Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 802 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
new file mode 100644
index 000000000..de3b60951
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -0,0 +1,802 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * drivers/i2c/busses/i2c-ibm_iic.c
+ *
+ * Support for the IIC peripheral on IBM PPC 4xx
+ *
+ * Copyright (c) 2003, 2004 Zultys Technologies.
+ * Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
+ *
+ * Copyright (c) 2008 PIKA Technologies
+ * Sean MacLennan <smaclennan@pikatech.com>
+ *
+ * Based on original work by
+ * 	Ian DaSilva  <idasilva@mvista.com>
+ *      Armin Kuster <akuster@mvista.com>
+ * 	Matt Porter  <mporter@mvista.com>
+ *
+ *      Copyright 2000-2003 MontaVista Software Inc.
+ *
+ * Original driver version was highly leveraged from i2c-elektor.c
+ *
+ *   	Copyright 1995-97 Simon G. Vogl
+ *                1998-99 Hans Berglund
+ *
+ *   	With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
+ *	and even Frodo Looijaard <frodol@dds.nl>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/sched/signal.h>
+
+#include <asm/irq.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+#include "i2c-ibm_iic.h"
+
+#define DRIVER_VERSION "2.2"
+
+MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
+MODULE_LICENSE("GPL");
+
+static bool iic_force_poll;
+module_param(iic_force_poll, bool, 0);
+MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
+
+static bool iic_force_fast;
+module_param(iic_force_fast, bool, 0);
+MODULE_PARM_DESC(iic_force_fast, "Force fast mode (400 kHz)");
+
+#define DBG_LEVEL 0
+
+#ifdef DBG
+#undef DBG
+#endif
+
+#ifdef DBG2
+#undef DBG2
+#endif
+
+#if DBG_LEVEL > 0
+#  define DBG(f,x...)	printk(KERN_DEBUG "ibm-iic" f, ##x)
+#else
+#  define DBG(f,x...)	((void)0)
+#endif
+#if DBG_LEVEL > 1
+#  define DBG2(f,x...) 	DBG(f, ##x)
+#else
+#  define DBG2(f,x...) 	((void)0)
+#endif
+#if DBG_LEVEL > 2
+static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header);
+	printk(KERN_DEBUG
+	       "  cntl     = 0x%02x, mdcntl = 0x%02x\n"
+	       "  sts      = 0x%02x, extsts = 0x%02x\n"
+	       "  clkdiv   = 0x%02x, xfrcnt = 0x%02x\n"
+	       "  xtcntlss = 0x%02x, directcntl = 0x%02x\n",
+		in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts),
+		in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt),
+		in_8(&iic->xtcntlss), in_8(&iic->directcntl));
+}
+#  define DUMP_REGS(h,dev)	dump_iic_regs((h),(dev))
+#else
+#  define DUMP_REGS(h,dev)	((void)0)
+#endif
+
+/* Bus timings (in ns) for bit-banging */
+static struct ibm_iic_timings {
+	unsigned int hd_sta;
+	unsigned int su_sto;
+	unsigned int low;
+	unsigned int high;
+	unsigned int buf;
+} timings [] = {
+/* Standard mode (100 KHz) */
+{
+	.hd_sta	= 4000,
+	.su_sto	= 4000,
+	.low	= 4700,
+	.high	= 4000,
+	.buf	= 4700,
+},
+/* Fast mode (400 KHz) */
+{
+	.hd_sta = 600,
+	.su_sto	= 600,
+	.low 	= 1300,
+	.high 	= 600,
+	.buf	= 1300,
+}};
+
+/* Enable/disable interrupt generation */
+static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable)
+{
+	out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0);
+}
+
+/*
+ * Initialize IIC interface.
