I2C bus driver for IMX

Changes from previous version:
1. Used i2c_add_numbered_adapter() instead i2c_add_adapter()
2. Added i2c_imx->adapter.class = I2C_CLASS_HWMON;

Signed-off-by Darius Augulis <[email protected]>

---

Index: linux-2.6.26-rc1/arch/arm/mach-imx/mx1ads.c
===================================================================

arch/arm/mach-imx/mx1ads.c +21 -0

@@ -109,10 +109,31 @@ static struct platform_device imx_uart2_
 	}
 };
 
+static struct resource imx_i2c_resources[] = {
+	[0] = {
+		.start  = 0x00217000,
+		.end    = 0x00217010,
+		.flags  = IORESOURCE_MEM,
+	},
+	[1] = {
+		.start  = I2C_INT,
+		.end    = I2C_INT,
+		.flags  = IORESOURCE_IRQ,
+	},
+};
+
+static struct platform_device imx_i2c_device = {
+	.name           = "imx-i2c",
+	.id             = 0,
+	.resource       = imx_i2c_resources,
+	.num_resources  = ARRAY_SIZE(imx_i2c_resources),
+};
+
 static struct platform_device *devices[] __initdata = {
 	&cs89x0_device,
 	&imx_uart1_device,
 	&imx_uart2_device,
+	&imx_i2c_device,
 };
 
 #ifdef CONFIG_MMC_IMX

Index: linux-2.6.26-rc1/drivers/i2c/busses/i2c-imx.c
===================================================================

drivers/i2c/busses/i2c-imx.c new file +83 -0

@@ -0,0 +1,612 @@
+/*
+ *	Copyright (C) 2002 Motorola GSG-China
+ *
+ *	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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ *	USA.
+ *
+ * File Name:	i2c-imx.c
+ *
+ * Author:	Darius Augulis, Teltonika Inc.
+ *
+ * Desc.:	Implementation of I2C Adapter/Algorithm Driver
+ *		Driver for I2C Bus integrated in i.MXL, i.MX1
+ *
+ *		module parameters:
+ *				- clkfreq:
+ *					Sets the desired clock rate
+ *					The default value is 100000
+ *					Max value is 400000
+ *				- imxslave:
+ *					IMX slave I2C address in decimal format
+ *					The default value is 0xAC in hex
+ *
+ *		Derived from Motorola GSG China I2C example driver
+ *
+ *		Copyright (C) 2002 Motorola GSG-China
+ *		Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
+ *		Portions:
+ *		Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
+ *		Copyright (C) 2007 RightHand Technologies, Inc. <adyer at righthandtech.com>
+ *		Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
+ *
+ */
+
+/** Includes *******************************************************************
+*******************************************************************************/
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+
+#include <asm/arch/irqs.h>
+#include <asm/arch/hardware.h>
+#include <asm/io.h>
+
+#include <asm/arch/imx-regs.h>
+
+/** Defines ********************************************************************
+*******************************************************************************/
+
+/* This will be the driver name the kernel reports */
+#define DRIVER_NAME "imx-i2c"
+
+/* Default values of module parameters */
+#define IMX_I2C_SLAVE_ADDR	0xAC
+#define IMX_I2C_BIT_RATE	100000	/* 100kHz */
+
+/* Timeouts */
+#define I2C_IMX_TIME_BUSY	2000	/* loop count */
+#define I2C_IMX_TIME_ACK	2000	/* loop count */
+#define I2C_IMX_TIME_TRX	5	/* seconds */
+
+/* Error numbers */
+#define I2C_IMX_ERR_BUSY	1
+#define I2C_IMX_ERR_TX_TIMEOUT	2

