[PATCH 0/2] iio: adc: qcom-pm8xxx-xoadc improvements

[PATCH 0/2] iio: adc: qcom-pm8xxx-xoadc improvements

[Antony Kurniawan Soemardi]

This small series improves the Qualcomm PM8xxx XOADC driver in two ways:

1. Adds support for reading channel labels through sysfs.
   This helps user-space tools identify ADC channels by name.

2. Fixes incorrect calibration values used on msm8960-based devices.
   Previously, the driver failed to apply the proper ratiometric scaling
   and incorrectly set certain bits in the ADC_ARB_USRP_DIG_PARAM
   register. This resulted in inaccurate voltage readings from the IIO
   interface. With the fix, calibration values now match downstream
   implementations, and readings for channels like USB_VBUS and 125V
   are correct.

Tested on Sony Xperia SP.

Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
---
Antony Kurniawan Soemardi (2):
      iio: adc: qcom-pm8xxx-xoadc: add support for reading channel labels
      iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

 drivers/iio/adc/qcom-pm8xxx-xoadc.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
---
base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa
change-id: 20251018-pm8xxx-xoadc-fix-b98f8ff20f57

Best regards,
--
Antony Kurniawan Soemardi <linux@smankusors.com>

[PATCH 1/2] iio: adc: qcom-pm8xxx-xoadc: add support for reading channel labels

[Antony Kurniawan Soemardi]

This allows user-space tools to identify ADC channels by name through
the IIO sysfs interface.

Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
---
 drivers/iio/adc/qcom-pm8xxx-xoadc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
index 31f88cf7f7f18297132d152648b312c0fb60608e..8555f34036fb13c41ac720dc02c1dc39876e9198 100644
--- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
+++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
@@ -725,8 +725,15 @@ static int pm8xxx_fwnode_xlate(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int pm8xxx_read_label(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, char *label)
+{
+	return sysfs_emit(label, "%s\n", chan->datasheet_name);
+}
+
 static const struct iio_info pm8xxx_xoadc_info = {
 	.fwnode_xlate = pm8xxx_fwnode_xlate,
+	.read_label = pm8xxx_read_label,
 	.read_raw = pm8xxx_read_raw,
 };
 

-- 
2.34.1

Re: [PATCH 1/2] iio: adc: qcom-pm8xxx-xoadc: add support for reading channel labels

[Andy Shevchenko]

On Mon, Oct 27, 2025 at 05:29:16PM +0000, Antony Kurniawan Soemardi wrote:
> This allows user-space tools to identify ADC channels by name through
> the IIO sysfs interface.

...

> +static int pm8xxx_read_label(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan, char *label)
> +{
> +	return sysfs_emit(label, "%s\n", chan->datasheet_name);
> +}

Hmm... In another thread there is a discussion on label vs. datasheet_name.
So, why datasheet name and not something that it's more reliable as a platform
description? As far as I understand there many mysterious ways of HW
engineering and how to connect available pins to something interesting. Even
datasheet names may be quite mislead on a certain platform (due to above).
I would expect this to come from DT or another platform description and user
space should rely on the information from _there_.

-- 
With Best Regards,
Andy Shevchenko

[PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Antony Kurniawan Soemardi]

On msm8960 phones, the XOADC driver was using incorrect calibration
values:
absolute calibration dx = 625000 uV, dy = 4 units
ratiometric calibration dx = 1800, dy = -29041 units

As a result, reading from the IIO bus returned unexpected results:
in_voltage_7 (USB_VBUS): 0
in_voltage_10 (125V): 0

The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
from the predefined channels. Additionally, the downstream code always
set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
those bits caused calibration errors too, so they were removed.

