Hi Geert Uytterhoeven,
> Subject: Re: [PATCH 2/2 RESEND] power: supply: sbs-battery: Convert enum-
> >pointer for data in the match tables
>
> Hi Biju,
>
> On Mon, Aug 21, 2023 at 10:53 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> wrote:
> > > Subject: Re: [PATCH 2/2 RESEND] power: supply: sbs-battery: Convert
> > > enum-
> > > >pointer for data in the match tables
> > > On Mon, Aug 21, 2023 at 10:2 AM Biju Das
> > > <biju.das.jz@xxxxxxxxxxxxxx>
> > > wrote:
> > > > > On Sun, Aug 20, 2023 at 7:12 PM Biju Das
> > > > > <biju.das.jz@xxxxxxxxxxxxxx>
> > > > > wrote:
> > > > > > Convert enum->pointer for data in the match tables, so that
> > > > > > device_get_match_data() can do match against OF/ACPI/I2C
> > > > > > tables, once i2c bus type match support added to it and it
> > > > > > returns NULL for
> > > non-match.
> > > > > >
> > > > > > Therefore it is better to convert enum->pointer for data match
> > > > > > and extend match support for both ID and OF tables using
> > > > > > i2c_get_match_data() by adding struct sbs_data with flags
> > > > > > variable and replacing flags->data in struct sbs_info.
> > > > > >
> > > > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > > >
> > > > > > --- a/drivers/power/supply/sbs-battery.c
> > > > > > +++ b/drivers/power/supply/sbs-battery.c
> > > > > > @@ -201,6 +201,10 @@ static const enum power_supply_property
> > > > > > string_properties[] = {
> > > > > >
> > > > > > #define NR_STRING_BUFFERS ARRAY_SIZE(string_properties)
> > > > > >
> > > > > > +struct sbs_data {
> > > > > > + u32 flags;
> > > > > > +};
> > > > >
> > > > > Unless you plan to add more members to struct sbs_data, I see no
> > > > > point in this patch: it only increases kernel size.
> > > > >
> > > > > The various "data" members in <foo>_id structures are intended
> > > > > to contain either a pointer or a single integral value.
> > > >
> > > > The match data value for sbs_battery is 0. Here the API returns
> > > > NULL for a non-match. That is the reason it is converted to pointer.
> > > >
> > > > So, we cannot differentiate actual matched data and error in this
> case.
> > >
> > > If the driver's .probe() method is called, there must have been a
> > > valid match, so i2c_get_match_data() will never return NULL due to a
> non-match.
> >
> > I agree. but "return data" can be 0,if the matched value is 0 (for eg:
> here "sbs_battery").
>
> Yes, so what is the problem?
> Zero is the expected value for these.
Thanks for the explanation. I agree, for this driver
there is no need for enum->pointer conversion
as Zero is expected value.
Cheers,
Biju
