Re: [PATCH V3] I2C driver for IMX

[Ben Dooks <ben-linux-arm@fluff.org>]

On Tue, Apr 08, 2008 at 11:01:25AM +0300, Darius wrote:
> changes:
> 1. Removed hardcoded constants
> 2. Fixed bug in chip hardware
> 3. Added i2c device for mx1ads
> 
> Tested with mx1ads v2.0 board and LCD on I2C interface driver
> 
> Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
> ---

Hmm, this hasn't appeared on the i2c list where it should be being
reviewed before submission. Not bothered to look or snip the rest.

> diff -uprN -X linux-2.6.24.4-orig/Documentation/dontdiff linux-2.6.24.4-orig/arch/arm/mach-imx/mx1ads.c linux-2.6.24.4/arch/arm/mach-imx/mx1ads.c
> --- linux-2.6.24.4-orig/arch/arm/mach-imx/mx1ads.c	2008-01-25 00:58:37.000000000 +0200
> +++ linux-2.6.24.4/arch/arm/mach-imx/mx1ads.c	2008-04-07 15:28:17.000000000 +0300
> @@ -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
> diff -uprN -X linux-2.6.24.4-orig/Documentation/dontdiff linux-2.6.24.4-orig/drivers/i2c/busses/i2c-imx.c linux-2.6.24.4/drivers/i2c/busses/i2c-imx.c
> --- linux-2.6.24.4-orig/drivers/i2c/busses/i2c-imx.c	1970-01-01 03:00:00.000000000 +0300
> +++ linux-2.6.24.4/drivers/i2c/busses/i2c-imx.c	2008-04-08 10:43:08.000000000 +0300
> @@ -0,0 +1,611 @@
> +/*
> + *	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
> +#define I2C_IMX_ERR_RX_TIMEOUT	3
> +#define I2C_IMX_ERR_RX_NO_ACK	4
> +
> +/* Macros */
> +#define print_err(f,x...)	printk(KERN_ERR f, ##x)
> +#ifdef CONFIG_I2C_DEBUG_BUS
> +#define print_dbg(f,x...)	printk(KERN_DEBUG f, ##x)
> +#else
> +#define print_dbg(f,x...)	((void)0)
> +#endif
> +
> +/** Function prototypes ********************************************************
> +*******************************************************************************/
> +
> +static int		i2c_imx_xfer	(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num);
> +static u32          	i2c_imx_func	(struct i2c_adapter *adapter);
> +static int __init	i2c_imx_probe	(struct platform_device *pdev);
> +static int		i2c_imx_remove	(struct platform_device *pdev);
> +
> +/** 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 ***************************************
> +*******************************************************************************/
> +
> +static int i2c_imx_bus_busy (struct imx_i2c_struct *i2c_imx) {
> +
> +	unsigned int i = 0;
> +
> +	print_dbg("I2C: <i2c_imx_bus_busy>\n");
> +
> +	/* wait for bus not busy */
> +	for (i=0; i<I2C_IMX_TIME_BUSY; i++) {
> +		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");
> +	temp = readb ( i2c_imx->base + IMX_I2C_I2CR);
> +	temp |= I2CR_MSTA;
> +	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +	temp |= (I2CR_IIEN | I2CR_MTX | I2CR_TXAK);
> +	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +
> +	temp = readb (i2c_imx->base + IMX_I2C_I2CR);
> +	print_dbg("I2C: <i2c_imx_start> 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_start> 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));
> +}
> +
> +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));
> +}
> +
> +static int __init i2c_imx_set_clk (struct imx_i2c_struct *i2c_imx, unsigned int rate) {
> +
> +	unsigned int hclk, sysclk;
> +	unsigned int desired_div;
> +	int i;
> +
> +	print_dbg("I2C: <i2c_imx_set_clk>\n");
> +	sysclk = imx_get_system_clk ();
> +	hclk = imx_get_hclk();
> +	desired_div = hclk / rate;
> +	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++) {
> +		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;
> +	if (i2c_imx_acked(i2c_imx))
> +		return -I2C_IMX_ERR_RX_NO_ACK;
> +