drivers/i2c/busses/i2c-imx.c new file +54 -0

+
+/** Variables ******************************************************************
+*******************************************************************************/
+
+static unsigned int clkfreq = IMX_I2C_BIT_RATE;
+static unsigned int imxslave = IMX_I2C_SLAVE_ADDR;
+static unsigned int disable_delay = 0;			/* Dummy delay. Default value - 0 (no delay) */
+
+/*
+ * sorted list of clock divider, register value pairs
+ * taken from table 26-5, p.26-9, Freescale i.MX
+ * Integrated Portable System Processor Reference Manual
+ * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
+ *
+ * Duplicated divider values removed from list
+ */
+
+static int __initdata i2c_imx_clk_divider [50] [2] = {
+	{ 22,	0x20 },{ 24,	0x21 },{ 26,	0x22 },{ 28,	0x23 },{ 30,	0x00 },
+	{ 32,	0x24 },{ 36,	0x25 },{ 40,	0x26 },{ 42,	0x03 },{ 44,	0x27 },
+	{ 48,	0x28 },{ 52,	0x05 },{ 56,	0x29 },{ 60,	0x06 },{ 64,	0x2A },
+	{ 72,	0x2B },{ 80,	0x2C },{ 88,	0x09 },{ 96,	0x2D },{ 104,	0x0A },
+	{ 112,	0x2E },{ 128,	0x2F },{ 144,	0x0C },{ 160,	0x30 },{ 192,	0x31 },
+	{ 224,	0x32 },{ 240,	0x0F },{ 256,	0x33 },{ 288,	0x10 },{ 320,	0x34 },
+	{ 384,	0x35 },{ 448,	0x36 },{ 480,	0x13 },{ 512,	0x37 },{ 576,	0x14 },
+	{ 640,	0x38 },{ 768,	0x39 },{ 896,	0x3A },{ 960,	0x17 },{ 1024,	0x3B },
+	{ 1152,	0x18 },{ 1280,	0x3C },{ 1536,	0x3D },{ 1792,	0x3E },{ 1920,	0x1B },
+	{ 2048,	0x3F },{ 2304,	0x1C },{ 2560,	0x1D },{ 3072,	0x1E },{ 3840,	0x1F }
+};
+
+static struct platform_driver i2c_imx_driver = {
+	.probe	= i2c_imx_probe,
+	.remove	= i2c_imx_remove,
+	.driver	= {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+	}
+};
+
+static struct i2c_algorithm i2c_imx_algo = {
+	.master_xfer	= i2c_imx_xfer,
+	.functionality	= i2c_imx_func,
+};
+
+struct imx_i2c_struct {
+	struct i2c_adapter	adapter;
+	struct resource		*res;
+	void __iomem		*base;
+	int			irq;
+	wait_queue_head_t	queue;
+	unsigned long		i2csr;
+};
+
+/** Functions for IMX I2C adapter driver ***************************************

drivers/i2c/busses/i2c-imx.c new file +67 -0

+		if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & (I2SR_IBB | I2SR_IAL)))
+			return 0;
+		udelay(1);
+	}
+	print_dbg("I2C: <i2c_imx_bus_busy> I2C bus is busy!\n");
+	return -I2C_IMX_ERR_BUSY;
+}
+
+static int i2c_imx_trx_complete (struct imx_i2c_struct *i2c_imx) {
+
+	int result;
+
+	print_dbg("I2C: <i2c_imx_trx_complete>\n");
+	result = wait_event_interruptible_timeout(i2c_imx->queue,
+		(i2c_imx->i2csr & I2SR_IIF), I2C_IMX_TIME_TRX * HZ);
+
+	if (unlikely(result < 0)) {
+		print_dbg("I2C: <i2c_imx_trx_complete> result < 0!\n");
+		return result;
+	}
+	else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+		print_dbg("I2C: <i2c_imx_trx_complete> Timeout!\n");
+		return -I2C_IMX_ERR_TX_TIMEOUT;
+	}
+	print_dbg("I2C: <i2c_imx_trx_complete> TRX complete!\n");
+	i2c_imx->i2csr = 0;
+	return 0;
+}
+
+static int i2c_imx_acked (struct imx_i2c_struct *i2c_imx) {
+
+	unsigned int i = 0;
+
+	print_dbg("I2C: <i2c_imx_acked>\n");
+	for (i=0; i<I2C_IMX_TIME_ACK; i++) {
+		if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK)) {
+			print_dbg("I2C: <i2c_imx_acked> ACK received\n");
+			return 0;
+		}
+		udelay(1);
+	}
+	print_dbg("I2C: <i2c_imx_acked> No ACK!\n");
+	return -I2C_IMX_ERR_RX_NO_ACK;   /* No ACK */
+}
+
+static void i2c_imx_enable (struct imx_i2c_struct *i2c_imx) {
+	print_dbg("I2C: <i2c_imx_enable>\n");
+	writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
+}
+
+static void i2c_imx_disable (struct imx_i2c_struct *i2c_imx) {
+
+	print_dbg("I2C: <i2c_imx_disable>\n");
+
+	/* setup chip registers to defaults */
+	writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
+	writeb(0, i2c_imx->base + IMX_I2C_I2SR);
+	/* This delay caused by i.MXL hardware bug. If no (or to short) delay, no "STOP" bit will be generated */
+	udelay(disable_delay);
+	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+}
+
+static void i2c_imx_start (struct imx_i2c_struct *i2c_imx) {
+
+	unsigned int temp = 0;
+
+	print_dbg("I2C: <i2c_imx_start>\n");

