Re: [PATCH V9] I2C driver for IMX

[Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>]

On Fri, Jul 11, 2008 at 09:29:29AM +0300, Darius wrote:
> Changes from V8 version:
>
> - Error numbers replaced to standard numbers from errno.h
> - Enable/Start and Disable/Stop functions merged into two Start and Stop functions
> - Removed all unused info about slave mode
> - Removed unused includes
>
> Can somebody review functional part of this I2C driver? Because all other part is already acked by ARM Linux kernel guys.
>
> Signed-off-by: Darius Augulis <augulis.darius-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---

I'll need a reasonable header/description in place of the
changelog before this can be merged.

> Index: linux-2.6.26-rc9/arch/arm/mach-imx/mx1ads.c
> ===================================================================
> --- linux-2.6.26-rc9.orig/arch/arm/mach-imx/mx1ads.c
> +++ linux-2.6.26-rc9/arch/arm/mach-imx/mx1ads.c
> @@ -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

I'm not going to step on RMK's toes unless he gives me explicit
acknowledgement to merge arch/arm/mach-imx/mx1ads.c 

> Index: linux-2.6.26-rc9/drivers/i2c/busses/i2c-imx.c
> ===================================================================
> --- /dev/null
> +++ linux-2.6.26-rc9/drivers/i2c/busses/i2c-imx.c
> @@ -0,0 +1,602 @@
> +/*
> + *	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.
> + *
> + * 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
> + *
> + *	Derived from Motorola GSG China I2C example driver
> + *
> + *	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. <adyeratrighthandtech.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/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <asm/arch/irqs.h>
> +#include <asm/arch/hardware.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_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 */
> +
> +/* IMX I2C registers */
> +#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 */
> +
> +/* Bits of IMX I2C registers */
> +#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
> +
> +/** Variables ******************************************************************
> +*******************************************************************************/
> +
> +static unsigned int clkfreq = IMX_I2C_BIT_RATE;
> +static unsigned int disable_delay;	/* Dummy 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 u16 __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 }
> +};
> +
> +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;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +
> +	/* 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);
> +	}
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> I2C bus is busy!\n", __func__);
> +	return -EBUSY;
> +}

out of interest, do you really want to be busy-looping here and
not allowing the task to sleep?

> +
> +static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
> +{
> +	int result;
> +
> +	result = wait_event_interruptible_timeout(i2c_imx->queue,
> +		(i2c_imx->i2csr & I2SR_IIF), I2C_IMX_TIME_TRX * HZ);
> +
> +	if (unlikely(result < 0)) {
> +		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0!\n", __func__);
> +		return result;
> +	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
> +		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout!\n", __func__);
> +		return -ETIMEDOUT;
> +	}

debugging or error messages really shouldn't have ! marks after them.

> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete!\n", __func__);
> +	i2c_imx->i2csr = 0;
> +	return 0;
> +}
> +
> +static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int i = 0;
> +
> +	for (i = 0; i < I2C_IMX_TIME_ACK; i++) {
> +		if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK)) {
> +			dev_dbg(&i2c_imx->adapter.dev,
> +				"<%s> ACK received\n", __func__);
> +			return 0;
> +		}
> +		udelay(1);
> +	}
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK!\n", __func__);
> +	return -EIO;   /* No ACK */
> +}
> +
> +static void i2c_imx_start(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int temp = 0;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +
> +	/* Enable I2C controller */
> +	writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
> +	/* Start I2C transaction */
> +	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);
> +}
> +
> +static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
> +{
> +	unsigned int temp = 0;
> +
> +	/* Stop I2C transaction */
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +	temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +	temp &= ~I2CR_MSTA;
> +	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +	/* 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 an i.MXL hardware bug.
> +	 * If no (or too short) delay, no "STOP" bit will be generated.
> +	 */
> +	udelay(disable_delay);
> +	/* Disable I2C controller */
> +	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
> +}
> +
> +static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, unsigned int rate)
> +{
> +	unsigned int hclk;
> +	unsigned int desired_div;
> +	int i;
> +
> +	/* Divider value calculation */
> +	hclk = imx_get_hclk();
> +	desired_div = (hclk + rate - 1) / rate;
> +	if (desired_div < i2c_imx_clk_divider[0][0])
> +		i = 0;
> +	else if (desired_div > i2c_imx_clk_divider[ARRAY_SIZE(i2c_imx_clk_divider)-1][0])
> +		i = ARRAY_SIZE(i2c_imx_clk_divider) - 1;
> +	else
> +		for (i = 0; i2c_imx_clk_divider[i][0] < desired_div; i++);
> +
> +	/* Write divider value to register */
> +	writeb(i2c_imx_clk_divider[i][1], i2c_imx->base + IMX_I2C_IFDR);
> +
> +	/*
> +	 * 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 = (500000U * i2c_imx_clk_divider[i][0]
> +		+ (hclk / 2) - 1) / (hclk / 2);
> +
> +	/* dev_dbg() can't be used, because adapter is not yet registered */
> +#ifdef CONFIG_I2C_DEBUG_BUS
> +	unsigned int sysclk;
> +	sysclk = imx_get_system_clk();
> +	printk(KERN_DEBUG "I2C: <%s> SYSCLK=%d, HCLK=%d, REQ DIV=%d\n",
> +		__func__, sysclk, hclk, desired_div);
> +	printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n", __func__,
> +		i2c_imx_clk_divider[i][1], i2c_imx_clk_divider[i][0]);
> +#endif
> +}
> +
> +static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
> +{
> +	struct imx_i2c_struct *i2c_imx = dev_id;
> +	unsigned int temp;
> +
> +	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, result;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
> +		__func__, (msgs->addr));
> +
> +	/* write slave address */
> +	writeb((msgs->addr), i2c_imx->base + IMX_I2C_I2DR);
> +	result = i2c_imx_trx_complete(i2c_imx);
> +	if (result)
> +		return result;
> +	result = i2c_imx_acked(i2c_imx);
> +	if (result)
> +		return result;
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
> +
> +	/* write data */
> +	for (i = 0; i < msgs->len; i++) {
> +		dev_dbg(&i2c_imx->adapter.dev,
> +			"<%s> write byte: B%d=0x%X\n", __func__,
> +			i, msgs->buf[i]);
> +		writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
> +		result = i2c_imx_trx_complete(i2c_imx);
> +		if (result)
> +			return result;
> +		result = i2c_imx_acked(i2c_imx);
> +		if (result)
> +			return result;
> +	}
> +	return 0;
> +}
> +
> +static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
> +{
> +	int i, result;
> +	unsigned int temp;
> +
> +	dev_dbg(&i2c_imx->adapter.dev,
> +		"<%s> write slave address: addr=0x%x\n", __func__,
> +		((msgs->addr)|0x01));
> +
> +	/* write slave address */
> +	writeb(((msgs->addr)|0x01), i2c_imx->base + IMX_I2C_I2DR);

you don't need the () around msgs->addr, or ((msgs->addr)|0x01

	writeb( msgs->addr | 0x01, i2c_imx->base + IMX_I2C_I2DR);

is acceptable.

> +	result = i2c_imx_trx_complete(i2c_imx);
> +	if (result)
> +		return result;
> +	result = i2c_imx_acked(i2c_imx);
> +	if (result)
> +		return result;
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
> +
> +	/* 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);
> +	readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
> +
> +	/* read data */
> +	for (i = 0; i < msgs->len; i++) {
> +		result = i2c_imx_trx_complete(i2c_imx);
> +		if (result)
> +			return result;
> +		if (i == (msgs->len-1)) {
> +			dev_dbg(&i2c_imx->adapter.dev,
> +				"<%s> clear MSTA\n", __func__);
> +			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)) {

again, spaces between items... many of these about.

		if (i == (msgs->len - 2)) {

> +			dev_dbg(&i2c_imx->adapter.dev,
> +				"<%s> set TXAK\n", __func__);
> +			temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +			temp |= I2CR_TXAK;
> +			writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +		}
> +		msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
> +		dev_dbg(&i2c_imx->adapter.dev,
> +			"<%s> read byte: B%d=0x%X\n", __func__,
> +			i, msgs->buf[i]);
> +	}
> +	return 0;
> +}
> +
> +static int i2c_imx_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
> +{
> +	unsigned int i, temp;
> +	int result;
> +	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
> +
> +	/* Check or i2c bus is not busy */
> +	result = i2c_imx_bus_busy(i2c_imx);
> +	if (result)
> +		goto fail0;
> +
> +	/* Start I2C transfer */
> +	i2c_imx_start(i2c_imx);
> +
> +	/* read/write data */
> +	for (i = 0; i < num; i++) {
> +		if (i) {
> +			dev_dbg(&i2c_imx->adapter.dev,
> +				"<%s> repeated start\n", __func__);
> +			temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +			temp |= I2CR_RSTA;
> +			writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> +		}
> +		dev_dbg(&i2c_imx->adapter.dev,
> +			"<%s> transfer message: %d\n", __func__, i);
> +		/* write/read data */
> +#ifdef CONFIG_I2C_DEBUG_BUS
> +		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> +		dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
> +			"MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
> +			(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));

			     ^ spaces in here please.