With these fixes, calibration now uses the correct values:
absolute calibration dx = 625000 uV, dy = 6307 units
ratiometric calibration dx = 1800, dy = 18249 units

Reading from the IIO bus now returns expected results:
in_voltage_7 (USB_VBUS): 4973836
in_voltage_10 (125V): 1249405

[1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408

Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
---
 drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
--- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
+++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
@@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
 		goto unlock;
 
 	/* Decimation factor */
-	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
-			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
-			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
-			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
+	ret = regmap_update_bits(adc->map,
+				 ADC_ARB_USRP_DIG_PARAM,
+				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
+				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
+				 ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
 	if (ret)
 		goto unlock;
 
@@ -783,6 +784,7 @@ static int pm8xxx_xoadc_parse_channel(struct device *dev,
 	ch->calibration = VADC_CALIB_ABSOLUTE;
 	/* Everyone seems to use default ("type 2") decimation */
 	ch->decimation = VADC_DEF_DECIMATION;
+	ch->amux_ip_rsv = hwchan->amux_ip_rsv;
 
 	if (!fwnode_property_read_u32(fwnode, "qcom,ratiometric", &rsv)) {
 		ch->calibration = VADC_CALIB_RATIOMETRIC;

-- 
2.34.1

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[David Lechner]

On 10/27/25 12:29 PM, Antony Kurniawan Soemardi wrote:
> On msm8960 phones, the XOADC driver was using incorrect calibration
> values:
> absolute calibration dx = 625000 uV, dy = 4 units
> ratiometric calibration dx = 1800, dy = -29041 units
> 
> As a result, reading from the IIO bus returned unexpected results:
> in_voltage_7 (USB_VBUS): 0
> in_voltage_10 (125V): 0
> 
> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
> from the predefined channels. Additionally, the downstream code always

Mentioning downstream kernels is usually a red flag. :-) 

We can justify it here though by saying that there is no documentation
available other than downstream source code, so we are just using it
as a reference.

> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
> those bits caused calibration errors too, so they were removed.
> 
> With these fixes, calibration now uses the correct values:
> absolute calibration dx = 625000 uV, dy = 6307 units
> ratiometric calibration dx = 1800, dy = 18249 units
> 
> Reading from the IIO bus now returns expected results:
> in_voltage_7 (USB_VBUS): 4973836
> in_voltage_10 (125V): 1249405

Would be useful to mention which hardware you tested with in case
it turns out that there is some other hardware that does require the
SHIFT0/1 bits to be set.

> 
> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
> 

Since this is a fix, it should have a Fixes: tag. And it sounds like
possibly two separate fixes. In that case, it should be two separate
patches.

> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
> ---
>  drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>  		goto unlock;
>  
>  	/* Decimation factor */
> -	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
> -			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
> +	ret = regmap_update_bits(adc->map,
> +				 ADC_ARB_USRP_DIG_PARAM,
> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
> +				 ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);

As a follow-up patch, it would be nice to update the driver to use FIELD_PREP().

I.e. remove ADC_ARB_USRP_DIG_PARAM_DEC_RATE0, ADC_ARB_USRP_DIG_PARAM_DEC_RATE1
and ADC_DIG_PARAM_DEC_SHIFT macros and replace them with one macro:

#define ADC_ARB_USRP_DIG_PARAM_DEC_RATE		GENMASK(6, 5)

Then use it like:

	ret = regmap_update_bits(adc->map,
				 ADC_ARB_USRP_DIG_PARAM,
				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
				 FIELD_PREP(ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
					    ch->decimation));

This should be done for all of the similar multi-bit fields.

>  	if (ret)
>  		goto unlock;
>  
> @@ -783,6 +784,7 @@ static int pm8xxx_xoadc_parse_channel(struct device *dev,
>  	ch->calibration = VADC_CALIB_ABSOLUTE;
>  	/* Everyone seems to use default ("type 2") decimation */
>  	ch->decimation = VADC_DEF_DECIMATION;
> +	ch->amux_ip_rsv = hwchan->amux_ip_rsv;
>  
>  	if (!fwnode_property_read_u32(fwnode, "qcom,ratiometric", &rsv)) {
>  		ch->calibration = VADC_CALIB_RATIOMETRIC;
> 

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Antony Kurniawan Soemardi]

