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

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Message-ID: <CAHO=5PHUPy=2_HZg26Akogv3Hbic7JPydGpz0j3QfA=3TUgCJw@mail.gmail.com>
Date:   Mon, 23 Mar 2020 14:43:45 +0530
From:   Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
To:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        BCM Kernel Feedback <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 Mailing List <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 1:58 PM Uwe Kleine-König
<u.kleine-koenig@...gutronix.de> wrote:
>
> 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.
Its reported by internal coverity tool.
>
> Also the commit log suggests that IPROC_PWM_DUTY_CYCLE_MIN is zero.
> Maybe mentioning that explicitly is a nice addition, too.
Okay, will add this to commit message. Thanks.
>
> > 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/ |