> +		temp = readb(i2c_imx->base + IMX_I2C_I2SR);
> +		dev_dbg(&i2c_imx->adapter.dev,
> +			"<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
> +			"IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
> +			(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));
> +#endif
> +		if (msgs[i].flags & I2C_M_RD)
> +			result = i2c_imx_read(i2c_imx, &msgs[i]);
> +		else
> +			result = i2c_imx_write(i2c_imx, &msgs[i]);
> +	}
> +
> +fail0:
> +	/* Stop I2C transfer */
> +	i2c_imx_stop(i2c_imx);
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
> +		(result < 0) ? "error" : "success msg", (result < 0) ? result : num);

line is too long.

> +	return (result < 0) ? result : num;
> +}
> +
> +static u32 i2c_imx_func(struct i2c_adapter *adapter)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static struct i2c_algorithm i2c_imx_algo = {
> +	.master_xfer	= i2c_imx_xfer,
> +	.functionality	= i2c_imx_func,
> +};
> +
> +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;
> +
> +	dev_dbg(&pdev->dev, "<%s>\n", __func__);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_irq(pdev, 0);
> +	if (!res) {
> +		dev_err(&pdev->dev, "can't get device resources!\n");
> +		return -ENODEV;
> +	}
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "can't get irq number!\n");
> +		return -ENODEV;
> +	}
> +	res_size = (res->end) - (res->start) + 1;

why with the () again?

> +	if (!request_mem_region(res->start, res_size, res->name)) {
> +		dev_err(&pdev->dev, "can't allocate %d bytes at %d address!\n",
> +			res_size, res->start);
> +		return -ENOMEM;
> +	}
> +	base = ioremap(res->start, res_size);
> +	if (!base) {
> +		dev_err(&pdev->dev, "ioremap failed!\n");
> +		ret = -EIO;
> +		goto fail0;
> +	}
> +	i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
> +	if (!i2c_imx) {
> +		dev_err(&pdev->dev, "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) {
> +		dev_err(&pdev->dev, "cannot claim irq %d !\n", i2c_imx->irq);
> +		goto fail2;
> +	}
> +
> +	/* Set up adapter data */
> +	i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
> +
> +	/* Set up clock divider */
> +	i2c_imx_set_clk(i2c_imx, clkfreq);
> +
> +	/* 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);
> +
> +
> +	/* Add I2C adapter */
> +	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "registration failed\n");
> +		goto fail3;
> +	}
> +
> +	dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq);
> +	dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
> +		i2c_imx->res->start, i2c_imx->res->end);
> +	dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n",
> +		res_size, i2c_imx->res->start);
> +	dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
> +		i2c_imx->adapter.name);
> +	dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
> +
> +	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 __devexit i2c_imx_remove(struct platform_device *pdev)
> +{
> +	struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
> +
> +	/* remove adapter */
> +	dev_dbg(&i2c_imx->adapter.dev, "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 struct platform_driver i2c_imx_driver = {
> +	.probe		= i2c_imx_probe,
> +	.remove		= __devexit_p(i2c_imx_remove),
> +	.driver	= {
> +		.name	= DRIVER_NAME,
> +		.owner	= THIS_MODULE,
> +	}
> +};
> +
> +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_param(clkfreq, uint, S_IRUGO);
> +MODULE_PARM_DESC(clkfreq, "desired IMX I2C Clock Rate in Hz");
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Darius Augulis");
> +MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> Index: linux-2.6.26-rc9/drivers/i2c/busses/Kconfig
> ===================================================================
> --- linux-2.6.26-rc9.orig/drivers/i2c/busses/Kconfig
> +++ linux-2.6.26-rc9/drivers/i2c/busses/Kconfig
> @@ -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-rc9/drivers/i2c/busses/Makefile
> ===================================================================
> --- linux-2.6.26-rc9.orig/drivers/i2c/busses/Makefile
> +++ linux-2.6.26-rc9/drivers/i2c/busses/Makefile
> @@ -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

> _______________________________________________
> i2c mailing list
> i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org
> http://lists.lm-sensors.org/mailman/listinfo/i2c

My only comments are:

1) over-use of () where they are not needed
2) you need to insert spaces in expressions.

-- 
Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

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