Re: [RFC] irqchip: add support for LS1021A external interrupt lines

From: Marc Zyngier
Date: Mon Dec 11 2017 - 13:30:08 EST


On 11/12/17 09:30, Rasmus Villemoes wrote:
> On 2017-12-08 17:02, Marc Zyngier wrote:

[...]

>> Overall, it is a bit annoying that you just copied the driver altogether
>> instead of trying to allow the common stuff to be shared between
>> drivers. Most of this is just boilerplate code...
>
> Yes, it did annoy me as well. However, the real meat of this is which
> bits of which register to poke to support a negative polarity irq, and
> there doesn't seem to be a good way to express that in DT. The register
> offset and the mapping from external irq# to the GIC one is reasonably
> easy (and would thus get rid of my NIRQ and INTPCR macros), but
> describing the mapping from IRQ# to the bit that needs to be set (or
> cleared) seems much harder. I cannot generalize from one example, so
> lacking documentation for any other Layerscape SOC, whatever I might
> come up with might not actually be useful for other hardware, making it
> rather pointless. But if you have any suggestions for how the DT
> bindings might look, I'm all ears.

You could have a list of <bit irq> pairs defining the mapping, for
example. But I'd encourage you to get in touch with the Freescale/NXP
folks and find out how this HW works. get_maintainers.pl gives me this:

Shawn Guo <shawnguo@xxxxxxxxxx>
Tang Yuantian <Yuantian.Tang@xxxxxxx>
Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
Madalin Bucur <madalin.bucur@xxxxxxx>
Minghuan Lian <Minghuan.Lian@xxxxxxx>
Yuantian Tang <andy.tang@xxxxxxx>
Yangbo Lu <yangbo.lu@xxxxxxx>
"Horia GeantÄ" <horia.geanta@xxxxxxx>

I suggest you spam them and find out.

Thanks,

M.
--
Jazz is not dead. It just smells funny...