i2c: Add support for I2C bus on Freescale CPM1/CPM2 controllers

This driver uses the port of 2.4 code from Vitaly Bordug
<vitb@kernel.crashing.org> and the actual algorithm used by the i2c
driver of the DBox code on cvs.tuxboc.org from Felix Domke
(tmbinc@gmx.net) and Gillem (htoa@gmx.net) converted to an
of_platform_driver. Tested on CPM1 (MPC823 on dbox2 hardware) and
CPM2 (MPC8272).
Signed-off-by: Jochen Friedrich <jochen@scram.de>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/Kconfig

@@ -299,6 +299,16 @@ config I2C_BLACKFIN_TWI_CLK_KHZ
 	help
 	  The unit of the TWI clock is kHz.
 
+config I2C_CPM
+	tristate "Freescale CPM1 or CPM2 (MPC8xx/826x)"
+	depends on (CPM1 || CPM2) && OF_I2C
+	help
+	  This supports the use of the I2C interface on Freescale
+	  processors with CPM1 or CPM2.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-cpm.
+
 config I2C_DAVINCI
 	tristate "DaVinci I2C driver"
 	depends on ARCH_DAVINCI

drivers/i2c/busses/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_BLACKFIN_TWI)	+= i2c-bfin-twi.o
+obj-$(CONFIG_I2C_CPM)		+= i2c-cpm.o
 obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
 obj-$(CONFIG_I2C_GPIO)		+= i2c-gpio.o
 obj-$(CONFIG_I2C_IBM_IIC)	+= i2c-ibm_iic.o

drivers/i2c/busses/i2c-cpm.c

+/*
+ * Freescale CPM1/CPM2 I2C interface.
+ * Copyright (c) 1999 Dan Malek (dmalek@jlc.net).
+ *
+ * moved into proper i2c interface;
+ * Brad Parker (brad@heeltoe.com)
+ *
+ * Parts from dbox2_i2c.c (cvs.tuxbox.org)
+ * (C) 2000-2001 Felix Domke (tmbinc@gmx.net), Gillem (htoa@gmx.net)
+ *
+ * (C) 2007 Montavista Software, Inc.
+ * Vitaly Bordug <vitb@kernel.crashing.org>
+ *
+ * Converted to of_platform_device. Renamed to i2c-cpm.c.
+ * (C) 2007,2008 Jochen Friedrich <jochen@scram.de>
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/stddef.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_i2c.h>
+#include <sysdev/fsl_soc.h>
+#include <asm/cpm.h>
+
+/* Try to define this if you have an older CPU (earlier than rev D4) */
+/* However, better use a GPIO based bitbang driver in this case :/   */
+#undef	I2C_CHIP_ERRATA
+
+#define CPM_MAX_READ    513
+#define CPM_MAXBD       4
+
+#define I2C_EB			(0x10) /* Big endian mode */
+#define I2C_EB_CPM2		(0x30) /* Big endian mode, memory snoop */
+
+#define DPRAM_BASE		((u8 __iomem __force *)cpm_muram_addr(0))
+
+/* I2C parameter RAM. */
+struct i2c_ram {
+	ushort  rbase;		/* Rx Buffer descriptor base address */
+	ushort  tbase;		/* Tx Buffer descriptor base address */
+	u_char  rfcr;		/* Rx function code */
+	u_char  tfcr;		/* Tx function code */
+	ushort  mrblr;		/* Max receive buffer length */
+	uint    rstate;		/* Internal */
+	uint    rdp;		/* Internal */
+	ushort  rbptr;		/* Rx Buffer descriptor pointer */
