Re: [PATCH] pinctrl: msm: Add support for MSM TLMM pinmux

[Hanumant Singh]

On 7/30/2013 8:59 PM, Stephen Warren wrote:
> On 07/30/2013 06:13 PM, Hanumant Singh wrote:
> > On 7/30/2013 5:08 PM, Stephen Warren wrote:
> > > On 07/30/2013 06:01 PM, Hanumant Singh wrote:
> > > > On 7/30/2013 2:22 PM, Stephen Warren wrote:
> > > > > On 07/30/2013 03:10 PM, hanumant wrote:
> > > > > ...
> > > > > > We actually have the same TLMM pinmux used by several socs of a
> > > > > > family.
> > > > > > The number of pins on each soc may vary.
> > > > > > Also a given soc gets used in a number of boards.
> > > > > > The device tree for a given soc is split into the different boards
> > > > > > that
> > > > > > its in ie the boards inherit a common soc.dtsi but have separate dts.
> > > > > > The boards for the same soc may use different pin groups for
> > > > > > accomplishing a function, since we have multiple i2c, spi uart etc
> > > > > > peripheral instances on a soc. A different instance of each of the
> > > > > > above
> > > > > > peripherals, can be used in different boards, utilizing different
> > > > > > or subset of same pin groups.
> > > > > > Thus I would need to have multiple C files for one soc, based on the
> > > > > > boards that it goes into.
> > > > >
> > > > > The pinctrl driver should be exposing the raw capabilities of the HW.
> > > > > All the board-specific configuration should be expressed in DT. So, the
> > > > > driver shouldn't have to know anything about different boards at
> > > > > compile-time.
> > > > I agree, so I wanted to keep the pin grouping information in DT, we
> > > > already have a board based differentiation of dts files in DT, for the
> > > > same soc.
> > >
> > > That's the opposite of what I was saying. Pin groups are a feature of
> > > the SoC design, not the board.
> > Sorry I guess I wasn't clear.
> > Right now I have a soc-pinctrl.dtsi containing pin groupings.
> > This will be "inherited" by soc-boardtype.dts.
> > The pinctrl client device nodes in soc-boardtype.dts will point to pin
> > groupings in soc-pinctrl.dtsi that are valid for that particular boardtype.
> > Is this a valid design?
>
> OK, so you have two types of child node inside the pinctrl DT node; some
> define the pin groups the SoC has (in soc.dtsi) and some define pinctrl
> states that reference the pin group nodes and are referenced by the
> client nodes.
>
> That's probably fine. However, I'd still question putting the pin group
> nodes in DT at all; I'm not convinced it's better than just putting
> those into the driver itself. You end up with the same data tables after
> parsing the DT anyway.

Any feedback for the rest of the patch?

Thanks
Hanumant

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