drivers/i2c/busses/i2c-imx.c new file +18 -0

+static void i2c_imx_stop (struct imx_i2c_struct *i2c_imx) {
+
+	unsigned int temp = 0;
+
+	print_dbg("I2C: <i2c_imx_stop>\n");
+	temp = readb ( i2c_imx->base + IMX_I2C_I2CR);
+	temp &= ~I2CR_MSTA;
+	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+	temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+	print_dbg("I2C: <i2c_imx_stop> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+		(temp&I2CR_IEN?1:0),(temp&I2CR_IIEN?1:0),(temp&I2CR_MSTA?1:0),(temp&I2CR_MTX?1:0),
+		(temp&I2CR_TXAK?1:0),(temp&I2CR_RSTA?1:0));
+	temp = readb (i2c_imx->base + IMX_I2C_I2SR);
+	print_dbg("I2C: <i2c_imx_stop> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+		(temp&I2SR_ICF?1:0),(temp&I2SR_IAAS?1:0),(temp&I2SR_IBB?1:0),(temp&I2SR_IAL?1:0),
+		(temp&I2SR_SRW?1:0),(temp&I2SR_IIF?1:0),(temp&I2SR_RXAK?1:0));
+}
+

drivers/i2c/busses/i2c-imx.c new file +82 -0

+		if (i2c_imx_clk_divider[i][0] >= desired_div)
+			break;
+	}
+
+	/*
+	 * There dummy delay is calculated. It should be about one I2C clock period long
+	 * This delay is used in I2C bus disable function to fix chip hardware bug.
+	 */
+
+	disable_delay = (1000000 / (hclk / i2c_imx_clk_divider[i][0])) + 1;
+
+	print_dbg("I2C: <i2c_imx_set_clk> SYSCLK=%d, HCLK=%d, REQ DIV=%d\n", sysclk, hclk, desired_div);
+	print_dbg("I2C: <i2c_imx_set_clk> IFDR[IC]=0x%x, REAL DIV=%d\n", i2c_imx_clk_divider[i][1], i2c_imx_clk_divider[i][0]);
+	writeb(i2c_imx_clk_divider[i][1], i2c_imx->base + IMX_I2C_IFDR);
+	return 0;
+}
+
+static irqreturn_t i2c_imx_isr (int irq, void *dev_id) {
+
+	struct imx_i2c_struct *i2c_imx = dev_id;
+	unsigned int temp;
+
+	print_dbg("I2C: <i2c_imx_isr>\n");
+	temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+	print_dbg("I2C: <i2c_imx_isr> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+		(temp&I2CR_IEN?1:0),(temp&I2CR_IIEN?1:0),(temp&I2CR_MSTA?1:0),(temp&I2CR_MTX?1:0),
+		(temp&I2CR_TXAK?1:0),(temp&I2CR_RSTA?1:0));
+	temp = readb (i2c_imx->base + IMX_I2C_I2SR);
+	print_dbg("I2C: <i2c_imx_isr> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+		(temp&I2SR_ICF?1:0),(temp&I2SR_IAAS?1:0),(temp&I2SR_IBB?1:0),(temp&I2SR_IAL?1:0),
+		(temp&I2SR_SRW?1:0),(temp&I2SR_IIF?1:0),(temp&I2SR_RXAK?1:0));
+
+	temp = readb(i2c_imx->base + IMX_I2C_I2SR);
+	if (temp & I2SR_IIF) {
+		/* save status register */
+		i2c_imx->i2csr = temp;
+		temp &= ~I2SR_IIF;
+		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
+		wake_up_interruptible(&i2c_imx->queue);
+	}
+	return IRQ_HANDLED;
+}
+
+static int i2c_imx_write (struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) {
+
+	int i;
+
+	print_dbg("I2C: <i2c_imx_write>\n");
+	print_dbg("I2C: <i2c_imx_write> write slave address: addr=0x%x\n", (msgs->addr<<1));
+
+	/* write slave address */
+	writeb((msgs->addr<<1), i2c_imx->base + IMX_I2C_I2DR);
+	if (i2c_imx_trx_complete(i2c_imx))
+		return -I2C_IMX_ERR_TX_TIMEOUT;
+	if (i2c_imx_acked(i2c_imx))
+		return -I2C_IMX_ERR_RX_NO_ACK;
+	print_dbg("I2C: <i2c_imx_write> write data\n");
+
+	/* write data */
+	for (i = 0; i<msgs->len; i++) {
+		print_dbg("I2C: <i2c_imx_write> write byte: %d, b=0x%x\n", i, msgs->buf[i]);
+		writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
+		if (i2c_imx_trx_complete(i2c_imx))
+			return -I2C_IMX_ERR_TX_TIMEOUT;
+		if (i2c_imx_acked(i2c_imx))
+			return -I2C_IMX_ERR_RX_NO_ACK;
+	}
+	return 0;
+}
+
+static int i2c_imx_read (struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) {
+
+	int i;
+	unsigned int temp;
+
+	print_dbg("I2C: <i2c_imx_read>\n");
+	print_dbg("I2C: <i2c_imx_read> write slave address: addr=0x%x\n", (msgs->addr<<1));
+
+	/* write slave address */
+	writeb((msgs->addr<<1)|0x01, i2c_imx->base + IMX_I2C_I2DR);
+	if (i2c_imx_trx_complete(i2c_imx))
+		return -I2C_IMX_ERR_TX_TIMEOUT;

