1 files changed, 675 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
new file mode 100644
index 000000000..dd0687e36
--- /dev/null
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -0,0 +1,675 @@
+/*
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/i2c.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define UNIPHIER_FI2C_CR	0x00	/* control register */
+#define     UNIPHIER_FI2C_CR_MST	BIT(3)	/* master mode */
+#define     UNIPHIER_FI2C_CR_STA	BIT(2)	/* start condition */
+#define     UNIPHIER_FI2C_CR_STO	BIT(1)	/* stop condition */
+#define     UNIPHIER_FI2C_CR_NACK	BIT(0)	/* do not return ACK */
+#define UNIPHIER_FI2C_DTTX	0x04	/* TX FIFO */
+#define     UNIPHIER_FI2C_DTTX_CMD	BIT(8)	/* send command (slave addr) */
+#define     UNIPHIER_FI2C_DTTX_RD	BIT(0)	/* read transaction */
+#define UNIPHIER_FI2C_DTRX	0x04	/* RX FIFO */
+#define UNIPHIER_FI2C_SLAD	0x0c	/* slave address */
+#define UNIPHIER_FI2C_CYC	0x10	/* clock cycle control */
+#define UNIPHIER_FI2C_LCTL	0x14	/* clock low period control */
+#define UNIPHIER_FI2C_SSUT	0x18	/* restart/stop setup time control */
+#define UNIPHIER_FI2C_DSUT	0x1c	/* data setup time control */
+#define UNIPHIER_FI2C_INT	0x20	/* interrupt status */
+#define UNIPHIER_FI2C_IE	0x24	/* interrupt enable */
+#define UNIPHIER_FI2C_IC	0x28	/* interrupt clear */
+#define     UNIPHIER_FI2C_INT_TE	BIT(9)	/* TX FIFO empty */
+#define     UNIPHIER_FI2C_INT_RF	BIT(8)	/* RX FIFO full */
+#define     UNIPHIER_FI2C_INT_TC	BIT(7)	/* send complete (STOP) */
+#define     UNIPHIER_FI2C_INT_RC	BIT(6)	/* receive complete (STOP) */
+#define     UNIPHIER_FI2C_INT_TB	BIT(5)	/* sent specified bytes */
+#define     UNIPHIER_FI2C_INT_RB	BIT(4)	/* received specified bytes */
+#define     UNIPHIER_FI2C_INT_NA	BIT(2)	/* no ACK */
+#define     UNIPHIER_FI2C_INT_AL	BIT(1)	/* arbitration lost */
+#define UNIPHIER_FI2C_SR	0x2c	/* status register */
+#define     UNIPHIER_FI2C_SR_DB		BIT(12)	/* device busy */
+#define     UNIPHIER_FI2C_SR_STS	BIT(11)	/* stop condition detected */
+#define     UNIPHIER_FI2C_SR_BB		BIT(8)	/* bus busy */
+#define     UNIPHIER_FI2C_SR_RFF	BIT(3)	/* RX FIFO full */
+#define     UNIPHIER_FI2C_SR_RNE	BIT(2)	/* RX FIFO not empty */
+#define     UNIPHIER_FI2C_SR_TNF	BIT(1)	/* TX FIFO not full */
+#define     UNIPHIER_FI2C_SR_TFE	BIT(0)	/* TX FIFO empty */
+#define UNIPHIER_FI2C_RST	0x34	/* reset control */
+#define     UNIPHIER_FI2C_RST_TBRST	BIT(2)	/* clear TX FIFO */
+#define     UNIPHIER_FI2C_RST_RBRST	BIT(1)	/* clear RX FIFO */
+#define     UNIPHIER_FI2C_RST_RST	BIT(0)	/* forcible bus reset */
+#define UNIPHIER_FI2C_BM	0x38	/* bus monitor */
+#define     UNIPHIER_FI2C_BM_SDAO	BIT(3)	/* output for SDA line */
+#define     UNIPHIER_FI2C_BM_SDAS	BIT(2)	/* readback of SDA line */
+#define     UNIPHIER_FI2C_BM_SCLO	BIT(1)	/* output for SCL line */
+#define     UNIPHIER_FI2C_BM_SCLS	BIT(0)	/* readback of SCL line */
+#define UNIPHIER_FI2C_NOISE	0x3c	/* noise filter control */
+#define UNIPHIER_FI2C_TBC	0x40	/* TX byte count setting */
+#define UNIPHIER_FI2C_RBC	0x44	/* RX byte count setting */
+#define UNIPHIER_FI2C_TBCM	0x48	/* TX byte count monitor */
+#define UNIPHIER_FI2C_RBCM	0x4c	/* RX byte count monitor */
+#define UNIPHIER_FI2C_BRST	0x50	/* bus reset */
+#define     UNIPHIER_FI2C_BRST_FOEN	BIT(1)	/* normal operation */
