Re: [PATCH v5 1/3] gpio: Cygnus: define Broadcom Cygnus GPIO binding

[Ray Jui]

On 12/15/2014 1:57 PM, Arnd Bergmann wrote:
> On Monday 15 December 2014 13:35:47 Ray Jui wrote:
> > Like I said previously, dynamic GPIO allocation works fine in the
> > kernel, as long as all of our GPIO clients in the kernel use gpiod based
> > API, which is what we will enforce going forward. The only problem is
> > with some of our customers who use GPIO through sysfs and expect fixed
> > global GPIO numbers. Thinking about this more, it's probably not that
> > difficult to add a script for those customers to convert/map the GPIO
> > numbers based on readings parsed from sysfs, so I guess that's fine.
>
> I think we discussed the user space interface a number of times
> in the past, but I forgot the outcome. Either there is already
> a way to name gpio lines uniquely in sysfs, or there should be
> one.
>
> Can you reach the gpio interfaces using /sys/devices/0001234.bus/1234566.gpiocontroller/...?
>
> 	Arnd
We use entries under /sys/class/gpio/ to control GPIOs. All base, label, 
and ngpio info specific to a GPIO controller can be found there.
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