Re: [RFC PATCH v3] irqchip: Add support for Tango interrupt controller
From: Mark Rutland
Date: Wed Jan 20 2016 - 12:03:06 EST
On Wed, Jan 20, 2016 at 05:24:14PM +0100, Marc Gonzalez wrote:
> On 20/01/2016 17:10, MÃns RullgÃrd wrote:
> > Marc Zyngier wrote:
> >>> + if (of_property_read_u32(node, "reg", &ctl))
> >>> + panic("%s: failed to get reg base", node->name);
> >>> +
> >>> + chip = kzalloc(sizeof(*chip), GFP_KERNEL);
> >>> + chip->ctl = ctl;
> >>> + chip->base = base;
> > As I said before, this assumes the outer DT node uses a ranges
> > property. Normally reg properties work the same whether they specify an
> > offset within an outer "ranges" or have a full address directly. It
> > would be easy enough to make this work with either, so I don't see any
> > reason not to.
> IIRC, I was told very early in the review process that the ranges prop
> was mandatory. Lemme look for it... It was Arnd:
I believe Arnd's point was that you need _a_ ranges property, rather
than specifically requiring an idmap/empty ranges property.
As Marc pointed out, you can use of_iomap on the child nodes to map the
portions described by the reg properties, which will handle any
ranges-based translation automatically.
When you put together the binding document, please point out that the
ranges property is necessary.