Re: [PATCH 2/2] tools/gpio: add the gpio-hammer tool

[Linus Walleij <linus.walleij@linaro.org>]

On Thu, Jun 2, 2016 at 4:59 PM, Michael Welling <mwelling@ieee.org> wrote:
> On Wed, Jun 01, 2016 at 11:40:04PM +0200, Linus Walleij wrote:
>> On Wed, Jun 1, 2016 at 8:09 PM, Michael Welling <mwelling@ieee.org> wrote:
>>
>> > Is there a way to name a group of GPIOs?
>>
>> Do you mean from the producer side or the consumer side?
>
> Producer side is what I am thinking.
>
>> There is gpio-line-names in DT for the producer side.
>>
> The gpio-line-names are naming individual GPIO on a controller.
> I am looking to take a set of GPIOs and name them as a group and
> be able to access them by that name. Either individually or
> simultaneously.

There is no such mechanism currently, all lines are individual
resources.

>> Sorry not following, I guess you need to post me some part of
>> the patch or so...
>
> +       fprintf(stdout, "] on %s, initial states: [", device_name);
> +       for (i = 0; i < nlines; i++) {
> +               fprintf(stdout, "%d", data.values[i]);
>
> data.values[i];
>
> Each bit is stored in a byte.

Yeah the userspace interface is wasteful in that sense. It's a trade-off
between storage and simplicity and I had to choose something.

If I try to bitstuff the bits then I need to add another ABI to describe
how the bits are stuffed in the words. So I get complexity somewhere
else instead.

Yours,
Linus Walleij