On 04/01/2016 07:38 PM, Drew Fustini wrote:
On Thu, Mar 31, 2016 at 12:20 PM, Crestez Dan Leonard
<leonard.crestez@xxxxxxxxx> 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
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