Re: [PATCH 2/3] iio: adc: mt6397-auxadc: add mt6397 PMIC AUXADC driver

[sashiko-bot@kernel.org]

> The mt6397 AUXADC is a 10-bit ADC behind the SoC's PMIC wrapper. On boards
> built around this PMIC it is the only way to read the battery: the SoC's
> AUXADC is wired to board thermistors and the charger ICs these boards use
> have no ADC of their own.
> 
> Add a driver exposing the battery voltage and battery temperature
> channels. Only those two are described, so a channel ID in the device tree
> is an index into the driver's channel array rather than the PMIC's channel
> number, as mt6323-auxadc does. The ready bit lives in a channel's raw
> result register, but the value comes from the chip's trimmed copy of it,
> which is what the vendor driver reads for a measurement.
> 
> Both channels need more than that, as the vendor programs them. The
> battery voltage is measured through ISENSE, because a board with a
> switching charger in the power path leaves BATSNS on the charger's system
> rail instead of on the pack. The thermistor only reads correctly with the
> PMIC's battery-detect bias and input buffer enabled, which take 20 ms to
> settle. Both are switched back off afterwards.
> 
> Reads average sixteen conversions in software; the chip's sample
> accumulator makes no measurable difference at any setting, so it is left
> at one sample per conversion.
> 
> Assisted-by: LLM
> Signed-off-by: Ryan Brue <ryanbrue.dev@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260915-rbrue-suez-upstreaming-mt6397-auxadc-v1-0-d35d2ac3d6f0@gmail.com?part=2