drivers/i2c/busses/i2c-imx.c new file +9 -0

+	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+
+	print_dbg("I2C: <i2c_imx_read> dummy read\n");
+	readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
+
+	print_dbg("I2C: <i2c_imx_read> read data\n");
+
+	/* read data */
+	for (i=0; i < msgs->len; i++) {

drivers/i2c/busses/i2c-imx.c new file +44 -0

+		else if (i==(msgs->len-2)) {
+			print_dbg("I2C: <i2c_imx_read> set TXAK\n");
+	    		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+	    		temp |= I2CR_TXAK;
+	    		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+		}
+	    	print_dbg("I2C: <i2c_imx_read> read byte B%d\n", i);
+		msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
+	}
+	return 0;
+}
+
+static int i2c_imx_xfer (struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) {
+
+	int i, temp;
+	int err = 0;
+	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
+
+	print_dbg("I2C: <i2c_imx_xfer>\n");
+
+	/* Check or i2c bus is not busy */
+	err = i2c_imx_bus_busy(i2c_imx);
+	if (err)
+		goto fail0;
+
+	/* Enable i2c */
+	i2c_imx_enable(i2c_imx);
+
+	/* Start I2C transfer */
+	i2c_imx_start (i2c_imx);
+
+	temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+	print_dbg("I2C: <i2c_imx_xfer> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+		(temp&I2CR_IEN?1:0),(temp&I2CR_IIEN?1:0),(temp&I2CR_MSTA?1:0),(temp&I2CR_MTX?1:0),
+		(temp&I2CR_TXAK?1:0),(temp&I2CR_RSTA?1:0));
+	temp = readb (i2c_imx->base + IMX_I2C_I2SR);
+	print_dbg("I2C: <i2c_imx_xfer> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+		(temp&I2SR_ICF?1:0),(temp&I2SR_IAAS?1:0),(temp&I2SR_IBB?1:0),(temp&I2SR_IAL?1:0),
+		(temp&I2SR_SRW?1:0),(temp&I2SR_IIF?1:0),(temp&I2SR_RXAK?1:0));
+
+	/* read/write data */
+	for (i=0; i<num; i++) {
+		if (i) {
+			print_dbg("I2C: <i2c_imx_read> repeated start\n");

