[U-Boot] [PATCH 03/24] mxc_i2c: create tx_byte function

[Troy Kisky <troy.kisky@boundarydevices.com>]

On 6/22/2012 9:58 AM, Marek Vasut wrote:
> Dear Troy Kisky,
>
>> Use tx_byte function instead of having 3 copies
>> of the code.
>>
>> Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
>> ---
>>   drivers/i2c/mxc_i2c.c |   72
>> +++++++++++++++---------------------------------- 1 file changed, 21
>> insertions(+), 51 deletions(-)
>>
>> diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
>> index 0b46c9c..0fd508a 100644
>> --- a/drivers/i2c/mxc_i2c.c
>> +++ b/drivers/i2c/mxc_i2c.c
>> @@ -33,6 +33,7 @@
>>   #include <common.h>
>>   #include <asm/arch/clock.h>
>>   #include <asm/arch/imx-regs.h>
>> +#include <asm/errno.h>
>>   #include <asm/io.h>
>>   #include <i2c.h>
>>
>> @@ -207,17 +208,21 @@ int i2c_imx_trx_complete(void)
>>   		udelay(1);
>>   	}
>>
>> -	return 1;
>> +	return -ETIMEDOUT;
>>   }
>>
>> -/*
>> - * Check if the transaction was ACKed
>> - */
>> -int i2c_imx_acked(void)
>> +static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte)
>>   {
>> -	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
>> +	unsigned ret;
>>
>> -	return readb(&i2c_regs->i2sr) & I2SR_RX_NO_AK;
>> +	writeb(byte, &i2c_regs->i2dr);
>> +	ret = i2c_imx_trx_complete();
>> +	if (ret < 0)
>> +		return ret;
>> +	ret = readb(&i2c_regs->i2sr);
>> +	if (ret & I2SR_RX_NO_AK)
>> +		return -ENODEV;
>> +	return 0;
>>   }
>>
>>   /*
>> @@ -271,30 +276,6 @@ void i2c_imx_stop(void)
>>   }
>>
>>   /*
>> - * Set chip address and access mode
>> - *
>> - * read = 1: READ access
>> - * read = 0: WRITE access
>> - */
>> -int i2c_imx_set_chip_addr(uchar chip, int read)
>> -{
>> -	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
>> -	int ret;
>> -
>> -	writeb((chip << 1) | read, &i2c_regs->i2dr);
>> -
>> -	ret = i2c_imx_trx_complete();
>> -	if (ret)
>> -		return ret;
>> -
>> -	ret = i2c_imx_acked();
>> -	if (ret)
>> -		return ret;
>> -
>> -	return ret;
>> -}
>> -
>> -/*
>>    * Write register address
>>    */
>>   int i2c_imx_set_reg_addr(uint addr, int alen)
>> @@ -303,14 +284,8 @@ int i2c_imx_set_reg_addr(uint addr, int alen)
>>   	int ret = 0;
>>
>>   	while (alen--) {
>> -		writeb((addr >> (alen * 8)) & 0xff, &i2c_regs->i2dr);
>> -
>> -		ret = i2c_imx_trx_complete();
>> -		if (ret)
>> -			break;
>> -
>> -		ret = i2c_imx_acked();
>> -		if (ret)
>> +		ret =  tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff);
>> +		if (ret < 0)
>>   			break;
>>   	}
>>
>> @@ -322,13 +297,14 @@ int i2c_imx_set_reg_addr(uint addr, int alen)
>>    */
>>   int i2c_probe(uchar chip)
>>   {
>> +	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
>>   	int ret;
>>
>>   	ret = i2c_imx_start();
>>   	if (ret)
>>   		return ret;
>>
>> -	ret = i2c_imx_set_chip_addr(chip, 0);
>> +	ret = tx_byte(i2c_regs, chip << 1);
>>   	if (ret)
>>   		return ret;
>>
>> @@ -352,7 +328,7 @@ int i2c_read(uchar chip, uint addr, int alen, uchar
>> *buf, int len) return ret;
>>
>>   	/* write slave address */
>> -	ret = i2c_imx_set_chip_addr(chip, 0);
>> +	ret = tx_byte(i2c_regs, chip << 1);
>>   	if (ret)
>>   		return ret;
>>
>> @@ -364,7 +340,7 @@ int i2c_read(uchar chip, uint addr, int alen, uchar
>> *buf, int len) temp |= I2CR_RSTA;
>>   	writeb(temp, &i2c_regs->i2cr);
>>
>> -	ret = i2c_imx_set_chip_addr(chip, 1);
>> +	ret = tx_byte(i2c_regs, (chip << 1) | 1);
> Isn't this | 1 and | 0 stuff #define-d somewhere? I think there was
> I2C_READ_SOMETHING in i2c.h and I2C_WRITE_SOMETHING...

I could not find what you are referring to. All drivers in i2c seem to 
use "| 1"
"| dir" and I2C_READ_BIT, I2C_WRITE_BIT

#define I2C_READ_BIT  1
#define I2C_WRITE_BIT 0

in fsl_i2c.c


But these are not defined in a header file.

>>   	if (ret)
>>   		return ret;
>>
> Otherwise
> Acked-by: Marek Vasut <marex@denx.de>
>
> Best regards,
> Marek Vasut
>