[PATCH v7 3/3] pwm: sifive: Fix the error in the idempotent test within the pwm_apply_state_debug function

Nylon Chen
2024-01-23T06:18:07Z

Round the result to the nearest whole number. This ensures that
real_period is always a reasonable integer that is not lower than the
actual value.

e.g.
$ echo 110 > /sys/devices/platform/led-controller-1/leds/d12/brightness
$ .apply is not idempotent (ena=1 pol=0 1739692/4032985) -> (ena=1 pol=0 1739630/4032985)

Co-developed-by: Zong Li <zong.li@sifve.com>
Signed-off-by: Zong Li <zong.li@sifve.com>
Signed-off-by: Nylon Chen <nylon.chen@sifive.com>
---
drivers/pwm/pwm-sifive.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index b07c8598bb21..7cf7a76cdb44 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -101,7 +101,7 @@ static void pwm_sifive_update_clock(struct pwm_sifive_ddata *ddata,

/* As scale <= 15 the shift operation cannot overflow. */
num = (unsigned long long)NSEC_PER_SEC << (PWM_SIFIVE_CMPWIDTH + scale);
- ddata->real_period = div64_ul(num, rate);
+ ddata->real_period = DIV_ROUND_UP_ULL(num, rate);
dev_dbg(ddata->chip.dev,
"New real_period = %u ns\n", ddata->real_period);
}
--
2.42.0