On Wed, Aug 28, 2013 at 04:47:36PM +0200, Christian Ruppert wrote:

On Thu, Aug 22, 2013 at 02:10:55PM -0600, Stephen Warren wrote:
[...]

quoted

Pin groups are supposed to be something that represents some property of
the pinctrl HW itself. So, if you have register "X" bits 3-0 that define
the mux function for pins 8, 9, 10, and 11, then there really is a pin
group that exists in HW, and that pin group will still exist with that
same definition no matter what SoC you put the pinctrl HW into. If this
changes, it's not the same pinctrl HW module.

In TB10x, every function can be activated on exactly one pin group, and
Documentation/pinctrl.txt says "If only one possible group of pins is
available for the function, no group name need to be supplied.".

Maybe the answer to our concrete question of the tb10x driver is thus
renaming the pingrp device tree property of the original patch into
something like function (by which a pin group can be implied)?

For example:
iomux: iomux@FF10601c {
        compatible = "abilis,tb10x-iomux";
        reg = <0xFF10601c 0x4>;
        pctl_gpio_a: pctl-gpio-a {
                abilis,function = "gpioa";
        };
        pctl_uart0: pctl-uart0 {
                abilis,function = "uart0";
        };
};

What do you think?

There doesn't seem to be any opposition to this proposal so please find
a revised patch set in the follow up.

Greetings,
  Christian