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From: Liam Beguin <liambeguin@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: lvb@xiphos.com, linux-iio@vger.kernel.org
Subject: Re: [bug report] iio: adc: ad7949: add vref selection support
Date: Thu, 23 Sep 2021 20:21:02 -0400	[thread overview]
Message-ID: <YU0Z7sMsu6i9YkYh@shaak> (raw)
In-Reply-To: <20210923054358.GX2116@kadam>

On Thu, Sep 23, 2021 at 08:47:52AM +0300, Dan Carpenter wrote:
> > > >  		if (ret != -ENODEV)
> > > >  			return ret;
> > > >  		/* unbuffered? */
> > > >  		ad7949_adc->vref = devm_regulator_get_optional(dev, "vref");
> > > >  		if (IS_ERR(ad7949_adc->vref)) {
> > > >  			ret = PTR_ERR(ad7949_adc->vref);
> > > > +			ad7949_adc->vref = NULL;
> > > 
> > > But this also won't work.  Passing a NULL to regulator_enable() will
> > > cause an Oops.  All the reference to ->vref need checks.  :/
> > 
> > I believe it still work since these conditions around
> > devm_regulator_get_optional() also set ad7949_adc->refsel.
> > 
> > ad7949_adc->refsel is then checked before calling regulator_enable() and
> > regulator_get_voltage().
> > 
> > Even without the patch, I don't think we can call regulor_enable()
> > without having it be defined. Am I missing something else?

Hi Dan,

> Actually, you're right.  This warning is a 100% false positive.  Smatch
> doesn't handle bit wise tests very well.  I've been meaning to write
> that code but I haven't done it yet.  When I do the false positive will
> go away.
> 
> Sorry for the noise on this.

No worries, thanks for your support on this.

> regards,
> dan carpenter

Liam

      reply	other threads:[~2021-09-24  0:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21  6:35 [bug report] iio: adc: ad7949: add vref selection support Dan Carpenter
2021-09-22  5:10 ` Liam Beguin
2021-09-22  6:00   ` Dan Carpenter
2021-09-22 14:48     ` Liam Beguin
2021-09-23  5:47       ` Dan Carpenter
2021-09-24  0:21         ` Liam Beguin [this message]

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