RE: [EXT] Re: [PATCH v10 2/2] rtc: Add NXP PCF85053 driver support

[Lakshay Piplani]

NXP Public
> -----Original Message-----
> From: Potin Lai <potin.lai.pt@xxxxxxxxx>
> Sent: Tuesday, October 20, 2026 10:09 AM
> To: alexandre.belloni@xxxxxxxxxxx; linux-rtc@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; robh@xxxxxxxxxx; krzk+dt@xxxxxxxxxx;
> conor+dt@xxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Cc: Pankit Garg <pankit.garg@xxxxxxx>; Vikash Bansal
> <vikash.bansal@xxxxxxx>; Priyanka Jain <priyanka.jain@xxxxxxx>; Lakshay
> Piplani <lakshay.piplani@xxxxxxx>; Daniel Aguirre
> <daniel.aguirre@xxxxxxx>; potin.lai@xxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH v10 2/2] rtc: Add NXP PCF85053 driver support
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> On Mon, 14 Sep 2026 19:45:37 +0530, Lakshay Piplani
> <lakshay.piplani@xxxxxxx> wrote:
> > diff --git a/drivers/rtc/rtc-pcf85053.c b/drivers/rtc/rtc-pcf85053.c
> > new file mode 100644 index 000000000000..2eb94b1da3ed
> > --- /dev/null
> > +++ b/drivers/rtc/rtc-pcf85053.c
> > @@ -0,0 +1,900 @@
> > [ ... skip 770 lines ... ]
> > +
> > +     dev_set_drvdata(dev, pcf85053);
> > +
> > +     if (of_property_read_string(dev->of_node, "nxp,interface", &iface))
> > +             return dev_err_probe(dev, -EINVAL,
> > +                                  "Missing mandatory property:
> > + nxp,interface\n");
>
> Hi Lakshay,
>
> Would it be possible to provide a fallback default true for `pcf85053-
> >is_primary` if the property is omitted?
>
> In the current implementation, nxp,interface is strictly mandatory.
> However, when users instantiate the device via the sysfs new_device interface
> (e.g., echo pcf85053a 0x6f > /sys/bus/i2c/devices/i2c-X/new_device),
> there is no way to pass Device Tree properties. Because of this, probe will
> always fail with -EINVAL.
>
> Thanks,
> Potin
>
> --
> Potin Lai <potin.lai.pt@xxxxxxxxx>

Hi Potin,

Yes, that makes sense. I will make nxp,interface optional and default pcf85053->is_primary to true when the property is absent. Explicit "primary" and "secondary" values will continue to be validated. I will update the DT binding accordingly.

Thanks,
Lakshay