+	ushort  rbc;		/* Internal */
+	uint    rxtmp;		/* Internal */
+	uint    tstate;		/* Internal */
+	uint    tdp;		/* Internal */
+	ushort  tbptr;		/* Tx Buffer descriptor pointer */
+	ushort  tbc;		/* Internal */
+	uint    txtmp;		/* Internal */
+	char    res1[4];	/* Reserved */
+	ushort  rpbase;		/* Relocation pointer */
+	char    res2[2];	/* Reserved */
+};
+
+#define I2COM_START	0x80
+#define I2COM_MASTER	0x01
+#define I2CER_TXE	0x10
+#define I2CER_BUSY	0x04
+#define I2CER_TXB	0x02
+#define I2CER_RXB	0x01
+#define I2MOD_EN	0x01
+
+/* I2C Registers */
+struct i2c_reg {
+	u8	i2mod;
+	u8	res1[3];
+	u8	i2add;
+	u8	res2[3];
+	u8	i2brg;
+	u8	res3[3];
+	u8	i2com;
+	u8	res4[3];
+	u8	i2cer;
+	u8	res5[3];
+	u8	i2cmr;
+};
+
+struct cpm_i2c {
+	char *base;
+	struct of_device *ofdev;
+	struct i2c_adapter adap;
+	uint dp_addr;
+	int version; /* CPM1=1, CPM2=2 */
+	int irq;
+	int cp_command;
+	int freq;
+	struct i2c_reg __iomem *i2c_reg;
+	struct i2c_ram __iomem *i2c_ram;
+	u16 i2c_addr;
+	wait_queue_head_t i2c_wait;
+	cbd_t __iomem *tbase;
+	cbd_t __iomem *rbase;
+	u_char *txbuf[CPM_MAXBD];
+	u_char *rxbuf[CPM_MAXBD];
+	u32 txdma[CPM_MAXBD];
+	u32 rxdma[CPM_MAXBD];
+};
+
+static irqreturn_t cpm_i2c_interrupt(int irq, void *dev_id)
+{
+	struct cpm_i2c *cpm;
+	struct i2c_reg __iomem *i2c_reg;
+	struct i2c_adapter *adap = dev_id;
+	int i;
+
+	cpm = i2c_get_adapdata(dev_id);
+	i2c_reg = cpm->i2c_reg;
+
+	/* Clear interrupt. */
+	i = in_8(&i2c_reg->i2cer);
+	out_8(&i2c_reg->i2cer, i);
+
+	dev_dbg(&adap->dev, "Interrupt: %x\n", i);
+
+	wake_up_interruptible(&cpm->i2c_wait);
+
+	return i ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static void cpm_reset_i2c_params(struct cpm_i2c *cpm)
+{
+	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
+
+	/* Set up the I2C parameters in the parameter ram. */
+	out_be16(&i2c_ram->tbase, (u8 __iomem *)cpm->tbase - DPRAM_BASE);
+	out_be16(&i2c_ram->rbase, (u8 __iomem *)cpm->rbase - DPRAM_BASE);
+
+	if (cpm->version == 1) {
+		out_8(&i2c_ram->tfcr, I2C_EB);
+		out_8(&i2c_ram->rfcr, I2C_EB);
+	} else {
+		out_8(&i2c_ram->tfcr, I2C_EB_CPM2);
+		out_8(&i2c_ram->rfcr, I2C_EB_CPM2);
+	}
+
+	out_be16(&i2c_ram->mrblr, CPM_MAX_READ);
+
+	out_be32(&i2c_ram->rstate, 0);
+	out_be32(&i2c_ram->rdp, 0);
+	out_be16(&i2c_ram->rbptr, 0);
+	out_be16(&i2c_ram->rbc, 0);
+	out_be32(&i2c_ram->rxtmp, 0);
+	out_be32(&i2c_ram->tstate, 0);
+	out_be32(&i2c_ram->tdp, 0);
+	out_be16(&i2c_ram->tbptr, 0);
+	out_be16(&i2c_ram->tbc, 0);
+	out_be32(&i2c_ram->txtmp, 0);
+}
+
+static void cpm_i2c_force_close(struct i2c_adapter *adap)
+{
+	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
+	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
+
+	dev_dbg(&adap->dev, "cpm_i2c_force_close()\n");
+
