Re: [PATCH v2 2/2] regulator: fp9931: Fix handling of mandatory "vin" supply

[Andreas Kemnade <andreas@kemnade.info>]

On Fri, 13 Mar 2026 17:24:31 +0000
Conor Dooley <conor@kernel.org> wrote:

> On Fri, Mar 13, 2026 at 09:31:02PM +0800, Robby Cai wrote:
> > The FP9931 requires a mandatory "vin" power supply to operate.
> > Replace devm_regulator_get_optional() with devm_regulator_get() to
> > enforce this mandatory dependency.
> > 
> > Fixes: 12d821bd13d42 ("regulator: Add FP9931/JD9930 driver")
> > Signed-off-by: Robby Cai <robby.cai@nxp.com>
> > ---
> >  drivers/regulator/fp9931.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/regulator/fp9931.c b/drivers/regulator/fp9931.c
> > index 69b3c712e5d58..d4ba818ec2c15 100644
> > --- a/drivers/regulator/fp9931.c
> > +++ b/drivers/regulator/fp9931.c
> > @@ -444,7 +444,7 @@ static int fp9931_probe(struct i2c_client *client)
> >  		return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
> >  				     "failed to allocate regmap!\n");
> >  
> > -	data->vin_reg = devm_regulator_get_optional(&client->dev, "vin");
> > +	data->vin_reg = devm_regulator_get(&client->dev, "vin");  
> 
> And this isn't an ABI break because the regulator core will invent a
> dummy regulator?
> 
On most devices I see a dummy regulator somewhere.

What IMHO itches more is that one has to invent a regulator in devicetree
if the property is mandatory and the supply is not known, you have to add
a dummy regulator in the devicetree to make dtbs_check happy.

Regards,
Andreas