Re: [PATCH v7 2/6] gpio: Add Delta TN48M CPLD GPIO driver

[Michael Walle]

Am 2021-11-05 12:34, schrieb Robert Marko:
> On Tue, Nov 2, 2021 at 8:28 PM Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx> wrote:
> > On Tue, Nov 2, 2021 at 6:57 PM Robert Marko <robert.marko@xxxxxxxxxx> 
> > wrote:
> > >
> > > Delta TN48M switch has an onboard Lattice CPLD that is used as a GPIO
> > > expander.
> > >
> > > The CPLD provides 12 pins in total on the TN48M, but on more advanced
> > > switch models it provides up to 192 pins, so the driver is extendable
> > > to support more switches.
> >
> > ...
> >
> > > +static int tn48m_gpio_probe(struct platform_device *pdev)
> > > +{
> >
> > > +       const struct tn48m_gpio_config *gpio_config = NULL;
> > > +       struct gpio_regmap_config config = {0};
> >
> > I don't see a point in assigning these variables.
>
> Hi,
> The NULL one isn't required, but the regmap one is, otherwise the
> devm_gpio_regmap_register call will
> return -EINVAL.
>
> It will fail here:
> https://elixir.bootlin.com/linux/latest/source/drivers/gpio/gpio-regmap.c#L209
>
> I see that Michael Walle who did the GPIO regmap uses it as well in
> the Kontron CPLD driver.
> Michael, can you shed some light on this?

I guess this was already clarified? Because you don't set
all the properties of the config you have to initialize it.
Otherwise anything could happen.

-michael