Initial import

1 files changed, 1004 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
new file mode 100644
index 000000000..007818b3e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -0,0 +1,1004 @@
+/*
+ * SuperH Mobile I2C Controller
+ *
+ * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Portions of the code based on out-of-tree driver i2c-sh7343.c
+ * Copyright (c) 2006 Carlos Munoz <carlos@kenati.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
+ *
+ * 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/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/i2c/i2c-sh_mobile.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+/* Transmit operation:                                                      */
+/*                                                                          */
+/* 0 byte transmit                                                          */
+/* BUS:     S     A8     ACK   P(*)                                         */
+/* IRQ:       DTE   WAIT                                                    */
+/* ICIC:                                                                    */
+/* ICCR: 0x94 0x90                                                          */
+/* ICDR:      A8                                                            */
+/*                                                                          */
+/* 1 byte transmit                                                          */
+/* BUS:     S     A8     ACK   D8(1)   ACK   P(*)                           */
+/* IRQ:       DTE   WAIT         WAIT                                       */
+/* ICIC:      -DTE                                                          */
+/* ICCR: 0x94       0x90                                                    */
+/* ICDR:      A8    D8(1)                                                   */
+/*                                                                          */
+/* 2 byte transmit                                                          */
+/* BUS:     S     A8     ACK   D8(1)   ACK   D8(2)   ACK   P(*)             */
+/* IRQ:       DTE   WAIT         WAIT          WAIT                         */
+/* ICIC:      -DTE                                                          */
+/* ICCR: 0x94                    0x90                                       */
+/* ICDR:      A8    D8(1)        D8(2)                                      */
+/*                                                                          */
+/* 3 bytes or more, +---------+ gets repeated                               */
+/*                                                                          */
+/*                                                                          */
+/* Receive operation:                                                       */
+/*                                                                          */
+/* 0 byte receive - not supported since slave may hold SDA low              */
+/*                                                                          */
+/* 1 byte receive       [TX] | [RX]                                         */
+/* BUS:     S     A8     ACK | D8(1)   ACK   P(*)                           */
+/* IRQ:       DTE   WAIT     |   WAIT     DTE                               */
+/* ICIC:      -DTE           |   +DTE                                       */
+/* ICCR: 0x94       0x81     |   0xc0                                       */
+/* ICDR:      A8             |            D8(1)                             */
+/*                                                                          */
+/* 2 byte receive        [TX]| [RX]                                         */
+/* BUS:     S     A8     ACK | D8(1)   ACK   D8(2)   ACK   P(*)             */
+/* IRQ:       DTE   WAIT     |   WAIT          WAIT     DTE                 */
+/* ICIC:      -DTE           |                 +DTE                         */
+/* ICCR: 0x94       0x81     |                 0xc0                         */
+/* ICDR:      A8             |                 D8(1)    D8(2)               */
+/*                                                                          */
+/* 3 byte receive       [TX] | [RX]                                     (*) */
+/* BUS:     S     A8     ACK | D8(1)   ACK   D8(2)   ACK   D8(3)   ACK    P */
+/* IRQ:       DTE   WAIT     |   WAIT          WAIT         WAIT      DTE   */
+/* ICIC:      -DTE           |                              +DTE            */
+/* ICCR: 0x94       0x81     |                              0xc0            */
+/* ICDR:      A8             |                 D8(1)        D8(2)     D8(3) */
+/*                                                                          */
+/* 4 bytes or more, this part is repeated    +---------+                    */
