From: Bob Feretich <bob.feretich@prodigy.net>
To: u-boot@lists.denx.de
Subject: [U-Boot] OMAP3 Beagle Pin Mux initialization issue
Date: Fri, 25 Feb 2011 13:44:44 -0800 [thread overview]
Message-ID: <4D6822CC.406@prodigy.net> (raw)
In-Reply-To: <20110222072813.F0E6214F034@gemini.denx.de>
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
>
next prev parent reply other threads:[~2011-02-25 21:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 1:51 [U-Boot] OMAP3 Beagle Pin Mux initialization issue Bob Feretich
2011-02-22 7:28 ` Wolfgang Denk
2011-02-25 21:44 ` Bob Feretich [this message]
2011-02-25 22:23 ` Albert ARIBAUD
2011-02-25 22:24 ` Albert ARIBAUD
2011-02-26 6:25 ` Bob Feretich
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