Configuration of i2c on 8248 (cpm2) help

["Alan Bennett" <alan@akb.net>]

[-- Attachment #1: Type: text/plain, Size: 3108 bytes --]

I'm working to adapt some work by Jochen Friedrich to support CPM2 i2c
devices.  It appears I have the bus loaded and think I am configuring
it properly, but my results tell me different.  I see no messages when
I attach a i2c monitor after u-boot loads.

Can anyone spot what is going wrong based on the following information
and the resulting output?  Does this look proper for a successful
configuration of the cpm2 i2c bus?
  i2c-cpm: iip e0008afc, dp_addr 0x240
  i2c-cpm: iic_tbase 576, iic_rbase 608

Any insight would be greatly appreciated.

-Alan

My Device tree entry:
               i2c@11860 {
                   compatible = "fsl,mpc8248-i2c",
                        "fsl,cpm2-i2c",
                        "fsl,cpm-i2c";
                   reg = <11860 20 8afc 30>;
                     interrupts = <1 8>;
                   interrupt-parent = <&PIC>;
                   fsl,cpm-command = <29600000>;
               };
... and then later:
			muram@0 {
				#address-cells = <1>;
				#size-cells = <1>;
				ranges = <0 0 10000>;

				data@0 {
					compatible = "fsl,cpm-muram-data";
					reg = <80 1f80 9800 800>;
				};
			};
dump of 0xe0008afc (my immr_base=0xe0000000) at boot
    e0008afc : 02600240 10100201 00000000 00000000
    e0008b0c : 02600000 00000000 00000000 00000000
    e0008b1c : 02400000 00000000 78c7ebaf bdefeab1

Probe debug results:
  i2c-cpm: cpm_iic_init()
  i2c-cpm: iip e0008afc, dp_addr 0x240
  i2c-cpm: iic_tbase 576, iic_rbase 608

Log after modprobe:
  modprobe i2c-dev
   Jan  1 00:08:02 192 kernel: i2c /dev entries driver
   Jan  1 00:08:02 192 kernel: i2c-core: driver [dev_driver] registered
   Jan  1 00:08:02 192 kernel: i2c-dev: adapter [i2c-cpm] registered as minor 0

Log entries after trying an i2cset:  (NOTE: sometimes it hangs doing this)
  i2cset 0 0x41 0x1 0xff b
	cpm_xfer:478
	cpm_parse_message:329
	kernel: i2c-adapter i2c-0: ioctl, cmd=0x720, arg=0xbfecaa0c
	kernel: i2c-adapter i2c-0: master_xfer[0] W, addr=0x41, len2
	kernel: cpm_xfer:478
	kernel: i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 0
	kernel: cpm_parse_message:329
	kernel: i2c-adapter i2c-0: cpm_iic_write(abyte=0x82)
	kernel: i2c-adapter i2c-0: tx sc 0 bc00
	kernel: i2c-adapter i2c-0: test ready.
	kernel: i2c-adapter i2c-0: not ready.
	cpm_xfer:478
	cpm_parse_message:329
	cpm_parse_message:329
	kernel: i2c-adapter i2c-0: force_close()
	kernel: i2c-adapter i2c-0: IIC read: timeout!
	kernel: i2c-adapter i2c-0: ioctl, cmd=0x720, arg=0xbfecaa0c
	kernel: i2c-adapter i2c-0: master_xfer[0] W, addr=0x41, len1
	kernel: i2c-adapter i2c-0: master_xfer[1] R, addr=0x41, len1
	kernel: cpm_xfer:478
	kernel: i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 0
	kernel: cpm_parse_message:329
	kernel: i2c-adapter i2c-0: cpm_iic_write(abyte=0x82)
	kernel: i2c-adapter i2c-0: tx sc 0 9400
	kernel: i2c-adapter i2c-0: i2c-algo-cpm.o: R: 0 T: 1
	kernel: cpm_parse_message:329
	kernel: i2c-adapter i2c-0: cpm_iic_read(abyte=0x83)
	kernel: i2c-adapter i2c-0: test ready.
	kernel: i2c-adapter i2c-0: not ready.
	kernel: i2c-adapter i2c-0: force_close()
	kernel: i2c-adapter i2c-0: IIC read: timeout!

