Sorry for taking eternities to look into this.

On Tue, Jun 18, 2013 at 11:29 AM, Christian Ruppert
[off-list ref] wrote:

The pinmux driver of the Abilis Systems TB10x platform based on ARC700 CPUs.
Used to control the pinmux and is a prerequisite for the GPIO driver.

Signed-off-by: Christian Ruppert <redacted>
Signed-off-by: Pierrick Hascoet <redacted>

(...)

+The following pin groups are available:
+  - GPIO ports: gpioa_pins, gpiob_pins, gpioc_pins, gpiod_pins, gpioe_pins,
+                gpiof_pins, gpiog_pins, gpioh_pins, gpioi_pins, gpioj_pins,
+                gpiok_pins, gpiol_pins, gpiom_pins, gpion_pins

I would not attempt to define groups for all GPIO pins.

(...)

+gpioa: gpio@FF140000 {
+       compatible = "abilis,tb10x-gpio";
+       reg = <0xFF140000 0x1000>;
+       gpio-controller;
+       #gpio-cells = <2>;
+       ngpio = <3>;
+       gpio-ranges = <&iomux 0 0>;
+       gpio-ranges-group-names = "gpioa_pins";

This uses that feature to define GPIO ranges from a group does
it not? I'm not certain about that feature.

I don't see any of the port concept creeping into the device tree
in this version and that is how I think it should be kept:
the "port" particulars is a thing for the driver and not the
device tree.

Yours,
Linus Walleij