linux-kernel - Re: [PATCH v1 2/2] pwm: bcm-iproc: remove unnecessary check of 'duty'

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Message-ID: <20200323082823.twvpagq7tvrt76ws@pengutronix.de>
Date:   Mon, 23 Mar 2020 09:28:23 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Yendapally Reddy Dhananjaya Reddy 
        <yendapally.reddy@...adcom.com>, linux-pwm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/2] pwm: bcm-iproc: remove unnecessary check of 'duty'

On Mon, Mar 23, 2020 at 12:23:18PM +0530, Rayagonda Kokatanur wrote:
> Variable 'duty' is u32. Hence the less-than zero
> comparison is never true, remove the check.

How did you find that one? I assume it was a compiler warning you fixed
here? In this case quoting the warning improves the commit log.

Also the commit log suggests that IPROC_PWM_DUTY_CYCLE_MIN is zero.
Maybe mentioning that explicitly is a nice addition, too.

> Fixes: daa5abc41c80 ("pwm: Add support for Broadcom iProc PWM controller")
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
> ---
>  drivers/pwm/pwm-bcm-iproc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
> index 8bbd2a04fead..1bb66721f985 100644
> --- a/drivers/pwm/pwm-bcm-iproc.c
> +++ b/drivers/pwm/pwm-bcm-iproc.c
> @@ -149,8 +149,7 @@ static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  		value = rate * state->duty_cycle;
>  		duty = div64_u64(value, div);
>  
> -		if (period < IPROC_PWM_PERIOD_MIN ||
> -		    duty < IPROC_PWM_DUTY_CYCLE_MIN)
> +		if (period < IPROC_PWM_PERIOD_MIN)
>  			return -EINVAL;

Best regards
Uwe

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