Re: [PATCH 1/2] dt-bindings: pinctrl: renesas,r9a09g077: Document pin configuration properties

Conor Dooley
2026-03-19T01:36:39Z

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On Wed, Mar 18, 2026 at 09:30:06PM +0000, Lad, Prabhakar wrote:
> Hi All,
>
> On Mon, Jan 19, 2026 at 12:10 AM Linus Walleij <linusw@kernel.org> wrote:
> >
> > Hi Lad,
> >
> > I think this back-and-forth must be a bit stressful. Sorry about that.
> >
> > On Wed, Jan 14, 2026 at 9:53 PM Lad, Prabhakar
> > <prabhakar.csengg@gmail.com> wrote:
> >
> > > > > > > > + renesas,drive-strength:
> > > > > > > > + description:
> > > > > > > > + Drive strength configuration value. Valid values are 0 to 3, representing
> > > > > > > > + increasing drive strength from low, medium, high and ultra high.
> > > > > > >
> >
> > > I got the feedback from the HW team "The RZ/T2H drive strength
> > > (driving ability) is expressed using abstract levels such as Low,
> > > Middle, and High. These values do not correspond directly to specific
> > > mA units.
> >
> > But they do correspond to *something* electrical inside the
> > silicon do they not? Then what is that?
> >
> > I think it is just 1, 2, 3 or 4 driver stages.
> >
> > > To determine how much current the pin can actually drive,
> > > the engineer must refer to the electrical characteristics table.
> > > Therefore, the drive strength in RZ/T2H is a parameter that switches
> > > the internal output transistor mode rather than directly representing
> > > a physical drive current.
> > >
> > > Consequently, expressing RZ/T2H drive strength in milli- or
> > > micro-amps, as suggested by the reviewer, is inappropriate. To
> > > accurately reflect the SoC's hardware specification, introducing a
> > > custom property is essential."
> >
> Sorry for the confusion , there was a miscommunication regarding the
> specs, but it’s all been sorted out. The drive-strength settings on
> this chip are 2.5/5/9/11.8 mA, I will represent them using the
> drive-strength-microamp DT property and send a new version.

neat :)

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