+/*                                                                          */
+/*                                                                          */
+/* Interrupt order and BUSY flag                                            */
+/*     ___                                                 _                */
+/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/                 */
+/* SCL      \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/                   */
+/*                                                                          */
+/*        S   D7  D6  D5  D4  D3  D2  D1  D0              P(*)              */
+/*                                           ___                            */
+/* WAIT IRQ ________________________________/   \___________                */
+/* TACK IRQ ____________________________________/   \_______                */
+/* DTE  IRQ __________________________________________/   \_                */
+/* AL   IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                */
+/*         _______________________________________________                  */
+/* BUSY __/                                               \_                */
+/*                                                                          */
+/* (*) The STOP condition is only sent by the master at the end of the last */
+/* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
+/* only cleared after the STOP condition, so, between messages we have to   */
+/* poll for the DTE bit.                                                    */
+/*                                                                          */
+
+enum sh_mobile_i2c_op {
+	OP_START = 0,
+	OP_TX_FIRST,
+	OP_TX,
+	OP_TX_STOP,
+	OP_TX_STOP_DATA,
+	OP_TX_TO_RX,
+	OP_RX,
+	OP_RX_STOP,
+	OP_RX_STOP_DATA,
+};
+
+struct sh_mobile_i2c_data {
+	struct device *dev;
+	void __iomem *reg;
+	struct i2c_adapter adap;
+	unsigned long bus_speed;
+	unsigned int clks_per_count;
+	struct clk *clk;
+	u_int8_t icic;
+	u_int8_t flags;
+	u_int16_t iccl;
+	u_int16_t icch;
+
+	spinlock_t lock;
+	wait_queue_head_t wait;
+	struct i2c_msg *msg;
+	int pos;
+	int sr;
+	bool send_stop;
+	bool stop_after_dma;
+
+	struct resource *res;
+	struct dma_chan *dma_tx;
+	struct dma_chan *dma_rx;
+	struct scatterlist sg;
+	enum dma_data_direction dma_direction;
+};
+
+struct sh_mobile_dt_config {
+	int clks_per_count;
+};
+
+#define IIC_FLAG_HAS_ICIC67	(1 << 0)
+
+#define STANDARD_MODE		100000
+#define FAST_MODE		400000
+
+/* Register offsets */
+#define ICDR			0x00
+#define ICCR			0x04
+#define ICSR			0x08
+#define ICIC			0x0c
+#define ICCL			0x10
+#define ICCH			0x14
+
+/* Register bits */
+#define ICCR_ICE		0x80
+#define ICCR_RACK		0x40
+#define ICCR_TRS		0x10
+#define ICCR_BBSY		0x04
+#define ICCR_SCP		0x01
+
+#define ICSR_SCLM		0x80
+#define ICSR_SDAM		0x40
+#define SW_DONE			0x20
+#define ICSR_BUSY		0x10
+#define ICSR_AL			0x08
+#define ICSR_TACK		0x04
+#define ICSR_WAIT		0x02
+#define ICSR_DTE		0x01
+
+#define ICIC_ICCLB8		0x80
+#define ICIC_ICCHB8		0x40
+#define ICIC_TDMAE		0x20
+#define ICIC_RDMAE		0x10
+#define ICIC_ALE		0x08
+#define ICIC_TACKE		0x04
+#define ICIC_WAITE		0x02
+#define ICIC_DTEE		0x01
+
+static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
+{
+	if (offs == ICIC)
+		data |= pd->icic;
+
+	iowrite8(data, pd->reg + offs);
+}
+
+static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
+{
+	return ioread8(pd->reg + offs);
+}
+
+static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
+			unsigned char set, unsigned char clr)
+{
+	iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
+}
+
+static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
+{
+	/*
+	 * Conditional expression:
+	 *   ICCL >= COUNT_CLK * (tLOW + tf)
+	 *
+	 * SH-Mobile IIC hardware starts counting the LOW period of
+	 * the SCL signal (tLOW) as soon as it pulls the SCL line.
+	 * In order to meet the tLOW timing spec, we need to take into
+	 * account the fall time of SCL signal (tf).  Default tf value
+	 * should be 0.3 us, for safety.
+	 */
+	return (((count_khz * (tLOW + tf)) + 5000) / 10000);
+}
+
+static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
+{
+	/*
+	 * Conditional expression:
+	 *   ICCH >= COUNT_CLK * (tHIGH + tf)
+	 *
+	 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
+	 * and can ignore it.  SH-Mobile IIC controller starts counting
+	 * the HIGH period of the SCL signal (tHIGH) after the SCL input
+	 * voltage increases at VIH.
+	 *
+	 * Afterward it turned out calculating ICCH using only tHIGH spec
+	 * will result in violation of the tHD;STA timing spec.  We need
+	 * to take into account the fall time of SDA signal (tf) at START
+	 * condition, in order to meet both tHIGH and tHD;STA specs.
