[PATCH 3/5] dt-bindings: pinctrl: add imx7ulp pinctrl binding doc

[A.S. Dong]

> -----Original Message-----
> From: Shawn Guo [mailto:shawnguo at kernel.org]
> Sent: Monday, May 15, 2017 8:21 PM
> To: A.S. Dong
> Cc: Mark Rutland; devicetree at vger.kernel.org; Andy Duan; Jacky Bai;
> linus.walleij at linaro.org; stefan at agner.ch; linux-gpio at vger.kernel.org; Rob
> Herring; kernel at pengutronix.de; linux-arm-kernel at lists.infradead.org
> Subject: Re: [PATCH 3/5] dt-bindings: pinctrl: add imx7ulp pinctrl binding
> doc
> 
> On Mon, May 15, 2017 at 12:06:19PM +0000, A.S. Dong wrote:
> > > > @@ -0,0 +1,56 @@
> > > > +* Freescale i.MX7ULP IOMUX Controller
> > > > +
> > > > +Please refer to fsl,imx-pinctrl.txt in this directory for common
> > > > +binding part and usage.
> > >
> > > Are imx7ulp-pinctrl bindings more alike to fsl,imx-pinctrl.txt or
> > > generic pinctrl-bindings.txt?  My personal feeling is that it might
> > > be better to take pinctrl-bindings.txt as the reference base and
> > > highlight how imx7ulp- pinctrl bindings differ from it.
> > >
> >
> > It seems still more like fsl,imx-pinctrl.txt.
> >
> > I know fsl,imx-pinctrl.txt is a bit out of date, especially after we
> > add generic pinconf.
> >
> > I plan to update it later after adding generic pin conf support to
> > legacy SoCs (MX6 & 7) as well, do you think it's ok?
> 
> Please do not.  Let's use generic pinconf support only for new SoCs, and
> not bother with legacy SoCs.
> 

I wonder there may be some guys interested more in generic Pinconfig format
rather than old one when they add new board support, or someone else
adding the support for legacy SoCs as the pinctrl-imx core already
supports it after this patch series.

So I'm not quite sure if there's strong reason to block to them to do it.

> <snip>
> 
> > > > diff --git a/include/dt-bindings/pinctrl/imx7ulp-pinfunc.h
> > > > b/include/dt-bindings/pinctrl/imx7ulp-pinfunc.h
> > > > new file mode 100644
> > > > index 0000000..b6db73f
> > > > --- /dev/null
> > > > +++ b/include/dt-bindings/pinctrl/imx7ulp-pinfunc.h
> > >
> > > The header will only be used by dts files, right?  If so,
> > > arch/arm/boot/dts is the better place.
> > >
> >
> > I can do it, but I'm just a bit confused that only IMX is still
> > Putting pinctrl headfile under arch/arm/boot/dts/.
> 
> It makes sense to define DT constants in include/dt-bindings/pinctrl/ only
> when they are referenced by both kernel and dts.  If it's only included by
> dts, arch/arm/boot/dts/ should definitely be the better place.
> 

Okay, understand.
In the future, I probably may added a pinctrl headfile for config macro defines.
But since that is for config only, probably may need create a new file.
e.g.
include/dt-binding/pinctrl/imx7ulp.h
or
include/dt-binding/pinctrl/imx.h (if we supports legacy SoCs)

So we could still keep imx7ulp-pinfunc.h in arch/arm/boot/dts.

Regards
Dong Aisheng

> Shawn