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Date: Thu, 1 Feb 2024 22:29:45 +0100
From: Andrew Lunn <andrew@lunn.ch>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Christina Quast <contact@christina-quast.de>,
	Miguel Ojeda <ojeda@kernel.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@gmail.com>,
	Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
	=?iso-8859-1?Q?Bj=F6rn?= Roy Baron <bjorn3_gh@protonmail.com>,
	Benno Lossin <benno.lossin@proton.me>,
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	Alice Ryhl <aliceryhl@google.com>,
	FUJITA Tomonori <fujita.tomonori@gmail.com>,
	Trevor Gross <tmgross@umich.edu>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Heiko Stuebner <heiko@sntech.de>, rust-for-linux@vger.kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v2 3/3] net: phy: add Rust Rockchip PHY driver
Message-ID: <6725eeac-45ee-4f3f-a612-0ef5725b9fd9@lunn.ch>
References: <20240201-rockchip-rust-phy_depend-v2-0-c5fa4faab924@christina-quast.de>
 <20240201-rockchip-rust-phy_depend-v2-3-c5fa4faab924@christina-quast.de>
 <2024020105-bankroll-opium-a6e5@gregkh>
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In-Reply-To: <2024020105-bankroll-opium-a6e5@gregkh>

On Thu, Feb 01, 2024 at 10:23:03AM -0800, Greg KH wrote:
> On Thu, Feb 01, 2024 at 07:07:00PM +0100, Christina Quast wrote:
> > This is the Rust implementation of drivers/net/phy/rockchip.c. The
> > features are equivalent. You can choose C or Rust version kernel
> > configuration.
> > 
> > Signed-off-by: Christina Quast <contact@christina-quast.de>
> Cool, but why?  Is this going to happen for all phy drivers going
> forward?  What's the end-game here, dropping all .c phy drivers that are
> in rust?  Or having duplicates for all of them?

As one of the PHY Maintainers, i would say no.

Now we have an example, i think we should be a lot more strict about
what we actually merge. It should be a driver for hardware which does
not have a C driver.

We cannot drop C drivers since Rust at the moment does not support all
architectures GCC/Clang does. PHY drivers are architecture
independent, and in real life used on multiple architectures. When
Rust eventually catches up, we could consider dropping C drivers when
there is an equivalent Rust driver, but from what i hear, that is a
few years away. I don't want to be supporting a C and Rust driver for
the same hardware.

     Andrew