GPIO.split(&mut rcc.apb2) Not sure how this works?

[jemo07]

Hi all, just found this community, wish I would have done so earlier!

Here is my issue, in the examples in the book there is no reference to code for GPIO like:

let mut gpio = dp.GPIOC.split(&mut rcc.apb2);

"My logic" was guiding me to write the code like:
let mut gpio = dp.GPIOC(&mut rcc.apb2);

Can someone explain how this is working?
I'm using the same variable as the Hal to keep the consistency in the code, and the code above was the only way I could manage to get a blinky going from scratch as I learn rust on embedded.
I came to this solution from combining this example from https://droogmic.github.io/microrust/hello-world/03.01.SOLUTION.html?highlight=split()#solution where the GPIO is using split(),

// Split GPIO
        let mut gpio = p.GPIO.split();

And access to the Advance Peripheral Bus, from the Hal https://docs.rs/stm32f1xx-hal/0.7.0/stm32f1xx_hal/rcc/struct.APB2.html

let dp = pac::Peripherals::take().unwrap();
let mut rcc = dp.RCC.constrain();
function_that_uses_apb2(&mut rcc.apb2);

I did it out of desperation with all the circles of compiler failures and "Nothingness" for something so trivial. Can someone enlighten me with a reference as to where this is explained or a quick summary?

Cheers from Spain & THANK YOU!!!

[jemo07]

I installed Rust Analyzer, and now I can figure this out. Although it might be well worth considering adding a chapter in the book with details on GPIO that might include this example.

Thank you all if you read this!