linux-kernel - Re: [PATCH v2 1/2] iio: adc: ti-ads8344: properly byte swap value

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: <CAHp75VeUdj4kkGMaapZu2i96faxmdnhC4a4GF1UoGfSKAVtg6g@mail.gmail.com>
Date:   Fri, 17 Apr 2020 13:47:33 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Gregory CLEMENT <gregory.clement@...tlin.com>,
        linux-iio <linux-iio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] iio: adc: ti-ads8344: properly byte swap value

On Fri, Apr 17, 2020 at 1:44 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> On Thu, Apr 16, 2020 at 11:55 PM Alexandre Belloni
> <alexandre.belloni@...tlin.com> wrote:
> >
> > The first received byte is the MSB, followed by the LSB so the value needs
> > to be byte swapped.
> >
> > Also, the ADC actually has a delay of one clock on the SPI bus. Read three
> > bytes to get the last bit.
> >
>
> Can you show example of what is read and what is expected to be a correct value?
> Because it seems I have been reported with similar issue on other TI
> ADC chip [1]. Perhaps we have to fix all of them?
>
> [1]: https://github.com/edison-fw/meta-intel-edison/issues/108

Also, forgot to mention that TI ADC are 16 bit word, so, we need to
read two u16 rather then bytes.

Some configuration won't allow to do byte reads.

> > Fixes: 8dd2d7c0fed7 ("iio: adc: Add driver for the TI ADS8344 A/DC chips")
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>

-- 
With Best Regards,
Andy Shevchenko