From: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
commit 9017dc4fbd59c09463019ce494cfe36d654495a8 upstream.
Calculating the hardware value for the duty from the hardware value of
the period resulted in a precision loss versus calculating it from the
clock rate directly.
(Also remove a cast that doesn't really need to be here)
Fixes: f6b8a5700057 ("pwm: Add Ingenic JZ4740 support")
Cc: <stable@xxxxxxxxxxxxxxx>
Suggested-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx>
[ukl: backport to v5.4.y and adapt commit log accordingly]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pwm/pwm-jz4740.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -108,8 +108,8 @@ static int jz4740_pwm_apply(struct pwm_c
if (prescaler == 6)
return -EINVAL;
- tmp = (unsigned long long)period * state->duty_cycle;
- do_div(tmp, state->period);
+ tmp = (unsigned long long)rate * state->duty_cycle;
+ do_div(tmp, NSEC_PER_SEC);
duty = period - tmp;
if (duty >= period)
