Re: [PATCH v2 01/12] ARM: Orion: DT support for IRQ and GPIO Controllers

On 07/05/2012 04:54 PM, Arnd Bergmann wrote:

This way you have multiple nodes with the same register
and different names, which is not how it normally works.

Ok.

quoted

This would have the advantage that DT describes gpio-to-irq dependencies.
Moreover, nodes that reference gpios can do gpios =<&gpio 71 0>; instead of
gpios =<&gpio3 7 0>;

Is that desired?

The device tree representation should match what is in the data sheet
normally. If they are in a single continuous number range, then we should
probably have a single device node with multiple register ranges
rather than one device node for each 32-bit register. Looking at
arch/arm/plat-orion/gpio.c I think that is not actually the case though
and having separate banks is more logical.

Well, looking at the datasheet of Dove GPIOs are numbered [63:0] plus
GPOs [71:64]. This dt will be a lot shorter and maybe it is describing
the hardware as it is. (Not sure about the syntax for irqs, though)

gpio@d0400 {
	compatible = "marvell,orion-gpio";
	gpio-controller;
	reg = <0xd0400 0x20>, /* GPIO[31: 0] */
	      <0xd0420 0x20>, /* GPIO[63:32] */
	      <0xe8400 0x0c>; /* GPO [71:64] */
	ngpio = <72>;
	interrupts = <12 13 14 15>, <61>;
};

Sebastian