+#define     UNIPHIER_FI2C_BRST_RSCL	BIT(0)	/* release SCL */
+
+#define UNIPHIER_FI2C_INT_FAULTS	\
+				(UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
+#define UNIPHIER_FI2C_INT_STOP		\
+				(UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
+
+#define UNIPHIER_FI2C_RD		BIT(0)
+#define UNIPHIER_FI2C_STOP		BIT(1)
+#define UNIPHIER_FI2C_MANUAL_NACK	BIT(2)
+#define UNIPHIER_FI2C_BYTE_WISE		BIT(3)
+#define UNIPHIER_FI2C_DEFER_STOP_COMP	BIT(4)
+
+#define UNIPHIER_FI2C_DEFAULT_SPEED	100000
+#define UNIPHIER_FI2C_MAX_SPEED		400000
+#define UNIPHIER_FI2C_FIFO_SIZE		8
+
+struct uniphier_fi2c_priv {
+	struct completion comp;
+	struct i2c_adapter adap;
+	void __iomem *membase;
+	struct clk *clk;
+	unsigned int len;
+	u8 *buf;
+	u32 enabled_irqs;
+	int error;
+	unsigned int flags;
+	unsigned int busy_cnt;
+	unsigned int clk_cycle;
+	spinlock_t lock;	/* IRQ synchronization */
+};
+
+static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
+				      bool first)
+{
+	int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
+
+	/*
+	 * TX-FIFO stores slave address in it for the first access.
+	 * Decrement the counter.
+	 */
+	if (first)
+		fifo_space--;
+
+	while (priv->len) {
+		if (fifo_space-- <= 0)
+			break;
+
+		dev_dbg(&priv->adap.dev, "write data: %02x\n", *priv->buf);
+		writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
+		priv->len--;
+	}
+}
+
+static void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
+{
+	int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
+						1 : UNIPHIER_FI2C_FIFO_SIZE;
+
+	while (priv->len) {
+		if (fifo_left-- <= 0)
+			break;
+
+		*priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
+		dev_dbg(&priv->adap.dev, "read data: %02x\n", priv->buf[-1]);
+		priv->len--;
+	}
+}
+
+static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
+{
+	writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
+}
+
+static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
+				     u32 mask)
+{
+	writel(mask, priv->membase + UNIPHIER_FI2C_IC);
+}
+
+static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
+{
+	dev_dbg(&priv->adap.dev, "stop condition\n");
+
+	priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
+	uniphier_fi2c_set_irqs(priv);
+	writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
+	       priv->membase + UNIPHIER_FI2C_CR);
+}
+
+static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
+{
+	struct uniphier_fi2c_priv *priv = dev_id;
+	u32 irq_status;
+
+	spin_lock(&priv->lock);
+
+	irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
+	irq_status &= priv->enabled_irqs;
+
+	dev_dbg(&priv->adap.dev,
+		"interrupt: enabled_irqs=%04x, irq_status=%04x\n",
+		priv->enabled_irqs, irq_status);
+
+	if (irq_status & UNIPHIER_FI2C_INT_STOP)
+		goto complete;
+
+	if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
+		dev_dbg(&priv->adap.dev, "arbitration lost\n");
+		priv->error = -EAGAIN;
+		goto complete;
+	}
+
+	if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
+		dev_dbg(&priv->adap.dev, "could not get ACK\n");
+		priv->error = -ENXIO;
+		if (priv->flags & UNIPHIER_FI2C_RD) {
+			/*
+			 * work around a hardware bug:
+			 * The receive-completed interrupt is never set even if
+			 * STOP condition is detected after the address phase
+			 * of read transaction fails to get ACK.
