Re: [PATCH v6 2/3] rust: i2c: Add basic I2C driver abstractions

[Igor Korotin]

Hello Danilo

On 10/27/2025 10:00 PM, Danilo Krummrich wrote:
> In fact, quite some C drivers are already doing exactly this by hand. For
> instance, see [3]. Four lines after [3], raa215300_rtc_unregister_device() is
> registered with devm_add_action_or_reset(), which calls i2c_unregister_device().

Now that you’ve mentioned the parent device, I finally understand what 
you mean.
Originally, I started my Rust-for-Linux journey with the goal of 
rewriting one of
our platform drivers that has I2C children — and yes, it has a root 
platform_device.
For now, I’ve put that rewrite on hold and focused on the I2C part 
instead, which
is why I was thinking from the perspective of rust_driver_i2c.rs: it’s a 
purely
artificial sample driver that creates an I2C client for a non-existent 
physical
device using an I2C adapter. That’s why the puzzle didn’t fit together 
for me earlier.

> Having that said, I'm a bit curious now: What is your use-case for
> i2c:Registration?

As for my view of i2c::Registration, I see it as a safe wrapper around 
i2c_new_client_device that holds a pointer to the newly created I2C 
client and releases it automatically when dropped.

Thanks for the explanation, I'll drop a new version when ready

Best Regards
Igor