+	cpm_command(cpm->cp_command, CPM_CR_CLOSE_RX_BD);
+
+	out_8(&i2c_reg->i2cmr, 0x00);	/* Disable all interrupts */
+	out_8(&i2c_reg->i2cer, 0xff);
+}
+
+static void cpm_i2c_parse_message(struct i2c_adapter *adap,
+	struct i2c_msg *pmsg, int num, int tx, int rx)
+{
+	cbd_t __iomem *tbdf;
+	cbd_t __iomem *rbdf;
+	u_char addr;
+	u_char *tb;
+	u_char *rb;
+	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
+
+	tbdf = cpm->tbase + tx;
+	rbdf = cpm->rbase + rx;
+
+	addr = pmsg->addr << 1;
+	if (pmsg->flags & I2C_M_RD)
+		addr |= 1;
+
+	tb = cpm->txbuf[tx];
+	rb = cpm->rxbuf[rx];
+
+	/* Align read buffer */
+	rb = (u_char *) (((ulong) rb + 1) & ~1);
+
+	tb[0] = addr;		/* Device address byte w/rw flag */
+
+	out_be16(&tbdf->cbd_datlen, pmsg->len + 1);
+	out_be16(&tbdf->cbd_sc, 0);
+
+	if (!(pmsg->flags & I2C_M_NOSTART))
+		setbits16(&tbdf->cbd_sc, BD_I2C_START);
+
+	if (tx + 1 == num)
+		setbits16(&tbdf->cbd_sc, BD_SC_LAST | BD_SC_WRAP);
+
+	if (pmsg->flags & I2C_M_RD) {
+		/*
+		 * To read, we need an empty buffer of the proper length.
+		 * All that is used is the first byte for address, the remainder
+		 * is just used for timing (and doesn't really have to exist).
+		 */
+
+		dev_dbg(&adap->dev, "cpm_i2c_read(abyte=0x%x)\n", addr);
+
+		out_be16(&rbdf->cbd_datlen, 0);
+		out_be16(&rbdf->cbd_sc, BD_SC_EMPTY | BD_SC_INTRPT);
+
+		if (rx + 1 == CPM_MAXBD)
+			setbits16(&rbdf->cbd_sc, BD_SC_WRAP);
+
+		eieio();
+		setbits16(&tbdf->cbd_sc, BD_SC_READY);
+	} else {
+		dev_dbg(&adap->dev, "cpm_iic_write(abyte=0x%x)\n", addr);
+
+		memcpy(tb+1, pmsg->buf, pmsg->len);
+
+		eieio();
+		setbits16(&tbdf->cbd_sc, BD_SC_READY | BD_SC_INTRPT);
+	}
+}
+
+static int cpm_i2c_check_message(struct i2c_adapter *adap,
+	struct i2c_msg *pmsg, int tx, int rx)
+{
+	cbd_t __iomem *tbdf;
+	cbd_t __iomem *rbdf;
+	u_char *tb;
+	u_char *rb;
+	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
+
+	tbdf = cpm->tbase + tx;
+	rbdf = cpm->rbase + rx;
+
+	tb = cpm->txbuf[tx];
+	rb = cpm->rxbuf[rx];
+
+	/* Align read buffer */
+	rb = (u_char *) (((uint) rb + 1) & ~1);
+
+	eieio();
+	if (pmsg->flags & I2C_M_RD) {
+		dev_dbg(&adap->dev, "tx sc 0x%04x, rx sc 0x%04x\n",
+			in_be16(&tbdf->cbd_sc), in_be16(&rbdf->cbd_sc));
+
+		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
+			dev_dbg(&adap->dev, "I2C read; No ack\n");
+			return -ENXIO;
+		}
+		if (in_be16(&rbdf->cbd_sc) & BD_SC_EMPTY) {
+			dev_err(&adap->dev,
+				"I2C read; complete but rbuf empty\n");
+			return -EREMOTEIO;
+		}
+		if (in_be16(&rbdf->cbd_sc) & BD_SC_OV) {
+			dev_err(&adap->dev, "I2C read; Overrun\n");
+			return -EREMOTEIO;
+		}
+		memcpy(pmsg->buf, rb, pmsg->len);
+	} else {
+		dev_dbg(&adap->dev, "tx sc %d 0x%04x\n", tx,
+			in_be16(&tbdf->cbd_sc));
+
