On Wed, May 02, 2018 at 12:01:53PM +0100, Andre Przywara wrote: > >>>> It looks like there are more users of those power rails, so we could > >>>> keep those supplies connected to these fixed regulators here, even with > >>>> AXP-805 support in the kernel. > >>> > >>> It's not a good choice. > >>> > >>>> > >>>> Or we keep this back until we get proper AXP support in the kernel? I > >>>> guess it's quite close to the existing PMICs, so it might be more a > >>>> copy&paste exercise to support the AXP-805? > >>> > >>> It's not a reason to keep it back. > >> > >> So I compared the manuals of the AXP806 and the AXP805, the register > >> interface looks identical to me. I only have a (somewhat) Chinese > >> version of the AXP806 manual, so couldn't really find the difference > >> between the two. Do you know more about it? Is it just maybe the > >> packaging and the electrical properties (like max current supported)? > >> > >> If the I2C register interface is really the same, we could just add the > >> DT nodes for the regulator and be done. > > > > And that argument is only valid if you 100% trust the fact that both > > datasheet are complete and accurate. > > > > And experience show that you can't. > > Well, but I wonder how paranoid we are going to be? And in this case we > have confirmation from Wink that they are the same.
Paranoid enough so that we don't blindly trust that the reviewer had a coffee, no interruptions or moment of distraction, or that the datasheet is correct. But not so paranoid that having the driver running on a kernel is enough. > So I think we can go with just a DT addition, given that we test it > and confirm that it works for our use case. Should we discover > something odd or undocumented later, I'd consider this a bug fix, > which we then (and only then!) could fix by adding the compatible > string to the driver. Any DT would be fine already, because we list > both compatible strings in there. In this particular case, yeah, it seems reasonable. Maxime -- Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