+			 * To avoid time-out error, we issue STOP here,
+			 * but do not wait for its completion.
+			 * It should be checked after exiting this handler.
+			 */
+			uniphier_fi2c_stop(priv);
+			priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
+			goto complete;
+		}
+		goto stop;
+	}
+
+	if (irq_status & UNIPHIER_FI2C_INT_TE) {
+		if (!priv->len)
+			goto data_done;
+
+		uniphier_fi2c_fill_txfifo(priv, false);
+		goto handled;
+	}
+
+	if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
+		uniphier_fi2c_drain_rxfifo(priv);
+		/*
+		 * If the number of bytes to read is multiple of the FIFO size
+		 * (msg->len == 8, 16, 24, ...), the INT_RF bit is set a little
+		 * earlier than INT_RB. We wait for INT_RB to confirm the
+		 * completion of the current message.
+		 */
+		if (!priv->len && (irq_status & UNIPHIER_FI2C_INT_RB))
+			goto data_done;
+
+		if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
+			if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
+			    !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
+				dev_dbg(&priv->adap.dev,
+					"enable read byte count IRQ\n");
+				priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
+				uniphier_fi2c_set_irqs(priv);
+				priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
+			}
+			if (priv->len <= 1) {
+				dev_dbg(&priv->adap.dev, "set NACK\n");
+				writel(UNIPHIER_FI2C_CR_MST |
+				       UNIPHIER_FI2C_CR_NACK,
+				       priv->membase + UNIPHIER_FI2C_CR);
+			}
+		}
+
+		goto handled;
+	}
+
+	spin_unlock(&priv->lock);
+
+	return IRQ_NONE;
+
+data_done:
+	if (priv->flags & UNIPHIER_FI2C_STOP) {
+stop:
+		uniphier_fi2c_stop(priv);
+	} else {
+complete:
+		priv->enabled_irqs = 0;
+		uniphier_fi2c_set_irqs(priv);
+		complete(&priv->comp);
+	}
+
+handled:
+	/*
+	 * This controller makes a pause while any bit of the IRQ status is
+	 * asserted. Clear the asserted bit to kick the controller just before
+	 * exiting the handler.
+	 */
+	uniphier_fi2c_clear_irqs(priv, irq_status);
+
+	spin_unlock(&priv->lock);
+
+	return IRQ_HANDLED;
+}
+
+static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
+{
+	priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
+	uniphier_fi2c_set_irqs(priv);
+
+	/* do not use TX byte counter */
+	writel(0, priv->membase + UNIPHIER_FI2C_TBC);
+	/* set slave address */
+	writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
+	       priv->membase + UNIPHIER_FI2C_DTTX);
+	/* first chunk of data */
+	uniphier_fi2c_fill_txfifo(priv, true);
+}
+
+static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
+{
+	priv->flags |= UNIPHIER_FI2C_RD;
+
+	if (likely(priv->len < 256)) {
+		/*
+		 * If possible, use RX byte counter.
+		 * It can automatically handle NACK for the last byte.
+		 */
+		writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
+		priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
+				      UNIPHIER_FI2C_INT_RB;
+	} else {
+		/*
+		 * The byte counter can not count over 256.  In this case,
+		 * do not use it at all.  Drain data when FIFO gets full,
+		 * but treat the last portion as a special case.
