFO not full */
+
+/* SPCOM register values */
+#define SPCOM_CS(x)		((x) << 30)
+#define SPCOM_DO		BIT(28) /* Dual output */
+#define SPCOM_TO		BIT(27) /* TX only */
+#define SPCOM_RXSKIP(x)		((x) << 16)
+#define SPCOM_TRANLEN(x)	((x) << 0)
+
+#define	SPCOM_TRANLEN_MAX	0x10000	/* Max transaction length */
+
+#define AUTOSUSPEND_TIMEOUT 2000
+
+struct fsl_espi {
+	struct device *dev;
+	void __iomem *reg_base;
+
+	struct list_head *m_transfers;
+	struct spi_transfer *tx_t;
+	unsigned int tx_pos;
+	bool tx_done;
+	struct spi_transfer *rx_t;
+	unsigned int rx_pos;
+	bool rx_done;
+
+	bool swab;
+	unsigned int rxskip;
+
+	spinlock_t lock;
+
+	u32 spibrg;             /* SPIBRG input clock */
+
+	struct completion done;
+};
+
+struct fsl_espi_cs {
+	u32 hw_mode;
+};
+
+static inline u32 fsl_espi_read_reg(struct fsl_espi *espi, int offset)
+{
+	return ioread32be(espi->reg_base + offset);
+}
+
+static inline u16 fsl_espi_read_reg16(struct fsl_espi *espi, int offset)
+{
+	return ioread16be(espi->reg_base + offset);
+}
+
+static inline u8 fsl_espi_read_reg8(struct fsl_espi *espi, int offset)
+{
+	return ioread8(espi->reg_base + offset);
+}
+
+static inline void fsl_espi_write_reg(struct fsl_espi *espi, int offset,
+				      u32 val)
+{
+	iowrite32be(val, espi->reg_base + offset);
+}
+
+static inline void fsl_espi_write_reg16(struct fsl_espi *espi, int offset,
+					u16 val)
+{
+	iowrite16be(val, espi->reg_base + offset);
+}
+
+static inline void fsl_espi_write_reg8(struct fsl_espi *espi, int offset,
+				       u8 val)
+{
+	iowrite8(val, espi->reg_base + offset);
+}
+
+static int fsl_espi_check_message(struct spi_message *m)
+{
+	struct fsl_espi *espi = spi_controller_get_devdata(m->spi->controller);
+	struct spi_transfer *t, *first;
+
+	if (m->frame_length > SPCOM_TRANLEN_MAX) {
+		dev_err(espi->dev, "message too long, size is %u bytes\n",
+			m->frame_length);
+		return -EMSGSIZE;
+	}
+
+	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) {
+			dev_err(espi->dev, "bits_per_word/speed_hz should be the same for all transfers\n");
+			return -EINVAL;
+		}
+	}
+
+	/* ESPI supports MSB-first transfers for word size 8 / 16 only */
+	if (!(m->spi->mode & SPI_LSB_FIRST) && first->bits_per_word != 8 &&
+	    first->bits_per_word != 16) {
+		dev_err(espi->dev,
+			"MSB-first transfer not supported for wordsize %u\n",
+			first->bits_per_word);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static unsigned int fsl_espi_check_rxskip_mode(struct spi_message *m)
+{
+	struct spi_transfer *t;
+	unsigned int i = 0, rxskip = 0;
+
+	/*
+	 * prerequisites for ESPI rxskip mode:
+	 * - message has two transfers
+	 * - first transfer is a write and second is a read
+	 *
+	 * In addition the current low-level transfer mechanism requires
+	 * that the rxskip bytes fit into the TX FIFO. Else the transfer
+	 * would hang because after the first FSL_ESPI_FIFO_SIZE bytes
+	 * the TX FIFO isn't re-filled.
