[PATCH v3 0/2] pwm: th1520: Fix 32-bit build with COMPILE_TEST

[FUJITA Tomonori <tomo@flapping.org>]

From: FUJITA Tomonori <fujita.tomonori@gmail.com>

This series fixes the 32-bit build of the TH1520 PWM driver with
COMPILE_TEST. v2 limited COMPILE_TEST to 64BIT. Uwe asked to use the
div helpers instead, so v3 does that.

Patch 1 adds a math module to the kernel crate with Rust versions of
div64_u64() and DIV64_U64_ROUND_UP(). Patch 2 uses them in the driver.

The driver only needs u64 by u64 division. It does not need a 128-bit
intermediate value like mul_u64_u64_div_u64().

Uwe, are you OK with this series going through the Rust tree?

chenhan's series [1] also adds rust/kernel/math.rs, with signed
division helpers. Both series use the same module header, so whichever
is applied later needs only a small rebase.

Tested with the doctests on x86_64 and 32-bit ARM QEMU.

[1] https://lore.kernel.org/rust-for-linux/20261023130413.178487-1-chenhan0017.work@gmail.com/

v3:
- Use div helpers instead of limiting COMPILE_TEST to 64BIT (Uwe)
- Add a math module with div64_u64() and div64_u64_round_up()
- Drop Cc: stable and the Reviewed-by tags, since the change is different
v2: https://lore.kernel.org/rust-for-linux/20260930101257.1649945-1-tomo@flapping.org/
- Fix a typo in the commit message
- Add Cc: stable, Reported-by and Closes tags
- Add Reviewed-by tags from Andreas and Gary
- Rebase on v7.3-rc5
v1: https://lore.kernel.org/all/20260929095612.1072417-1-tomo@flapping.org/

FUJITA Tomonori (2):
  rust: math: add div64_u64() and div64_u64_round_up()
  pwm: th1520: Fix 32-bit build with COMPILE_TEST

 drivers/pwm/pwm_th1520.rs |  8 +++--
 rust/kernel/lib.rs        |  1 +
 rust/kernel/math.rs       | 71 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 2 deletions(-)
 create mode 100644 rust/kernel/math.rs


base-commit: c339f4010dea8b0d754f84ace70cd1b089878ef8
-- 
2.43.0