[U-Boot] [PATCH] serial: add environment control for SERIAL_MULTI

[Joe Hershberger]

Hi Allen,

On Thu, Oct 25, 2012 at 5:50 PM, Allen Martin <amartin at nvidia.com> wrote:
> On Thu, Oct 25, 2012 at 03:46:01PM -0700, Joe Hershberger wrote:
>> Hi Stephen,
>>
>> On Thu, Oct 25, 2012 at 5:43 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
>> > On 10/25/2012 03:59 PM, Allen Martin wrote:
>> >> Add a new special environment variable "serial" that allows selection
>> >> of serial device when CONFIG_SERIAL_MULTI is defined.  This replaces
>> >> the existing calls to serial_assign() from cmd_nvedit.c and iomux.c
>> >> that were not doing anything.
>> >
>> > So I think this requires (for example) the following environment variables:
>> >
>> > stdout=serial
>> > serial=eserial0
>> >
>> > Is it possible to allow the following instead:
>> >
>> > stdout=eserial0
>>
>> This is precisely what the patch I had pre-Marek serial did.
>
> In your patch would "stdout=serial" still work for case where there is
> only one serial port?  I think it's important to try to preserve that
> to no be too disruptive.

It used to support stdout=serial based on not being
CONFIG_SERIAL_MULTI.  Now that that's gone, I'm guessing it would
simply be based on only having one registered serial device.

>>
>> > That way, one could presumably set:
>> >
>> > stdout=eserial0,eserial3
>>
>> Though it didn't allow this.
>>
>
> Shouldn't that be (nearly) transparent through iomux?

If that's what iomux does, then sure!  I haven't used I/O mux on a
device before.

-Joe