+ */
+static void iic_dev_init(struct ibm_iic_private* dev)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+
+	DBG("%d: init\n", dev->idx);
+
+	/* Clear master address */
+	out_8(&iic->lmadr, 0);
+	out_8(&iic->hmadr, 0);
+
+	/* Clear slave address */
+	out_8(&iic->lsadr, 0);
+	out_8(&iic->hsadr, 0);
+
+	/* Clear status & extended status */
+	out_8(&iic->sts, STS_SCMP | STS_IRQA);
+	out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA
+			    | EXTSTS_ICT | EXTSTS_XFRA);
+
+	/* Set clock divider */
+	out_8(&iic->clkdiv, dev->clckdiv);
+
+	/* Clear transfer count */
+	out_8(&iic->xfrcnt, 0);
+
+	/* Clear extended control and status */
+	out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC
+			    | XTCNTLSS_SWS);
+
+	/* Clear control register */
+	out_8(&iic->cntl, 0);
+
+	/* Enable interrupts if possible */
+	iic_interrupt_mode(dev, dev->irq >= 0);
+
+	/* Set mode control */
+	out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS
+			    | (dev->fast_mode ? MDCNTL_FSM : 0));
+
+	DUMP_REGS("iic_init", dev);
+}
+
+/*
+ * Reset IIC interface
+ */
+static void iic_dev_reset(struct ibm_iic_private* dev)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	int i;
+	u8 dc;
+
+	DBG("%d: soft reset\n", dev->idx);
+	DUMP_REGS("reset", dev);
+
+    	/* Place chip in the reset state */
+	out_8(&iic->xtcntlss, XTCNTLSS_SRST);
+
+	/* Check if bus is free */
+	dc = in_8(&iic->directcntl);
+	if (!DIRCTNL_FREE(dc)){
+		DBG("%d: trying to regain bus control\n", dev->idx);
+
+		/* Try to set bus free state */
+		out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
+
+		/* Wait until we regain bus control */
+		for (i = 0; i < 100; ++i){
+			dc = in_8(&iic->directcntl);
+			if (DIRCTNL_FREE(dc))
+				break;
+
+			/* Toggle SCL line */
+			dc ^= DIRCNTL_SCC;
+			out_8(&iic->directcntl, dc);
+			udelay(10);
+			dc ^= DIRCNTL_SCC;
+			out_8(&iic->directcntl, dc);
+
+			/* be nice */
+			cond_resched();
+		}
+	}
+
+	/* Remove reset */
+	out_8(&iic->xtcntlss, 0);
+
+	/* Reinitialize interface */
+	iic_dev_init(dev);
+}
+
+/*
+ * Do 0-length transaction using bit-banging through IIC_DIRECTCNTL register.
+ */
+
+/* Wait for SCL and/or SDA to be high */
+static int iic_dc_wait(volatile struct iic_regs __iomem *iic, u8 mask)
+{
+	unsigned long x = jiffies + HZ / 28 + 2;
+	while ((in_8(&iic->directcntl) & mask) != mask){
+		if (unlikely(time_after(jiffies, x)))
+			return -1;
+		cond_resched();
+	}
+	return 0;
+}
+
+static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	const struct ibm_iic_timings *t = &timings[dev->fast_mode ? 1 : 0];
+	u8 mask, v, sda;
+	int i, res;
+
+	/* Only 7-bit addresses are supported */
+	if (unlikely(p->flags & I2C_M_TEN)){
+		DBG("%d: smbus_quick - 10 bit addresses are not supported\n",
+			dev->idx);
+		return -EINVAL;
+	}
+
+	DBG("%d: smbus_quick(0x%02x)\n", dev->idx, p->addr);
+
+	/* Reset IIC interface */
+	out_8(&iic->xtcntlss, XTCNTLSS_SRST);
+
+	/* Wait for bus to become free */
+	out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
+	if (unlikely(iic_dc_wait(iic, DIRCNTL_MSDA | DIRCNTL_MSC)))
+		goto err;
+	ndelay(t->buf);
+
+	/* START */
+	out_8(&iic->directcntl, DIRCNTL_SCC);