+	 */
+	return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
+}
+
+static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
+{
+	unsigned long i2c_clk_khz;
+	u32 tHIGH, tLOW, tf;
+	uint16_t max_val;
+
+	/* Get clock rate after clock is enabled */
+	clk_prepare_enable(pd->clk);
+	i2c_clk_khz = clk_get_rate(pd->clk) / 1000;
+	clk_disable_unprepare(pd->clk);
+	i2c_clk_khz /= pd->clks_per_count;
+
+	if (pd->bus_speed == STANDARD_MODE) {
+		tLOW	= 47;	/* tLOW = 4.7 us */
+		tHIGH	= 40;	/* tHD;STA = tHIGH = 4.0 us */
+		tf	= 3;	/* tf = 0.3 us */
+	} else if (pd->bus_speed == FAST_MODE) {
+		tLOW	= 13;	/* tLOW = 1.3 us */
+		tHIGH	= 6;	/* tHD;STA = tHIGH = 0.6 us */
+		tf	= 3;	/* tf = 0.3 us */
+	} else {
+		dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
+			pd->bus_speed);
+		return -EINVAL;
+	}
+
+	pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
+	pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
+
+	max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
+	if (pd->iccl > max_val || pd->icch > max_val) {
+		dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
+			pd->iccl, pd->icch);
+		return -EINVAL;
+	}
+
+	/* one more bit of ICCL in ICIC */
+	if (pd->iccl & 0x100)
+		pd->icic |= ICIC_ICCLB8;
+	else
+		pd->icic &= ~ICIC_ICCLB8;
+
+	/* one more bit of ICCH in ICIC */
+	if (pd->icch & 0x100)
+		pd->icic |= ICIC_ICCHB8;
+	else
+		pd->icic &= ~ICIC_ICCHB8;
+
+	dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
+	return 0;
+}
+
+static void activate_ch(struct sh_mobile_i2c_data *pd)
+{
+	/* Wake up device and enable clock */
+	pm_runtime_get_sync(pd->dev);
+	clk_prepare_enable(pd->clk);
+
+	/* Enable channel and configure rx ack */
+	iic_set_clr(pd, ICCR, ICCR_ICE, 0);
+
+	/* Mask all interrupts */
+	iic_wr(pd, ICIC, 0);
+
+	/* Set the clock */
+	iic_wr(pd, ICCL, pd->iccl & 0xff);
+	iic_wr(pd, ICCH, pd->icch & 0xff);
+}
+
+static void deactivate_ch(struct sh_mobile_i2c_data *pd)
+{
+	/* Clear/disable interrupts */
+	iic_wr(pd, ICSR, 0);
+	iic_wr(pd, ICIC, 0);
+
+	/* Disable channel */
+	iic_set_clr(pd, ICCR, 0, ICCR_ICE);
+
+	/* Disable clock and mark device as idle */
+	clk_disable_unprepare(pd->clk);
+	pm_runtime_put_sync(pd->dev);
+}
+
+static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
+			    enum sh_mobile_i2c_op op, unsigned char data)
+{
+	unsigned char ret = 0;
+	unsigned long flags;
+
+	dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
+
+	spin_lock_irqsave(&pd->lock, flags);
+
+	switch (op) {
+	case OP_START: /* issue start and trigger DTE interrupt */
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
+		break;
+	case OP_TX_FIRST: /* disable DTE interrupt and write data */
+		iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+		iic_wr(pd, ICDR, data);
+		break;
+	case OP_TX: /* write data */
+		iic_wr(pd, ICDR, data);
+		break;
+	case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
+		iic_wr(pd, ICDR, data);
+		/* fallthrough */
+	case OP_TX_STOP: /* issue a stop */
+		iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
+					       : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
+		break;
+	case OP_TX_TO_RX: /* select read mode */
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
+		break;
+	case OP_RX: /* just read data */
+		ret = iic_rd(pd, ICDR);
+		break;
+	case OP_RX_STOP: /* enable DTE interrupt, issue stop */
+		iic_wr(pd, ICIC,
+		       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
+		break;
+	case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
+		iic_wr(pd, ICIC,
+		       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+		ret = iic_rd(pd, ICDR);
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
+		break;
+	}
+
+	spin_unlock_irqrestore(&pd->lock, flags);
+
+	dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
+	return ret;
+}
+
+static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
+{
