Re: [PATCH 2/4] iio: adc: mt6323-auxadc: add mt6323 PMIC AUXADC driver

[Nuno Sá]

On Tue, 2026-06-02 at 15:46 +0300, Roman Vivchar via B4 Relay wrote:
> From: Roman Vivchar <rva333@xxxxxxxxxxxxxx>
> 
> The mt6323 AUXADC is a 15-bit ADC used for system monitoring. This driver
> provides support for reading various channels including battery and
> charger voltages, battery and chip temperature, current sensing and
> accessory detection.
> 
> Add a driver for the AUXADC found in the MediaTek mt6323 PMIC.
> 
> Tested-by: Ben Grisdale <bengris32@xxxxxxxxxxxxx> # Amazon Echo Dot (2nd
> Generation)
> Signed-off-by: Roman Vivchar <rva333@xxxxxxxxxxxxxx>
> ---
>  MAINTAINERS                     |   8 ++
>  drivers/iio/adc/Kconfig         |  11 ++
>  drivers/iio/adc/Makefile        |   1 +
>  drivers/iio/adc/mt6323-auxadc.c | 299 ++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 319 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d1cc0e12fe1f..c9ad2417a3ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16256,6 +16256,14 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>  F:	drivers/mmc/host/mtk-sd.c
>  
> +MEDIATEK MT6323 PMIC AUXADC DRIVER
> +M:	Roman Vivchar <rva333@xxxxxxxxxxxxxx>
> +L:	linux-iio@xxxxxxxxxxxxxxx
> +L:	linux-mediatek@xxxxxxxxxxxxxxxxxxx (moderated for non-subscribers)
> +S:	Maintained
> +F:	drivers/iio/adc/mt6323-auxadc.c
> +F:	include/dt-bindings/iio/adc/mediatek,mt6323-auxadc.h

The above file was not added in this patch

...

> +
> +static const struct iio_chan_spec mt6323_auxadc_channels[] = {
> +	MTK_PMIC_IIO_CHAN(baton2,    MT6323_AUXADC_BATON2,    MT6323_AUXADC_ADC6, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(ch6,       MT6323_AUXADC_CH6,       MT6323_AUXADC_ADC11,
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(bat_temp,  MT6323_AUXADC_BAT_TEMP,  MT6323_AUXADC_ADC5, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(chip_temp, MT6323_AUXADC_CHIP_TEMP, MT6323_AUXADC_ADC4, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(vcdt,      MT6323_AUXADC_VCDT,      MT6323_AUXADC_ADC2, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(baton1,    MT6323_AUXADC_BATON1,    MT6323_AUXADC_ADC3, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(isense,    MT6323_AUXADC_ISENSE,    MT6323_AUXADC_ADC1, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(batsns,    MT6323_AUXADC_BATSNS,    MT6323_AUXADC_ADC0, 
> IIO_VOLTAGE),
> +	MTK_PMIC_IIO_CHAN(accdet,    MT6323_AUXADC_ACCDET,    MT6323_AUXADC_ADC7, 
> IIO_VOLTAGE),
> +};

All of the above are IIO_VOLTAGE. Just remove _ch_type then.

> +
> +/**
> + * struct mt6323_auxadc - Main driver structure
> + * @regmap:        Regmap from PWRAP
> + * @lock:          Mutex to serialize AUXADC reading vs configuration
> + *
> + * The MediaTek MT6323 (as well as a lot of other PMICs) has the following
> hierarchy:
> + * PMIC AUXADC <- PMIC MFD <- SoC PWRAP (wrapper for PWRAP FSM)
> + *
> + * Therefore, PWRAP regmap should be obtained using dev->parent->parent.
> + */

The above kerneldoc seems unnecessary to me.

> +struct mt6323_auxadc {
> +	struct regmap *regmap;
> +	struct mutex lock;
> +};

...

> 
> +
> +static int mt6323_auxadc_read_raw(struct iio_dev *indio_dev,
> +				  const struct iio_chan_spec *chan,
> +				  int *val, int *val2, long mask)
> +{
> +	struct mt6323_auxadc *auxadc = iio_priv(indio_dev);
> +	int ret, mult;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		if (chan->channel == MT6323_AUXADC_ISENSE ||
> +		    chan->channel == MT6323_AUXADC_BATSNS)
> +			mult = 4;
> +		else
> +			mult = 1;
> +
> +		/* 1800mV full range with 15-bit resolution. */
> +		*val = mult * 1800;
> +		*val2 = 15;
> +
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	case IIO_CHAN_INFO_RAW:
> +		scoped_guard(mutex, &auxadc->lock) {
> +			ret = mt6323_auxadc_prepare_channel(auxadc);
> +			if (ret)
> +				return ret;
> +
> +			ret = mt6323_auxadc_request(auxadc, chan->channel);
> +			if (ret)
> +				return ret;
> +
> +			/* Hardware limitation: the AUXADC needs a delay to become
> ready. */
> +			fsleep(300);
> +
> +			ret = mt6323_auxadc_read(auxadc, chan, val);
> +			if (ret)
> +				return ret;

Could be return mt6323_auxadc_read(...)

- Nuno Sá
> 
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("MediaTek MT6323 PMIC AUXADC Driver");