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: i2c-cpm.c --]
[-- Type: text/x-csrc; name=i2c-cpm.c, Size: 17704 bytes --]

/*
 * Freescale CPM1/CPM2 I2C interface.
 * Copyright (c) 1999 Dan Malek (dmalek@jlc.net).
 *
 * moved into proper i2c interface;
 * Brad Parker (brad@heeltoe.com)
 *
 * (C) 2007 Montavista Software, Inc.
 * Vitaly Bordug <vitb@kernel.crashing.org>
 *
 * RPX lite specific parts of the i2c interface
 * Update:  There actually isn't anything RPXLite-specific about this module.
 * This should work for most any CPM board.  The console messages have been
 * changed to eliminate RPXLite references.
 *
    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.
 *
 * moved into proper i2c interface; separated out platform specific
 * parts into i2c-8xx.c
 * Brad Parker (brad@heeltoe.com)
 *
 * Parts from dbox2_i2c.c (cvs.tuxbox.org)
 * (C) 2000-2001 Tmbinc, 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 Jochen Friedrich <jochen@scram.de>
 */

#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/sched.h>
#include <linux/stddef.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/time.h>
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <sysdev/fsl_soc.h>

#ifdef CONFIG_CPM2
#include <asm/cpm2.h>
#else
#include <asm/commproc.h>
#endif
/* 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

struct cpm_i2c {
	char *base;
	struct of_device *ofdev;
	struct i2c_adapter adap;
	uint dp_addr;
	int reloc;
	int irq;
	int cp_command;
#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c;
#else
	i2c8xx_t __iomem *i2c;
#endif
	iic_t __iomem *iip;
	wait_queue_head_t iic_wait;
	struct mutex iic_mutex; /* Protects I2C CPM */
	u_char *txbuf[CPM_MAXBD];
	u_char *rxbuf[CPM_MAXBD];
	u32 txdma[CPM_MAXBD];
	u32 rxdma[CPM_MAXBD];
};

static irqreturn_t cpm_iic_interrupt(int irq, void *dev_id)
{
	struct i2c_adapter *adap;
	struct cpm_i2c *cpm;
#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c;
#else
	i2c8xx_t __iomem *i2c;
#endif
	int i;

	printk ("%s:%d\n", __FUNCTION__,__LINE__);
	adap = (struct i2c_adapter *) dev_id;
	cpm = i2c_get_adapdata(adap);
	i2c = cpm->i2c;

	/* Clear interrupt.
	 */
	i = in_8(&i2c->i2c_i2cer);
	out_8(&i2c->i2c_i2cer, i);

	dev_dbg(&adap->dev, "Interrupt: %x\n", i);

	/* Get 'me going again.
	 */
	wake_up_interruptible(&cpm->iic_wait);

	return i ? IRQ_HANDLED : IRQ_NONE;
}

static void cpm_reset_iic_params(struct cpm_i2c *cpm)
{
	iic_t __iomem *iip = cpm->iip;

	/* Set up the IIC parameters in the parameter ram.
	 */
	out_be16(&iip->iic_tbase, cpm->dp_addr);
	out_be16(&iip->iic_rbase, cpm->dp_addr + sizeof(cbd_t) * CPM_MAXBD);

#ifdef CONFIG_CPM2
	out_8(&iip->iic_tfcr, CPMFCR_EB);
	out_8(&iip->iic_rfcr, CPMFCR_EB);
#else
	out_8(&iip->iic_tfcr, SMC_EB);
	out_8(&iip->iic_rfcr, SMC_EB);
#endif

	out_be16(&iip->iic_mrblr, CPM_MAX_READ);

	out_be32(&iip->iic_rstate, 0);
	out_be32(&iip->iic_rdp, 0);
	out_be16(&iip->iic_rbptr, in_be16(&iip->iic_rbase));
	out_be16(&iip->iic_rbc, 0);
	out_be32(&iip->iic_rxtmp, 0);
	out_be32(&iip->iic_tstate, 0);
	out_be32(&iip->iic_tdp, 0);
	out_be16(&iip->iic_tbptr, in_be16(&iip->iic_tbase));
	out_be16(&iip->iic_tbc, 0);
	out_be32(&iip->iic_txtmp, 0);
}

static int cpm_iic_init(struct i2c_adapter *adap)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	iic_t __iomem *iip = cpm->iip;
#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c = cpm->i2c;
#else
	i2c8xx_t __iomem *i2c = cpm->i2c;
#endif
	unsigned char brg;
	int ret, i, res;
#ifdef CONFIG_CPM2
	u32 v;
#else
	u16 v;
#endif

	printk("i2c-cpm: cpm_iic_init()\n");

	ret = 0;
	init_waitqueue_head(&cpm->iic_wait);
	mutex_init(&cpm->iic_mutex);