+	sda = 0;
+	ndelay(t->hd_sta);
+
+	/* Send address */
+	v = i2c_8bit_addr_from_msg(p);
+	for (i = 0, mask = 0x80; i < 8; ++i, mask >>= 1){
+		out_8(&iic->directcntl, sda);
+		ndelay(t->low / 2);
+		sda = (v & mask) ? DIRCNTL_SDAC : 0;
+		out_8(&iic->directcntl, sda);
+		ndelay(t->low / 2);
+
+		out_8(&iic->directcntl, DIRCNTL_SCC | sda);
+		if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
+			goto err;
+		ndelay(t->high);
+	}
+
+	/* ACK */
+	out_8(&iic->directcntl, sda);
+	ndelay(t->low / 2);
+	out_8(&iic->directcntl, DIRCNTL_SDAC);
+	ndelay(t->low / 2);
+	out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
+	if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
+		goto err;
+	res = (in_8(&iic->directcntl) & DIRCNTL_MSDA) ? -EREMOTEIO : 1;
+	ndelay(t->high);
+
+	/* STOP */
+	out_8(&iic->directcntl, 0);
+	ndelay(t->low);
+	out_8(&iic->directcntl, DIRCNTL_SCC);
+	if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
+		goto err;
+	ndelay(t->su_sto);
+	out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
+
+	ndelay(t->buf);
+
+	DBG("%d: smbus_quick -> %s\n", dev->idx, res ? "NACK" : "ACK");
+out:
+	/* Remove reset */
+	out_8(&iic->xtcntlss, 0);
+
+	/* Reinitialize interface */
+	iic_dev_init(dev);
+
+	return res;
+err:
+	DBG("%d: smbus_quick - bus is stuck\n", dev->idx);
+	res = -EREMOTEIO;
+	goto out;
+}
+
+/*
+ * IIC interrupt handler
+ */
+static irqreturn_t iic_handler(int irq, void *dev_id)
+{
+	struct ibm_iic_private* dev = (struct ibm_iic_private*)dev_id;
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+
+	DBG2("%d: irq handler, STS = 0x%02x, EXTSTS = 0x%02x\n",
+	     dev->idx, in_8(&iic->sts), in_8(&iic->extsts));
+
+	/* Acknowledge IRQ and wakeup iic_wait_for_tc */
+	out_8(&iic->sts, STS_IRQA | STS_SCMP);
+	wake_up_interruptible(&dev->wq);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Get master transfer result and clear errors if any.
+ * Returns the number of actually transferred bytes or error (<0)
+ */
+static int iic_xfer_result(struct ibm_iic_private* dev)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+
+	if (unlikely(in_8(&iic->sts) & STS_ERR)){
+		DBG("%d: xfer error, EXTSTS = 0x%02x\n", dev->idx,
+			in_8(&iic->extsts));
+
+		/* Clear errors and possible pending IRQs */
+		out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD |
+			EXTSTS_LA | EXTSTS_ICT | EXTSTS_XFRA);
+
+		/* Flush master data buffer */
+		out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
+
+		/* Is bus free?
+		 * If error happened during combined xfer
+		 * IIC interface is usually stuck in some strange
+		 * state, the only way out - soft reset.
+		 */
+		if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
+			DBG("%d: bus is stuck, resetting\n", dev->idx);
+			iic_dev_reset(dev);
+		}
+		return -EREMOTEIO;
+	}
+	else
+		return in_8(&iic->xfrcnt) & XFRCNT_MTC_MASK;
+}
+
+/*
+ * Try to abort active transfer.
+ */
+static void iic_abort_xfer(struct ibm_iic_private* dev)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	unsigned long x;
+
+	DBG("%d: iic_abort_xfer\n", dev->idx);
+
+	out_8(&iic->cntl, CNTL_HMT);
+
+	/*
+	 * Wait for the abort command to complete.
