diff mbox series

[2/5] gpio: mvebu: improve pwm period calculation accuracy

Message ID b6fcb9829f06c1dfe2451ed57c84ba499b235022.1610362661.git.baruch@tkos.co.il (mailing list archive)
State New, archived
Headers show
Series gpio: mvebu: pwm fixes and improvements | expand

Commit Message

Baruch Siach Jan. 11, 2021, 11:17 a.m. UTC
Divide the full period value to reduce rounding error.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
 drivers/gpio/gpio-mvebu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Uwe Kleine-König Jan. 11, 2021, 8:18 p.m. UTC | #1
On Mon, Jan 11, 2021 at 01:17:03PM +0200, Baruch Siach wrote:
> Divide the full period value to reduce rounding error.
> 
> Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe
diff mbox series

Patch

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index a912a8fed197..c424d88e9e2b 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -715,9 +715,9 @@  static int mvebu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	else
 		on = 1;
 
-	val = (unsigned long long) mvpwm->clk_rate *
-		(state->period - state->duty_cycle);
+	val = (unsigned long long) mvpwm->clk_rate * state->period;
 	do_div(val, NSEC_PER_SEC);
+	val -= on;
 	if (val > UINT_MAX)
 		return -EINVAL;
 	if (val)