	/* Initialize Tx/Rx parameters.
	 */

	cpm_reset_iic_params(cpm);

	printk("i2c-cpm: iip %p, dp_addr 0x%x\n", cpm->iip, cpm->dp_addr);
	printk("i2c-cpm: iic_tbase %d, iic_rbase %d\n",
		in_be16(&iip->iic_tbase), in_be16(&iip->iic_rbase));

	v = cpm->cp_command | (CPM_CR_INIT_TRX << 8) | CPM_CR_FLG;

#ifdef CONFIG_CPM2
	out_be32(&cpmp->cp_cpcr, v);
	res = wait_event_timeout(cpm->iic_wait,
			 !(in_be32(&cpmp->cp_cpcr) & CPM_CR_FLG), HZ * 10);
#else
	out_be16(&cpmp->cp_cpcr, v);
	res = wait_event_timeout(cpm->iic_wait,
			 !(in_be16(&cpmp->cp_cpcr) & CPM_CR_FLG), HZ * 10);
#endif
	if (!res)
		return -EIO;

	/* Select an invalid address. Just make sure we don't use loopback mode
	 */
	out_8(&i2c->i2c_i2add, 0xfe);

	/* Make clock run at 60 kHz.
	 */

	brg = get_brgfreq() / (32 * 2 * 60000) - 3;
	out_8(&i2c->i2c_i2brg, brg);

	out_8(&i2c->i2c_i2mod, 0x00);
	out_8(&i2c->i2c_i2com, 0x01);	/* Master mode */

	/* Disable interrupts.
	 */
	out_8(&i2c->i2c_i2cmr, 0);
	out_8(&i2c->i2c_i2cer, 0xff);

	/* Allocate TX and RX buffers */
	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;
		}
		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;
		}
	}

	/* Install interrupt handler.
	 */
	ret = request_irq(cpm->irq, cpm_iic_interrupt, 0, "cpm_i2c", adap);
	if (ret)
		goto out;

	return 0;

out:
	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]);
	}
	return ret;
}

static int cpm_iic_shutdown(struct i2c_adapter *adap)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	int i;

#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c = cpm->i2c;
#else
	i2c8xx_t __iomem *i2c = cpm->i2c;
#endif

	/* Shut down IIC.
	 */
	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
	out_8(&i2c->i2c_i2cmr, 0);
	out_8(&i2c->i2c_i2cer, 0xff);

	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]);
	}

	free_irq(cpm->irq, adap);

	return 0;
}

#define BD_SC_NAK		(0x0004) /* NAK - did not respond */
#define BD_SC_OV		(0x0002) /* OV - receive overrun */
#define CPM_CR_CLOSE_RXBD	(0x0007)

static void force_close(struct i2c_adapter *adap)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c = cpm->i2c;
	u32 v;
#else
	i2c8xx_t __iomem *i2c = cpm->i2c;
	u16 v;
#endif

	dev_dbg(&adap->dev, "force_close()\n");
	v = cpm->cp_command | (CPM_CR_CLOSE_RXBD << 8) | CPM_CR_FLG;
#ifdef CONFIG_CPM2
	out_be32(&cpmp->cp_cpcr, v);
	wait_event_timeout(cpm->iic_wait,
			   !(in_be32(&cpmp->cp_cpcr) & CPM_CR_FLG), HZ * 5);
#else
	out_be16(&cpmp->cp_cpcr, v);
	wait_event_timeout(cpm->iic_wait,
			   !(in_be16(&cpmp->cp_cpcr) & CPM_CR_FLG), HZ * 5);
#endif

	out_8(&i2c->i2c_i2cmr, 0x00);	/* Disable all interrupts */
	out_8(&i2c->i2c_i2cer, 0xff);
}

static void cpm_parse_message(struct i2c_adapter *adap, struct i2c_msg *pmsg,
	int num, int tx, int rx)
{
	cbd_t *tbdf, *rbdf;
	u_char addr;
	u_char *tb;
	u_char *rb;
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	iic_t __iomem *iip = cpm->iip;
	int i, dscan;

	printk ("%s:%d\n", __FUNCTION__,__LINE__);
	tbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_tbase));
	rbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_rbase));

