Re: [PATCH v3 2/7] mfd: retu: Add OF device ID table

[Tony Lindgren]

* Aaro Koskinen <aaro.koskinen@xxxxxx> [170403 15:56]:
> Hi,
> 
> On Mon, Apr 03, 2017 at 06:24:39PM -0400, Javier Martinez Canillas wrote:
> > On 04/03/2017 06:20 PM, Rob Herring wrote:
> > > On Mon, Apr 03, 2017 at 11:45:14AM -0400, Javier Martinez Canillas wrote:
> > >> Hello Lee,
> > >>
> > >> On 04/03/2017 07:15 AM, Lee Jones wrote:
> > >>
> > >> [snip]
> > >>
> > >>>>  
> > >>>> +static const struct of_device_id retu_of_match[] = {
> > >>>> +	{ .compatible = "nokia,retu-mfd" },
> > >>>> +	{ .compatible = "nokia,tahvo-mfd" },
> > >>>
> > >>> Please drop the "-mfd".
> > >>>
> > >>
> > >> Yes, I also didn't like it but I didn't want to change it since that would
> > >> mean that backward compatiblity and bisect-ability will be broken by this
> > >> change.
> > >>
> > >> In other words, just adding a vendor prefix won't cause an issue if patches
> > >> are merged independently since if DTS patches are merged before, the driver
> > >> will still lookup using the I2C device ID table. And if the drivers patches
> > >> are picked before, the DTS will match using the OF device ID table.
> > >>
> > >> But changing to "nokia,retu" and "nokia,tahvo" means that you will need to
> > >> pick all patches and also that the DTS and drivers changes will have to be
> > >> done in the same patch. If you are OK with that, then I can change in the
> > >> next version.
> > > 
> > > tahvo is not documented nor used in any dts (in the kernel at least). 
> 
> True, there are no known DT users of Tahvo.
> 
> > > retu is used by 1 board and happened to work, but was never documented. 
> > > So I think it is okay to change unless the N800 folks object.
> > 
> > I'm fine with changing it (in fact I just want to fix the I2C of modalias
> > reporting). Does this mean that backward compatibility and bisect-ability
> > should be preserved? Or it's OK to split the changes in different patches?
> 
> There are 2 boards actually, N800 and N810. Retu is critical, because
> if retu-mfd/watchdog fails to probe the device will power off soon after
> boot. So for bisect-ability you should make changes in a single patch.

Also I wonder if this will work with arch/arm/mach-omap1/board-nokia770.c
that does I2C_BOARD_INFO("tahvo-mfd", 0x02). Seems they all need to be
changed with a single patch?

Regards,

Tony