+	 */
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		if (i == 0) {
+			if (!t->tx_buf || t->rx_buf ||
+			    t->len > FSL_ESPI_FIFO_SIZE)
+				return 0;
+			rxskip = t->len;
+		} else if (i == 1) {
+			if (t->tx_buf || !t->rx_buf)
+				return 0;
+		}
+		i++;
+	}
+
+	return i == 2 ? rxskip : 0;
+}
+
+static void fsl_espi_fill_tx_fifo(struct fsl_espi *espi, u32 events)
+{
+	u32 tx_fifo_avail;
+	unsigned int tx_left;
+	const void *tx_buf;
+
+	/* if events is zero transfer has not started and tx fifo is empty */
+	tx_fifo_avail = events ? SPIE_TXCNT(events) :  FSL_ESPI_FIFO_SIZE;
+start:
+	tx_left = espi->tx_t->len - espi->tx_pos;
+	tx_buf = espi->tx_t->tx_buf;
+	while (tx_fifo_avail >= min(4U, tx_left) && tx_left) {
+		if (tx_left >= 4) {
+			if (!tx_buf)
+				fsl_espi_write_reg(espi, ESPI_SPITF, 0);
+			else if (espi->swab)
+				fsl_espi_write_reg(espi, ESPI_SPITF,
+					swahb32p(tx_buf + espi->tx_pos));
+			else
+				fsl_espi_write_reg(espi, ESPI_SPITF,
+					*(u32 *)(tx_buf + espi->tx_pos));
+			espi->tx_pos += 4;
+			tx_left -= 4;
+			tx_fifo_avail -= 4;
+		} else if (tx_left >= 2 && tx_buf && espi->swab) {
+			fsl_espi_write_reg16(espi, ESPI_SPITF,
+					swab16p(tx_buf + espi->tx_pos));
+			espi->tx_pos += 2;
+			tx_left -= 2;
+			tx_fifo_avail -= 2;
+		} else {
+			if (!tx_buf)
+				fsl_espi_write_reg8(espi, ESPI_SPITF, 0);
+			else
+				fsl_espi_write_reg8(espi, ESPI_SPITF,
+					*(u8 *)(tx_buf + espi->tx_pos));
+			espi->tx_pos += 1;
+			tx_left -= 1;
+			tx_fifo_avail -= 1;
+		}
+	}
+
+	if (!tx_left) {
+		/* Last transfer finished, in rxskip mode only one is needed */
+		if (list_is_last(&espi->tx_t->transfer_list,
+		    espi->m_transfers) || espi->rxskip) {
+			espi->tx_done = true;
+			return;
+		}
+		espi->tx_t = list_next_entry(espi->tx_t, transfer_list);
+		espi->tx_pos = 0;
+		/* continue with next transfer if tx fifo is not full */
+		if (tx_fifo_avail)
+			goto start;
+	}
+}
+
+static void fsl_espi_read_rx_fifo(struct fsl_espi *espi, u32 events)
+{
+	u32 rx_fifo_avail = SPIE_RXCNT(events);
+	unsigned int rx_left;
+	void *rx_buf;
+
+start:
+	rx_left = espi->rx_t->len - espi->rx_pos;
+	rx_buf = espi->rx_t->rx_buf;
+	while (rx_fifo_avail >= min(4U, rx_left) && rx_left) {
+		if (rx_left >= 4) {
+			u32 val = fsl_espi_read_reg(espi, ESPI_SPIRF);
+
+			if (rx_buf && espi->swab)
+				*(u32 *)(rx_buf + espi->rx_pos) = swahb32(val);
+			else if (rx_buf)
+				*(u32 *)(rx_buf + espi->rx_pos) = val;
+			espi->rx_pos += 4;
+			rx_left -= 4;
+			rx_fifo_avail -= 4;
+		} else if (rx_left >= 2 && rx_buf && espi->swab) {
+			u16 val = fsl_espi_read_reg16(espi, ESPI_SPIRF);
+
+			*(u16 *)(rx_buf + espi->rx_pos) = swab16(val);
+			espi->rx_pos += 2;
+			rx_left -= 2;
+			rx_fifo_avail -= 2;
+		} else {
+			u8 val = fsl_espi_read_reg8(espi, ESPI_SPIRF);
+
+			if (rx_buf)
+				*(u8 *)(rx_buf + espi->rx_pos) = val;
+			espi->rx_pos += 1;
+			rx_left -= 1;
+			rx_fifo_avail -= 1;
+		}
+	}
+
+	if (!rx_left) {
+		if (list_is_last(&espi->rx_t->transfer_list,
+		    espi->m_transfers)) {
+			espi->rx_done = true;
+			return;
+		}
+		espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
+		espi->rx_pos = 0;
+		/* continue with next transfer if rx fifo is not empty */
+		if (rx_fifo_avail)
+			goto start;