	/* This chip can't do zero length writes. However, the i2c core uses
	   them to scan for devices. The best we can do is to convert them
	   into 1 byte reads */

	dscan = ((pmsg->len == 0) && (num == 1));

	addr = pmsg->addr << 1;
	if ((pmsg->flags & I2C_M_RD) || dscan)
		addr |= 1;

	tb = cpm->txbuf[tx];
	rb = cpm->rxbuf[rx];

	/* Align read buffer */
	rb = (u_char *) (((ulong) rb + 1) & ~1);

	if ((pmsg->flags & I2C_M_RD) || dscan) {
		/* 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).
		 */
		tb[0] = addr;		/* Device address byte w/rw flag */

		dev_dbg(&adap->dev, "cpm_iic_read(abyte=0x%x)\n", addr);
		tbdf[tx].cbd_bufaddr = cpm->txdma[tx];

		if (dscan)
			tbdf[tx].cbd_datlen = 2;
		else
			tbdf[tx].cbd_datlen = pmsg->len + 1;

		tbdf[tx].cbd_sc = 0;

		if (!(pmsg->flags & I2C_M_NOSTART))
			tbdf[tx].cbd_sc |= BD_IIC_START;
		if (tx + 1 == num)
			tbdf[tx].cbd_sc |= BD_SC_LAST | BD_SC_WRAP;

		rbdf[rx].cbd_datlen = 0;
		rbdf[rx].cbd_bufaddr = ((cpm->rxdma[rx] + 1) & ~1);
		rbdf[rx].cbd_sc = BD_SC_EMPTY | BD_SC_INTRPT;

		if (rx + 1 == CPM_MAXBD)
			tbdf[rx].cbd_sc |= BD_SC_WRAP;

		eieio();
		tbdf[tx].cbd_sc |= BD_SC_READY;
	} else {
		tb[0] = addr;		/* Device address byte w/rw flag */
		for (i = 0; i < pmsg->len; i++)
			tb[i+1] = pmsg->buf[i];

		dev_dbg(&adap->dev, "cpm_iic_write(abyte=0x%x)\n", addr);

		tbdf[tx].cbd_bufaddr = cpm->txdma[tx];
		tbdf[tx].cbd_datlen = pmsg->len + 1;
		tbdf[tx].cbd_sc = 0;

		if (!(pmsg->flags & I2C_M_NOSTART))
			tbdf[tx].cbd_sc |= BD_IIC_START;

		if (tx + 1 == num)
			tbdf[tx].cbd_sc |= BD_SC_LAST | BD_SC_WRAP;

		eieio();
		tbdf[tx].cbd_sc |= BD_SC_READY | BD_SC_INTRPT;

		dev_dbg(&adap->dev, "tx sc %d %04x\n",
			tx, tbdf[tx].cbd_sc);
	}
}

static int cpm_check_message(struct i2c_adapter *adap, struct i2c_msg *pmsg,
	int tx, int rx)
{
	cbd_t *tbdf, *rbdf;
	u_char *tb;
	u_char *rb;
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
	iic_t __iomem *iip = cpm->iip;
	int i;

	printk ("%s:%d\n", __FUNCTION__,__LINE__);
	tbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_tbase));
	rbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_rbase));

	tb = cpm->txbuf[tx];
	rb = cpm->rxbuf[rx];

	/* Align read buffer */
	rb = (u_char *) (((uint) rb + 1) & ~1);

	if (pmsg->flags & I2C_M_RD) {
		dev_dbg(&adap->dev, "rx sc %04x, rx sc %04x\n",
			tbdf[tx].cbd_sc, rbdf[rx].cbd_sc);

		if (tbdf[tx].cbd_sc & BD_SC_NAK) {
			dev_dbg(&adap->dev, "IIC read; no ack\n");

			if (pmsg->flags & I2C_M_IGNORE_NAK)
				return 0;
			else
				return -EIO;
		}
		if (rbdf[rx].cbd_sc & BD_SC_EMPTY) {
			dev_dbg(&adap->dev,
				"IIC read; complete but rbuf empty\n");
			return -EREMOTEIO;
		}
		if (rbdf[rx].cbd_sc & BD_SC_OV) {
			dev_dbg(&adap->dev, "IIC read; Overrun\n");
			return -EREMOTEIO;
		}
		for (i = 0; i < pmsg->len; i++)
			pmsg->buf[i] = rb[i];
	} else {
		dev_dbg(&adap->dev, "tx sc %d %04x\n", tx, tbdf[tx].cbd_sc);