On 10/28/2025 1:35 AM, David Lechner wrote:
> On 10/27/25 12:29 PM, Antony Kurniawan Soemardi wrote:
>> On msm8960 phones, the XOADC driver was using incorrect calibration
>> values:
>> absolute calibration dx = 625000 uV, dy = 4 units
>> ratiometric calibration dx = 1800, dy = -29041 units
>>
>> As a result, reading from the IIO bus returned unexpected results:
>> in_voltage_7 (USB_VBUS): 0
>> in_voltage_10 (125V): 0
>>
>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
>> from the predefined channels. Additionally, the downstream code always
> Mentioning downstream kernels is usually a red flag. :-)
>
> We can justify it here though by saying that there is no documentation
> available other than downstream source code, so we are just using it
> as a reference.
ah ok, rewording needed then
>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
>> those bits caused calibration errors too, so they were removed.
>>
>> With these fixes, calibration now uses the correct values:
>> absolute calibration dx = 625000 uV, dy = 6307 units
>> ratiometric calibration dx = 1800, dy = 18249 units
>>
>> Reading from the IIO bus now returns expected results:
>> in_voltage_7 (USB_VBUS): 4973836
>> in_voltage_10 (125V): 1249405
> Would be useful to mention which hardware you tested with in case
> it turns out that there is some other hardware that does require the
> SHIFT0/1 bits to be set.
I did mention Sony Xperia SP from cover letter, but I haven't
referenced it in this commit yet. Also I tried to search on Github for
SHIFT0/1 bits, but couldn't find any usage of them...
>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
>>
> Since this is a fix, it should have a Fixes: tag. And it sounds like
> possibly two separate fixes. In that case, it should be two separate
> patches.
Fixes into 63c3ecd946d4ae2879ec0d8c6dcb90132a74d831?
>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
>> ---
>>   drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>>   		goto unlock;
>>   
>>   	/* Decimation factor */
>> -	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
>> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
>> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
>> -			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>> +	ret = regmap_update_bits(adc->map,
>> +				 ADC_ARB_USRP_DIG_PARAM,
>> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
>> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
>> +				 ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
> As a follow-up patch, it would be nice to update the driver to use FIELD_PREP().
>
> I.e. remove ADC_ARB_USRP_DIG_PARAM_DEC_RATE0, ADC_ARB_USRP_DIG_PARAM_DEC_RATE1
> and ADC_DIG_PARAM_DEC_SHIFT macros and replace them with one macro:
>
> #define ADC_ARB_USRP_DIG_PARAM_DEC_RATE		GENMASK(6, 5)
>
> Then use it like:
>
> 	ret = regmap_update_bits(adc->map,
> 				 ADC_ARB_USRP_DIG_PARAM,
> 				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
> 				 FIELD_PREP(ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
> 					    ch->decimation));
>
> This should be done for all of the similar multi-bit fields.
as a follow up patch, you mean next version of this patch series, or
separate patch series?
>>   	if (ret)
>>   		goto unlock;
>>   
>> @@ -783,6 +784,7 @@ static int pm8xxx_xoadc_parse_channel(struct device *dev,
>>   	ch->calibration = VADC_CALIB_ABSOLUTE;
>>   	/* Everyone seems to use default ("type 2") decimation */
>>   	ch->decimation = VADC_DEF_DECIMATION;
>> +	ch->amux_ip_rsv = hwchan->amux_ip_rsv;
>>   
>>   	if (!fwnode_property_read_u32(fwnode, "qcom,ratiometric", &rsv)) {
>>   		ch->calibration = VADC_CALIB_RATIOMETRIC;
>>

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[David Lechner]

