[linux-sunxi] [PATCH 1/2] ARM: sun8i: v3s: add device nodes for DE2 display pipeline

[icenowy@aosc.io (icenowy at aosc.io)]

? 2017-05-29 16:59?Maxime Ripard ???
> On Thu, May 25, 2017 at 10:28:24PM +0800, Icenowy Zheng wrote:
>> >>>> +                       compatible = "allwinner,sun8i-v3s-de2-mixer";
>> >>>> +                       reg = <0x01100000 0x100000>;
>> >>>
>> >>>The display engine also has an interrupt. Please list it
>> >>
>> >> It's a overall interrupt for DE2, not mixer interrupt.
>> >>
>> >> I will add it after we have proper interrupt chaining facility
>> >> for DE2.
>> >>
>> >> It cannot fit here in mixer node.
>> >
>> > Could you elaborate? If it is just shared, then listing it several
>> > times is OK. If the interrupt registers are not in this address
>> > space, then
>> 
>> The interrupt dealing code is still not so clear, and totally not
>> present in BSP DE2 code (the BSP just didn't use the interrupt).
>> 
>> We doesn't even know where the interrupt register is, and we cannot
>> promise it's not broken (as their is even no application of it in 
>> BSP).
> 
> Whether it's broken or not is out of the question here. Adding it
> later would either break the DT compatibility, or introduce a crippled
> driver for users that do not have a recent enough DT. None of the two
> are really acceptable.
> 
> Especially if your plan is to add support for these.

I have no such plan -- even the BSP driver doesn't use the IRQ at all.

> 
> Maxime
> 
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com