		if (tbdf[tx].cbd_sc & BD_SC_NAK) {
			dev_dbg(&adap->dev, "IIC write; no ack\n");

			if (pmsg->flags & I2C_M_IGNORE_NAK)
				return 0;
			else
				return -EIO;
		}
	}
	return 0;
}

static int cpm_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
#ifdef CONFIG_CPM2
	i2c_cpm2_t __iomem *i2c = cpm->i2c;
#else
	i2c8xx_t __iomem *i2c = cpm->i2c;
#endif
	iic_t __iomem *iip = cpm->iip;
	struct i2c_msg *pmsg, *rmsg;
	int ret, i;
	int tptr;
	int rptr;
	cbd_t *tbdf, *rbdf;

	printk ("%s:%d\n", __FUNCTION__,__LINE__);
	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;
	}

	mutex_lock(&cpm->iic_mutex);

	/* Reset to use first buffer */
	out_be16(&iip->iic_rbptr, in_be16(&iip->iic_rbase));
	out_be16(&iip->iic_tbptr, in_be16(&iip->iic_tbase));

	tbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_tbase));
	rbdf = (cbd_t *) cpm_muram_addr(in_be16(&iip->iic_rbase));

	tptr = 0;
	rptr = 0;

	while (tptr < num) {
		pmsg = &msgs[tptr];
		dev_dbg(&adap->dev, "i2c-algo-cpm.o: " "R: %d T: %d\n",
			rptr, tptr);

		cpm_parse_message(adap, pmsg, num, tptr, rptr);
		if (pmsg->flags & I2C_M_RD)
			rptr++;
		tptr++;
	}
	/* Start transfer now */
	/* Chip bug, set enable here */
	out_8(&i2c->i2c_i2cmr, 0x13);	/* Enable some interupts */
	out_8(&i2c->i2c_i2cer, 0xff);
	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | 1);	/* Enable */
	/* Begin transmission */
	out_8(&i2c->i2c_i2com, in_8(&i2c->i2c_i2com) | 0x80);

	tptr = 0;
	rptr = 0;

	while (tptr < num) {
		/* Check for outstanding messages */
		dev_dbg(&adap->dev, "test ready.\n");
		if (!(tbdf[tptr].cbd_sc & BD_SC_READY)) {
			dev_dbg(&adap->dev, "ready.\n");
			rmsg = &msgs[tptr];
			ret = cpm_check_message(adap, rmsg, tptr, rptr);
			tptr++;
			if (rmsg->flags & I2C_M_RD)
				rptr++;
			if (ret) {
				force_close(adap);
				mutex_unlock(&cpm->iic_mutex);
				return ret;
			}
		} else {
			dev_dbg(&adap->dev, "not ready.\n");
			ret = wait_event_interruptible_timeout(cpm->iic_wait,
				!(tbdf[tptr].cbd_sc & BD_SC_READY), 1 * HZ);
			if (ret == 0) {
				force_close(adap);
				dev_dbg(&adap->dev, "IIC read: timeout!\n");
				mutex_unlock(&cpm->iic_mutex);
				return -EREMOTEIO;
			}
		}
	}
#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);
	out_8(&i2c->i2c_i2mod, in_8(&i2c->i2c_i2mod) | ~1);
#endif
	mutex_unlock(&cpm->iic_mutex);
	return (num);
}

static u32 cpm_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

/* -----exported algorithm data: -------------------------------------	*/

static struct i2c_algorithm cpm_algo = {
	.master_xfer = cpm_xfer,
	.functionality = cpm_func,
};

/*
 * registering functions to load algorithms at runtime
 */
int i2c_cpm_add_bus(struct i2c_adapter *adap)
{
	int res;

	printk("i2c-cpm: hw routines for %s registered.\n", adap->name);

