[PATCH 2/3] pinctrl: meson: add device tree bindings documentation
b.galvani at gmail.com
Sun Oct 26 11:25:41 PDT 2014
On Fri, Oct 24, 2014 at 01:53:28PM +0200, Linus Walleij wrote:
> On Tue, Oct 7, 2014 at 11:32 PM, Beniamino Galvani <b.galvani at gmail.com> wrote:
> > Add device tree bindings documentation for Amlogic Meson pinmux and
> > GPIO controller.
> > Signed-off-by: Beniamino Galvani <b.galvani at gmail.com>
> > +Required properties for gpio sub-nodes:
> > + - reg: should contain address and size for mux, pull-enable, pull and
> > + gpio register sets
> > + - reg-names: an array of strings describing the "reg" entries. Must
> > + contain "mux", "pull" and "gpio". "pull-enable" is optional and
> > + when it is missing the "pull" registers are used instead
> So it seems segmenting the registers is done to sort of control the
> hardware versioning.
> I think it's better to use the compatible string to indicate different
> versions of the hardware and then have just have one big
> regs to cover all registers.
The problem here is that the register ranges are not contiguous and
the holes in between are used by other devices, so I can't use a
> > +Valid gpio sub-nodes name are:
> > + - "banks" for the standard banks
> > + - "ao-bank" for the AO bank which belong to the special always-on
> > + power domain
> I think it's unnecessary to split up banks, the compatible property
> should be enough to know how many banks this controller has
> and where they are located in relation to the base offset.
I wanted to avoid a reg property with a list of 7 ranges. Anyway, I
agree that the split seems a bit arbitrary; I'll remove it.
> > +Required properties for configuration nodes:
> > + - pins: the name of a pin group. The list of all available groups can
> > + be found in driver sources.
> > + - function: the name of a function to activate for the specified set
> > + of groups. The list of all available functions can be found in
> > + driver sources.
> This is interesting. I have established that for controllers mapping
> functions to groups we use
> "function" and "groups".
> So for per-pin configuration, "function" and "pins" would be
I will use "groups" instead of "pins" for the pinmux configuration.
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