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Date: Thu, 09 Oct 2025 14:08:24 +0200
Message-Id: <DDDS2V0V2NVJ.16ZKXCKUA1HUV@kernel.org>
Subject: Re: [PATCH 1/4] rust: i2c: add read and write byte data
 abstractions
Cc: "Lee Jones" <lee@kernel.org>, "Pavel Machek" <pavel@kernel.org>, "Miguel
 Ojeda" <ojeda@kernel.org>, "Alex Gaynor" <alex.gaynor@gmail.com>, "Igor
 Korotin" <igor.korotin.linux@gmail.com>, "Lorenzo Stoakes"
 <lorenzo.stoakes@oracle.com>, "Vlastimil Babka" <vbabka@suse.cz>, "Liam R.
 Howlett" <Liam.Howlett@oracle.com>, "Uladzislau Rezki" <urezki@gmail.com>,
 "Boqun Feng" <boqun.feng@gmail.com>, "Gary Guo" <gary@garyguo.net>,
 <bjorn3_gh@protonmail.com>, "Benno Lossin" <lossin@kernel.org>, "Andreas
 Hindborg" <a.hindborg@kernel.org>, "Alice Ryhl" <aliceryhl@google.com>,
 "Trevor Gross" <tmgross@umich.edu>, "Daniel Almeida"
 <daniel.almeida@collabora.com>, <linux-leds@vger.kernel.org>,
 <rust-for-linux@vger.kernel.org>, <linux-kernel@vger.kernel.org>
To: "Markus Probst" <markus.probst@posteo.de>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20251008181027.662616-1-markus.probst@posteo.de>
 <20251008181027.662616-2-markus.probst@posteo.de>
In-Reply-To: <20251008181027.662616-2-markus.probst@posteo.de>

On Wed Oct 8, 2025 at 8:10 PM CEST, Markus Probst wrote:
> In addition to the core abstractions, implement
>
> * `i2c::I2cClient::read_byte` - read a byte from the i2c client
> * `i2c::I2cClient::write_byte` - write a byte to the i2c client
>
> * `i2c::I2cClient::read_byte_data` - read byte data from the i2c client
> * `i2c::I2cClient::write_byte_data` - write byte data to the i2c client
>
> * `i2c::I2cClient::read_word_data` - read word data from the i2c client
> * `i2c::I2cClient::write_word_data` - write word data to the i2c client

I don't think those should be implemented to be used by drivers directly.

Instead we should generalize the Io type [1] and allow for arbitrary backen=
ds,
such that we can use the register!() macro [2] to define register types for=
 I2C
devices.

Ideally, an I2C / SMBus backend should use regmap right away.

The register!() macro is currently moved into the generic infrastructure [3=
].

[1] https://rust.docs.kernel.org/kernel/io/struct.Io.html
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree=
/drivers/gpu/nova-core/regs/macros.rs
[3] https://lore.kernel.org/all/20251003154748.1687160-1-joelagnelf@nvidia.=
com/