linux-iio.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Crestez Dan Leonard <leonard.crestez@intel.com>
To: Drew Fustini <drew@beagleboard.org>
Cc: linux-iio@vger.kernel.org, Daniel Baluta <daniel.baluta@intel.com>
Subject: Re: [PATCH 0/2] Add support for adc101c* and adc121c*
Date: Tue, 5 Apr 2016 14:03:11 +0300	[thread overview]
Message-ID: <57039B6F.6090908@intel.com> (raw)
In-Reply-To: <CAPgEAj5bGwGXqgJQg1Qdu=rVsMFEGWKvUTKy7c17RjsawZN9Og@mail.gmail.com>

On 04/01/2016 07:38 PM, Drew Fustini wrote:
> On Thu, Mar 31, 2016 at 12:20 PM, Crestez Dan Leonard
> <leonard.crestez@intel.com> wrote:
>> This adds support for adc101c* and adc121c* using the ti-adc081c driver.
>
> Thanks for posting this.  I am eager to try it out on the BeagleBone
> Green for this SeeedStudio Grove I2C ADC module which uses ADC121C021:
> http://www.seeedstudio.com/wiki/Grove_-_I2C_ADC

It would be nice if somebody else confirmed that this driver used 
correctly, especially on another arch.

Please note that in order for the driver to correctly report actual 
voltage a "voltage regulator" needs to be configured somehow. These 
chips report voltage relative to I2C supply voltage (which can vary) and 
correctly calculating the input voltage requires fetching the current 
voltage from a regulator. If no regulator is available then reading 
in_voltage_raw will work but in_voltage_scale will fail.

The module you linked ensures that the chip input voltage is 3V no 
matter the i2c supply voltage. This is specific to that PCB not the 
actual ti adc chip.

The easiest way to handle this would be to create a fixed-regulator 
reporting a constant 3V in your device tree and pointing the adc's 
vref-supply to it.

Regards,
Leonard


      reply	other threads:[~2016-04-05 11:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-31 17:20 [PATCH 0/2] Add support for adc101c* and adc121c* Crestez Dan Leonard
2016-03-31 17:20 ` [PATCH 1/2] ti-adc081c: " Crestez Dan Leonard
2016-04-01  8:17   ` Peter Meerwald-Stadler
2016-04-03  9:16   ` Jonathan Cameron
2016-03-31 17:20 ` [PATCH 2/2] ti-adc081c: Initial triggered buffer support Crestez Dan Leonard
2016-04-01  8:08   ` Crt Mori
2016-04-01  9:23     ` Lars-Peter Clausen
2016-04-01  8:34   ` Peter Meerwald-Stadler
2016-04-01 11:13     ` Leonard Crestez
2016-04-03  9:25     ` Jonathan Cameron
2016-04-01 16:38 ` [PATCH 0/2] Add support for adc101c* and adc121c* Drew Fustini
2016-04-05 11:03   ` Crestez Dan Leonard [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=57039B6F.6090908@intel.com \
    --to=leonard.crestez@intel.com \
    --cc=daniel.baluta@intel.com \
    --cc=drew@beagleboard.org \
    --cc=linux-iio@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).