Re: [PATCH v4 4/5] iio: adc: ti-adc128s052: Add lower resolution devices support
From: Andy Shevchenko
Date: Sun Jun 29 2025 - 02:07:38 EST
On Sun, Jun 29, 2025 at 2:30 AM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
> On 6/28/25 6:09 PM, Sukrut Bellary wrote:
> > On Sat, Jun 14, 2025 at 09:45:43PM +0300, Andy Shevchenko wrote:
> >> On Sat, Jun 14, 2025 at 12:15 PM Sukrut Bellary <sbellary@xxxxxxxxxxxx> wrote:
> >>>
> >>> The adcxx communicates with a host processor via an SPI/Microwire Bus
> >>> interface. The device family responds with 12-bit data, of which the LSB bits
> >>> are transmitted by the lower resolution devices as 0.
> >>> The unavailable bits are 0 in LSB.
> >>> Shift is calculated per resolution and used in scaling and raw data read.
> >>>
> >>> Lets reuse the driver to support the family of devices with name
> >>> ADC<bb><c>S<sss>, where
> >>
> >> I believe it's incorrect, i.e. it's something like ...S<ss><?>, where
> >> <?> is something you need to clarify, and <ss> is definitely a speed
> >> in kSPS.
> >>
> > Thank you for the review.
> > I am not sure about the last s in <sss>.
> > It could be TI's silicon spins versioning.
> > I couldn't find any information about it in any of the datasheets.
> > I can drop the last s or mark it as <ssx> and specify the first two <ss> as
> > maximum speed.
> >
> I have a hunch that the last digit has to do with pinout/number of
> power supplies. adc128s052 has two supplies V_A and V_D while the
> others only have V_A.
>
> If this sounds vaguely familiar, it is because it was discussed
> today in this thread [1] that Jonathan CC'ed you in. :-)
With all this being said, please, switch to <ss><p> and describe <p>,
but with the caveat that the <p> is empirically deducted based on what
community observes.
> [1]: https://lore.kernel.org/linux-iio/20250628162910.1256b220@jic23-huawei/
--
With Best Regards,
Andy Shevchenko