Re: [PATCH v8 03/12] hwmon: pwm-fan: Use 64-bit division macro

[Guenter Roeck]

On Tue, Mar 10, 2020 at 06:41:12PM -0700, Guru Das Srinagesh wrote:
> Since the PWM framework is switching struct pwm_args.period's datatype
> to u64, prepare for this transition by using DIV_ROUND_UP_ULL to handle
> a 64-bit dividend.
> 
> Cc: Kamil Debski <kamil@xxxxxxxxx>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> Cc: Jean Delvare <jdelvare@xxxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: linux-hwmon@xxxxxxxxxxxxxxx
> 
> Signed-off-by: Guru Das Srinagesh <gurus@xxxxxxxxxxxxxx>

Not sure if I entirely buy the use case, but then the performance
impact is minimal, at least for this driver, so

Acked-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Guenter

> ---
>  drivers/hwmon/pwm-fan.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 42ffd2e..283423a 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -437,7 +437,7 @@ static int pwm_fan_resume(struct device *dev)
>  		return 0;
>  
>  	pwm_get_args(ctx->pwm, &pargs);
> -	duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
> +	duty = DIV_ROUND_UP_ULL(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
>  	ret = pwm_config(ctx->pwm, duty, pargs.period);
>  	if (ret)
>  		return ret;
> -- 
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