linux-kernel - Re: [PATCH v2 07/15] Documentation: ABI: testing: mt6370: Add ADC sysfs guideline

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Date:   Mon, 20 Jun 2022 14:00:43 +0800
From:   ChiaEn Wu <peterwu.pub@...il.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     lars@...afoo.de, matthias.bgg@...il.com, lee.jones@...aro.org,
        Daniel Thompson <daniel.thompson@...aro.org>,
        jingoohan1@...il.com, pavel@....cz, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, linux-iio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-fbdev@...r.kernel.org,
        szunichen@...il.com, ChiaEn Wu <chiaen_wu@...htek.com>
Subject: Re: [PATCH v2 07/15] Documentation: ABI: testing: mt6370: Add ADC
 sysfs guideline

Hi Jonathan,

Thanks for your helpful comments, and I have some questions want to
ask you below.

Jonathan Cameron <jic23@...nel.org> 於 2022年6月18日 週六 晚上11:39寫道：
>
> On Mon, 13 Jun 2022 19:11:38 +0800
> ChiaEn Wu <peterwu.pub@...il.com> wrote:
>
> > From: ChiaEn Wu <chiaen_wu@...htek.com>
> >
> > Add ABI documentation for mt6370 non-standard ADC sysfs interfaces.
> >
> > Signed-off-by: ChiaEn Wu <chiaen_wu@...htek.com>
> > ---
> >  .../ABI/testing/sysfs-bus-iio-adc-mt6370      | 36 +++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-mt6370
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-mt6370 b/Documentation/ABI/testing/sysfs-bus-iio-adc-mt6370
> > new file mode 100644
> > index 000000000000..039b3381176a
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-mt6370
> > @@ -0,0 +1,36 @@
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_voltage0_raw
>
> Unfortunately the kernel documentation build scripts do no support duplicating
> standard ABI for particular devices so as to provide more information.
> Hence you can't have anything in this file.
>

I want to confirm with you again,
because my ABI file duplicates with standard sysfs-bus-iio (voltage,
current, and temperature channels),
Should I just remove this ABI file and modify the code of mt6370-adc
to meet your expectations??

>
> > +KernelVersion:       5.18
> > +Contact:     chiaen_wu@...htek.com
> > +Description:
> > +             Indicated MT6370 VBUS ADC with lower accuracy(+-75mA)
> Curious though, voltage with a mA accuracy range?

Yes, this description is based on the data sheet.

> This scale should be presented directly to userspace anyway so no need
> for this doc.
>
> > +             higher measure range(1~22V)
> > +             Calculating with scale returns voltage in uV
>
> No. All channels return in mV. That's the ABI requirement as
> in sysfs-bus-iio and we cannot vary if for particular drivers.  If we did
> no generic tooling would work.

Ok, I got it!

>
> > +
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_voltage1_raw
> > +KernelVersion:       5.18
> > +Contact:     chiaen_wu@...htek.com
> > +Description:
> > +             Indicated MT6370 VBUS ADC with higher accuracy(+-30mA)
> > +             lower measure range(1~9.76V)
> > +             Calculating with scale offset returns voltage in uV
> > +
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_voltage4_raw
> > +KernelVersion:       5.18
> > +Contact:     chiaen_wu@...htek.com
> > +Description:
> > +             Indicated MT6370 TS_BAT ADC
> > +             Calculating with scale returns voltage in uV
> > +
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_voltage7_raw
> > +KernelVersion:       5.18
> > +Contact:     chiaen_wu@...htek.com
> > +Description:
> > +             Indicated MT6370 CHG_VDDP ADC
> > +             Calculating with scale returns voltage in mV
> > +
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_temp8_raw
> > +KernelVersion:       5.18
> > +Contact:     chiaen_wu@...htek.com
> > +Description:
> > +             Indicated MT6370 IC junction temperature
> > +             Calculating with scale and offset returns temperature in degree

Shall I modify the scale of temperature to milli degrees in
mt6370-adc.c and remove this item??

>

Best regards,
ChiaEn Wu