[U-Boot] Detecting board revision that needs to be done after relocation

[Andrew E. Mileski]

On 05/28/2012 11:25 PM, Fabio Estevam wrote:
>
> I need to provide a get_board_rev() function that depends on I2C probe
> of a PMIC to decide between the board revision.
>
> I2C is only available after relocation, so what is the correct way to
> "delay" get_board_rev, so that it gets called only at a time when I2C
> is ready?

I2C is usually available earlier, as it is used to read the SPD on 
memory modules.

When I last did it, I had to change U-Boot slightly to support a second 
I2C bus, as the bus selection variable was located in flash before 
relocation (very old version of U-Boot, so may not apply still).

I've only had a problem using I2C very early in the boot sequence, like 
before the system clocks have been setup, then the solution to that was 
to just use a GPIO strapping instead for clock selection.

-- 
Andrew E. Mileski