[Letux-kernel] Kobolino: rc5t619 adc

[Andreas Kemnade]

On Sat, 21 Dec 2019 09:05:49 +0100
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:


> BTW, I there a table mapping voltage channels like this one for twl6037/Palmas?
> 
static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
        RN5T618_ADC_CHANNEL(0, IIO_CURRENT, "LIMMON"),
        RN5T618_ADC_CHANNEL(1, IIO_VOLTAGE, "VBAT"),
        RN5T618_ADC_CHANNEL(2, IIO_VOLTAGE, "VADP"),
        RN5T618_ADC_CHANNEL(3, IIO_VOLTAGE, "VUSB"),
        RN5T618_ADC_CHANNEL(4, IIO_VOLTAGE, "VSYS"),
        RN5T618_ADC_CHANNEL(5, IIO_VOLTAGE, "VTHM"),
        RN5T618_ADC_CHANNEL(6, IIO_VOLTAGE, "AIN1"),
        RN5T618_ADC_CHANNEL(7, IIO_VOLTAGE, "AIN0")
};


> # channels
> # 0 battery type (source current 0, 5, 15, 20 uA)
> # 1 battery NTC
> # 2 audio accessory/GP
> # 3 temp with ext. diode
> # 4 GP
> # 5 GP
> # 6 VBAT_SENSE
> # 7 VCC_SENSE
> # 8 Backup Battery
> # 9 external charger (VCHG)
> # 10 VBUS
> # 11 DC-DC current probe (how does this work?)
> # 12 internal die temp
> # 13 internal die temp
> # 14 USB ID line voltage
> # 15 test network
> 
> > 
> > What is unkown is the calculation of LIMMON:
> > /sys/bus/iio/devices/iio\:device0/in_current0_raw
> > it corresponds to the current going from VUSB to VSYS,
> > measured by a shunt between ILP and ILM. Any ideas? For the
> > voltages things are quite clear from the datasheet.  
> 
> There is a similar "current" sensor in the twl chips.
> Also not with much information how it relates to hardware... 
> See #11 :)
> 
https://www.e-devices.ricoh.co.jp/en/products/product_pmic/multiple-pmu/rc5t619/rc5t619.pdf

well, there is at least on page 15 a shunt
between ILM and ILP. So the only question is the amplify factor of that
current sensor. Relation to ADC is on page 19.

Regards,
Andreas