[U-Boot] [PATCH v2 4/4] cmd_eeprom: bug fix for i2c read/write

[Alexey Brodkin]

On Thu, 2013-11-28 at 10:47 +0800, Kuo-Jung Su wrote:
> From: Kuo-Jung Su <dantesu at faraday-tech.com>
> 
> The local pointer of address (i.e., addr) only gets
> referenced in SPI mode, and it won't be appropriate
> to pass only 1 bytes addr[1] to i2c_read/i2c_write while
> CONFIG_SYS_I2C_EEPROM_ADDR_LEN > 1.
> 
> To avoid ambiguity, this patch would drop the use of
> address pointer in I2C mode, and directly pass (dev_addr, offset)
> to i2c_read/i2c_write.

Unfortunately this patch breaks cases with
"CONFIG_SYS_I2C_EEPROM_ADDR_LEN = 1" where address is limited to 1 byte
- thus a need to pass "addr[0]" which is combined from real I2C device
address and 256-byte word offset (i.e. MSB part of offset). And
"addr[1]" only carries lower 8 bit of offset.

So I would recommend to separate 2 invocations of "i2c_{read|write}":
1) for "CONFIG_SYS_I2C_EEPROM_ADDR_LEN = 1"
2) for "CONFIG_SYS_I2C_EEPROM_ADDR_LEN > 1"

-Alexey

> 
>  common/cmd_eeprom.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/common/cmd_eeprom.c b/common/cmd_eeprom.c
> index 02539c4..0edc259 100644
> --- a/common/cmd_eeprom.c
> +++ b/common/cmd_eeprom.c
> @@ -161,7 +161,7 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt
>  #if defined(CONFIG_SPI) && !defined(CONFIG_ENV_EEPROM_IS_ON_I2C)
>  		spi_read (addr, alen, buffer, len);
>  #else
> -		if (i2c_read (addr[0], addr[1], alen-1, buffer, len) != 0)
> +		if (i2c_read (dev_addr, offset, alen-1, buffer, len) != 0)
>  			rcode = 1;
>  #endif
>  		buffer += len;
> @@ -339,7 +339,7 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
>  		/* Write is enabled ... now write eeprom value.
>  		 */
>  #endif
> -		if (i2c_write (addr[0], addr[1], alen-1, buffer, len) != 0)
> +		if (i2c_write (dev_addr, offset, alen-1, buffer, len) != 0)
>  			rcode = 1;
> 
>  #endif
> --
> 1.7.9.5
>