On 10/27/25 2:53 PM, Antony Kurniawan Soemardi wrote:
> On 10/28/2025 1:35 AM, David Lechner wrote:
>> On 10/27/25 12:29 PM, Antony Kurniawan Soemardi wrote:
>>> On msm8960 phones, the XOADC driver was using incorrect calibration
>>> values:
>>> absolute calibration dx = 625000 uV, dy = 4 units
>>> ratiometric calibration dx = 1800, dy = -29041 units
>>>
>>> As a result, reading from the IIO bus returned unexpected results:
>>> in_voltage_7 (USB_VBUS): 0
>>> in_voltage_10 (125V): 0
>>>
>>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
>>> from the predefined channels. Additionally, the downstream code always
>> Mentioning downstream kernels is usually a red flag. :-)
>>
>> We can justify it here though by saying that there is no documentation
>> available other than downstream source code, so we are just using it
>> as a reference.
> ah ok, rewording needed then
>>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
>>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
>>> those bits caused calibration errors too, so they were removed.
>>>
>>> With these fixes, calibration now uses the correct values:
>>> absolute calibration dx = 625000 uV, dy = 6307 units
>>> ratiometric calibration dx = 1800, dy = 18249 units
>>>
>>> Reading from the IIO bus now returns expected results:
>>> in_voltage_7 (USB_VBUS): 4973836
>>> in_voltage_10 (125V): 1249405
>> Would be useful to mention which hardware you tested with in case
>> it turns out that there is some other hardware that does require the
>> SHIFT0/1 bits to be set.
> I did mention Sony Xperia SP from cover letter, but I haven't
> referenced it in this commit yet. Also I tried to search on Github for
> SHIFT0/1 bits, but couldn't find any usage of them...
>>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
>>>
>> Since this is a fix, it should have a Fixes: tag. And it sounds like
>> possibly two separate fixes. In that case, it should be two separate
>> patches.
> Fixes into 63c3ecd946d4ae2879ec0d8c6dcb90132a74d831?

The correct format is:

Fixes: 63c3ecd946d4 ("iio: adc: add a driver for Qualcomm PM8xxx HK/XOADC")

See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-changes

>>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
>>> ---
>>>   drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
>>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>>>           goto unlock;
>>>         /* Decimation factor */
>>> -    ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
>>> -               ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>>> +    ret = regmap_update_bits(adc->map,
>>> +                 ADC_ARB_USRP_DIG_PARAM,
>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
>>> +                 ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>> As a follow-up patch, it would be nice to update the driver to use FIELD_PREP().
>>
>> I.e. remove ADC_ARB_USRP_DIG_PARAM_DEC_RATE0, ADC_ARB_USRP_DIG_PARAM_DEC_RATE1
>> and ADC_DIG_PARAM_DEC_SHIFT macros and replace them with one macro:
>>
>> #define ADC_ARB_USRP_DIG_PARAM_DEC_RATE        GENMASK(6, 5)
>>
>> Then use it like:
>>
>>     ret = regmap_update_bits(adc->map,
>>                  ADC_ARB_USRP_DIG_PARAM,
>>                  ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
>>                  FIELD_PREP(ADC_ARB_USRP_DIG_PARAM_DEC_RATE,
>>                         ch->decimation));
>>
>> This should be done for all of the similar multi-bit fields.
> as a follow up patch, you mean next version of this patch series, or
> separate patch series?

Either way is fine. It's just a "nice to have" change.

>>>       if (ret)
>>>           goto unlock;
>>>   @@ -783,6 +784,7 @@ static int pm8xxx_xoadc_parse_channel(struct device *dev,
>>>       ch->calibration = VADC_CALIB_ABSOLUTE;
>>>       /* Everyone seems to use default ("type 2") decimation */
>>>       ch->decimation = VADC_DEF_DECIMATION;
>>> +    ch->amux_ip_rsv = hwchan->amux_ip_rsv;
>>>         if (!fwnode_property_read_u32(fwnode, "qcom,ratiometric", &rsv)) {
>>>           ch->calibration = VADC_CALIB_RATIOMETRIC;
>>>
> 

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Konrad Dybcio]

