pwm: loongson: Fix u32 overflow in waveform calculation

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mul_u64_u64_div_u64() returns an u64 that might be bigger than U32_MAX.
To properly handle this case it must not be directly assigned to an u32
value.

Use a wider type for duty and period to make the idiom:

	duty = mul_u64_u64_div_u64(...)
	if (duty > U32_MAX)
		duty = U32_MAX;

actually work as intended.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/44f3c764-8b65-49a9-b3ad-797e9fbb96f5@stanley.mountain
Fixes: 2b62c89448 ("pwm: Add Loongson PWM controller support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
Link: https://lore.kernel.org/r/20250412122124.1636152-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

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Uwe Kleine-König 2025-04-12 14:21:24 +02:00 • committed by Uwe Kleine-König

parent 29f1d5cac2

commit dcb882bd43

1 changed files with 1 additions and 1 deletions

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drivers/pwm/pwm-loongson.c

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