drivers/i2c/busses/i2c-imx.c new file +20 -0

+	}
+
+fail0:
+	/* Stop bus */
+	i2c_imx_stop (i2c_imx);
+	/* disable i2c bus */
+	i2c_imx_disable (i2c_imx);
+	print_dbg("I2C: <i2c_imx_xfer> exit with: %s: %d\n", (err < 0)?"error":"success msg", (err < 0)?err:num);
+	return (err < 0) ? err : num;
+}
+
+static u32 i2c_imx_func (struct i2c_adapter *adapter) {
+	return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL);
+}
+
+static int __init i2c_imx_probe (struct platform_device *pdev) {
+
+	struct imx_i2c_struct *i2c_imx;
+	struct resource *res;
+	void __iomem *base;

drivers/i2c/busses/i2c-imx.c new file +119 -0

+	if (!request_mem_region(res->start, res_size, res->name)) {
+		print_err("I2C: can't allocate %d bytes at %d address!\n", res_size, res->start);
+		return -ENOMEM;
+	}
+	base = ioremap (res->start, res_size);
+	if (!base) {
+	    	print_err("I2C: ioremap failed!\n");
+		ret = -EIO;
+		goto fail0;
+	}
+	i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
+	if (!i2c_imx) {
+		print_err("I2C: can't allocate interface!\n");
+		ret = -ENOMEM;
+		goto fail1;
+	}
+
+	/* Setup i2c_imx driver structure */
+	strcpy (i2c_imx->adapter.name, pdev->name);
+	i2c_imx->adapter.owner		= THIS_MODULE;
+	i2c_imx->adapter.algo		= &i2c_imx_algo;
+	i2c_imx->adapter.dev.parent	= &pdev->dev;
+	i2c_imx->adapter.class 		= I2C_CLASS_HWMON;
+	i2c_imx->adapter.nr 		= pdev->id;
+	i2c_imx->irq			= irq;
+	i2c_imx->base			= base;
+	i2c_imx->res			= res;
+
+	init_waitqueue_head(&i2c_imx->queue);
+
+	/* Set up platform driver data */
+	platform_set_drvdata(pdev, i2c_imx);
+
+	ret = request_irq(i2c_imx->irq, i2c_imx_isr, IRQF_DISABLED, pdev->name, i2c_imx);
+	if (ret) {
+		print_err("I2C: %s: cannot claim irq %d !\n", i2c_imx->adapter.dev.bus_id, i2c_imx->irq);
+		goto fail2;
+	}
+
+	/* Set up clock divider */
+	i2c_imx_set_clk(i2c_imx, clkfreq);
+
+	/* Set up IMX I2C slave address */
+	writeb(imxslave, i2c_imx->base + IMX_I2C_IADR);
+
+	/* Set up I/O pins for I2C*/
+	imx_gpio_mode(PA15_PF_I2C_SDA);
+	imx_gpio_mode(PA16_PF_I2C_SCL);
+
+	/* Set up chip registers to defaults */
+	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+	writeb(0, i2c_imx->base + IMX_I2C_I2SR);
+
+	/* Set up adapter data */
+	i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
+
+	/* Add I2C adapter */
+	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
+	if (ret < 0) {
+		print_err("I2C: %s: registration failed\n", i2c_imx->adapter.dev.bus_id);
+		goto fail3;
+	}
+
+	print_dbg("I2C: %s: claimed irq %d\n", i2c_imx->adapter.dev.bus_id, i2c_imx->irq);
+	print_dbg("I2C: %s: device resources from 0x%x to 0x%x\n", i2c_imx->adapter.dev.bus_id, i2c_imx->res->start, i2c_imx->res->end);
+	print_dbg("I2C: %s: allocated %d bytes at 0x%x \n", i2c_imx->adapter.dev.bus_id, res_size, i2c_imx->res->start);
+	print_dbg("I2C: %s: adapter name: \"%s\"\n", i2c_imx->adapter.dev.bus_id, i2c_imx->adapter.name);
+	print_dbg("I2C: adapter \"%s\" associated with driver \"%s\"\n", i2c_imx->adapter.dev.bus_id, i2c_imx_driver.driver.name);
+	print_dbg("I2C: %s: IMX I2C adapter registered\n", i2c_imx->adapter.dev.bus_id);
+	return 0;   /* Return OK */
+
+fail3:
+	free_irq(i2c_imx->irq, i2c_imx);
+fail2:
+	platform_set_drvdata(pdev, NULL);
+	kfree(i2c_imx);
+fail1:
+	iounmap(i2c_imx->base);
+fail0:
+	release_mem_region(res->start, res_size);
+	return ret; /* Return error number */
+}
+
+static int i2c_imx_remove (struct platform_device *pdev) {
+
+	struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
+
+	/* remove adapter */
+	print_dbg("I2C: adapter removed\n");
+	i2c_del_adapter(&i2c_imx->adapter);
+	platform_set_drvdata(pdev, NULL);
+
+	/* free interrupt */
+	free_irq(i2c_imx->irq, i2c_imx);
+
+	/* setup chip registers to defaults */
+	writeb(0, i2c_imx->base + IMX_I2C_IADR);
+	writeb(0, i2c_imx->base + IMX_I2C_IFDR);
+	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+	writeb(0, i2c_imx->base + IMX_I2C_I2SR);
+
+	/* release memory */
+	release_mem_region(i2c_imx->res->start, (i2c_imx->res->end - i2c_imx->res->start) + 1);
+	iounmap(i2c_imx->base);
+	kfree(i2c_imx);
+	return 0;
+}
+
+static int __init i2c_adap_imx_init (void) {
+	return platform_driver_register(&i2c_imx_driver);
+}
+
+static void __exit i2c_adap_imx_exit (void) {
+	platform_driver_unregister(&i2c_imx_driver);
+	return;
+}
+
+module_init(i2c_adap_imx_init);
+module_exit(i2c_adap_imx_exit);