+		if (in_be16(&tbdf->cbd_sc) & BD_SC_NAK) {
+			dev_dbg(&adap->dev, "I2C write; No ack\n");
+			return -ENXIO;
+		}
+		if (in_be16(&tbdf->cbd_sc) & BD_SC_UN) {
+			dev_err(&adap->dev, "I2C write; Underrun\n");
+			return -EIO;
+		}
+		if (in_be16(&tbdf->cbd_sc) & BD_SC_CL) {
+			dev_err(&adap->dev, "I2C write; Collision\n");
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
+	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
+	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
+	struct i2c_msg *pmsg;
+	int ret, i;
+	int tptr;
+	int rptr;
+	cbd_t __iomem *tbdf;
+	cbd_t __iomem *rbdf;
+
+	if (num > CPM_MAXBD)
+		return -EINVAL;
+
+	/* Check if we have any oversized READ requests */
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+		if (pmsg->len >= CPM_MAX_READ)
+			return -EINVAL;
+	}
+
+	/* Reset to use first buffer */
+	out_be16(&i2c_ram->rbptr, in_be16(&i2c_ram->rbase));
+	out_be16(&i2c_ram->tbptr, in_be16(&i2c_ram->tbase));
+
+	tbdf = cpm->tbase;
+	rbdf = cpm->rbase;
+
+	tptr = 0;
+	rptr = 0;
+
+	while (tptr < num) {
+		pmsg = &msgs[tptr];
+		dev_dbg(&adap->dev, "R: %d T: %d\n", rptr, tptr);
+
+		cpm_i2c_parse_message(adap, pmsg, num, tptr, rptr);
+		if (pmsg->flags & I2C_M_RD)
+			rptr++;
+		tptr++;
+	}
+	/* Start transfer now */
+	/* Enable RX/TX/Error interupts */
+	out_8(&i2c_reg->i2cmr, I2CER_BUSY | I2CER_TXB | I2CER_RXB);
+	out_8(&i2c_reg->i2cer, 0xff);	/* Clear interrupt status */
+	/* Chip bug, set enable here */
+	setbits8(&i2c_reg->i2mod, I2MOD_EN);	/* Enable */
+	/* Begin transmission */
+	setbits8(&i2c_reg->i2com, I2COM_START);
+
+	tptr = 0;
+	rptr = 0;
+
+	while (tptr < num) {
+		/* Check for outstanding messages */
+		dev_dbg(&adap->dev, "test ready.\n");
+		pmsg = &msgs[tptr];
+		if (pmsg->flags & I2C_M_RD)
+			ret = wait_event_interruptible_timeout(cpm->i2c_wait,
+				!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
+				1 * HZ);
+		else
+			ret = wait_event_interruptible_timeout(cpm->i2c_wait,
+				!(in_be16(&tbdf[tptr].cbd_sc) & BD_SC_READY),
+				1 * HZ);
+		if (ret == 0) {
+			ret = -EREMOTEIO;
+			dev_err(&adap->dev, "I2C transfer: timeout\n");
+			goto out_err;
+		}
+		if (ret > 0) {
+			dev_dbg(&adap->dev, "ready.\n");
+			ret = cpm_i2c_check_message(adap, pmsg, tptr, rptr);
+			tptr++;
+			if (pmsg->flags & I2C_M_RD)
+				rptr++;
+			if (ret)
+				goto out_err;
+		}
+	}
+#ifdef I2C_CHIP_ERRATA
+	/*
+	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
+	 * Disabling I2C too early may cause too short stop condition
+	 */
+	udelay(4);
+	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
+#endif
+	return (num);
+
+out_err:
+	cpm_i2c_force_close(adap);
+#ifdef I2C_CHIP_ERRATA
+	/*
+	 * Chip errata, clear enable. This is not needed on rev D4 CPUs.
