[PATCH] pwm: th1520: fix `CLIPPY=1` warning

[Alice Ryhl]

On Mon, Feb 9, 2026 at 9:56 AM Uwe Kleine-König
<u.kleine-koenig at baylibre.com> wrote:
>
> Hello Miguel,
>
> On Wed, Jan 21, 2026 at 07:37:19PM +0100, Miguel Ojeda wrote:
> > The Rust kernel code should be kept `CLIPPY=1`-clean [1].
> >
> > Clippy reports:
> >
> >     error: this pattern reimplements `Option::unwrap_or`
> >       --> drivers/pwm/pwm_th1520.rs:64:5
> >        |
> >     64 | /     (match ns.checked_mul(rate_hz) {
> >     65 | |         Some(product) => product,
> >     66 | |         None => u64::MAX,
> >     67 | |     }) / NSEC_PER_SEC_U64
> >        | |______^ help: replace with: `ns.checked_mul(rate_hz).unwrap_or(u64::MAX)`
> >        |
> >        = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#manual_unwrap_or
> >        = note: `-D clippy::manual-unwrap-or` implied by `-D warnings`
> >        = help: to override `-D warnings` add `#[allow(clippy::manual_unwrap_or)]`
> >
> > Applying the suggestion then triggers:
> >
> >     error: manual saturating arithmetic
> >       --> drivers/pwm/pwm_th1520.rs:64:5
> >        |
> >     64 |     ns.checked_mul(rate_hz).unwrap_or(u64::MAX) / NSEC_PER_SEC_U64
> >        |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `saturating_mul`: `ns.saturating_mul(rate_hz)`
> >        |
> >        = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.92.0/index.html#manual_saturating_arithmetic
> >        = note: `-D clippy::manual-saturating-arithmetic` implied by `-D warnings`
> >        = help: to override `-D warnings` add `#[allow(clippy::manual_saturating_arithmetic)]`
> >
> > Thus fix it by using saturating arithmatic, which simplifies the code
> > as well.
> >
> > Link: https://rust-for-linux.com/contributing#submit-checklist-addendum [1]
> > Fixes: e03724aac758 ("pwm: Add Rust driver for T-HEAD TH1520 SoC")
> > Signed-off-by: Miguel Ojeda <ojeda at kernel.org>
> > ---
>
> Looks good to me. I'll wait for Michal to add his blessing and then when
> picking it up tend to drop the Fixes line. Or do we also care about
> CLIPPY-cleanness in stable?

I think we do care about that.

Alice