RE: [PATCH v5 1/2] platform/mellanox: Add bootctl driver for Mellanox BlueField Soc

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
Date: Mon, 20 May 2019 20:43:53 +0000	[thread overview]
Message-ID: <DB6PR05MB3223F25A2E2B78053FE96D5BA1060@DB6PR05MB3223.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20190520191209.GA29776@kroah.com>

> -----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.org>; Vadim Pasternak <vadimp@mellanox.com>; David
> Woods <dwoods@mellanox.com>; platform-driver-x86@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v5 1/2] platform/mellanox: Add bootctl driver for Mellanox BlueField Soc
> 
> On Mon, May 20, 2019 at 06:07:44PM +0000, Liming Sun wrote:
> > > > +static struct platform_driver mlxbf_bootctl_driver = {
> > > > +	.probe = mlxbf_bootctl_probe,
> > > > +	.driver = {
> > > > +		.name = "mlxbf-bootctl",
> > > > +		.groups = mlxbf_bootctl_groups,
> > > > +		.acpi_match_table = 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 state,
> > 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, etc)?
> > Please correct me if I misunderstand the comments. Thanks!.
> 
> 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 :(
> 
> 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 code.
The vendor or platform specific drivers are spread in other various directories,
most of which are 'platform' drivers. 

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

> 
> thanks,
> 
> greg k-h