[PATCH V3 5/5] ARM: bcm2708: instantiate console UART

Arnd Bergmann arnd at arndb.de
Thu Sep 13 06:36:29 EDT 2012


On Thursday 13 September 2012, Stephen Warren wrote:
> On 09/12/2012 04:45 AM, Arnd Bergmann wrote:
> > On Wednesday 12 September 2012, Stephen Warren wrote:
> >> From: Simon Arlott <simon at fire.lp0.eu>
> >>
> >> This patch was extracted from git://github.com/lp0/linux.git branch
> >> rpi-split as of 2012/09/08, and modified as follows:
> >>
> >> * Modified UART DT node to use a unit-address to differentiate UART node
> >>   names, rather than using different base names "uart0" and "uart1".
> >>   Note that UART 1 (the Broadcom "mini UART") is not yet present, but
> >>   I'm naming the DT node in anticipation that it will be added.
> >>
> > 
> > Shouldn't the selection be done using an alias like this?
> > 
> >       aliases {
> >               serial0 = &/uart at 20201000;
> >       };
> 
> The "differentiate" was more "ensure that node names in DT are unique"
> than anything to do with user-visible selection/identification.
> 
> I can certainly add the alias if you want, but I don't know what benefit
> it will have, since I've never used aliases before.

The idea of the aliases is that you can identify which port to use
if one passes an argument like "console=ttyS0" or opens a specific
/dev/tty* device node. I believe we don't actually use it that way
at the moment though.

	Arnd



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