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Date: Sun, 28 Apr 2024 17:34:22 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Aren Moynihan <aren@peacevolution.org>, Lars-Peter Clausen
 <lars@metafoo.de>, Rob Herring <robh@kernel.org>, Krzysztof Kozlowski
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Subject: Re: [PATCH v2 2/6] iio: light: stk3310: Implement vdd supply and
 power it off during suspend
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On Wed, 24 Apr 2024 02:16:06 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Wed, Apr 24, 2024 at 1:41=E2=80=AFAM Aren Moynihan <aren@peacevolution=
org> wrote:
> >
> > From: Ondrej Jirman <megi@xff.cz>
> >
> > VDD power input can be used to completely power off the chip during
> > system suspend. Do so if available. =20
>=20
> ...
>=20
> >         ret =3D stk3310_init(indio_dev);
> >         if (ret < 0)
> > -               return ret;
> > +               goto err_vdd_disable; =20
>=20
> This is wrong. You will have the regulator being disabled _before_
> IRQ. Note, that the original code likely has a bug which sets states
> before disabling IRQ and removing a handler.
>=20
> Side note, you may make the driver neater with help of
>=20
>   struct device *dev =3D &client->dev;
>=20
> defined in this patch.
>=20
> ...
>=20
> >  static int stk3310_suspend(struct device *dev)
> >  {
> >         struct stk3310_data *data; =20
>=20
> >         data =3D iio_priv(i2c_get_clientdata(to_i2c_client(dev))); =20
>=20
> Side note: This may be updated (in a separate change) to use
> dev_get_drvdata() directly.
>=20
> Jonathan, do we have something like iio_priv_from_drvdata(struct
> device *dev)? Seems many drivers may utilise it.

Not yet, but I'm not sure it's a good idea as there is no inherent
reason to assume the drvdata is a struct iio_dev.  It often is but
adding a function that assumes that is a path to subtle bugs.

Jonathan

>=20
> >  } =20
>=20
> ...
>=20
> >  static int stk3310_resume(struct device *dev) =20
>=20
> Ditto.
>=20
> --
> With Best Regards,
> Andy Shevchenko