diff options
| author | Uwe Kleine-König <u.kleine-koenig@baylibre.com> | 2025-04-12 14:21:24 +0200 |
|---|---|---|
| committer | Uwe Kleine-König <ukleinek@kernel.org> | 2025-04-16 07:20:23 +0200 |
| commit | dcb882bd436e2124e37640671cfa773dfaed485c (patch) | |
| tree | e8c3388573a89f9551b3d33ebfd9f05d02ee3d34 /drivers/pwm/pwm-loongson.c | |
| parent | 29f1d5cac294dbc0e9ebb9d1fea4e2c1c1d2e5f4 (diff) | |
pwm: loongson: Fix u32 overflow in waveform calculation
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: 2b62c89448dd ("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>
Diffstat (limited to 'drivers/pwm/pwm-loongson.c')
| -rw-r--r-- | drivers/pwm/pwm-loongson.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-loongson.c b/drivers/pwm/pwm-loongson.c index 412c67739ef9..6392c4e34136 100644 --- a/drivers/pwm/pwm-loongson.c +++ b/drivers/pwm/pwm-loongson.c @@ -118,7 +118,7 @@ static int pwm_loongson_enable(struct pwm_chip *chip, struct pwm_device *pwm) static int pwm_loongson_config(struct pwm_chip *chip, struct pwm_device *pwm, u64 duty_ns, u64 period_ns) { - u32 duty, period; + u64 duty, period; struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip); /* duty = duty_ns * ddata->clk_rate / NSEC_PER_SEC */ |