+	 * It's not worth to be optimized, just poll (timeout >= 1 tick)
+	 */
+	x = jiffies + 2;
+	while ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
+		if (time_after(jiffies, x)){
+			DBG("%d: abort timeout, resetting...\n", dev->idx);
+			iic_dev_reset(dev);
+			return;
+		}
+		schedule();
+	}
+
+	/* Just to clear errors */
+	iic_xfer_result(dev);
+}
+
+/*
+ * Wait for master transfer to complete.
+ * It puts current process to sleep until we get interrupt or timeout expires.
+ * Returns the number of transferred bytes or error (<0)
+ */
+static int iic_wait_for_tc(struct ibm_iic_private* dev){
+
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	int ret = 0;
+
+	if (dev->irq >= 0){
+		/* Interrupt mode */
+		ret = wait_event_interruptible_timeout(dev->wq,
+			!(in_8(&iic->sts) & STS_PT), dev->adap.timeout);
+
+		if (unlikely(ret < 0))
+			DBG("%d: wait interrupted\n", dev->idx);
+		else if (unlikely(in_8(&iic->sts) & STS_PT)){
+			DBG("%d: wait timeout\n", dev->idx);
+			ret = -ETIMEDOUT;
+		}
+	}
+	else {
+		/* Polling mode */
+		unsigned long x = jiffies + dev->adap.timeout;
+
+		while (in_8(&iic->sts) & STS_PT){
+			if (unlikely(time_after(jiffies, x))){
+				DBG("%d: poll timeout\n", dev->idx);
+				ret = -ETIMEDOUT;
+				break;
+			}
+
+			if (signal_pending(current)){
+				DBG("%d: poll interrupted\n", dev->idx);
+				ret = -ERESTARTSYS;
+				break;
+			}
+			schedule();
+		}
+	}
+
+	if (unlikely(ret < 0))
+		iic_abort_xfer(dev);
+	else
+		ret = iic_xfer_result(dev);
+
+	DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret);
+
+	return ret;
+}
+
+/*
+ * Low level master transfer routine
+ */
+static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm,
+			  int combined_xfer)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	char* buf = pm->buf;
+	int i, j, loops, ret = 0;
+	int len = pm->len;
+
+	u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT;
+	if (pm->flags & I2C_M_RD)
+		cntl |= CNTL_RW;
+
+	loops = (len + 3) / 4;
+	for (i = 0; i < loops; ++i, len -= 4){
+		int count = len > 4 ? 4 : len;
+		u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT);
+
+		if (!(cntl & CNTL_RW))
+			for (j = 0; j < count; ++j)
+				out_8((void __iomem *)&iic->mdbuf, *buf++);
+
+		if (i < loops - 1)
+			cmd |= CNTL_CHT;
+		else if (combined_xfer)
+			cmd |= CNTL_RPST;
+
+		DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd);
+
+		/* Start transfer */
+		out_8(&iic->cntl, cmd);
+
+		/* Wait for completion */
+		ret = iic_wait_for_tc(dev);
+
+		if (unlikely(ret < 0))
+			break;
+		else if (unlikely(ret != count)){
+			DBG("%d: xfer_bytes, requested %d, transferred %d\n",
+				dev->idx, count, ret);
+
+			/* If it's not a last part of xfer, abort it */
+			if (combined_xfer || (i < loops - 1))
+    				iic_abort_xfer(dev);
+
+			ret = -EREMOTEIO;
+			break;
+		}
+
+		if (cntl & CNTL_RW)
+			for (j = 0; j < count; ++j)
+				*buf++ = in_8((void __iomem *)&iic->mdbuf);
+	}
+
+	return ret > 0 ? 0 : ret;
+}
+
+/*
+ * Set target slave address for master transfer
+ */
+static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg)
+{
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	u16 addr = msg->addr;
+
+	DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx,
+		addr, msg->flags & I2C_M_TEN ? 10 : 7);
+
+	if (msg->flags & I2C_M_TEN){
+	    out_8(&iic->cntl, CNTL_AMD);
+	    out_8(&iic->lmadr, addr);
+	    out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06));
+	}
+	else {
+	    out_8(&iic->cntl, 0);
+	    out_8(&iic->lmadr, addr << 1);
+	}
+}
+
+static inline int iic_invalid_address(const struct i2c_msg* p)
+{
+	return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f));
+}
+
+static inline int iic_address_neq(const struct i2c_msg* p1,
+				  const struct i2c_msg* p2)
+{
+	return (p1->addr != p2->addr)
+		|| ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN));
+}
+
+/*
+ * Generic master transfer entrypoint.
