Re: [PATCH v4 1/2] gpio: gpio-mlxbf3: Add gpio driver support

[Andy Shevchenko]

On Fri, Feb 24, 2023 at 12:51 AM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:

...

> > > > > Ah that’s my bad. The property should be called "ngpios" like in
> > > > > the DT
> > > > documentation. Will fix.
> > > >
> > > > And why do you need it? What's a corner case that the GPIO library
> > > > doesn't handle yet?
> > >
> > > We have 2 gpiochips, gpiochip 0 supports 32 gpio pins and gpiochip 1
> > supports only 24 pins.
> > > If I remove the logic from gpio-mlxbf3.c, the gpiolib.c logic will correctly set
> > the ngpios = 32 for gpiochip 0 but will wrongly set ngpios=32 for gpiogchip 1:
> >
> > So, either you need to have two entries in DT per chip or ngpios should be 56.
> >
> I already have 2 entries in my ACPI table, in the first entry, ngpios = 32 and in the second entry ngpios = 24.

Can you show the DSDT excerpt of this device? (Also including the
pieces for pin control)

Is this a table of the device in the wild?

> Gpiochip_add_data_with_keys only reads the ngpios property if (ngpios == 0) which is not the case when
> bgpio_init is called. bgpio_init uses "sz" argument to populate the ngpio in bgpio_init, which is not what we want.

Maybe bgpio_init() is not a good API for your case?

--
With Best Regards,
Andy Shevchenko