Re: [PATCH v6 1/5] spi: dt-bindings: Add spi-device-addr peripheral property

[Nuno Sá]

On Wed, Jul 15, 2026 at 02:37:12PM +0100, Mark Brown wrote:
> On Wed, Jul 15, 2026 at 03:29:32PM +0200, Nuno Sá wrote:
> > On Wed, Jul 15, 2026 at 02:09:19PM +0100, Mark Brown wrote:
> 
> > > This really isn't a generic SPI thing, if nothing else you need *far*
> > > more information in there about how exactly this would be put onto the
> > > bus.  If it belongs anywhere outside of the specific device's binding it
> > > feels like it might be regmap.
> 
> > Just for some context,
> 
> > For the analog chip, it can share the same CS line with another 3
> > identical chips. It has two pins that depending on how they are set act
> > as the device address (so only one replies to a given transfer -
> > naturally the peripheral driver needs to setup the correct transfer
> > and that depends on these pins setup and hence dt property). 
> 
> > This property reflects that. Apparently some microchip chips are doing something
> > very similar so Conor proposed a generic property given that we would have at
> > least 3 users of it.
> 
> You still need to work out how the ID appears in the byte stream that
> gets sent to/from the device, that's way more information than just a
> number and not something the byte stream SPI offers is going to cope
> well with.

Not sure if I'm following you. Those ID pins just become something you
need to set on the spi_xfer. Or in Janani case, she's using regmap
reg_base in order to set the right thing depending on the address. I
would image this is always something that peripherals need to address in
terms of how the message/stream needs to be set. So my understanding is
that this should be pretty much transparent for the spi core.

But I might be just focused on this usecase and missing the big picture.

Thx!
- Nuno Sá