+	 */
+	clrbits8(&i2c_reg->i2mod, I2MOD_EN);
+#endif
+	return ret;
+}
+
+static u32 cpm_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+/* -----exported algorithm data: -------------------------------------	*/
+
+static const struct i2c_algorithm cpm_i2c_algo = {
+	.master_xfer = cpm_i2c_xfer,
+	.functionality = cpm_i2c_func,
+};
+
+static const struct i2c_adapter cpm_ops = {
+	.owner		= THIS_MODULE,
+	.name		= "i2c-cpm",
+	.algo		= &cpm_i2c_algo,
+	.class		= I2C_CLASS_HWMON,
+};
+
+static int __devinit cpm_i2c_setup(struct cpm_i2c *cpm)
+{
+	struct of_device *ofdev = cpm->ofdev;
+	const u32 *data;
+	int len, ret, i;
+	void __iomem *i2c_base;
+	cbd_t __iomem *tbdf;
+	cbd_t __iomem *rbdf;
+	unsigned char brg;
+
+	dev_dbg(&cpm->ofdev->dev, "cpm_i2c_setup()\n");
+
+	init_waitqueue_head(&cpm->i2c_wait);
+
+	cpm->irq = of_irq_to_resource(ofdev->node, 0, NULL);
+	if (cpm->irq == NO_IRQ)
+		return -EINVAL;
+
+	/* Install interrupt handler. */
+	ret = request_irq(cpm->irq, cpm_i2c_interrupt, 0, "cpm_i2c",
+			  &cpm->adap);
+	if (ret)
+		return ret;
+
+	/* I2C parameter RAM */
+	i2c_base = of_iomap(ofdev->node, 1);
+	if (i2c_base == NULL) {
+		ret = -EINVAL;
+		goto out_irq;
+	}
+
+	if (of_device_is_compatible(ofdev->node, "fsl,cpm1-i2c")) {
+
+		/* Check for and use a microcode relocation patch. */
+		cpm->i2c_ram = i2c_base;
+		cpm->i2c_addr = in_be16(&cpm->i2c_ram->rpbase);
+
+		/*
+		 * Maybe should use cpm_muram_alloc instead of hardcoding
+		 * this in micropatch.c
+		 */
+		if (cpm->i2c_addr) {
+			cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
+			iounmap(i2c_base);
+		}
+
+		cpm->version = 1;
+
+	} else if (of_device_is_compatible(ofdev->node, "fsl,cpm2-i2c")) {
+		cpm->i2c_addr = cpm_muram_alloc(sizeof(struct i2c_ram), 64);
+		cpm->i2c_ram = cpm_muram_addr(cpm->i2c_addr);
+		out_be16(i2c_base, cpm->i2c_addr);
+		iounmap(i2c_base);
+
+		cpm->version = 2;
+
+	} else {
+		iounmap(i2c_base);
+		ret = -EINVAL;
+		goto out_irq;
+	}
+
+	/* I2C control/status registers */
+	cpm->i2c_reg = of_iomap(ofdev->node, 0);
+	if (cpm->i2c_reg == NULL) {
+		ret = -EINVAL;
+		goto out_ram;
+	}
+
+	data = of_get_property(ofdev->node, "fsl,cpm-command", &len);
+	if (!data || len != 4) {
+		ret = -EINVAL;
+		goto out_reg;
+	}
+	cpm->cp_command = *data;
+
+	data = of_get_property(ofdev->node, "linux,i2c-class", &len);
+	if (data && len == 4)
+		cpm->adap.class = *data;
+
+	data = of_get_property(ofdev->node, "clock-frequency", &len);
+	if (data && len == 4)
+		cpm->freq = *data;
+	else
+		cpm->freq = 60000; /* use 60kHz i2c clock by default */
+
+	/*
+	 * Allocate space for CPM_MAXBD transmit and receive buffer
+	 * descriptors in the DP ram.
