Re: [PATCH 1/2] gpio: dwapb: Use human understandable gpio numbering.

[Michael van der Westhuizen <michael@xxxxxxxxxxxxxxxx>]

> On 02 Jul 2015, at 4:54 PM, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> 
> On 07/02/2015 05:21 PM, Richard Cochran wrote:
>> On Thu, Jul 02, 2015 at 04:30:47PM +0200, Sebastian Andrzej Siewior wrote:
>>> On 07/02/2015 04:26 PM, Richard Cochran wrote:
>>>> On Thu, Jul 02, 2015 at 09:36:22AM +0200, Sebastian Andrzej Siewior wrote:
>>>>> If you are in a specific SoC you could do
>>>>> 	base = of_alias_get_id(np, "gpio") * num_of_gpio_per_chip
>>>>> and get consistent numbers / sane.
>>>> 
>>>> And what about /sys/class/gpio ?
>>> 
>>> What about it?
>> 
>> The poor users of that interface cannot use "of_alias_get_id" as you suggest.
> 
> You do that in the driver. The only problem with that is that the
> synopsys controller can have between one and four banks and a bank can
> have 1-32 GPIOs if I remember correctly. That means you can't have a
> static number of GPIOs like others do.

This is correct.

> Therefore I think a starting property is the only way and I would
> prefer a generic one.

I would prefer a generic property too.  I was rather surprised that one did not exist.

> 
> What confuses me a little: Why is there a snps,nr-gpios property?
> Doesn't the snps' IP-Core expose this information?

Not in the documentation I have (but there’s an awful lot of reserved space in the
register map).

Michael

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