+	return pd->pos == -1;
+}
+
+static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
+{
+	return pd->pos == pd->msg->len - 1;
+}
+
+static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
+				   unsigned char *buf)
+{
+	switch (pd->pos) {
+	case -1:
+		*buf = (pd->msg->addr & 0x7f) << 1;
+		*buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
+		break;
+	default:
+		*buf = pd->msg->buf[pd->pos];
+	}
+}
+
+static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
+{
+	unsigned char data;
+
+	if (pd->pos == pd->msg->len) {
+		/* Send stop if we haven't yet (DMA case) */
+		if (pd->send_stop && pd->stop_after_dma)
+			i2c_op(pd, OP_TX_STOP, 0);
+		return 1;
+	}
+
+	sh_mobile_i2c_get_data(pd, &data);
+
+	if (sh_mobile_i2c_is_last_byte(pd))
+		i2c_op(pd, OP_TX_STOP_DATA, data);
+	else if (sh_mobile_i2c_is_first_byte(pd))
+		i2c_op(pd, OP_TX_FIRST, data);
+	else
+		i2c_op(pd, OP_TX, data);
+
+	pd->pos++;
+	return 0;
+}
+
+static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
+{
+	unsigned char data;
+	int real_pos;
+
+	do {
+		if (pd->pos <= -1) {
+			sh_mobile_i2c_get_data(pd, &data);
+
+			if (sh_mobile_i2c_is_first_byte(pd))
+				i2c_op(pd, OP_TX_FIRST, data);
+			else
+				i2c_op(pd, OP_TX, data);
+			break;
+		}
+
+		if (pd->pos == 0) {
+			i2c_op(pd, OP_TX_TO_RX, 0);
+			break;
+		}
+
+		real_pos = pd->pos - 2;
+
+		if (pd->pos == pd->msg->len) {
+			if (pd->stop_after_dma) {
+				/* Simulate PIO end condition after DMA transfer */
+				i2c_op(pd, OP_RX_STOP, 0);
+				pd->pos++;
+				break;
+			}
+
+			if (real_pos < 0) {
+				i2c_op(pd, OP_RX_STOP, 0);
+				break;
+			}
+			data = i2c_op(pd, OP_RX_STOP_DATA, 0);
+		} else
+			data = i2c_op(pd, OP_RX, 0);
+
+		if (real_pos >= 0)
+			pd->msg->buf[real_pos] = data;
+	} while (0);
+
+	pd->pos++;
+	return pd->pos == (pd->msg->len + 2);
+}
+
+static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
+{
+	struct sh_mobile_i2c_data *pd = dev_id;
+	unsigned char sr;
+	int wakeup = 0;
+
+	sr = iic_rd(pd, ICSR);
+	pd->sr |= sr; /* remember state */
+
+	dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
+	       (pd->msg->flags & I2C_M_RD) ? "read" : "write",
+	       pd->pos, pd->msg->len);
+
+	/* Kick off TxDMA after preface was done */
+	if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
+		iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
+	else if (sr & (ICSR_AL | ICSR_TACK))
+		/* don't interrupt transaction - continue to issue stop */
+		iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
+	else if (pd->msg->flags & I2C_M_RD)
+		wakeup = sh_mobile_i2c_isr_rx(pd);
+	else
+		wakeup = sh_mobile_i2c_isr_tx(pd);
+
+	/* Kick off RxDMA after preface was done */
+	if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
+		iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
+
+	if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
+		iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
+
+	if (wakeup) {
+		pd->sr |= SW_DONE;
+		wake_up(&pd->wait);
+	}
+
+	/* defeat write posting to avoid spurious WAIT interrupts */
+	iic_rd(pd, ICSR);
+
+	return IRQ_HANDLED;
+}
+
+static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
+{
+	struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
+				? pd->dma_rx : pd->dma_tx;
+
+	dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
+			 pd->msg->len, pd->dma_direction);
+
+	pd->dma_direction = DMA_NONE;
+}
+
+static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
+{
+	if (pd->dma_direction == DMA_NONE)
+		return;
+	else if (pd->dma_direction == DMA_FROM_DEVICE)
+		dmaengine_terminate_all(pd->dma_rx);
+	else if (pd->dma_direction == DMA_TO_DEVICE)
+		dmaengine_terminate_all(pd->dma_tx);
+
+	sh_mobile_i2c_dma_unmap(pd);
+}
+
+static void sh_mobile_i2c_dma_callback(void *data)
+{
+	struct sh_mobile_i2c_data *pd = data;
+
+	sh_mobile_i2c_dma_unmap(pd);
+	pd->pos = pd->msg->len;
+	pd->stop_after_dma = true;
+
+	iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
+}
+
+static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
+				enum dma_transfer_direction dir, dma_addr_t port_addr)
+{
+	struct dma_chan *chan;
+	struct dma_slave_config cfg;
+	char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
+	int ret;
+
+	chan = dma_request_slave_channel_reason(dev, chan_name);
+	if (IS_ERR(chan)) {
+		ret = PTR_ERR(chan);
+		dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
+		return chan;
+	}
+
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.direction = dir;
+	if (dir == DMA_MEM_TO_DEV) {
+		cfg.dst_addr = port_addr;
+		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	} else {
+		cfg.src_addr = port_addr;
+		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	}
+
+	ret = dmaengine_slave_config(chan, &cfg);
+	if (ret) {
+		dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
+		dma_release_channel(chan);
+		return ERR_PTR(ret);
+	}
+
+	dev_dbg(dev, "got DMA channel for %s\n", chan_name);
+	return chan;
+}
+
+static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
+{
+	bool read = pd->msg->flags & I2C_M_RD;
+	enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+	struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
+	struct dma_async_tx_descriptor *txdesc;
+	dma_addr_t dma_addr;
+	dma_cookie_t cookie;
+
+	if (PTR_ERR(chan) == -EPROBE_DEFER) {
+		if (read)
+			chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
+									   pd->res->start + ICDR);
+		else
+			chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
+									   pd->res->start + ICDR);
+	}
+
+	if (IS_ERR(chan))
+		return;
+
+	dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
+	if (dma_mapping_error(pd->dev, dma_addr)) {
+		dev_dbg(pd->dev, "dma map failed, using PIO\n");
+		return;
+	}
+
+	sg_dma_len(&pd->sg) = pd->msg->len;
+	sg_dma_address(&pd->sg) = dma_addr;
+
+	pd->dma_direction = dir;
+
+	txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
+					 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
+					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!txdesc) {
+		dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
+		sh_mobile_i2c_cleanup_dma(pd);
+		return;
+	}
+
+	txdesc->callback = sh_mobile_i2c_dma_callback;
+	txdesc->callback_param = pd;
+
+	cookie = dmaengine_submit(txdesc);
+	if (dma_submit_error(cookie)) {
+		dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
+		sh_mobile_i2c_cleanup_dma(pd);
+		return;
+	}
+
+	dma_async_issue_pending(chan);
+}
+
+static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
+		    bool do_init)
+{
+	if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
+		dev_err(pd->dev, "Unsupported zero length i2c read\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (do_init) {
+		/* Initialize channel registers */
+		iic_set_clr(pd, ICCR, 0, ICCR_ICE);
+
+		/* Enable channel and configure rx ack */
+		iic_set_clr(pd, ICCR, ICCR_ICE, 0);
+
+		/* Set the clock */
+		iic_wr(pd, ICCL, pd->iccl & 0xff);
+		iic_wr(pd, ICCH, pd->icch & 0xff);
+	}
+
+	pd->msg = usr_msg;
+	pd->pos = -1;
+	pd->sr = 0;
+
+	if (pd->msg->len > 8)
+		sh_mobile_i2c_xfer_dma(pd);
+
+	/* Enable all interrupts to begin with */
+	iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+	return 0;
+}
+
+static int poll_dte(struct sh_mobile_i2c_data *pd)
+{
+	int i;
+
+	for (i = 1000; i; i--) {
+		u_int8_t val = iic_rd(pd, ICSR);
+
+		if (val & ICSR_DTE)
+			break;
+
+		if (val & ICSR_TACK)
+			return -ENXIO;
+
+		udelay(10);
+	}
+
+	return i ? 0 : -ETIMEDOUT;
+}
+
+static int poll_busy(struct sh_mobile_i2c_data *pd)
+{
+	int i;
+
+	for (i = 1000; i; i--) {
+		u_int8_t val = iic_rd(pd, ICSR);
+
+		dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
+
+		/* the interrupt handler may wake us up before the
+		 * transfer is finished, so poll the hardware
+		 * until we're done.
