Date:   Wed, 17 Nov 2021 15:54:19 +0100
From:   Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
To:     cgel.zte@gmail.com
Cc:     alexandre.belloni@bootlin.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: Re: [PATCH V2] pwm: Use div64_ul instead of do_div
Message-ID: <20211117145419.b4wb6zp42rjdpgn5@pengutronix.de>
References: <20211117112400.bkscb2pyavonpfsn@pengutronix.de>
 <20211117124653.161699-1-deng.changcheng@zte.com.cn>
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On Wed, Nov 17, 2021 at 12:46:53PM +0000, cgel.zte@gmail.com wrote:
> From: Changcheng Deng <deng.changcheng@zte.com.cn>
>=20
> do_div() does a 64-by-32 division. If the divisor is unsigned long, using
> div64_ul can avoid truncation to 32-bit.
>=20
> 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(-)
>=20
> 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, st=
ruct pwm_device *pwm,
>  				return -EINVAL;
> =20
>  			clk_period_ns =3D (u64)NSEC_PER_SEC * 256;
> -			do_div(clk_period_ns, clk_freq);
> +			clk_period_ns =3D div64_ul(clk_period_ns, clk_freq);
>  		}
> =20
>  		/* Errata: cannot use slow clk on some IP revisions */
> @@ -72,7 +72,7 @@ static int atmel_hlcdc_pwm_apply(struct pwm_chip *c, st=
ruct pwm_device *pwm,
>  				return -EINVAL;
> =20
>  			clk_period_ns =3D (u64)NSEC_PER_SEC * 256;
> -			do_div(clk_period_ns, clk_freq);
> +			clk_period_ns =3D div64_ul(clk_period_ns, clk_freq);

The code change is good now, the commit log is as confusing as in v1.

Best regards
Uwe

--=20
Pengutronix e.K.                           | Uwe Kleine-K=F6nig            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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