+ * Returns the number of processed messages or error (<0)
+ */
+static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+    	struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap));
+	volatile struct iic_regs __iomem *iic = dev->vaddr;
+	int i, ret = 0;
+
+	DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num);
+
+	/* Check the sanity of the passed messages.
+	 * Uhh, generic i2c layer is more suitable place for such code...
+	 */
+	if (unlikely(iic_invalid_address(&msgs[0]))){
+		DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx,
+			msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7);
+		return -EINVAL;
+	}
+	for (i = 0; i < num; ++i){
+		if (unlikely(msgs[i].len <= 0)){
+			if (num == 1 && !msgs[0].len){
+				/* Special case for I2C_SMBUS_QUICK emulation.
+				 * IBM IIC doesn't support 0-length transactions
+				 * so we have to emulate them using bit-banging.
+				 */
+				return iic_smbus_quick(dev, &msgs[0]);
+			}
+			DBG("%d: invalid len %d in msg[%d]\n", dev->idx,
+				msgs[i].len, i);
+			return -EINVAL;
+		}
+		if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){
+			DBG("%d: invalid addr in msg[%d]\n", dev->idx, i);
+			return -EINVAL;
+		}
+	}
+
+	/* Check bus state */
+	if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){
+		DBG("%d: iic_xfer, bus is not free\n", dev->idx);
+
+		/* Usually it means something serious has happened.
+		 * We *cannot* have unfinished previous transfer
+		 * so it doesn't make any sense to try to stop it.
+		 * Probably we were not able to recover from the
+		 * previous error.
+		 * The only *reasonable* thing I can think of here
+		 * is soft reset.  --ebs
+		 */
+		iic_dev_reset(dev);
+
+		if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
+			DBG("%d: iic_xfer, bus is still not free\n", dev->idx);
+			return -EREMOTEIO;
+		}
+	}
+	else {
+		/* Flush master data buffer (just in case) */
+		out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
+	}
+
+	/* Load slave address */
+	iic_address(dev, &msgs[0]);
+
+	/* Do real transfer */
+    	for (i = 0; i < num && !ret; ++i)
+		ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1);
+
+	return ret < 0 ? ret : num;
+}
+
+static u32 iic_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
+}
+
+static const struct i2c_algorithm iic_algo = {
+	.master_xfer 	= iic_xfer,
+	.functionality	= iic_func
+};
+
+/*
+ * Calculates IICx_CLCKDIV value for a specific OPB clock frequency
+ */
+static inline u8 iic_clckdiv(unsigned int opb)
+{
+	/* Compatibility kludge, should go away after all cards
+	 * are fixed to fill correct value for opbfreq.
+	 * Previous driver version used hardcoded divider value 4,
+	 * it corresponds to OPB frequency from the range (40, 50] MHz
+	 */
+	if (!opb){
+		printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq,"
+			" fix your board specific setup\n");
+		opb = 50000000;
+	}
+
+	/* Convert to MHz */
+	opb /= 1000000;
+
+	if (opb < 20 || opb > 150){
+		printk(KERN_WARNING "ibm-iic: invalid OPB clock frequency %u MHz\n",
+			opb);
+		opb = opb < 20 ? 20 : 150;
+	}
+	return (u8)((opb + 9) / 10 - 1);
+}
+
+static int iic_request_irq(struct platform_device *ofdev,
+				     struct ibm_iic_private *dev)
+{
+	struct device_node *np = ofdev->dev.of_node;
+	int irq;
+
+	if (iic_force_poll)
+		return 0;
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n");
+		return 0;
+	}
+
+	/* Disable interrupts until we finish initialization, assumes
+	 *  level-sensitive IRQ setup...
