Re: [PATCH V3 2/2] rust: Add initial clk abstractions

[Viresh Kumar]

On 05-03-25, 14:31, Stephen Boyd wrote:
> Does this mean that a clk consumer has to keep the Result returned from
> enable() in scope until they want to disable the clk?

Yes and no.

> I don't see how
> that makes sense, because most of the time a consumer will enable a clk
> during probe and leave it enabled until system suspend or runtime PM
> suspend time. At that point, they would disable the clk explicitly with
> disable(), but now they would need to drop a reference to do that?

Broadly there are two type of clk users I believe:

1. clk is enabled / disabled from same routine:

   In this case the result can be kept in a local variable and the matching
   cleanup fn will be called at exit.

   fn transfer_data(...) -> Result {
        let _guard = clk.enable()?;

        ...
        transfer-data here
        ...
        // clk.disable() will be called automatically as soon as _guard goes out
        // of scope.
   }

2. clk is enabled / disabled from different routines:

   In this case the caller needs to call dismiss to avoid the automatic freeing
   of resource. Alternatively the returned value can be stored too somewhere,
   but I am not sure if it what users will end up doing.

   fn probe(...) -> Result {
        clk.enable()?.dismiss();

        ...
   }

   fn remove (...) {
        clk.disable();

        ...
   }

-- 
viresh