Re: [PATCH v3 4/4] arm64: dts: ti: Add support for J784S4 EVM board

[Andrew Davis]

On 11/18/22 12:08 PM, Nishanth Menon wrote:
> On 11:56-20221118, Andrew Davis wrote:
> > On 11/18/22 11:47 AM, Nishanth Menon wrote:
> > > On 11:40-20221118, Andrew Davis wrote:
> > > > On 11/16/22 7:04 AM, Apurva Nandan wrote:
> > >
> > > [...]
> > >
> > > > > +#include <dt-bindings/net/ti-dp83867.h>
> > > > > +#include <dt-bindings/gpio/gpio.h>
> > > > > +#include "k3-j784s4.dtsi"
> > > > > +
> > > > > +/ {
> > > > > +	compatible = "ti,j784s4-evm", "ti,j784s4";
> > > > > +	model = "Texas Instruments J784S4 EVM";
> > > > > +
> > > > > +	chosen {
> > > > > +		stdout-path = "serial2:115200n8";
> > > > > +	};
> > > > > +
> > > > > +	aliases {
> > > > > +		serial2 = &main_uart8;
> > > >
> > > > This feels hacky. Your chosen node picks serial2 as that is usually
> > > > the one that is wired up on K3 boards. But on this board it is main_uart8.
> > > > So why not have this be serial10, then choose
> > > >
> > > > stdout-path = "serial10:115200n8";
> > > >
> > > > Also, I've made comments on previous version of this series, it is
> > > > nice to include folks who have commented before in the CC for future
> > > > versions, that way our filters don't hide these away and we can more
> > > > easily check that our comments have been addressed.
> > >
> > > Please stick with the standard of serial2 as the linux console standard.
> > > We ended up with that to ease up capabilities of various distros to
> > > uniformly work across SoC and board variants.
> >
> > The chosen "stdout-path" is for setting the kernel's default output terminal.
> > Distros and other userspaces need to use their own policy mechanisms for
> > picking what serial port to run getty on or whatever the issue may be.
> >
> > Some look at the kernel command line, and our bootloader provides
> > that too, so still no reason to fake alias names here.
>
>
> We have had this conversation earlier as well.
>
> https://lore.kernel.org/linux-arm-kernel/CAK8P3a2VSBvOn1o+q1PYZaQ6LS9U4cz+DZGuDbisHkwNs2dAAw@xxxxxxxxxxxxxx/T/#m4ecb0dc6a78c84631f072faa1b0df0df46333d09
>
> This is also the reason why we picked serial2 as linux console as a
> standard across the boards based on the ecosystem.

I don't see either of those addressed in that thread, only that
the aliases should go in the .dts files and be trimmed, nothing
stops us from:

chosen {
	stdout-path = "serial10:115200n8";
};

aliases {
	serial10 = &main_uart8;
};

Andrew