Re: [PATCH v1] arm64: dts: ti: k3-am62-verdin: Update tla2024 adc compatible

[Francesco Dolcini <francesco@dolcini.it>]

Hello Krzysztof,

On Tue, Oct 01, 2024 at 01:54:56PM +0200, Krzysztof Kozlowski wrote:
> On 01/10/2024 13:14, João Paulo Gonçalves wrote:
> > From: João Paulo Gonçalves <joao.goncalves@toradex.com>
> > 
> > With commit f1c9ce0ced2d ("iio: adc: ti-ads1015: Add TLA2024 support") a
> > new compatible was introduced for TLA2024 ADC. Update the device
> > tree to use the correct compatible for the Verdin-AM62 hardware.
> > 
> > Signed-off-by: João Paulo Gonçalves <joao.goncalves@toradex.com>
> > ---
> >  arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi b/arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi
> > index 5bef31b8577b..f201722d81b3 100644
> > --- a/arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi
> > +++ b/arch/arm64/boot/dts/ti/k3-am62-verdin.dtsi
> > @@ -1220,7 +1220,7 @@ sensor@48 {
> >  	};
> > 
> >  	adc@49 {
> > -		compatible = "ti,ads1015";
> > +		compatible = "ti,tla2024";
> 
> So it is not always TI, who breaks their users. :) (as pointed out in
> LPC DT BoF).

So, let's adjust what I said at that time, I think is important, and I
appreciate you giving me an excuse for doing that :-)

Lately as Toradex we are working a lot with TI, and one of the reasons is
that they have a great software support, backed-up by a great strategy
on the way they contribute to the various upstream projects they build
their SDK on top (Linux, U-Boot, and more).

With that is normal that while working so closely with them we find
issues, everybody have those, it's just that those are the one we
care the most at the moment :-). Not to mention that we started working
with TI a couple of years ago, so TI is still somehow "new" to us and we
are still "learning".

On this regards I was recently working on updating our BSP to the
latest SDK from TI, that is based on a v6.6 stable kernel and looking at
the patches we had to apply on top, the total counts of the patches we
do not have in mainline to support the board subject of this patch is
just _zero_. This to me is a great achievement.

Nishant: this is also for you, and feel free to "market" this
internally/externally :-)


> If you want to break users, sure, but at least explain in commit msg why.

Now, on this specific topic, the actual device that is assembled on this
board is a TI TLA2024, and it's like that since ever, the board never
changed. The current compatible is not matching what is assembled on
board. It works because the device is close enough to TI ADS1015.

With that said, I do not think this is breaking any actual compatibility
issue.

 - The old DTB will keep working with old and new kernel.
 - The commit adding support for TI TLA2024 is in v5.19, and this board
   is supported only from kernel v6.5, so you cannot run an older kernel
   with this board. In addition to that I do not think that is
   reasonable to have someone using a "new" dtb with an "old" kernel.
 - The firmware, U-Boot, the only one that currently supports this board,
   is not making any use of this compatible nor of this ADC.


Francesco