+	}
+}
+
+static void fsl_espi_setup_transfer(struct spi_device *spi,
+					struct spi_transfer *t)
+{
+	struct fsl_espi *espi = spi_controller_get_devdata(spi->controller);
+	int bits_per_word = t ? t->bits_per_word : spi->bits_per_word;
+	u32 pm, hz = t ? t->speed_hz : spi->max_speed_hz;
+	struct fsl_espi_cs *cs = spi_get_ctldata(spi);
+	u32 hw_mode_old = cs->hw_mode;
+
+	/* 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 - 1);
+
+	pm = DIV_ROUND_UP(espi->spibrg, hz * 4) - 1;
+
+	if (pm > 15) {
+		cs->hw_mode |= CSMODE_DIV16;
+		pm = DIV_ROUND_UP(espi->spibrg, hz * 16 * 4) - 1;
+	}
+
+	cs->hw_mode |= CSMODE_PM(pm);
+
+	/* don't write the mode register if the mode doesn't change */
+	if (cs->hw_mode != hw_mode_old)
+		fsl_espi_write_reg(espi, ESPI_SPMODEx(spi_get_chipselect(spi, 0)),
+				   cs->hw_mode);
+}
+
+static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+	struct fsl_espi *espi = spi_controller_get_devdata(spi->controller);
+	unsigned int rx_len = t->len;
+	u32 mask, spcom;
+	int ret;
+
+	reinit_completion(&espi->done);
+
+	/* Set SPCOM[CS] and SPCOM[TRANLEN] field */
+	spcom = SPCOM_CS(spi_get_chipselect(spi, 0));
+	spcom |= SPCOM_TRANLEN(t->len - 1);
+
+	/* configure RXSKIP mode */
+	if (espi->rxskip) {
+		spcom |= SPCOM_RXSKIP(espi->rxskip);
+		rx_len = t->len - espi->rxskip;
+		if (t->rx_nbits == SPI_NBITS_DUAL)
+			spcom |= SPCOM_DO;
+	}
+
+	fsl_espi_write_reg(espi, ESPI_SPCOM, spcom);
+
+	/* enable interrupts */
+	mask = SPIM_DON;
+	if (rx_len > FSL_ESPI_FIFO_SIZE)
+		mask |= SPIM_RXT;
+	fsl_espi_write_reg(espi, ESPI_SPIM, mask);
+
+	/* Prevent filling the fifo from getting interrupted */
+	spin_lock_irq(&espi->lock);
+	fsl_espi_fill_tx_fifo(espi, 0);
+	spin_unlock_irq(&espi->lock);
+
+	/* Won't hang up forever, SPI bus sometimes got lost interrupts... */
+	ret = wait_for_completion_timeout(&espi->done, 2 * HZ);
+	if (ret == 0)
+		dev_err(espi->dev, "Transfer timed out!\n");
+
+	/* disable rx ints */
+	fsl_espi_write_reg(espi, ESPI_SPIM, 0);
+
+	return ret == 0 ? -ETIMEDOUT : 0;
+}
+
+static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
+{
+	struct fsl_espi *espi = spi_controller_get_devdata(m->spi->controller);
+	struct spi_device *spi = m->spi;
+	int ret;
+
+	/* In case of LSB-first and bits_per_word > 8 byte-swap all words */
+	espi->swab = spi->mode & SPI_LSB_FIRST && trans->bits_per_word > 8;
+
+	espi->m_transfers = &m->transfers;
+	espi->tx_t = list_first_entry(&m->transfers, struct spi_transfer,
+				      transfer_list);
+	espi->tx_pos = 0;
+	espi->tx_done = false;
+	espi->rx_t = list_first_entry(&m->transfers, struct spi_transfer,
+				      transfer_list);
+	espi->rx_pos = 0;
+	espi->rx_done = false;
+
+	espi->rxskip = fsl_espi_check_rxskip_mode(m);
+	if (trans->rx_nbits == SPI_NBITS_DUAL && !espi->rxskip) {
+		dev_err(espi->dev, "Dual output mode requires RXSKIP mode!\n");
+		return -EINVAL;
+	}
+
+	/* In RXSKIP mode skip first transfer for reads */
+	if (espi->rxskip)
+		espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
+
+	fsl_espi_setup_transfer(spi, trans);
+
+	ret = fsl_espi_bufs(spi, trans);
+
+	spi_transfer_delay_exec(trans);
+
+	return ret;
+}
+
+static int fsl_espi_do_one_msg(struct spi_controller *host,
+			       struct spi_message *m)
