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From:   Liming Sun <lsun@mellanox.com>
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     Andy Shevchenko <andy@infradead.org>,
        Darren Hart <dvhart@infradead.org>,
        Vadim Pasternak <vadimp@mellanox.com>,
        David Woods <dwoods@mellanox.com>,
        "platform-driver-x86@vger.kernel.org" 
        <platform-driver-x86@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v5 1/2] platform/mellanox: Add bootctl driver for Mellanox
 BlueField Soc
Thread-Topic: [PATCH v5 1/2] platform/mellanox: Add bootctl driver for
 Mellanox BlueField Soc
Thread-Index: AQHVDNjerktpZH/kD0q2FkOL+YtZAKZ0L50AgAAd9ECAABiUgIAAFpbg
Date:   Mon, 20 May 2019 20:43:53 +0000
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> -----Original Message-----
> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Monday, May 20, 2019 3:12 PM
> To: Liming Sun <lsun@mellanox.com>
> Cc: Andy Shevchenko <andy@infradead.org>; Darren Hart <dvhart@infradead.o=
rg>; Vadim Pasternak <vadimp@mellanox.com>; David
> Woods <dwoods@mellanox.com>; platform-driver-x86@vger.kernel.org; linux-k=
ernel@vger.kernel.org
> Subject: Re: [PATCH v5 1/2] platform/mellanox: Add bootctl driver for Mel=
lanox BlueField Soc
>=20
> On Mon, May 20, 2019 at 06:07:44PM +0000, Liming Sun wrote:
> > > > +static struct platform_driver mlxbf_bootctl_driver =3D {
> > > > +	.probe =3D mlxbf_bootctl_probe,
> > > > +	.driver =3D {
> > > > +		.name =3D "mlxbf-bootctl",
> > > > +		.groups =3D mlxbf_bootctl_groups,
> > > > +		.acpi_match_table =3D mlxbf_bootctl_acpi_ids,
> > >
> > > Why is an acpi driver a platform driver?  Isn't there a "real" acpi
> > > driver interface you should be tieing into instead?
> > >
> > > Only use a platform driver as an absolute last resort.  I don't think
> > > that is the case here.
> >
> > The driver is trying to configure boot-swapping and display secure stat=
e,
> > and is defined/initiated in ACPI table in UEFI. It seems a little hard =
to
> > categorize this driver to any existing subsystem. Any suggestion
> > where it might be a better fit (like drivers/misc, drivers/firmware, et=
c)?
> > Please correct me if I misunderstand the comments. Thanks!.
>=20
> The comment was asking why an acpi driver is a platform driver, but then
> I went and looked now at a bunch of acpi drivers, and they all are
> platform drivers :(
>=20
> Anyway, drivers/acpi/ seems like the best place for this file, right?

My understanding is that the "drivers/acpi" is mainly for the acpi common c=
ode.
The vendor or platform specific drivers are spread in other various directo=
ries,
most of which are 'platform' drivers.=20

For this driver, we didn't find better sub-component for it, thus put it un=
der
'drivers/platform/mellanox' which is vendor specific driver by its name.

>=20
> thanks,
>=20
> greg k-h