Index: linux-2.6.26-rc1/drivers/i2c/busses/Kconfig
===================================================================

drivers/i2c/busses/Kconfig +10 -0

@@ -257,6 +257,16 @@ config I2C_IBM_IIC
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-ibm_iic.
 
+config I2C_IMX
+	tristate "IMX I2C interface"
+	depends on ARCH_IMX
+	help
+	  Say Y here if you want to use the IIC bus controller on
+	  the Freescale i.MXL and i.MX1 processors.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-imx.
+
 config I2C_IOP3XX
 	tristate "Intel IOPx3xx and IXP4xx on-chip I2C interface"
 	depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IXP4XX || ARCH_IOP13XX

Index: linux-2.6.26-rc1/drivers/i2c/busses/Makefile
===================================================================

drivers/i2c/busses/Makefile +1 -0

@@ -18,6 +18,7 @@ obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_I801)		+= i2c-i801.o
 obj-$(CONFIG_I2C_I810)		+= i2c-i810.o
 obj-$(CONFIG_I2C_IBM_IIC)	+= i2c-ibm_iic.o
+obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
 obj-$(CONFIG_I2C_IXP2000)	+= i2c-ixp2000.o
 obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o

Index: linux-2.6.26-rc1/include/asm-arm/arch-imx/imx-regs.h
===================================================================

include/asm-arm/arch-imx/imx-regs.h +16 -0

@@ -479,4 +479,29 @@
 #define LCDISR_EOF     (1<<1)
 #define LCDISR_BOF     (1<<0)
 
+/*
+ * I2C
+ */
+
+#define IMX_I2C_IADR	0x00	/* i2c slave address */
+#define IMX_I2C_IFDR	0x04	/* i2c frequency divider */
+#define IMX_I2C_I2CR	0x08	/* i2c control */
+#define IMX_I2C_I2SR	0x0C	/* i2c status */
+#define IMX_I2C_I2DR	0x10	/* i2c transfer data */
+
+#define I2SR_RXAK	0x01
+#define I2SR_IIF	0x02
+#define I2SR_SRW	0x04
+#define I2SR_IAL	0x10
+#define I2SR_IBB	0x20
+#define I2SR_IAAS	0x40

do you really need to invent a new debugging type here? why not use dev_dbg() to do the work, and ensure that your debug output is also tagged with the device-id of the device it is being done for.

this is wrapping, how about not indenting. I do not belive yoy need to use __init in the forward decleration of these functions.