+		 */
+		if (!(val & ICSR_BUSY)) {
+			/* handle missing acknowledge and arbitration lost */
+			val |= pd->sr;
+			if (val & ICSR_TACK)
+				return -ENXIO;
+			if (val & ICSR_AL)
+				return -EAGAIN;
+			break;
+		}
+
+		udelay(10);
+	}
+
+	return i ? 0 : -ETIMEDOUT;
+}
+
+static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
+			      struct i2c_msg *msgs,
+			      int num)
+{
+	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
+	struct i2c_msg	*msg;
+	int err = 0;
+	int i, k;
+
+	activate_ch(pd);
+
+	/* Process all messages */
+	for (i = 0; i < num; i++) {
+		bool do_start = pd->send_stop || !i;
+		msg = &msgs[i];
+		pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
+		pd->stop_after_dma = false;
+
+		err = start_ch(pd, msg, do_start);
+		if (err)
+			break;
+
+		if (do_start)
+			i2c_op(pd, OP_START, 0);
+
+		/* The interrupt handler takes care of the rest... */
+		k = wait_event_timeout(pd->wait,
+				       pd->sr & (ICSR_TACK | SW_DONE),
+				       5 * HZ);
+		if (!k) {
+			dev_err(pd->dev, "Transfer request timed out\n");
+			if (pd->dma_direction != DMA_NONE)
+				sh_mobile_i2c_cleanup_dma(pd);
+
+			err = -ETIMEDOUT;
+			break;
+		}
+
+		if (pd->send_stop)
+			err = poll_busy(pd);
+		else
+			err = poll_dte(pd);
+		if (err < 0)
+			break;
+	}
+
+	deactivate_ch(pd);
+
+	if (!err)
+		err = num;
+	return err;
+}
+
+static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+static struct i2c_algorithm sh_mobile_i2c_algorithm = {
+	.functionality	= sh_mobile_i2c_func,
+	.master_xfer	= sh_mobile_i2c_xfer,
+};
+
+static const struct sh_mobile_dt_config default_dt_config = {
+	.clks_per_count = 1,
+};
+
+static const struct sh_mobile_dt_config fast_clock_dt_config = {
+	.clks_per_count = 2,
+};
+
+static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
+	{ .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
+	{ .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config },
+	{ .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
+
+static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
+{
+	if (!IS_ERR(pd->dma_tx)) {
+		dma_release_channel(pd->dma_tx);
+		pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
+	}
+
+	if (!IS_ERR(pd->dma_rx)) {
+		dma_release_channel(pd->dma_rx);
+		pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
+	}
+}
+
+static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
+{
+	struct resource *res;
+	resource_size_t n;
+	int k = 0, ret;
+
+	while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
+		for (n = res->start; n <= res->end; n++) {
+			ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
+					  0, dev_name(&dev->dev), pd);
+			if (ret) {
+				dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
+				return ret;
+			}
+		}
+		k++;
+	}
+
+	return k > 0 ? 0 : -ENOENT;
+}
+
+static int sh_mobile_i2c_probe(struct platform_device *dev)
+{
+	struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev);
+	struct sh_mobile_i2c_data *pd;
+	struct i2c_adapter *adap;
+	struct resource *res;
+	int ret;
+	u32 bus_speed;
+
+	pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
+
+	pd->clk = devm_clk_get(&dev->dev, NULL);
+	if (IS_ERR(pd->clk)) {
+		dev_err(&dev->dev, "cannot get clock\n");
+		return PTR_ERR(pd->clk);
+	}
+
+	ret = sh_mobile_i2c_hook_irqs(dev, pd);
+	if (ret)
+		return ret;
+
+	pd->dev = &dev->dev;
+	platform_set_drvdata(dev, pd);
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+
+	pd->res = res;
+	pd->reg = devm_ioremap_resource(&dev->dev, res);
+	if (IS_ERR(pd->reg))
+		return PTR_ERR(pd->reg);
+
+	/* Use platform data bus speed or STANDARD_MODE */
+	ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
+	pd->bus_speed = ret ? STANDARD_MODE : bus_speed;
+
+	pd->clks_per_count = 1;
+
+	if (dev->dev.of_node) {
+		const struct of_device_id *match;
+
+		match = of_match_device(sh_mobile_i2c_dt_ids, &dev->dev);
+		if (match) {
+			const struct sh_mobile_dt_config *config;
+
+			config = match->data;
+			pd->clks_per_count = config->clks_per_count;
+		}
+	} else {
+		if (pdata && pdata->bus_speed)
+			pd->bus_speed = pdata->bus_speed;
+		if (pdata && pdata->clks_per_count)
+			pd->clks_per_count = pdata->clks_per_count;
+	}
+
+	/* The IIC blocks on SH-Mobile ARM processors
+	 * come with two new bits in ICIC.
