[PATCH v2] pwm: th1520: Fix 32-bit build with COMPILE_TEST

[Michal Wilczynski]

On 9/30/26 12:12, FUJITA Tomonori wrote:
> From: FUJITA Tomonori <fujita.tomonori at gmail.com>
> 
> Fix the following build error on 32-bit ARM with COMPILE_TEST:
> 
>   ERROR: modpost: drivers/pwm/pwm_th1520.ko: symbol '__aeabi_uldivmod' undefined!
> 
> The driver divides u64 values when it converts between nanoseconds and
> clock cycles. On 32-bit ARM, these divisions are compiled to calls to
> __aeabi_uldivmod, which the kernel does not provide.
> 
> The TH1520 is a 64-bit RISC-V SoC, so the driver is only used on
> 64-bit kernels. There is no point in compile testing it on 32-bit.
> Limit COMPILE_TEST to 64BIT instead of changing the arithmetic to use
> the div64 helpers.
> 
> Fixes: 3c180003dffb ("pwm: th1520: Fix missing Kconfig dependencies")
> Cc: stable at vger.kernel.org
> Reported-by: Andreas Hindborg <a.hindborg at kernel.org>
> Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/291565-Help/topic/64bit.20division.20in.20.60pwm_th1520.2Ers.60/near/626825599
> Reviewed-by: Andreas Hindborg <a.hindborg at kernel.org>
> Reviewed-by: Gary Guo <gary at garyguo.net>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori at gmail.com>
> ---
> v2:
> - 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/
> ---
>  drivers/pwm/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 729776086879..abecd95b0c3c 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -772,7 +772,7 @@ config PWM_TEGRA
>  
>  config PWM_TH1520
>  	tristate "TH1520 PWM support"
> -	depends on ARCH_THEAD || COMPILE_TEST
> +	depends on ARCH_THEAD || (COMPILE_TEST && 64BIT)
>  	depends on RUST
>  	depends on HAS_IOMEM && COMMON_CLK
>  	select RUST_PWM_ABSTRACTIONS
> 
> base-commit: 72d3fcf802c45d00b300f25b848a93c3a2bd7c7e

Reviewed-by: Michal Wilczynski <m.wilczynski at samsung.com>