drivers/i2c/busses/i2c-imx.c line 165

Quoted 1 line

drivers/i2c/busses/i2c-imx.c new file +1 -0

+	for (i=0; i<I2C_IMX_TIME_BUSY; i++) {

spacing in here: for (i = 0; i < I2C_IMX_TIME_BUSY; i++)

spacing in here, (temp & I2CR_IEN) ? 1 : 0

given the amount of times these get used, an inline function would have made it easier to write this.

drivers/i2c/busses/i2c-imx.c line 276

Quoted 5 lines

drivers/i2c/busses/i2c-imx.c new file +5 -0

+
+	print_dbg("I2C: <i2c_imx_set_clk>\n");
+	sysclk = imx_get_system_clk ();
+	hclk = imx_get_hclk();
+	desired_div = hclk / rate;

really, is there not a decent clk_xxx() API support to get the system and HCLK values?

drivers/i2c/busses/i2c-imx.c line 283

Quoted 7 lines

drivers/i2c/busses/i2c-imx.c new file +7 -0

+	if (desired_div & 0x01)
+		desired_div++;
+	if (desired_div < 22)
+		desired_div = 22;
+	if (desired_div > 3840)
+		desired_div = 3840;
+	for (i=0; i<50; i++) {

ARRAY_SIZE() is applicable here.

drivers/i2c/busses/i2c-imx.c line 375

Quoted 6 lines

drivers/i2c/busses/i2c-imx.c new file +6 -0

+
+	/* setup bus to read data */
+	temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+	temp &= ~I2CR_MTX;
+	if (msgs->len-1)
+	temp &= ~I2CR_TXAK;

indentation here.. completely unreadable.

drivers/i2c/busses/i2c-imx.c line 394

Quoted 6 lines

drivers/i2c/busses/i2c-imx.c new file +6 -0

+		if (i==(msgs->len-1)) {
+			print_dbg("I2C: <i2c_imx_read> clear MSTA\n");
+	    		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+	    		temp &= ~I2CR_MSTA;
+	    		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+		}

no line break needed

keeping a pointer to the current message would have been more efficient here, ie:

	ptr = msgs;
	for (i = 0; i < num; i++, ptr++) {
		....
	}

use dev_err() here, and some line spacing wouldn't go amiss either.

drivers/i2c/busses/i2c-imx.c line 483

Quoted 1 line

drivers/i2c/busses/i2c-imx.c new file +1 -0

+	res_size = (res->end) - (res->start) + 1;

are the brackets necessary?

you've miseed the MODULE_ALIAS() for the platform device.

yeurk, put these in a seperate header file, or place them near the driver. The "One Big Register File" is horrible, and hopefully is going the same way as the Dodo.

Quoted 2 lines

drivers/i2c/busses/i2c-imx.c line 165

Quoted 1 line

drivers/i2c/busses/i2c-imx.c new file +1 -0

+	for (i=0; i<I2C_IMX_TIME_BUSY; i++) {

spacing in here: for (i = 0; i < I2C_IMX_TIME_BUSY; i++)

what is there wrong with spacing?

Quoted 1 line

spacing in here, (temp & I2CR_IEN) ? 1 : 0

I really should add dummy spaces...?

Quoted 2 lines

yeurk, put these in a seperate header file, or place them near the driver. The "One Big Register File" is horrible, and hopefully

seems, everybody has her own opinion. Is there somebody one, who can say how that should be? Because I have already two times changed that... I'm only beginner, so ambiguous comments are very unwanted... As I know, Jean Delvare is responsible for I2C drivers. So, his word is welcome:)

seems, everybody has her own opinion. Is there somebody one, who can say how that should be? Because I have already two times changed that... I'm only beginner, so ambiguous comments are very unwanted... As I know, Jean Delvare is responsible for I2C drivers. So, his word is welcome:)

All Ben comments accepted, coding style fixed, checked with checkpatch.pl. Only 5 warnings about line over 80 characters.
Tested on MXLADS V2.0 board with 2.6.26-rc1 kernel.

Also lets you do some
sort of macro:
#define dprintk(dev, fmt, args...) dev_dbg(dev, "<%s> " fmt, __func__, ## args)
or
#define dprintk(fmt, args...) dev_dbg(&i2c_imx->adapter.dev, "<%s> " fmt, __func__, ## args)