+		 */
+		writel(0, priv->membase + UNIPHIER_FI2C_RBC);
+		priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
+		priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
+	}
+
+	uniphier_fi2c_set_irqs(priv);
+
+	/* set slave address with RD bit */
+	writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
+	       priv->membase + UNIPHIER_FI2C_DTTX);
+}
+
+static void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
+{
+	writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
+}
+
+static void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
+{
+	writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
+	       priv->membase + UNIPHIER_FI2C_BRST);
+}
+
+static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
+{
+	uniphier_fi2c_reset(priv);
+	i2c_recover_bus(&priv->adap);
+}
+
+static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
+					 struct i2c_msg *msg, bool repeat,
+					 bool stop)
+{
+	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+	bool is_read = msg->flags & I2C_M_RD;
+	unsigned long time_left, flags;
+
+	dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, repeat=%d, stop=%d\n",
+		is_read ? "receive" : "transmit", msg->addr, msg->len,
+		repeat, stop);
+
+	priv->len = msg->len;
+	priv->buf = msg->buf;
+	priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
+	priv->error = 0;
+	priv->flags = 0;
+
+	if (stop)
+		priv->flags |= UNIPHIER_FI2C_STOP;
+
+	reinit_completion(&priv->comp);
+	uniphier_fi2c_clear_irqs(priv, U32_MAX);
+	writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
+	       priv->membase + UNIPHIER_FI2C_RST);	/* reset TX/RX FIFO */
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	if (is_read)
+		uniphier_fi2c_rx_init(priv, msg->addr);
+	else
+		uniphier_fi2c_tx_init(priv, msg->addr);
+
+	dev_dbg(&adap->dev, "start condition\n");
+	/*
+	 * For a repeated START condition, writing a slave address to the FIFO
+	 * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
+	 * written only for a non-repeated START condition.
+	 */
+	if (!repeat)
+		writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
+		       priv->membase + UNIPHIER_FI2C_CR);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->enabled_irqs = 0;
+	uniphier_fi2c_set_irqs(priv);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	if (!time_left) {
+		dev_err(&adap->dev, "transaction timeout.\n");
+		uniphier_fi2c_recover(priv);
+		return -ETIMEDOUT;
+	}
+	dev_dbg(&adap->dev, "complete\n");
+
+	if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
+		u32 status;
+		int ret;
+
+		ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR,
+					 status,
+					 (status & UNIPHIER_FI2C_SR_STS) &&
+					 !(status & UNIPHIER_FI2C_SR_BB),
+					 1, 20);
+		if (ret) {
+			dev_err(&adap->dev,
+				"stop condition was not completed.\n");
+			uniphier_fi2c_recover(priv);
+			return ret;
+		}
+	}
+
+	return priv->error;
+}
+
+static int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
+{
+	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+	if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
+		if (priv->busy_cnt++ > 3) {
+			/*
+			 * If bus busy continues too long, it is probably
+			 * in a wrong state.  Try bus recovery.
+			 */
+			uniphier_fi2c_recover(priv);
+			priv->busy_cnt = 0;
+		}
+
+		return -EAGAIN;
+	}
+
+	priv->busy_cnt = 0;
+	return 0;
+}
+
+static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
+				     struct i2c_msg *msgs, int num)
+{
+	struct i2c_msg *msg, *emsg = msgs + num;
+	bool repeat = false;
+	int ret;
+
+	ret = uniphier_fi2c_check_bus_busy(adap);
+	if (ret)
+		return ret;
+
+	for (msg = msgs; msg < emsg; msg++) {
+		/* Emit STOP if it is the last message or I2C_M_STOP is set. */
+		bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
+
+		ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
+		if (ret)
+			return ret;
+
+		repeat = !stop;
+	}
+
+	return num;
+}
+
+static u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm uniphier_fi2c_algo = {
+	.master_xfer = uniphier_fi2c_master_xfer,
+	.functionality = uniphier_fi2c_functionality,
+};
+
+static int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
+{
+	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+	return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
+							UNIPHIER_FI2C_BM_SCLS);
+}
+
+static void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
+{
+	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+	writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
+	       priv->membase + UNIPHIER_FI2C_BRST);
+}
+
+static int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
+{
+	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+	return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
+							UNIPHIER_FI2C_BM_SDAS);
+}
+
+static void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+	uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
+}
+
+static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
+	.recover_bus = i2c_generic_scl_recovery,
+	.get_scl = uniphier_fi2c_get_scl,
+	.set_scl = uniphier_fi2c_set_scl,
+	.get_sda = uniphier_fi2c_get_sda,
+	.unprepare_recovery = uniphier_fi2c_unprepare_recovery,
+};
+
+static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
+{
+	unsigned int cyc = priv->clk_cycle;
+	u32 tmp;
+
+	tmp = readl(priv->membase + UNIPHIER_FI2C_CR);
+	tmp |= UNIPHIER_FI2C_CR_MST;
+	writel(tmp, priv->membase + UNIPHIER_FI2C_CR);
+
+	uniphier_fi2c_reset(priv);
+
+	/*
+	 *  Standard-mode: tLOW + tHIGH = 10 us
+	 *  Fast-mode:     tLOW + tHIGH = 2.5 us
+	 */
+	writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
+	/*
+	 *  Standard-mode: tLOW = 4.7 us, tHIGH = 4.0 us, tBUF = 4.7 us
+	 *  Fast-mode:     tLOW = 1.3 us, tHIGH = 0.6 us, tBUF = 1.3 us
+	 * "tLow/tHIGH = 5/4" meets both.
