From: Wenhua Lin <Wenhua.Lin@unisoc.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Orson Zhai <orsonzhai@gmail.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Chunyan Zhang <zhang.lyra@gmail.com>, <linux-pwm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
wenhua lin <wenhua.lin1994@gmail.com>,
Wenhua Lin <Wenhua.Lin@unisoc.com>,
Xiongpeng Wu <xiongpeng.wu@unisoc.com>,
zhaochen su <zhaochen.su29@gmail.com>,
Zhaochen Su <Zhaochen.Su@unisoc.com>,
Xiaolong Wang <Xiaolong.Wang@unisoc.com>
Subject: [PATCH 3/6] pwm: sprd: Optimize the calculation method of duty
Date: Mon, 22 Jan 2024 16:17:51 +0800 [thread overview]
Message-ID: <20240122081754.17058-4-Wenhua.Lin@unisoc.com> (raw)
In-Reply-To: <20240122081754.17058-1-Wenhua.Lin@unisoc.com>
Use DIV_ROUND_CLOSEST_ULL to avoid overflow and improve accuracy
when calculating duty.
Signed-off-by: Wenhua Lin <Wenhua.Lin@unisoc.com>
---
drivers/pwm/pwm-sprd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-sprd.c b/drivers/pwm/pwm-sprd.c
index 411e91891c6d..22793e2b8707 100644
--- a/drivers/pwm/pwm-sprd.c
+++ b/drivers/pwm/pwm-sprd.c
@@ -156,7 +156,8 @@ static int sprd_pwm_config(struct sprd_pwm_chip *spc, struct pwm_device *pwm,
* given settings (MOD and input clock).
*/
mod = spc->mod[pwm->hwpwm];
- duty = duty_ns * mod / period_ns;
+ tmp = (u64)duty_ns * mod;
+ duty = DIV_ROUND_CLOSEST_ULL(tmp, period_ns);
tmp = (u64)chn->clk_rate * period_ns;
do_div(tmp, NSEC_PER_SEC);
--
2.17.1
next prev parent reply other threads:[~2024-01-22 8:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-22 8:17 [PATCH 0/6] pwm: sprd: Modification of UNISOC Platform PWM Driver Wenhua Lin
2024-01-22 8:17 ` [PATCH 1/6] pwm: sprd: Add support for UMS9620 Wenhua Lin
2024-01-26 7:19 ` Uwe Kleine-König
2024-01-22 8:17 ` [PATCH 2/6] pwm: sprd: Improve the pwm backlight control function Wenhua Lin
2024-01-22 15:46 ` Krzysztof Kozlowski
2024-01-22 8:17 ` Wenhua Lin [this message]
2024-01-22 8:17 ` [PATCH 4/6] dt-bindings: pwm: sprd: Convert to YAML Wenhua Lin
2024-01-22 15:44 ` Krzysztof Kozlowski
2024-01-22 8:17 ` [PATCH 5/6] pwm: sprd: Add sprd,ums9620-pwm compatible Wenhua Lin
2024-01-22 15:45 ` Krzysztof Kozlowski
2024-01-22 8:17 ` [PATCH 6/6] dt-bindings: pwm: sprd: Add sprd,mod attribute Wenhua Lin
2024-01-22 15:45 ` Krzysztof Kozlowski
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