On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
> On msm8960 phones, the XOADC driver was using incorrect calibration
> values:
> absolute calibration dx = 625000 uV, dy = 4 units
> ratiometric calibration dx = 1800, dy = -29041 units
> 
> As a result, reading from the IIO bus returned unexpected results:
> in_voltage_7 (USB_VBUS): 0
> in_voltage_10 (125V): 0
> 
> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
> from the predefined channels. Additionally, the downstream code always
> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
> those bits caused calibration errors too, so they were removed.
> 
> With these fixes, calibration now uses the correct values:
> absolute calibration dx = 625000 uV, dy = 6307 units
> ratiometric calibration dx = 1800, dy = 18249 units
> 
> Reading from the IIO bus now returns expected results:
> in_voltage_7 (USB_VBUS): 4973836
> in_voltage_10 (125V): 1249405
> 
> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
> 
> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
> ---
>  drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>  		goto unlock;
>  
>  	/* Decimation factor */
> -	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
> -			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
> +	ret = regmap_update_bits(adc->map,
> +				 ADC_ARB_USRP_DIG_PARAM,
> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,

The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
for a "1K" (1/1024?) ratio, although a comment in this file suggests
BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
surprised if that is the case

The previously set bits are a field called DECI_SEL but are otherwise left
undescribed

Hope this is useful

Konrad

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Antony Kurniawan Soemardi]

On 10/28/2025 4:44 PM, Konrad Dybcio wrote:
> On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
>> On msm8960 phones, the XOADC driver was using incorrect calibration
>> values:
>> absolute calibration dx = 625000 uV, dy = 4 units
>> ratiometric calibration dx = 1800, dy = -29041 units
>>
>> As a result, reading from the IIO bus returned unexpected results:
>> in_voltage_7 (USB_VBUS): 0
>> in_voltage_10 (125V): 0
>>
>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
>> from the predefined channels. Additionally, the downstream code always
>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
>> those bits caused calibration errors too, so they were removed.
>>
>> With these fixes, calibration now uses the correct values:
>> absolute calibration dx = 625000 uV, dy = 6307 units
>> ratiometric calibration dx = 1800, dy = 18249 units
>>
>> Reading from the IIO bus now returns expected results:
>> in_voltage_7 (USB_VBUS): 4973836
>> in_voltage_10 (125V): 1249405
>>
>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
>>
>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
>> ---
>>   drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>>   		goto unlock;
>>   
>>   	/* Decimation factor */
>> -	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
>> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
>> -			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
>> -			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>> +	ret = regmap_update_bits(adc->map,
>> +				 ADC_ARB_USRP_DIG_PARAM,
>> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
>> +				 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
> The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
> for a "1K" (1/1024?) ratio, although a comment in this file suggests
> BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
> surprised if that is the case
>
> The previously set bits are a field called DECI_SEL but are otherwise left
> undescribed

So, do you think we can leave the BIT(0) and BIT(1) as is? I have a feeling
that if they aren't set, these changes might prevent the APQ8060 Dragonboard
from reading the cm3605 sensor? or maybe not?

I mean this one, since the driver was originally tested on that board
https://github.com/torvalds/linux/blob/e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6/arch/arm/boot/dts/qcom/qcom-apq8060-dragonboard.dts#L67-L79

> Hope this is useful
>
> Konrad

Thanks,
Antony K. S.

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Konrad Dybcio]

