linux-kernel - Re: [PATCH v2 2/2] iio: adc: add Nuvoton NCT720x ADC driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CA+4VgcKjK9N+Y=q5iAz2nJOtcyyuBdkSPvggSd+5KQ49F=+ttg@mail.gmail.com>
Date: Tue, 10 Dec 2024 13:27:40 +0800
From: Yu-Hsian Yang <j2anfernee@...il.com>
To: David Lechner <dlechner@...libre.com>
Cc: avifishman70@...il.com, tmaimon77@...il.com, tali.perry1@...il.com, 
	venture@...gle.com, yuenn@...gle.com, benjaminfair@...gle.com, 
	jic23@...nel.org, lars@...afoo.de, robh@...nel.org, krzk+dt@...nel.org, 
	conor+dt@...nel.org, nuno.sa@...log.com, javier.carrasco.cruz@...il.com, 
	andriy.shevchenko@...ux.intel.com, marcelo.schmitt@...log.com, 
	olivier.moysan@...s.st.com, mitrutzceclan@...il.com, tgamblin@...libre.com, 
	matteomartelli3@...il.com, alisadariana@...il.com, gstols@...libre.com, 
	thomas.bonnefille@...tlin.com, ramona.nechita@...log.com, 
	mike.looijmans@...ic.nl, chanh@...amperecomputing.com, KWLIU@...oton.com, 
	yhyang2@...oton.com, openbmc@...ts.ozlabs.org, linux-iio@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] iio: adc: add Nuvoton NCT720x ADC driver

Dear David Lechner,

David Lechner <dlechner@...libre.com> 於 2024年12月6日 週五 上午3:01寫道：
>
> On 12/5/24 12:22 PM, David Lechner wrote:
> > On 12/3/24 3:15 AM, Eason Yang wrote:
>
>
> >> +static int nct720x_read_raw(struct iio_dev *indio_dev,
> >> +                        struct iio_chan_spec const *chan,
> >> +                        int *val, int *val2, long mask)
> >> +{
> >> +    int index = nct720x_chan_to_index[chan->address];
> >> +    u16 volt;
> >> +    unsigned int value;
> >> +    int err;
> >> +    struct nct720x_chip_info *chip = iio_priv(indio_dev);
> >> +
> >> +    if (chan->type != IIO_VOLTAGE)
> >> +            return -EOPNOTSUPP;
> >> +
> >> +    guard(mutex)(&chip->access_lock);
> >> +    switch (mask) {
> >> +    case IIO_CHAN_INFO_RAW:
> >> +            err = regmap_read(chip->regmap16, REG_VIN[index], &value);
> >> +            if (err < 0)
> >> +                    return err;
> >> +            volt = (u16)value;
> >> +            *val = volt >> 3;
> >
> > It seems strange that this is 13 bits when the chips are 8 and 12 bit.
> >
> >> +            return IIO_VAL_INT;
> >> +    case IIO_CHAN_INFO_SCALE:
> >> +            /* From the datasheet, we have to multiply by 0.0004995 */
> >
> > The scale is the same for both 8 bit and 12 bit chips?
> >
> >> +            *val = 0;
> >> +            *val2 = 499500;
> >> +            return IIO_VAL_INT_PLUS_NANO;
> >> +    default:
> >> +            return -EINVAL;
> >> +    }
> >> +}
> >> +
>
> Sorry, I got confused. The difference between the two chips is the
> number of channels, not the number of bits. Please ignore these two
> comments.

Yes, The difference between nct7201 and nct7202 is the vin numbers.
And VOLTAGE SENSE DATA FORMAT is
Voltage(V) =13bitCountValue * 0.0004995