+	 */
+	cpm->dp_addr = cpm_muram_alloc(sizeof(cbd_t) * 2 * CPM_MAXBD, 8);
+	if (!cpm->dp_addr) {
+		ret = -ENOMEM;
+		goto out_reg;
+	}
+
+	cpm->tbase = cpm_muram_addr(cpm->dp_addr);
+	cpm->rbase = cpm_muram_addr(cpm->dp_addr + sizeof(cbd_t) * CPM_MAXBD);
+
+	/* Allocate TX and RX buffers */
+
+	tbdf = cpm->tbase;
+	rbdf = cpm->rbase;
+
+	for (i = 0; i < CPM_MAXBD; i++) {
+		cpm->rxbuf[i] = dma_alloc_coherent(
+			NULL, CPM_MAX_READ + 1, &cpm->rxdma[i], GFP_KERNEL);
+		if (!cpm->rxbuf[i]) {
+			ret = -ENOMEM;
+			goto out_muram;
+		}
+		out_be32(&rbdf[i].cbd_bufaddr, ((cpm->rxdma[i] + 1) & ~1));
+
+		cpm->txbuf[i] = (unsigned char *)dma_alloc_coherent(
+			NULL, CPM_MAX_READ + 1, &cpm->txdma[i], GFP_KERNEL);
+		if (!cpm->txbuf[i]) {
+			ret = -ENOMEM;
+			goto out_muram;
+		}
+		out_be32(&tbdf[i].cbd_bufaddr, cpm->txdma[i]);
+	}
+
+	/* Initialize Tx/Rx parameters. */
+
+	cpm_reset_i2c_params(cpm);
+
+	dev_dbg(&cpm->ofdev->dev, "i2c_ram %p, i2c_addr 0x%04x\n",
+		cpm->i2c_ram, cpm->i2c_addr);
+	dev_dbg(&cpm->ofdev->dev, "tbase 0x%04x, rbase 0x%04x\n",
+		(u8 __iomem *)cpm->tbase - DPRAM_BASE,
+		(u8 __iomem *)cpm->rbase - DPRAM_BASE);
+
+	cpm_command(cpm->cp_command, CPM_CR_INIT_TRX);
+
+	/*
+	 * Select an invalid address. Just make sure we don't use loopback mode
+	 */
+	out_8(&cpm->i2c_reg->i2add, 0x7f << 1);
+
+	/*
+	 * PDIV is set to 00 in i2mod, so brgclk/32 is used as input to the
+	 * i2c baud rate generator. This is divided by 2 x (DIV + 3) to get
+	 * the actual i2c bus frequency.
+	 */
+	brg = get_brgfreq() / (32 * 2 * cpm->freq) - 3;
+	out_8(&cpm->i2c_reg->i2brg, brg);
+
+	out_8(&cpm->i2c_reg->i2mod, 0x00);
+	out_8(&cpm->i2c_reg->i2com, I2COM_MASTER);	/* Master mode */
+
+	/* Disable interrupts. */
+	out_8(&cpm->i2c_reg->i2cmr, 0);
+	out_8(&cpm->i2c_reg->i2cer, 0xff);
+
+	return 0;
+
+out_muram:
+	for (i = 0; i < CPM_MAXBD; i++) {
+		if (cpm->rxbuf[i])
+			dma_free_coherent(NULL, CPM_MAX_READ + 1,
+				cpm->rxbuf[i], cpm->rxdma[i]);
+		if (cpm->txbuf[i])
+			dma_free_coherent(NULL, CPM_MAX_READ + 1,
+				cpm->txbuf[i], cpm->txdma[i]);
+	}
+	cpm_muram_free(cpm->dp_addr);
+out_reg:
+	iounmap(cpm->i2c_reg);
+out_ram:
+	if ((cpm->version == 1) && (!cpm->i2c_addr))
+		iounmap(cpm->i2c_ram);
+	if (cpm->version == 2)
+		cpm_muram_free(cpm->i2c_addr);
+out_irq:
+	free_irq(cpm->irq, &cpm->adap);
+	return ret;
+}
+
+static void cpm_i2c_shutdown(struct cpm_i2c *cpm)
+{
+	int i;
+
+	/* Shut down I2C. */
+	clrbits8(&cpm->i2c_reg->i2mod, I2MOD_EN);
+
+	/* Disable interrupts */
+	out_8(&cpm->i2c_reg->i2cmr, 0);
+	out_8(&cpm->i2c_reg->i2cer, 0xff);
+
+	free_irq(cpm->irq, &cpm->adap);
+
+	/* Free all memory */
+	for (i = 0; i < CPM_MAXBD; i++) {