	/* register new adapter to i2c module... */

	adap->algo = &cpm_algo;

	res = cpm_iic_init(adap);

	if (res)
		return res;

	return i2c_add_adapter(adap);
}

int i2c_cpm_del_bus(struct i2c_adapter *adap)
{
	i2c_del_adapter(adap);

	return cpm_iic_shutdown(adap);
}

static const struct i2c_adapter cpm_ops = {
	.owner		= THIS_MODULE,
	.name		= "i2c-cpm",
	.id		= I2C_HW_MPC8XX_EPON,
	.class		= I2C_CLASS_HWMON,
};

static int i2c_cpm_setup(struct cpm_i2c *i2c)
{
	struct of_device *ofdev = i2c->ofdev;
	const u32 *data;
	int len;

	/* Pointer to Communication Processor
	 */
	i2c->irq = of_irq_to_resource(ofdev->node, 0, NULL);
	if (i2c->irq == NO_IRQ)
		return -EINVAL;

	i2c->iip = of_iomap(ofdev->node, 1);
	if (i2c->iip == NULL)
		return -EINVAL;

#ifndef CONFIG_CPM2
	/* Check for and use a microcode relocation patch.
	 */
	if (of_device_is_compatible(ofdev->node, "fsl,i2c-cpm1"))
		i2c->reloc = i2c->iip->iic_rpbase;

	/* Maybe should use ioremap instead?
	 */
	if (i2c->reloc) {
		iounmap(i2c->iip);
		i2c->iip = cpm_muram_addr(i2c->iip->iic_rpbase);
	}
#endif

	i2c->i2c = of_iomap(ofdev->node, 0);
	if (i2c->i2c == NULL)
		return -EINVAL;

	/* Allocate space for two transmit and two receive buffer
	 * descriptors in the DP ram.
	 */
	i2c->dp_addr = cpm_muram_alloc(sizeof(cbd_t) * 4, 8);
	if (!i2c->dp_addr)
		return -ENOMEM;

	data = of_get_property(ofdev->node, "fsl,cpm-command", &len);
	if (!data || len != 4)
		return -EINVAL;

	i2c->cp_command = *data;
	return 0;
}

static void i2c_cpm_release(struct cpm_i2c *i2c)
{
	if (i2c->dp_addr)
		cpm_muram_free(i2c->dp_addr);

	if (i2c->i2c)
		iounmap(i2c->i2c);

	if ((i2c->iip) && (!i2c->reloc))
		iounmap(i2c->iip);

	return;
}

static int i2c_cpm_probe(struct of_device *ofdev,
			 const struct of_device_id *match)
{
	int result;
	struct cpm_i2c *i2c;

	i2c = kzalloc(sizeof(struct cpm_i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	i2c->ofdev = ofdev;

	result = i2c_cpm_setup(i2c);
	if (result) {
		printk(KERN_ERR "i2c-cpm: Unable to register resources\n");
		goto out;
	}

	dev_set_drvdata(&ofdev->dev, i2c);

	i2c->adap = cpm_ops;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &ofdev->dev;

	result = i2c_cpm_add_bus(&i2c->adap);
	if (result < 0) {
		printk(KERN_ERR "i2c-cpm: Unable to register with I2C\n");
		goto out;
	}
	return 0;

out:
	i2c_cpm_release(i2c);
	kfree(i2c);
	return result;
}

static int i2c_cpm_remove(struct of_device *ofdev)
{
	struct cpm_i2c *i2c = dev_get_drvdata(&ofdev->dev);

	i2c_cpm_del_bus(&i2c->adap);
	dev_set_drvdata(&ofdev->dev, NULL);

	i2c_cpm_release(i2c);
	kfree(i2c);
	return 0;
}

static struct of_device_id i2c_cpm_match[] = {
	{
		.compatible = "fsl,cpm-i2c",
	},
	{},
};

MODULE_DEVICE_TABLE(of, i2c_cpm_match);

static struct of_platform_driver i2c_cpm_driver = {
	.name		= "fsl-i2c-cpm",
	.match_table	= i2c_cpm_match,
	.probe		= i2c_cpm_probe,
	.remove		= i2c_cpm_remove,
};

static int __init i2c_cpm_init(void)
{
	return of_register_platform_driver(&i2c_cpm_driver);
}

static void __exit i2c_cpm_exit(void)
{
	of_unregister_platform_driver(&i2c_cpm_driver);
}

module_init(i2c_cpm_init);
module_exit(i2c_cpm_exit);

MODULE_AUTHOR("Dan Malek <dmalek@jlc.net>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for CPM boards");
MODULE_LICENSE("GPL");