> +	print_dbg("I2C: <i2c_imx_read> setup bus\n");
> +
> +	/* setup bus to read data */
> +	temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +	temp &= ~I2CR_MTX;
> +	if (msgs->len-1)
> +	temp &= ~I2CR_TXAK;
> +	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++) {
> +
> +		if (i2c_imx_trx_complete(i2c_imx))
> +			return -I2C_IMX_ERR_RX_TIMEOUT;
> +
> +		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);
> +		}
> +		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");
> +	    		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +	    		temp |= I2CR_RSTA;
> +	    		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +		}
> +	    	print_dbg("I2C: <i2c_imx_xfer> transfer message: %d\n", i);
> +		/* write/read data */
> +		if (!(msgs[i].flags & I2C_M_RD))
> +			err = i2c_imx_write (i2c_imx, &msgs[i]);
> +		else
> +			err = i2c_imx_read  (i2c_imx, &msgs[i]);
> +	}
> +
> +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;
> +}
> +
> +static int __init i2c_imx_probe (struct platform_device *pdev) {
> +
> +	struct imx_i2c_struct *i2c_imx;
> +	struct resource *res;
> +	void __iomem *base;
> +	int irq;
> +	int res_size;
> +	int ret;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_irq(pdev, 0);
> +	if (!res) {
> +		print_err("I2C: can't get device resources!\n");
> +		return -ENODEV;
> +	}
> +	if (irq < 0) {
> +		print_err("I2C: can't get irq number!\n");
> +		return -ENODEV;
> +	}
> +	res_size = (res->end) - (res->start) + 1;
> +	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->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_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);
> +
> +MODULE_AUTHOR("Darius Augulis");
> +MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
> +MODULE_LICENSE("GPL");
> +
> +module_param(clkfreq, uint, S_IRUGO);
> +MODULE_PARM_DESC(clkfreq, "desired IMX I2C Clock Rate in Hz");
> +
> +module_param(imxslave, uint, S_IRUGO);
> +MODULE_PARM_DESC(imxslave, "desired IMX I2C slave address");
> diff -uprN -X linux-2.6.24.4-orig/Documentation/dontdiff linux-2.6.24.4-orig/drivers/i2c/busses/Kconfig linux-2.6.24.4/drivers/i2c/busses/Kconfig
> --- linux-2.6.24.4-orig/drivers/i2c/busses/Kconfig	2008-01-25 00:58:37.000000000 +0200
> +++ linux-2.6.24.4/drivers/i2c/busses/Kconfig	2008-04-07 15:33:28.000000000 +0300
> @@ -249,6 +249,16 @@ 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
> diff -uprN -X linux-2.6.24.4-orig/Documentation/dontdiff linux-2.6.24.4-orig/drivers/i2c/busses/Makefile linux-2.6.24.4/drivers/i2c/busses/Makefile
> --- linux-2.6.24.4-orig/drivers/i2c/busses/Makefile	2008-01-25 00:58:37.000000000 +0200
> +++ linux-2.6.24.4/drivers/i2c/busses/Makefile	2008-04-07 15:33:28.000000000 +0300
> @@ -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_IXP4XX)	+= i2c-ixp4xx.o
> diff -uprN -X linux-2.6.24.4-orig/Documentation/dontdiff linux-2.6.24.4-orig/include/asm-arm/arch-imx/imx-regs.h linux-2.6.24.4/include/asm-arm/arch-imx/imx-regs.h
> --- linux-2.6.24.4-orig/include/asm-arm/arch-imx/imx-regs.h	2008-01-25 00:58:37.000000000 +0200
> +++ linux-2.6.24.4/include/asm-arm/arch-imx/imx-regs.h	2008-04-07 15:33:28.000000000 +0300
> @@ -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
> +#define I2SR_ICF	0x80
> +
> +#define I2CR_RSTA	0x04
> +#define I2CR_TXAK	0x08
> +#define I2CR_MTX	0x10
> +#define I2CR_MSTA	0x20
> +#define I2CR_IIEN	0x40
> +#define I2CR_IEN	0x80
> +
>  #endif				// _IMX_REGS_H

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-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.


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