+{
+	unsigned int rx_nbits = 0, delay_nsecs = 0;
+	struct spi_transfer *t, trans = {};
+	int ret;
+
+	ret = fsl_espi_check_message(m);
+	if (ret)
+		goto out;
+
+	list_for_each_entry(t, &m->transfers, transfer_list) {
+		unsigned int delay = spi_delay_to_ns(&t->delay, t);
+
+		if (delay > delay_nsecs)
+			delay_nsecs = delay;
+		if (t->rx_nbits > rx_nbits)
+			rx_nbits = t->rx_nbits;
+	}
+
+	t = list_first_entry(&m->transfers, struct spi_transfer,
+			     transfer_list);
+
+	trans.len = m->frame_length;
+	trans.speed_hz = t->speed_hz;
+	trans.bits_per_word = t->bits_per_word;
+	trans.delay.value = delay_nsecs;
+	trans.delay.unit = SPI_DELAY_UNIT_NSECS;
+	trans.rx_nbits = rx_nbits;
+
+	if (trans.len)
+		ret = fsl_espi_trans(m, &trans);
+
+	m->actual_length = ret ? 0 : trans.len;
+out:
+	if (m->status == -EINPROGRESS)
+		m->status = ret;
+
+	spi_finalize_current_message(host);
+
+	return ret;
+}
+
+static int fsl_espi_setup(struct spi_device *spi)
+{
+	struct fsl_espi *espi;
+	u32 loop_mode;
+	struct fsl_espi_cs *cs = spi_get_ctldata(spi);
+
+	if (!cs) {
+		cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+		if (!cs)
+			return -ENOMEM;
+		spi_set_ctldata(spi, cs);
+	}
+
+	espi = spi_controller_get_devdata(spi->controller);
+
+	pm_runtime_get_sync(espi->dev);
+
+	cs->hw_mode = fsl_espi_read_reg(espi, ESPI_SPMODEx(spi_get_chipselect(spi, 0)));
+	/* 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 = fsl_espi_read_reg(espi, ESPI_SPMODE);
+	loop_mode &= ~SPMODE_LOOP;
+	if (spi->mode & SPI_LOOP)
+		loop_mode |= SPMODE_LOOP;
+	fsl_espi_write_reg(espi, ESPI_SPMODE, loop_mode);
+
+	fsl_espi_setup_transfer(spi, NULL);
+
+	pm_runtime_mark_last_busy(espi->dev);
+	pm_runtime_put_autosuspend(espi->dev);
+
+	return 0;
+}
+
+static void fsl_espi_cleanup(struct spi_device *spi)
+{
+	struct fsl_espi_cs *cs = spi_get_ctldata(spi);
+
+	kfree(cs);
+	spi_set_ctldata(spi, NULL);
+}
+
+static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
+{
+	if (!espi->rx_done)
+		fsl_espi_read_rx_fifo(espi, events);
+
+	if (!espi->tx_done)
+		fsl_espi_fill_tx_fifo(espi, events);
+
+	if (!espi->tx_done || !espi->rx_done)
+		return;
+
+	/* we're done, but check for errors before returning */
+	events = fsl_espi_read_reg(espi, ESPI_SPIE);
+
+	if (!(events & SPIE_DON))
+		dev_err(espi->dev,
+			"Transfer done but SPIE_DON isn't set!\n");
+
+	if (SPIE_RXCNT(events) || SPIE_TXCNT(events) != FSL_ESPI_FIFO_SIZE) {
+		dev_err(espi->dev, "Transfer done but rx/tx fifo's aren't empty!\n");
+		dev_err(espi->dev, "SPIE_RXCNT = %d, SPIE_TXCNT = %d\n",
+			SPIE_RXCNT(events), SPIE_TXCNT(events));
+	}
+
+	complete(&espi->done);
+}
+
+static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
+{
+	struct fsl_espi *espi = context_data;
+	u32 events, mask;
+
+	spin_lock(&espi->lock);
+
+	/* Get interrupt events(tx/rx) */
+	events = fsl_espi_read_reg(espi, ESPI_SPIE);
+	mask = fsl_espi_read_reg(espi, ESPI_SPIM);
+	if (!(events & mask)) {
+		spin_unlock(&espi->lock);
+		return IRQ_NONE;
+	}
+
+	dev_vdbg(espi->dev, "%s: events %x\n", __func__, events);
+
+	fsl_espi_cpu_irq(espi, events);
+
+	/* Clear the events */
+	fsl_espi_write_reg(espi, ESPI_SPIE, events);
+
+	spin_unlock(&espi->lock);
+
+	return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_PM
