Re: [RFC 02/10] property: add fwnode_get_match_data()

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Clément Léger" <clement.leger@bootlin.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Daniel Scally <djrscally@gmail.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Wolfram Sang <wsa@kernel.org>, Peter Rosin <peda@axentia.se>,
	Russell King <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	linux-i2c <linux-i2c@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [RFC 02/10] property: add fwnode_get_match_data()
Date: Tue, 22 Feb 2022 10:24:13 +0100	[thread overview]
Message-ID: <CAHp75VfduXwRvxkNg=At5jaN-tcP3=utiukEDL35PEv_grK4Pw@mail.gmail.com> (raw)
In-Reply-To: <20220222094623.1f7166c3@fixe.home>

On Tue, Feb 22, 2022 at 9:47 AM Clément Léger <clement.leger@bootlin.com> wrote:
> Le Tue, 22 Feb 2022 09:33:32 +0100,
> Andy Shevchenko <andy.shevchenko@gmail.com> a écrit :
> > On Tue, Feb 22, 2022 at 9:24 AM Clément Léger <clement.leger@bootlin.com> wrote:
> > > Le Mon, 21 Feb 2022 19:46:12 +0200,
> > > Andy Shevchenko <andriy.shevchenko@linux.intel.com> a écrit :

...

> > > The idea is to allow device with a software_node description to match
> > > with the content of the of_match_table. Without this, we would need a
> > > new type of match table that would probably duplicates part of the
> > > of_match_table to be able to match software_node against a driver.
> > > I did not found an other way to do it without modifying drivers
> > > individually to support software_nodes.
> >
> > software nodes should not be used as a replacement of the real
> > firmware nodes. The idea behind is to fill the gaps in the cases when
> > firmware doesn't provide enough information to the OS. I think Heikki
> > can confirm or correct me.
>
> Yes, the documentation states that:
>
> NOTE! The primary hardware description should always come from either
> ACPI tables or DT. Describing an entire system with software nodes,
> though possible, is not acceptable! The software nodes should only
> complement the primary hardware description.
>
> > If you want to use the device on an ACPI based platform, you need to
> > describe it in ACPI as much as possible. The rest we may discuss.
>
> Agreed but the PCIe card might also be plugged in a system using a
> device-tree description (ARM for instance). I should I do that without
> duplicating the description both in DT and ACPI ?

Why is it (duplication) a problem?
Each platform has its own kind of description, so one needs to provide
it in the format the platform accepts.

-- 
With Best Regards,
Andy Shevchenko