On 10/30/25 5:57 PM, Antony Kurniawan Soemardi wrote:
> On 10/28/2025 4:44 PM, Konrad Dybcio wrote:
>> On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
>>> On msm8960 phones, the XOADC driver was using incorrect calibration
>>> values:
>>> absolute calibration dx = 625000 uV, dy = 4 units
>>> ratiometric calibration dx = 1800, dy = -29041 units
>>>
>>> As a result, reading from the IIO bus returned unexpected results:
>>> in_voltage_7 (USB_VBUS): 0
>>> in_voltage_10 (125V): 0
>>>
>>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
>>> from the predefined channels. Additionally, the downstream code always
>>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
>>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
>>> those bits caused calibration errors too, so they were removed.
>>>
>>> With these fixes, calibration now uses the correct values:
>>> absolute calibration dx = 625000 uV, dy = 6307 units
>>> ratiometric calibration dx = 1800, dy = 18249 units
>>>
>>> Reading from the IIO bus now returns expected results:
>>> in_voltage_7 (USB_VBUS): 4973836
>>> in_voltage_10 (125V): 1249405
>>>
>>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
>>>
>>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
>>> ---
>>>   drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
>>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>>>           goto unlock;
>>>         /* Decimation factor */
>>> -    ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
>>> -               ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>>> +    ret = regmap_update_bits(adc->map,
>>> +                 ADC_ARB_USRP_DIG_PARAM,
>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
>> The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
>> for a "1K" (1/1024?) ratio, although a comment in this file suggests
>> BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
>> surprised if that is the case
>>
>> The previously set bits are a field called DECI_SEL but are otherwise left
>> undescribed
> 
> So, do you think we can leave the BIT(0) and BIT(1) as is? I have a feeling
> that if they aren't set, these changes might prevent the APQ8060 Dragonboard
> from reading the cm3605 sensor? or maybe not?
> 
> I mean this one, since the driver was originally tested on that board
> https://github.com/torvalds/linux/blob/e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6/arch/arm/boot/dts/qcom/qcom-apq8060-dragonboard.dts#L67-L79

+Dmitry would you have that (or similar) board in your museum?

Konrad

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Dmitry Baryshkov]

On Fri, Oct 31, 2025 at 10:00:25AM +0100, Konrad Dybcio wrote:
> On 10/30/25 5:57 PM, Antony Kurniawan Soemardi wrote:
> > On 10/28/2025 4:44 PM, Konrad Dybcio wrote:
> >> On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
> >>> On msm8960 phones, the XOADC driver was using incorrect calibration
> >>> values:
> >>> absolute calibration dx = 625000 uV, dy = 4 units
> >>> ratiometric calibration dx = 1800, dy = -29041 units
> >>>
> >>> As a result, reading from the IIO bus returned unexpected results:
> >>> in_voltage_7 (USB_VBUS): 0
> >>> in_voltage_10 (125V): 0
> >>>
> >>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
> >>> from the predefined channels. Additionally, the downstream code always
> >>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
> >>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
> >>> those bits caused calibration errors too, so they were removed.
> >>>
> >>> With these fixes, calibration now uses the correct values:
> >>> absolute calibration dx = 625000 uV, dy = 6307 units
> >>> ratiometric calibration dx = 1800, dy = 18249 units
> >>>
> >>> Reading from the IIO bus now returns expected results:
> >>> in_voltage_7 (USB_VBUS): 4973836
> >>> in_voltage_10 (125V): 1249405
> >>>
> >>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
> >>>
> >>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
> >>> ---
> >>>   drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
> >>>   1 file changed, 6 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> >>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
> >>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> >>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> >>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
> >>>           goto unlock;
> >>>         /* Decimation factor */
> >>> -    ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
> >>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
> >>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
> >>> -               ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
> >>> +    ret = regmap_update_bits(adc->map,
> >>> +                 ADC_ARB_USRP_DIG_PARAM,
> >>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
> >>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
> >> The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
> >> for a "1K" (1/1024?) ratio, although a comment in this file suggests
> >> BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
> >> surprised if that is the case
> >>
> >> The previously set bits are a field called DECI_SEL but are otherwise left
> >> undescribed
> > 
> > So, do you think we can leave the BIT(0) and BIT(1) as is? I have a feeling
> > that if they aren't set, these changes might prevent the APQ8060 Dragonboard
> > from reading the cm3605 sensor? or maybe not?
> > 
> > I mean this one, since the driver was originally tested on that board
> > https://github.com/torvalds/linux/blob/e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6/arch/arm/boot/dts/qcom/qcom-apq8060-dragonboard.dts#L67-L79
> 
> +Dmitry would you have that (or similar) board in your museum?

I do, but I sadly I didn't test it lately (nor do I remember if I have
sensors board or not). I can try testing it next week, if I have time.