+		dma_free_coherent(NULL, CPM_MAX_READ + 1,
+			cpm->rxbuf[i], cpm->rxdma[i]);
+		dma_free_coherent(NULL, CPM_MAX_READ + 1,
+			cpm->txbuf[i], cpm->txdma[i]);
+	}
+
+	cpm_muram_free(cpm->dp_addr);
+	iounmap(cpm->i2c_reg);
+
+	if ((cpm->version == 1) && (!cpm->i2c_addr))
+		iounmap(cpm->i2c_ram);
+	if (cpm->version == 2)
+		cpm_muram_free(cpm->i2c_addr);
+}
+
+static int __devinit cpm_i2c_probe(struct of_device *ofdev,
+			 const struct of_device_id *match)
+{
+	int result, len;
+	struct cpm_i2c *cpm;
+	const u32 *data;
+
+	cpm = kzalloc(sizeof(struct cpm_i2c), GFP_KERNEL);
+	if (!cpm)
+		return -ENOMEM;
+
+	cpm->ofdev = ofdev;
+
+	dev_set_drvdata(&ofdev->dev, cpm);
+
+	cpm->adap = cpm_ops;
+	i2c_set_adapdata(&cpm->adap, cpm);
+	cpm->adap.dev.parent = &ofdev->dev;
+
+	result = cpm_i2c_setup(cpm);
+	if (result) {
+		dev_err(&ofdev->dev, "Unable to init hardware\n");
+		goto out_free;
+	}
+
+	/* register new adapter to i2c module... */
+
+	data = of_get_property(ofdev->node, "linux,i2c-index", &len);
+	if (data && len == 4) {
+		cpm->adap.nr = *data;
+		result = i2c_add_numbered_adapter(&cpm->adap);
+	} else
+		result = i2c_add_adapter(&cpm->adap);
+
+	if (result < 0) {
+		dev_err(&ofdev->dev, "Unable to register with I2C\n");
+		goto out_shut;
+	}
+
+	dev_dbg(&ofdev->dev, "hw routines for %s registered.\n",
+		cpm->adap.name);
+
+	/*
+	 * register OF I2C devices
+	 */
+	of_register_i2c_devices(&cpm->adap, ofdev->node);
+
+	return 0;
+out_shut:
+	cpm_i2c_shutdown(cpm);
+out_free:
+	dev_set_drvdata(&ofdev->dev, NULL);
+	kfree(cpm);
+
+	return result;
+}
+
+static int __devexit cpm_i2c_remove(struct of_device *ofdev)
+{
+	struct cpm_i2c *cpm = dev_get_drvdata(&ofdev->dev);
+
+	i2c_del_adapter(&cpm->adap);
+
+	cpm_i2c_shutdown(cpm);
+
+	dev_set_drvdata(&ofdev->dev, NULL);
+	kfree(cpm);
+
+	return 0;
+}
+
+static const struct of_device_id cpm_i2c_match[] = {
+	{
+		.compatible = "fsl,cpm1-i2c",
+	},
+	{
+		.compatible = "fsl,cpm2-i2c",
+	},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, cpm_i2c_match);
+
+static struct of_platform_driver cpm_i2c_driver = {
+	.match_table	= cpm_i2c_match,
+	.probe		= cpm_i2c_probe,
+	.remove		= __devexit_p(cpm_i2c_remove),
+	.driver		= {
+		.name	= "fsl-i2c-cpm",
+		.owner	= THIS_MODULE,
+	}
+};
+
+static int __init cpm_i2c_init(void)
+{
+	return of_register_platform_driver(&cpm_i2c_driver);
+}
+
+static void __exit cpm_i2c_exit(void)
+{
+	of_unregister_platform_driver(&cpm_i2c_driver);
+}
+
+module_init(cpm_i2c_init);
+module_exit(cpm_i2c_exit);
+
+MODULE_AUTHOR("Jochen Friedrich <jochen@scram.de>");
+MODULE_DESCRIPTION("I2C-Bus adapter routines for CPM boards");
+MODULE_LICENSE("GPL");