[PATCH 4/7] pinctrl: zynq: Document DT binding

[Sören Brinkmann]

On Tue, 2014-11-11 at 04:00PM +0100, Linus Walleij wrote:
> On Mon, Nov 3, 2014 at 8:05 PM, Soren Brinkmann
> <soren.brinkmann at xilinx.com> wrote:
> 
> > Add documentation for the devicetree binding for the Zynq pincontroller.
> >
> > Signed-off-by: Soren Brinkmann <soren.brinkmann at xilinx.com>
> (...)
> > +Example:
> > +       pinctrl0: pinctrl at 700 {
> > +               compatible = "xlnx,pinctrl-zynq";
> > +               reg = <0x700 0x200>;
> > +               syscon = <&slcr>;
> > +
> > +               pinctrl_uart1_default: pinctrl-uart1-default {
> > +                       common {
> > +                               groups = "uart1_10_grp";
> > +                               function = "uart1";
> > +                               slew-rate = <0>;
> > +                               io-standard = <1>;
> > +                       };
> 
> I don't really like that you mix multiplexing and config in the
> same node. I would prefer if the generic bindings say we have
> muxing nodes and config nodes, and those are disparate.
> 
> Can't you just split this:
> 
> common-mux {
>     groups = "uart1_10_grp";
>     function = "uart1";
> };
> 
> common-config {
>     groups = "uart1_10_grp";
>     slew-rate = <0>;
>     io-standard = <1>;
> };
> 
> That way we can identify nodes as mux nodes (have "function")
> or config nodes (have "groups" or "pins" but not "function") which
> I think makes things easier to read.

I think such separation is not required by the bindings currently and
the parser assumes everything can be present in any node.
Can we add that requirement to the generic bindings without breaking
current users? I think it would make the implementation a little easier.
	
	Thanks,
	Sören