-- 
With best wishes
Dmitry

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Antony Kurniawan Soemardi]

On 11/1/2025 4:25 PM, Dmitry Baryshkov wrote:
> On Fri, Oct 31, 2025 at 10:00:25AM +0100, Konrad Dybcio wrote:
>> On 10/30/25 5:57 PM, Antony Kurniawan Soemardi wrote:
>>> On 10/28/2025 4:44 PM, Konrad Dybcio wrote:
>>>> On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
>>>>> On msm8960 phones, the XOADC driver was using incorrect calibration
>>>>> values:
>>>>> absolute calibration dx = 625000 uV, dy = 4 units
>>>>> ratiometric calibration dx = 1800, dy = -29041 units
>>>>>
>>>>> As a result, reading from the IIO bus returned unexpected results:
>>>>> in_voltage_7 (USB_VBUS): 0
>>>>> in_voltage_10 (125V): 0
>>>>>
>>>>> The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
>>>>> from the predefined channels. Additionally, the downstream code always
>>>>> set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
>>>>> That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
>>>>> those bits caused calibration errors too, so they were removed.
>>>>>
>>>>> With these fixes, calibration now uses the correct values:
>>>>> absolute calibration dx = 625000 uV, dy = 6307 units
>>>>> ratiometric calibration dx = 1800, dy = 18249 units
>>>>>
>>>>> Reading from the IIO bus now returns expected results:
>>>>> in_voltage_7 (USB_VBUS): 4973836
>>>>> in_voltage_10 (125V): 1249405
>>>>>
>>>>> [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
>>>>>
>>>>> Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
>>>>> ---
>>>>>    drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
>>>>>    1 file changed, 6 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>>>> index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
>>>>> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>>>> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
>>>>> @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
>>>>>            goto unlock;
>>>>>          /* Decimation factor */
>>>>> -    ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
>>>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
>>>>> -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
>>>>> -               ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
>>>>> +    ret = regmap_update_bits(adc->map,
>>>>> +                 ADC_ARB_USRP_DIG_PARAM,
>>>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
>>>>> +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
>>>> The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
>>>> for a "1K" (1/1024?) ratio, although a comment in this file suggests
>>>> BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
>>>> surprised if that is the case
>>>>
>>>> The previously set bits are a field called DECI_SEL but are otherwise left
>>>> undescribed
>>> So, do you think we can leave the BIT(0) and BIT(1) as is? I have a feeling
>>> that if they aren't set, these changes might prevent the APQ8060 Dragonboard
>>> from reading the cm3605 sensor? or maybe not?
>>>
>>> I mean this one, since the driver was originally tested on that board
>>> https://github.com/torvalds/linux/blob/e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6/arch/arm/boot/dts/qcom/qcom-apq8060-dragonboard.dts#L67-L79
>> +Dmitry would you have that (or similar) board in your museum?
> I do, but I sadly I didn't test it lately (nor do I remember if I have
> sensors board or not). I can try testing it next week, if I have time.
>
Hi Dmitry, I wanted to follow up and ask whether you’ve had a chance to 
test the APQ8060 DragonBoard though?

(Also happy new year! Eh, it's 12 days late...)

Thanks,

Re: [PATCH 2/2] iio: adc: qcom-pm8xxx-xoadc: fix incorrect calibration values

[Dmitry Baryshkov]

