linux-kernel - Re: [PATCH] iio: palmas: shut up warning about calibration mismatch (due to noise)

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Message-ID: <20220327171343.28d582e7@jic23-huawei>
Date:   Sun, 27 Mar 2022 17:13:43 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     "H. Nikolaus Schaller" <hns@...delico.com>
Cc:     Colin Ian King <colin.king@...el.com>,
        Sergiu Cuciurean <sergiu.cuciurean@...log.com>,
        Julia Lawall <Julia.Lawall@...ia.fr>,
        Lars-Peter Clausen <lars@...afoo.de>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        letux-kernel@...nphoenux.org, kernel@...a-handheld.com,
        linux-omap@...r.kernel.org
Subject: Re: [PATCH] iio: palmas: shut up warning about calibration mismatch
 (due to noise)

On Sun, 20 Mar 2022 17:28:21 +0100
"H. Nikolaus Schaller" <hns@...delico.com> wrote:

> Hi Jonathan,
> 
> > Am 20.03.2022 um 16:52 schrieb Jonathan Cameron <jic23@...nel.org>:
> > 
> > On Tue,  8 Mar 2022 13:53:03 +0100
> > "H. Nikolaus Schaller" <hns@...delico.com> wrote:
> >   
> >> Although technically checking for ADC values below 0 is correct,
> >> because they are outside of the calibration values, there is usually
> >> noise which spuriously fills the console log with error messages if
> >> calculated input voltage gets close to 0V.
> >> 
> >> Ignore small negative calculated values, but clamp them to 0.
> >> 
> >> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>  
> > Hi.
> > 
> > Should we treat this as a fix or a cleanup?
> > 
> > I don't mind either way.  
> 
> I don't mind either since we have it for long time in our distribution kernel.
> 
> BR and thanks,
> Nikolaus

Treated as cleanup so applied to the togreg branch of iio.git, but for now
only pushed out as testing because I'll be rebasing on rc1 next week.

Thanks,

Jonathan

> 
> > 
> > Jonathan
> > 
> >   
> >> ---
> >> drivers/iio/adc/palmas_gpadc.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/iio/adc/palmas_gpadc.c b/drivers/iio/adc/palmas_gpadc.c
> >> index f9c8385c72d3..bcfa6a7f6cb2 100644
> >> --- a/drivers/iio/adc/palmas_gpadc.c
> >> +++ b/drivers/iio/adc/palmas_gpadc.c
> >> @@ -376,7 +376,8 @@ static int palmas_gpadc_get_calibrated_code(struct palmas_gpadc *adc,
> >> 					adc->adc_info[adc_chan].gain_error;
> >> 
> >> 	if (val < 0) {
> >> -		dev_err(adc->dev, "Mismatch with calibration\n");
> >> +		if (val < -10)
> >> +			dev_err(adc->dev, "Mismatch with calibration var = %d\n", val);
> >> 		return 0;
> >> 	}
> >>   
> >   
>