+	 */
+	writel(cyc * 5 / 9, priv->membase + UNIPHIER_FI2C_LCTL);
+	/*
+	 *  Standard-mode: tHD;STA = 4.0 us, tSU;STA = 4.7 us, tSU;STO = 4.0 us
+	 *  Fast-mode:     tHD;STA = 0.6 us, tSU;STA = 0.6 us, tSU;STO = 0.6 us
+	 */
+	writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
+	/*
+	 *  Standard-mode: tSU;DAT = 250 ns
+	 *  Fast-mode:     tSU;DAT = 100 ns
+	 */
+	writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);
+
+	uniphier_fi2c_prepare_operation(priv);
+}
+
+static int uniphier_fi2c_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_fi2c_priv *priv;
+	struct resource *regs;
+	u32 bus_speed;
+	unsigned long clk_rate;
+	int irq, ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->membase = devm_ioremap_resource(dev, regs);
+	if (IS_ERR(priv->membase))
+		return PTR_ERR(priv->membase);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "failed to get IRQ number\n");
+		return irq;
+	}
+
+	if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
+		bus_speed = UNIPHIER_FI2C_DEFAULT_SPEED;
+
+	if (!bus_speed || bus_speed > UNIPHIER_FI2C_MAX_SPEED) {
+		dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
+		return -EINVAL;
+	}
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	clk_rate = clk_get_rate(priv->clk);
+	if (!clk_rate) {
+		dev_err(dev, "input clock rate should not be zero\n");
+		ret = -EINVAL;
+		goto disable_clk;
+	}
+
+	priv->clk_cycle = clk_rate / bus_speed;
+	init_completion(&priv->comp);
+	spin_lock_init(&priv->lock);
+	priv->adap.owner = THIS_MODULE;
+	priv->adap.algo = &uniphier_fi2c_algo;
+	priv->adap.dev.parent = dev;
+	priv->adap.dev.of_node = dev->of_node;
+	strlcpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
+	priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
+	i2c_set_adapdata(&priv->adap, priv);
+	platform_set_drvdata(pdev, priv);
+
+	uniphier_fi2c_hw_init(priv);
+
+	ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
+			       pdev->name, priv);
+	if (ret) {
+		dev_err(dev, "failed to request irq %d\n", irq);
+		goto disable_clk;
+	}
+
+	ret = i2c_add_adapter(&priv->adap);
+disable_clk:
+	if (ret)
+		clk_disable_unprepare(priv->clk);
+
+	return ret;
+}
+
+static int uniphier_fi2c_remove(struct platform_device *pdev)
+{
+	struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&priv->adap);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused uniphier_fi2c_suspend(struct device *dev)
+{
+	struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused uniphier_fi2c_resume(struct device *dev)
+{
+	struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	uniphier_fi2c_hw_init(priv);
+
+	return 0;
+}
+
+static const struct dev_pm_ops uniphier_fi2c_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(uniphier_fi2c_suspend, uniphier_fi2c_resume)
+};
+
+static const struct of_device_id uniphier_fi2c_match[] = {
+	{ .compatible = "socionext,uniphier-fi2c" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
+
+static struct platform_driver uniphier_fi2c_drv = {
+	.probe  = uniphier_fi2c_probe,
+	.remove = uniphier_fi2c_remove,
+	.driver = {
+		.name  = "uniphier-fi2c",
+		.of_match_table = uniphier_fi2c_match,
+		.pm = &uniphier_fi2c_pm_ops,
+	},
+};
+module_platform_driver(uniphier_fi2c_drv);
+
+MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
+MODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
+MODULE_LICENSE("GPL");