Quoting Gwendal Grignou (2021-02-08 18:36:19)
> On Fri, Feb 5, 2021 at 5:41 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> >
> > Quoting Gwendal Grignou (2021-02-05 13:49:12)
> > > On Tue, Feb 2, 2021 at 11:17 AM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> > > >
> > > > Quoting Gwendal Grignou (2021-02-01 22:45:41)
> > > > > diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
> > > > > index 37fd0b65a0140..1a8a441c9774d 100644
> > > > > --- a/drivers/iio/proximity/sx9310.c
> > > > > +++ b/drivers/iio/proximity/sx9310.c
> > > This method of asking first for the number of element and a second
> > > time for the values is already used at different places in the kernel:
> > > drivers/power/supply/gpio-charger.c : see init_charge_current_limit()
> > > or madera_get_variable_u32_array insound/soc/codecs/madera.c.
> >
> > Sure it's used but that doesn't really mean it's a good pattern to copy.
> > If the number is more than 4 I'd say we should ignore it and move on,
> > but if it's less than 4 is an error returned?
> >
> > >
> > > However, it could use device_property_count_u32(...), which is more
> > > readable than device_property_count_u32(..., NULL,0).
> > >
> >
> > How about
> >
> > ret = device_property_read_u32_array(dev, "semtech,combined-sensors", combined, ARRAY_SIZE(combined));
> > if (ret)
> > break; /* Must have overflowed or not existed; ignore */
> >
> > for (i = 0; i < ARRAY_SIZE(combined); i++)
> >
> > and then it should work as before?
> It will not work:
> If the DTD has a valid array of only 3 elements (for instance [CS0,
> CS1, CS2] as in
> Package (0x02)
> {
> "semtech,combined-sensors",
> Package (0x03)
> {
> Zero,
> One,
> 0x02
> }
> },
> )
>
> device_property_read_u32_array(...., 4) will return -EOVERFLOW and we
> will use the default in the driver, which we do not want.
>
Isn't that a bug in the ACPI property reading code? 3 doesn't overflow 4
so I'm lost why it would return an error code to indicate it can't fit
the whole property into an array that is one size larger.