+	 */
+	if (resource_size(res) > 0x17)
+		pd->flags |= IIC_FLAG_HAS_ICIC67;
+
+	ret = sh_mobile_i2c_init(pd);
+	if (ret)
+		return ret;
+
+	/* Init DMA */
+	sg_init_table(&pd->sg, 1);
+	pd->dma_direction = DMA_NONE;
+	pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
+
+	/* Enable Runtime PM for this device.
+	 *
+	 * Also tell the Runtime PM core to ignore children
+	 * for this device since it is valid for us to suspend
+	 * this I2C master driver even though the slave devices
+	 * on the I2C bus may not be suspended.
+	 *
+	 * The state of the I2C hardware bus is unaffected by
+	 * the Runtime PM state.
+	 */
+	pm_suspend_ignore_children(&dev->dev, true);
+	pm_runtime_enable(&dev->dev);
+
+	/* setup the private data */
+	adap = &pd->adap;
+	i2c_set_adapdata(adap, pd);
+
+	adap->owner = THIS_MODULE;
+	adap->algo = &sh_mobile_i2c_algorithm;
+	adap->dev.parent = &dev->dev;
+	adap->retries = 5;
+	adap->nr = dev->id;
+	adap->dev.of_node = dev->dev.of_node;
+
+	strlcpy(adap->name, dev->name, sizeof(adap->name));
+
+	spin_lock_init(&pd->lock);
+	init_waitqueue_head(&pd->wait);
+
+	ret = i2c_add_numbered_adapter(adap);
+	if (ret < 0) {
+		sh_mobile_i2c_release_dma(pd);
+		dev_err(&dev->dev, "cannot add numbered adapter\n");
+		return ret;
+	}
+
+	dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
+
+	return 0;
+}
+
+static int sh_mobile_i2c_remove(struct platform_device *dev)
+{
+	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
+
+	i2c_del_adapter(&pd->adap);
+	sh_mobile_i2c_release_dma(pd);
+	pm_runtime_disable(&dev->dev);
+	return 0;
+}
+
+static int sh_mobile_i2c_runtime_nop(struct device *dev)
+{
+	/* Runtime PM callback shared between ->runtime_suspend()
+	 * and ->runtime_resume(). Simply returns success.
+	 *
+	 * This driver re-initializes all registers after
+	 * pm_runtime_get_sync() anyway so there is no need
+	 * to save and restore registers here.
+	 */
+	return 0;
+}
+
+static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
+	.runtime_suspend = sh_mobile_i2c_runtime_nop,
+	.runtime_resume = sh_mobile_i2c_runtime_nop,
+};
+
+static struct platform_driver sh_mobile_i2c_driver = {
+	.driver		= {
+		.name		= "i2c-sh_mobile",
+		.pm		= &sh_mobile_i2c_dev_pm_ops,
+		.of_match_table = sh_mobile_i2c_dt_ids,
+	},
+	.probe		= sh_mobile_i2c_probe,
+	.remove		= sh_mobile_i2c_remove,
+};
+
+static int __init sh_mobile_i2c_adap_init(void)
+{
+	return platform_driver_register(&sh_mobile_i2c_driver);
+}
+subsys_initcall(sh_mobile_i2c_adap_init);
+
+static void __exit sh_mobile_i2c_adap_exit(void)
+{
+	platform_driver_unregister(&sh_mobile_i2c_driver);
+}
+module_exit(sh_mobile_i2c_adap_exit);
+
+MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
+MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-sh_mobile");