Re: [PATCHv3 1/4] mfd: smsc: Add support for smsc gpio io/keypad driver

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

On Tue, Oct 02, 2012 at 03:43:22PM +0300, Felipe Balbi wrote:

> BTW, OTOH writing all children into the DT actually describes the HW,
> no ? And depending on the device I feel it'd be better to write that

Well, it depends on the hardware.  Some hardware has a bunch of nice,
neat IPs which can usefully be reproduced and which map sensibly onto OS
abstractions but a lot of it doesn't and frequently the abstractions
which Linux wants to use don't bear a huge resemblance to the hardware
(and Linux's ideas can change over time, as with the clock API being
factored out for example).

> data to DT. Think of twlxxxx (TI's PMICs), we might have completely
> unrelated drivers using one of TWL's GPIO lines as an interrupt source.

> If that particular children isn't listed in DT, it can't be used as an
> interrupt-parent, right ?

You can have the interrupt controller there without having to list every
IP in the device, just make the parent device the interrupt controller
to DT.