Re: [PATCH v4 1/4] gpio: vf610: allow disabling the vf610 driver

[Martin Kaiser <martin@xxxxxxxxx>]

Thus wrote Francesco Dolcini (francesco@xxxxxxxxxx):

> On Wed, Jan 24, 2024 at 09:58:57PM +0100, Martin Kaiser wrote:
> > The vf610 gpio driver is enabled by default for all i.MX machines,
> > without any option to disable it in a board-specific config file.

> > Most i.MX chipsets have no hardware for this driver. Change the default
> > to enable GPIO_VF610 for SOC_VF610 and disable it otherwise.

> > Add a text description after the bool type, this makes the driver
> > selectable by make config etc.

> > Fixes: 30a35c07d9e9 ("gpio: vf610: drop the SOC_VF610 dependency for GPIO_VF610")
> > Signed-off-by: Martin Kaiser <martin@xxxxxxxxx>
> > ---
> > v4:
> >  - add a new patch to enable COMPILE_TEST

> > v3:
> >  - split the changes into three patches

> > v2:
> >  - enable the vf610 gpio driver in the defconfig files for arm_v7
> >    (i.MX7ULP) and arm64 (i.MX8QM, DXL, ULP and i.MX93)

> >  drivers/gpio/Kconfig | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)

> > diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> > index 1301cec94f12..353af1a4d0ac 100644
> > --- a/drivers/gpio/Kconfig
> > +++ b/drivers/gpio/Kconfig
> > @@ -711,7 +711,8 @@ config GPIO_UNIPHIER
> >  	  Say yes here to support UniPhier GPIOs.

> >  config GPIO_VF610
> > -	def_bool y
> > +	bool "VF610 GPIO support"
> > +	default y if SOC_VF610

> any reason for having this default y for SOC_VF610, but not for the
> other SOC that uses the same variant (i.MX7ULP, ... ?).

Ok, it's probably not as consistent as it could be.

It seems that there are three categories

* Vybrid SoCs

According to the reference manual, they all have the gpio-vf610 hardware.
Defaulting to y for SOC_VF610 makes sense. It's now possible to disable the
driver if a board doesn't need it.

There's a bunch of defconfigs, not sure which ones would have to enable
gpio-vf610 if it weren't on by default.

* imx7ulp

The devicetrees show that all imx7ulp have gpio-vf610 hardware. You're right,
we should use the same approach, i.e.
   default y if SOC_IMX7ULP
and get rid of the imx_v6_v7_defconfig change.

* imx8, imx9

For arm64, there are no SOC_... defines and there's only one defconfig. The
devicetrees don't show clearly which chip has gpio-vf610. We're on the safe
side if we enable gpio-vf610 in defconfig.

Does this make sense?

   Martin