Re: [PATCH] gpio: dwapb: Add support for 32 interrupts

[Geert Uytterhoeven]

Hi Phil,

On Thu, Apr 5, 2018 at 11:42 AM, Phil Edworthy
<phil.edworthy@xxxxxxxxxxx> wrote:
> On 30 March 2018 22:26 Andy Shevchenko wrote:
>> On Wed, Mar 28, 2018 at 5:22 PM, Phil Edworthy wrote:
>> > The DesignWare GPIO IP can be configured for either 1 or 32
>> > interrupts,
>>
>> 1 to 32, or just a choice between two?
> Just a choice of 1 or 32.
> Note that by 'configured' I am talking about the hardware being configured in
> RTL prior to manufacturing a device. Once made, you cannot change it.
> This configuration affects the number of output interrupt signals from the GPIO
> Controller block that are connected to an interrupt controller.

Differentiating between different versions of an IP block using DT properties
is usually a bad idea, for several reasons:
  - What if you discover another difference later?
  - You cannot add differentiating properties retroactively, because
of backwards
     compatibility with old DTBS.

Hence I think you should introduce a new compatible value instead.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds