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

[Marc Gonzalez]

On 20/01/2016 17:38, Måns Rullgård wrote:

> Marc Gonzalez <marc_gonzalez@xxxxxxxxxxxxxxxx> writes:
> 
>> 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."
> 
> That's going to get very messy since the generic irqchip code needs all
> the registers as offsets from a common base address.

The two suggestions are over my head at the moment.

Do you want to submit v4 and have Marc Z take a look?

Regards.