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From: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Thierry Reding
	<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Liam Girdwood <lgirdwood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
	Ian Campbell
	<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
	Srinivas Kandagatla
	<srinivas.kandagatla-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Brian Norris
	<briannorris-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Patrice Chotard <patrice.chotard-qxv4g6HH51o@public.gmane.org>,
	Doug Anderson <dianders-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Milo Kim <milo.kim-l0cyMroinI0@public.gmane.org>,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	kernel-F5mvAk5X5gdBDgjK7y7TUQ@public.gmane.org,
	Boris Brezillon
	<boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Maxime Coquelin <maxime.coquelin-qxv4g6HH51o@public.gmane.org>,
	Stephen Barber <smbarber-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Ajit Pal Singh <ajitpal.singh-qxv4g6HH51o@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Caesar Wang <wxt-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Subject: [PATCH 03/14] pwm: rockchip: Fix period and duty_cycle approximation
Date: Fri,  3 Jun 2016 10:23:01 +0200	[thread overview]
Message-ID: <1464942192-25967-4-git-send-email-boris.brezillon@free-electrons.com> (raw)
In-Reply-To: <1464942192-25967-1-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

The current implementation always round down the duty and period
values, while it would be better to round them to the closest integer.

Signed-off-by: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/pwm/pwm-rockchip.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index 7d9cc90..68d72ce 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -114,12 +114,11 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * default prescaler value for all practical clock rate values.
 	 */
 	div = clk_rate * period_ns;
-	do_div(div, pc->data->prescaler * NSEC_PER_SEC);
-	period = div;
+	period = DIV_ROUND_CLOSEST_ULL(div,
+				       pc->data->prescaler * NSEC_PER_SEC);
 
 	div = clk_rate * duty_ns;
-	do_div(div, pc->data->prescaler * NSEC_PER_SEC);
-	duty = div;
+	duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
 
 	ret = clk_enable(pc->clk);
 	if (ret)
-- 
2.7.4

  parent reply	other threads:[~2016-06-03  8:23 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-03  8:22 [PATCH 00/14] regulator: pwm: various improvements Boris Brezillon
2016-06-03  8:22 ` [PATCH 01/14] pwm: Add new helpers to create/manipulate PWM states Boris Brezillon
2016-06-03  8:23 ` [PATCH 04/14] pwm: rockchip: Add support for hardware readout Boris Brezillon
2016-06-03 20:07   ` Brian Norris
2016-06-03 20:20   ` Brian Norris
2016-06-04  6:24     ` Boris Brezillon
2016-06-07 17:26       ` Brian Norris
     [not found] ` <1464942192-25967-1-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2016-06-03  8:23   ` [PATCH 02/14] regulator: pwm: Drop unneeded pwm_enable() call Boris Brezillon
2016-06-03 11:08     ` Applied "regulator: pwm: Drop unneeded pwm_enable() call" to the regulator tree Mark Brown
2016-06-03  8:23   ` Boris Brezillon [this message]
2016-06-03 20:03     ` [PATCH 03/14] pwm: rockchip: Fix period and duty_cycle approximation Brian Norris
2016-06-04  6:19       ` Boris Brezillon
2016-06-07 17:25         ` Brian Norris
2016-06-03  8:23   ` [PATCH 05/14] pwm: rockchip: Avoid glitches on already running PWMs Boris Brezillon
2016-06-03 20:28     ` Brian Norris
2016-06-04  6:26       ` Boris Brezillon
2016-06-03  8:23   ` [PATCH 07/14] pwm: sti: Add support for hardware readout Boris Brezillon
2016-06-03  8:23   ` [PATCH 11/14] regulator: pwm: properly initialize the ->state field Boris Brezillon
2016-06-03 20:51     ` Brian Norris
2016-06-03  8:23   ` [PATCH 12/14] regulator: pwm: Retrieve correct voltage Boris Brezillon
2016-06-03 20:55     ` Brian Norris
2016-06-03  8:23 ` [PATCH 06/14] pwm: rockchip: Add support for atomic update Boris Brezillon
     [not found]   ` <1464942192-25967-7-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2016-06-03 20:37     ` Brian Norris
2016-06-03  8:23 ` [PATCH 08/14] pwm: sti: Avoid glitches on already running PWMs Boris Brezillon
2016-06-03 20:38   ` Brian Norris
2016-06-03  8:23 ` [PATCH 09/14] regulator: pwm: Adjust PWM config at probe time Boris Brezillon
2016-06-03 20:41   ` Brian Norris
2016-06-03  8:23 ` [PATCH 10/14] regulator: pwm: Switch to the atomic PWM API Boris Brezillon
     [not found]   ` <1464942192-25967-11-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2016-06-03 20:50     ` Brian Norris
2016-06-04  6:28       ` Boris Brezillon
2016-06-06  6:14         ` Laxman Dewangan
2016-06-03  8:23 ` [PATCH 13/14] regulator: pwm: Support extra continuous mode cases Boris Brezillon
2016-06-03 21:03   ` Brian Norris
2016-06-04  6:30     ` Boris Brezillon
2016-06-03  8:23 ` [PATCH 14/14] regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range Boris Brezillon
     [not found]   ` <1464942192-25967-15-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2016-06-03 21:04     ` Brian Norris
2016-06-06 14:09   ` Rob Herring

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