+static int fsl_espi_runtime_suspend(struct device *dev)
+{
+	struct spi_controller *host = dev_get_drvdata(dev);
+	struct fsl_espi *espi = spi_controller_get_devdata(host);
+	u32 regval;
+
+	regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
+	regval &= ~SPMODE_ENABLE;
+	fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
+
+	return 0;
+}
+
+static int fsl_espi_runtime_resume(struct device *dev)
+{
+	struct spi_controller *host = dev_get_drvdata(dev);
+	struct fsl_espi *espi = spi_controller_get_devdata(host);
+	u32 regval;
+
+	regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
+	regval |= SPMODE_ENABLE;
+	fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
+
+	return 0;
+}
+#endif
+
+static size_t fsl_espi_max_message_size(struct spi_device *spi)
+{
+	return SPCOM_TRANLEN_MAX;
+}
+
+static void fsl_espi_init_regs(struct device *dev, bool initial)
+{
+	struct spi_controller *host = dev_get_drvdata(dev);
+	struct fsl_espi *espi = spi_controller_get_devdata(host);
+	struct device_node *nc;
+	u32 csmode, cs, prop;
+	int ret;
+
+	/* SPI controller initializations */
+	fsl_espi_write_reg(espi, ESPI_SPMODE, 0);
+	fsl_espi_write_reg(espi, ESPI_SPIM, 0);
+	fsl_espi_write_reg(espi, ESPI_SPCOM, 0);
+	fsl_espi_write_reg(espi, ESPI_SPIE, 0xffffffff);
+
+	/* Init eSPI CS mode register */
+	for_each_available_child_of_node(host->dev.of_node, nc) {
+		/* get chip select */
+		ret = of_property_read_u32(nc, "reg", &cs);
+		if (ret || cs >= host->num_chipselect)
+			continue;
+
+		csmode = CSMODE_INIT_VAL;
+
+		/* check if CSBEF is set in device tree */
+		ret = of_property_read_u32(nc, "fsl,csbef", &prop);
+		if (!ret) {
+			csmode &= ~(CSMODE_BEF(0xf));
+			csmode |= CSMODE_BEF(prop);
+		}
+
+		/* check if CSAFT is set in device tree */
+		ret = of_property_read_u32(nc, "fsl,csaft", &prop);
+		if (!ret) {
+			csmode &= ~(CSMODE_AFT(0xf));
+			csmode |= CSMODE_AFT(prop);
+		}
+
+		fsl_espi_write_reg(espi, ESPI_SPMODEx(cs), csmode);
+
+		if (initial)
+			dev_info(dev, "cs=%u, init_csmode=0x%x\n", cs, csmode);
+	}
+
+	/* Enable SPI interface */
+	fsl_espi_write_reg(espi, ESPI_SPMODE, SPMODE_INIT_VAL | SPMODE_ENABLE);
+}
+
+static int fsl_espi_probe(struct device *dev, struct resource *mem,
+			  unsigned int irq, unsigned int num_cs)
+{
+	struct spi_controller *host;
+	struct fsl_espi *espi;
+	int ret;
+
+	host = spi_alloc_host(dev, sizeof(struct fsl_espi));
+	if (!host)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, host);
+
+	host->mode_bits = SPI_RX_DUAL | SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
+			  SPI_LSB_FIRST | SPI_LOOP;
+	host->dev.of_node = dev->of_node;
+	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
+	host->setup = fsl_espi_setup;
+	host->cleanup = fsl_espi_cleanup;
+	host->transfer_one_message = fsl_espi_do_one_msg;
+	host->auto_runtime_pm = true;
+	host->max_message_size = fsl_espi_max_message_size;
+	host->num_chipselect = num_cs;
+
+	espi = spi_controller_get_devdata(host);
+	spin_lock_init(&espi->lock);
+
+	espi->dev = dev;
+	espi->spibrg = fsl_get_sys_freq();
+	if (espi->spibrg == -1) {
+		dev_err(dev, "Can't get sys frequency!\n");
+		ret = -EINVAL;
+		goto err_probe;
+	}
+	/* determined by clock divider fields DIV16/PM in register SPMODEx */