+	 */
+	iic_interrupt_mode(dev, 0);
+	if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) {
+		dev_err(&ofdev->dev, "request_irq %d failed\n", irq);
+		/* Fallback to the polling mode */
+		return 0;
+	}
+
+	return irq;
+}
+
+/*
+ * Register single IIC interface
+ */
+static int iic_probe(struct platform_device *ofdev)
+{
+	struct device_node *np = ofdev->dev.of_node;
+	struct ibm_iic_private *dev;
+	struct i2c_adapter *adap;
+	const u32 *freq;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(ofdev, dev);
+
+	dev->vaddr = of_iomap(np, 0);
+	if (dev->vaddr == NULL) {
+		dev_err(&ofdev->dev, "failed to iomap device\n");
+		ret = -ENXIO;
+		goto error_cleanup;
+	}
+
+	init_waitqueue_head(&dev->wq);
+
+	dev->irq = iic_request_irq(ofdev, dev);
+	if (!dev->irq)
+		dev_warn(&ofdev->dev, "using polling mode\n");
+
+	/* Board specific settings */
+	if (iic_force_fast || of_get_property(np, "fast-mode", NULL))
+		dev->fast_mode = 1;
+
+	freq = of_get_property(np, "clock-frequency", NULL);
+	if (freq == NULL) {
+		freq = of_get_property(np->parent, "clock-frequency", NULL);
+		if (freq == NULL) {
+			dev_err(&ofdev->dev, "Unable to get bus frequency\n");
+			ret = -EINVAL;
+			goto error_cleanup;
+		}
+	}
+
+	dev->clckdiv = iic_clckdiv(*freq);
+	dev_dbg(&ofdev->dev, "clckdiv = %d\n", dev->clckdiv);
+
+	/* Initialize IIC interface */
+	iic_dev_init(dev);
+
+	/* Register it with i2c layer */
+	adap = &dev->adap;
+	adap->dev.parent = &ofdev->dev;
+	adap->dev.of_node = of_node_get(np);
+	strscpy(adap->name, "IBM IIC", sizeof(adap->name));
+	i2c_set_adapdata(adap, dev);
+	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adap->algo = &iic_algo;
+	adap->timeout = HZ;
+
+	ret = i2c_add_adapter(adap);
+	if (ret  < 0)
+		goto error_cleanup;
+
+	dev_info(&ofdev->dev, "using %s mode\n",
+		 dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
+
+	return 0;
+
+error_cleanup:
+	if (dev->irq) {
+		iic_interrupt_mode(dev, 0);
+		free_irq(dev->irq, dev);
+	}
+
+	if (dev->vaddr)
+		iounmap(dev->vaddr);
+
+	kfree(dev);
+	return ret;
+}
+
+/*
+ * Cleanup initialized IIC interface
+ */
+static int iic_remove(struct platform_device *ofdev)
+{
+	struct ibm_iic_private *dev = platform_get_drvdata(ofdev);
+
+	i2c_del_adapter(&dev->adap);
+
+	if (dev->irq) {
+		iic_interrupt_mode(dev, 0);
+		free_irq(dev->irq, dev);
+	}
+
+	iounmap(dev->vaddr);
+	kfree(dev);
+
+	return 0;
+}
+
+static const struct of_device_id ibm_iic_match[] = {
+	{ .compatible = "ibm,iic", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ibm_iic_match);
+
+static struct platform_driver ibm_iic_driver = {
+	.driver = {
+		.name = "ibm-iic",
+		.of_match_table = ibm_iic_match,
+	},
+	.probe	= iic_probe,
+	.remove	= iic_remove,
+};
+
+module_platform_driver(ibm_iic_driver);