Re: [PATCH 04/10] regulator: of: switch to using class_find_device_by_fwnode()

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Mark Brown <broonie@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Liam Girdwood <lgirdwood@gmail.com>, Lee Jones <lee@kernel.org>,
	Pavel Machek <pavel@kernel.org>, Peter Rosin <peda@axentia.se>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Moritz Fischer <mdf@kernel.org>, Xu Yilun <yilun.xu@intel.com>,
	Tom Rix <trix@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Danilo Krummrich <dakr@kernel.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-phy@lists.infradead.org, linux-spi@vger.kernel.org,
	linux-leds@vger.kernel.org, linux-fpga@vger.kernel.org,
	driver-core@lists.linux.dev
Subject: Re: [PATCH 04/10] regulator: of: switch to using class_find_device_by_fwnode()
Date: Tue, 24 Mar 2026 00:17:42 +0000	[thread overview]
Message-ID: <acHYJvbSZVPldSCU@shell.armlinux.org.uk> (raw)
In-Reply-To: <cf92122d-6b15-458a-bf89-189a0a6874f7@lunn.ch>

On Mon, Mar 23, 2026 at 09:01:47PM +0100, Andrew Lunn wrote:
> On Mon, Mar 23, 2026 at 07:05:13PM +0000, Mark Brown wrote:
> > On Mon, Mar 23, 2026 at 11:28:27AM -0700, Dmitry Torokhov wrote:
> > > On Mon, Mar 23, 2026 at 02:00:43PM +0000, Mark Brown wrote:
> > 
> > > > The regulator API is very deliberately specifically using the OF APIs,
> > > > not the ACPI APIs, since ACPI really doesn't want to model regulators.
> > 
> > > For now? We also have software nodes and maybe we come up with something
> > > else in the future...
> > 
> > > I think we should use firmware-agnostic APIs as much as possible, and
> > > only use OF- or ACPI-specific ones when there is no generic equivalent.
> > > This makes the code most flexible.
> > 
> > I think this is a worrying idea for core code like this, we have
> > specific firmware bindings for specific firmware interfaces with the
> > different interfaces having very different ideas of how things should be
> > modelled.  The chances that firmware agnostic code is going to do the
> > right thing seem low, and encouraging the use of generic APIs that might
> > happen to run OK raises the risk that we'll get firmware vendors relying
> > on them and leaving us with a conceptual mishmash to sort through.
> 
> How do you handle deprecated OF properties? This is a problem i've run
> into before. A developer needs an ACPI binding, so they blindly
> convert from of_ to device_ without engaging brain. As a result, they
> bring all the deprecated OF properties we want to die into the brand
> new ACPI bindings.
> 
> A agree with Mark here. OF != ACPI, and anything which makes it appear
> they are the same is just going to lead developers down the wrong path
> and increase Maintainers work pointing out all the problems.

That's three who agree.

-- 
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