linux-kernel - [PATCH 03/14] pwm: rockchip: Fix period and duty

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Message-Id: <1464942192-25967-4-git-send-email-boris.brezillon@free-electrons.com>
Date:	Fri,  3 Jun 2016 10:23:01 +0200
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Thierry Reding <thierry.reding@...il.com>,
	linux-pwm@...r.kernel.org, Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>
Cc:	Heiko Stuebner <heiko@...ech.de>,
	linux-rockchip@...ts.infradead.org,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Milo Kim <milo.kim@...com>,
	Doug Anderson <dianders@...gle.com>,
	Caesar Wang <wxt@...k-chips.com>,
	Stephen Barber <smbarber@...omium.org>,
	Brian Norris <briannorris@...omium.org>,
	Ajit Pal Singh <ajitpal.singh@...com>,
	Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
	Maxime Coquelin <maxime.coquelin@...com>,
	Patrice Chotard <patrice.chotard@...com>, kernel@...inux.com,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH 03/14] pwm: rockchip: Fix period and duty_cycle approximation

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@...e-electrons.com>
---
 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