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From:   Billy Tsai <billy_tsai@aspeedtech.com>
To:     Jonathan Cameron <jic23@kernel.org>
CC:     "lars@metafoo.de" <lars@metafoo.de>,
        "joel@jms.id.au" <joel@jms.id.au>,
        "andrew@aj.id.au" <andrew@aj.id.au>,
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        <linux-arm-kernel@lists.infradead.org>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Potin.Lai@quantatw.com" <Potin.Lai@quantatw.com>,
        "patrickw3@meta.com" <patrickw3@meta.com>
Subject: Re: [PATCH v1] iio: adc: aspeed: Support deglitch feature.
Thread-Topic: [PATCH v1] iio: adc: aspeed: Support deglitch feature.
Thread-Index: AQHZ74jrjlOSMsUvo0yNgHQbGiIz5LAzm9aAgAIo4C8=
Date:   Mon, 2 Oct 2023 02:30:43 +0000
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References: <20230925081845.4147424-1-billy_tsai@aspeedtech.com>
 <20230930174501.039095da@jic23-huawei>
In-Reply-To: <20230930174501.039095da@jic23-huawei>
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On Mon, 25 Sep 2023 16:18:45 +0800=0A=
Billy Tsai <billy_tsai@aspeedtech.com> wrote:=0A=
=0A=
> > Create event sysfs for applying the deglitch condition. When=0A=
> > in_voltageY_thresh_rising_en/in_voltageY_thresh_falling_en is set to tr=
ue,=0A=
> > the driver will use the in_voltageY_thresh_rising_value and=0A=
> > in_voltageY_thresh_falling_value as threshold values. If the ADC value=
=0A=
> > falls outside this threshold, the driver will wait for the ADC sampling=
=0A=
> > period and perform an additional read once to achieve the deglitching=
=0A=
> > purpose.=0A=
> >=0A=
> > Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>=0A=
=0A=
> Hi Billy=0A=
=0A=
> This is pushing the meaning of the events interface too far.=0A=
> You can't use it to hide a value you don't like from userspace.=0A=
=0A=
> If you can explain what the condition is that you are seeing=0A=
> and what you need to prevent happening if it is seen that would help=0A=
> us figure out if there is another way to do this.=0A=
=0A=
> Jonathan=0A=
=0A=
Hi Jonathan,=0A=
=0A=
Currently, we are experiencing some voltage glitches while reading from our=
=0A=
controller, but we do not wish to report these false alarms to the user spa=
ce.=0A=
Instead, we want to retry the operation as soon as possible. This is why th=
e=0A=
driver requires this patch to handle retries internally, rather than relyin=
g on user=0A=
space which could introduce unpredictable timing for retrying the reading p=
rocess.=0A=
This software approach aims to minimize the possibility of false alarms as =
much as possible.=0A=
=0A=
If you have any suggestions or recommendations regarding this situation, pl=
ease feel free to=0A=
share them with me.=0A=
=0A=
Thanks =0A=
=0A=
> > ---=0A=
> >  drivers/iio/adc/aspeed_adc.c | 193 ++++++++++++++++++++++++++++++++++-=
=0A=
> >  1 file changed, 189 insertions(+), 4 deletions(-)=0A=
> >=