From: cgel.zte@gmail.com
To: u.kleine-koenig@pengutronix.de
Cc: alexandre.belloni@bootlin.com, cgel.zte@gmail.com,
deng.changcheng@zte.com.cn, lee.jones@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
ludovic.desroches@microchip.com, nicolas.ferre@microchip.com,
thierry.reding@gmail.com, zealci@zte.com.cn
Subject: [PATCH V3] pwm: Use div64_ul instead of do_div
Date: Thu, 18 Nov 2021 02:52:54 +0000 [thread overview]
Message-ID: <20211118025254.163231-1-deng.changcheng@zte.com.cn> (raw)
In-Reply-To: <20211117145419.b4wb6zp42rjdpgn5@pengutronix.de>
From: Changcheng Deng <deng.changcheng@zte.com.cn>
do_div() does a 64-by-32 division. Here the divisor is an unsigned long
which on some platforms is 64 bit wide. So use div64_ul instead of do_div
to avoid a possible truncation.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
---
drivers/pwm/pwm-atmel-hlcdc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c
index a43b2babc809..1ae3d73b9832 100644
--- a/drivers/pwm/pwm-atmel-hlcdc.c
+++ b/drivers/pwm/pwm-atmel-hlcdc.c
@@ -60,7 +60,7 @@ static int atmel_hlcdc_pwm_apply(struct pwm_chip *c, struct pwm_device *pwm,
return -EINVAL;
clk_period_ns = (u64)NSEC_PER_SEC * 256;
- do_div(clk_period_ns, clk_freq);
+ clk_period_ns = div64_ul(clk_period_ns, clk_freq);
}
/* Errata: cannot use slow clk on some IP revisions */
@@ -72,7 +72,7 @@ static int atmel_hlcdc_pwm_apply(struct pwm_chip *c, struct pwm_device *pwm,
return -EINVAL;
clk_period_ns = (u64)NSEC_PER_SEC * 256;
- do_div(clk_period_ns, clk_freq);
+ clk_period_ns = div64_ul(clk_period_ns, clk_freq);
}
for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) {
--
2.25.1
next prev parent reply other threads:[~2021-11-18 2:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 2:04 [PATCH] pwm: Use div64_ul instead of do_div cgel.zte
2021-11-17 11:24 ` Uwe Kleine-König
2021-11-17 12:46 ` [PATCH V2] " cgel.zte
2021-11-17 14:54 ` Uwe Kleine-König
2021-11-18 2:52 ` cgel.zte [this message]
2021-11-18 9:54 ` [PATCH V3] " Uwe Kleine-König
2021-11-18 10:09 ` [PATCH] " Russell King (Oracle)
2021-11-18 13:19 ` Nicolas Ferre
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