On Sun, Jan 11, 2026 at 05:31:45PM +0000, Antony Kurniawan Soemardi wrote:
> On 11/1/2025 4:25 PM, Dmitry Baryshkov wrote:
> > On Fri, Oct 31, 2025 at 10:00:25AM +0100, Konrad Dybcio wrote:
> > > On 10/30/25 5:57 PM, Antony Kurniawan Soemardi wrote:
> > > > On 10/28/2025 4:44 PM, Konrad Dybcio wrote:
> > > > > On 10/27/25 6:29 PM, Antony Kurniawan Soemardi wrote:
> > > > > > On msm8960 phones, the XOADC driver was using incorrect calibration
> > > > > > values:
> > > > > > absolute calibration dx = 625000 uV, dy = 4 units
> > > > > > ratiometric calibration dx = 1800, dy = -29041 units
> > > > > > 
> > > > > > As a result, reading from the IIO bus returned unexpected results:
> > > > > > in_voltage_7 (USB_VBUS): 0
> > > > > > in_voltage_10 (125V): 0
> > > > > > 
> > > > > > The issue was caused by not setting the ratiometric scale (amux_ip_rsv)
> > > > > > from the predefined channels. Additionally, the downstream code always
> > > > > > set the ADC_ARB_USRP_DIG_PARAM register to PM8XXX_ADC_ARB_ANA_DIG [1].
> > > > > > That value does not include the SEL_SHIFT0 and SEL_SHIFT1 bits. Enabling
> > > > > > those bits caused calibration errors too, so they were removed.
> > > > > > 
> > > > > > With these fixes, calibration now uses the correct values:
> > > > > > absolute calibration dx = 625000 uV, dy = 6307 units
> > > > > > ratiometric calibration dx = 1800, dy = 18249 units
> > > > > > 
> > > > > > Reading from the IIO bus now returns expected results:
> > > > > > in_voltage_7 (USB_VBUS): 4973836
> > > > > > in_voltage_10 (125V): 1249405
> > > > > > 
> > > > > > [1] https://github.com/LineageOS/android_kernel_sony_msm8960t/blob/93319b1e5aa343ec1c1aabcb028c5e88c7df7c01/drivers/hwmon/pm8xxx-adc.c#L407-L408
> > > > > > 
> > > > > > Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
> > > > > > ---
> > > > > >    drivers/iio/adc/qcom-pm8xxx-xoadc.c | 10 ++++++----
> > > > > >    1 file changed, 6 insertions(+), 4 deletions(-)
> > > > > > 
> > > > > > diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> > > > > > index 8555f34036fb13c41ac720dc02c1dc39876e9198..a53d361456ec36b66d258041877bd96ab37838c4 100644
> > > > > > --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> > > > > > +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> > > > > > @@ -503,10 +503,11 @@ static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
> > > > > >            goto unlock;
> > > > > >          /* Decimation factor */
> > > > > > -    ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
> > > > > > -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
> > > > > > -               ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
> > > > > > -               ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
> > > > > > +    ret = regmap_update_bits(adc->map,
> > > > > > +                 ADC_ARB_USRP_DIG_PARAM,
> > > > > > +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE0 |
> > > > > > +                 ADC_ARB_USRP_DIG_PARAM_DEC_RATE1,
> > > > > The PM8921 datasheet suggests a single valid value of BIT(5)=1, BIT(6)=0
> > > > > for a "1K" (1/1024?) ratio, although a comment in this file suggests
> > > > > BIT(5)|BIT(6) is also valid and corresponds to 1/4096.. I wouldn't be
> > > > > surprised if that is the case
> > > > > 
> > > > > The previously set bits are a field called DECI_SEL but are otherwise left
> > > > > undescribed
> > > > So, do you think we can leave the BIT(0) and BIT(1) as is? I have a feeling
> > > > that if they aren't set, these changes might prevent the APQ8060 Dragonboard
> > > > from reading the cm3605 sensor? or maybe not?
> > > > 
> > > > I mean this one, since the driver was originally tested on that board
> > > > https://github.com/torvalds/linux/blob/e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6/arch/arm/boot/dts/qcom/qcom-apq8060-dragonboard.dts#L67-L79
> > > +Dmitry would you have that (or similar) board in your museum?
> > I do, but I sadly I didn't test it lately (nor do I remember if I have
> > sensors board or not). I can try testing it next week, if I have time.
> > 
> Hi Dmitry, I wanted to follow up and ask whether you’ve had a chance to test
> the APQ8060 DragonBoard though?

No, after reshuffling of the lab it's still in the box, sorry.

> 
> (Also happy new year! Eh, it's 12 days late...)
> 
> Thanks,

-- 
With best wishes
Dmitry