[U-Boot] OMAP3 Beagle Pin Mux initialization issue

Bob Feretich
2011-02-25T21:44:44Z

Comments inline...

On 2/21/2011 11:28 PM, Wolfgang Denk wrote:
> Dear Bob Feretich,
>
> In message<4D6316A8.4090900@prodigy.net> you wrote:
>> ... snipped...
> You are right. Can you please submit a patch? For instructions
> please see http://www.denx.de/wiki/U-Boot/Patches
The patch was submitted.
>> Also, I have observed the discussion regarding moving Pin Mux control to
>> the kernel. This is fine except for pins that need to be configured ASAP
>> after power-on. (The system could sit at the u-boot command prompt
>> indefinitely, so the kernel pin mux configuration can be significantly
>> delayed.). Please leave the hook so that u-boot customizers can
>> configure their critical pins muxes.
> Which pins would that be, for example?
For the BeagleBoard, the pins of interest are the ones routed to the
Expansion, J4, and J5 connectors. I am working with a local university.
Students are building projects that interface to these connectors.
Usually, the Linux boot delay is not a concern, but depending on the
project, sometimes the pins need to be initialized before a "set time
interval after power-on" expires (We can set the power-on reset delay to
several hundreds milliseconds, but the time must be bounded.)

By having the spot (beagle.c & beagle.h) in u-boot, where we can add our
I/O Pin Mux initialization code, we can satisfy the needs of a bounded
I/O initialization time.

Regards,
Bob Feretich
> Best regards,
>
> Wolfgang Denk
>