Re: Question about non-boolean gpio sysfs values

On Wed, Feb 5, 2014 at 2:54 AM, Alexandre Courbot [off-list ref] wrote:

On Sun, Feb 2, 2014 at 8:35 AM, Evgeny Boger [off-list ref] wrote:

quoted

Hello,

I'm now getting non-boolean values from gpio sysfs interface on 3.13, like
this

You didn't get this before?

This seems wrong to me, a GPIO should always be 0 or 1.

Yup.

As it turns out, bgpio_get() does the following:

    return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);

OK lemme patch this.

But I suppose it would also be nice to make
gpiod_get_value*() more consistent so the whole subsystem gets fixed
in one shot (I suspect a few other drivers are doing the same). I
mean, we never expect a GPIO to be something else than 0 or 1, do we?

We can clamp the returned value in gpiod_get_value() for sure.

Maybe we should even print a warning there if the driver returns
anything other that 0,1.

Maybe we should even retype the function to a bool, atleast in
the driver-facing API.

Yours,
Linus Walleij