Re: [PATCH V2 2/2] rust: Add basic bindings for clk APIs

[Rob Herring]

On Mon, Feb 24, 2025 at 4:00 AM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
>
> On 21-02-25, 15:59, Rob Herring wrote:
> > It would be nice to handle the optional case from the start. Otherwise,
> > driver writers handle optional or not optional themselves. The not
> > optional case is typically some form of error message duplicated in
> > every driver.
> >
> > Every foo_get() needs foo_get_optional(), so let's figure out the rust
> > way to handle this once for everyone.
>
> Are we talking about adding another field here (like below code) or
> something else ?

Either way, but generally I think 2 functions are preferred over 1
function and flags.

The harder part here is in C we just return NULL and all subsequent
functions (e.g. clk_enable()) just return with no error for a NULL
struct clk. For rust, I think we'd need a dummy Clk returned and then
handle comparing the passed in reference to the dummy Clk in the rust
bindings.

>
> impl Clk {
>         pub fn get(dev: &Device, name: Option<&CStr>, optional: bool) -> Result<Self> {
>                 ...
>
>                 let clk = if optional {
>                         bindings::clk_get(dev.as_raw(), con_id)
>                 else {
>                         bindings::clk_get_optional(dev.as_raw(), con_id)
>                 };
>
>                 Ok(Self(from_err_ptr(clk)?))
>         }
> }
>
> --
> viresh