Re: [RFC PATCH v3] irqchip: Add support for Tango interrupt controller

From: Marc Gonzalez
Date: Wed Jan 20 2016 - 11:37:11 EST

On 20/01/2016 17:25, Måns Rullgård wrote:

> Marc Zyngier <marc.zyngier@xxxxxxx> writes:
>> On 20/01/16 16:10, Måns Rullgård wrote:
>>> Marc Zyngier <marc.zyngier@xxxxxxx> writes:
>>>>> + 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.
>> Yup, that is a good point. I guess Marc can address this in the next
>> round, since we need a DT binding anyway.
> I'd suggest using of_address_to_resource() on both nodes and subtracting
> the start addresses returned.

For my own reference, Marc Zyngier suggested:
"you should use of_iomap to map the child nodes, and not mess with
the parent one."