+	host->min_speed_hz = DIV_ROUND_UP(espi->spibrg, 4 * 16 * 16);
+	host->max_speed_hz = DIV_ROUND_UP(espi->spibrg, 4);
+
+	init_completion(&espi->done);
+
+	espi->reg_base = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(espi->reg_base)) {
+		ret = PTR_ERR(espi->reg_base);
+		goto err_probe;
+	}
+
+	/* Register for SPI Interrupt */
+	ret = devm_request_irq(dev, irq, fsl_espi_irq, 0, "fsl_espi", espi);
+	if (ret)
+		goto err_probe;
+
+	fsl_espi_init_regs(dev, true);
+
+	pm_runtime_set_autosuspend_delay(dev, AUTOSUSPEND_TIMEOUT);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
+	ret = devm_spi_register_controller(dev, host);
+	if (ret < 0)
+		goto err_pm;
+
+	dev_info(dev, "irq = %u\n", irq);
+
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return 0;
+
+err_pm:
+	pm_runtime_put_noidle(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+err_probe:
+	spi_controller_put(host);
+	return ret;
+}
+
+static int of_fsl_espi_get_chipselects(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	u32 num_cs;
+	int ret;
+
+	ret = of_property_read_u32(np, "fsl,espi-num-chipselects", &num_cs);
+	if (ret) {
+		dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
+		return 0;
+	}
+
+	return num_cs;
+}
+
+static int of_fsl_espi_probe(struct platform_device *ofdev)
+{
+	struct device *dev = &ofdev->dev;
+	struct device_node *np = ofdev->dev.of_node;
+	struct resource mem;
+	unsigned int irq, num_cs;
+	int ret;
+
+	if (of_property_read_bool(np, "mode")) {
+		dev_err(dev, "mode property is not supported on ESPI!\n");
+		return -EINVAL;
+	}
+
+	num_cs = of_fsl_espi_get_chipselects(dev);
+	if (!num_cs)
+		return -EINVAL;
+
+	ret = of_address_to_resource(np, 0, &mem);
+	if (ret)
+		return ret;
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq)
+		return -EINVAL;
+
+	return fsl_espi_probe(dev, &mem, irq, num_cs);
+}
+
+static void of_fsl_espi_remove(struct platform_device *dev)
+{
+	pm_runtime_disable(&dev->dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int of_fsl_espi_suspend(struct device *dev)
+{
+	struct spi_controller *host = dev_get_drvdata(dev);
+	int ret;
+
+	ret = spi_controller_suspend(host);
+	if (ret)
+		return ret;
+
+	return pm_runtime_force_suspend(dev);
+}
+
+static int of_fsl_espi_resume(struct device *dev)
+{
+	struct spi_controller *host = dev_get_drvdata(dev);
+	int ret;
+
+	fsl_espi_init_regs(dev, false);
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret < 0)
+		return ret;
+
+	return spi_controller_resume(host);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops espi_pm = {
+	SET_RUNTIME_PM_OPS(fsl_espi_runtime_suspend,
+			   fsl_espi_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(of_fsl_espi_suspend, of_fsl_espi_resume)
+};
+
+static const struct of_device_id of_fsl_espi_match[] = {
+	{ .compatible = "fsl,mpc8536-espi" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
+
+static struct platform_driver fsl_espi_driver = {
+	.driver = {
+		.name = "fsl_espi",
+		.of_match_table = of_fsl_espi_match,
+		.pm = &espi_pm,
+	},
+	.probe		= of_fsl_espi_probe,
+	.remove_new	= of_fsl_espi_remove,
+};
+module_platform_driver(fsl_espi_driver);
+
+MODULE_AUTHOR("Mingkai Hu");
+MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
+MODULE_LICENSE("GPL");