Add silabs series 2 IADC driver with scan conversion and DMA support. #94264

Martinhoff-maker · 2025-08-08T10:57:49Z

This pull request introduces a new Silicon Labs IADC (Incremental ADC) driver for Series 2 SoCs, replaces the old device tree compatible string, and adds support for DMA-based ADC conversions. It also updates board overlays, device tree bindings, and test configurations to support and validate the new driver on multiple series 2 SoCs.

Tested all these tests and samples: adc_dt, adc_sequence, adc_api (normal, with DMA, with DMA async), adc_accuracy, adc_error_case
on all these boards:

slwrb4180a (xg21 SoC)
sltb010a (xg22 SoC)
xg23_rb4210a (xg23 SoC)
xg24_rb4187c (xg24 SoC)
xg27_dk2602a (xg27 SoC)
xg29_rb4412a (xg29 SoC)

Also tested the adc_sequence sample with PM over xg29_rb4412 and we got an average current consumption of 13 uA.

A few ideas for improvement:

Implement runtime calibration (described in Silicon Labs reference manual)
Implement internal IADC timer instead of using the kernel timer
Add more possibilities for the acquisition time (which is different from interval between samplings)

FYI:
The resolution property for an ADC channel node is not mandatory. When it is not present, we set the property to 0 in the channel struct.
I initially used this "0" value to let the driver set the default resolution value. However, in the adc_error_case test case, a resolution of "0" is considered an error.
Shouldn't we set the resolution as a mandatory property since 0 is not a valid resolution value?

sonarqubecloud · 2025-08-08T13:06:11Z

Quality Gate passed

Issues
7 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
4.0% Duplication on New Code

See analysis details on SonarQube Cloud

drivers/adc/adc_silabs_iadc.c

jhedberg · 2025-10-03T08:39:44Z

@JarmouniA the points you raise about platform_allow require broader discussion within the project. PR review comments don't give the issue the attention it deserves, IMO. This was also a topic that was raised at the recent TSC F2F meeting a month ago. I believe one reason why these keep getting added is downstream on-HW CI, since not having the platforms listed means you have to explicitly force twister to use a given platform for testing, rather than e.g. requesting it to "test on all Silabs platforms".

JarmouniA · 2025-10-03T08:59:27Z

I believe one reason why these keep getting added is downstream on-HW CI, since not having the platforms listed means you have to explicitly force twister to use a given platform for testing, rather than e.g. requesting it to "test on all Silabs platforms".

Using --force-platform allows to override filtering caused by platform_allow, platform_exclude, arch_allow and arch_exclude keys in test configuration files.
https://docs.zephyrproject.org/latest/develop/test/twister.html#selecting-platform-scope

Also, it does not make sense for downstream on-HW CI to test the same IP/driver with the same testcases on a ton of targets.

This is for tests, samples are completely different, they are demos, not supposed to be built for every single target in CI, and any added overlay/conf files should provide the user with extra info about configuring a certain IP/driver/subsystem... not already provided in another overlay/conf, otherwise we will end up with 8xx overlay/conf files in every sample.

Anyway, my comments above are non-blocking, but this will have to be cleaned up at some point.

jhedberg · 2025-10-03T09:09:59Z

Using --force-platform allows to override filtering caused by platform_allow, platform_exclude, arch_allow and arch_exclude keys in test configuration files. https://docs.zephyrproject.org/latest/develop/test/twister.html#selecting-platform-scope

I'm familiar with that. I still think it's rather clumsy to have to manually override each individual platform, instead of being able to use something like the --vendor VENDOR switch to cover all platforms for a given vendor.

It's also worth noting the definition of platform_allow in the above documentation, which is currently pretty clearly being violated in Zephyr's use of it:

"Do not use this option to limit testing or building in CI due to time or resource constraints, this option should only be used if the test or sample can only be run on the allowed platform and nothing else."

Also, it does not make sense for downstream on-HW CI to test the same IP/driver with the same testcases on a ton of targets.

Even though the IP is the same, details such as device tree properties may be different (e.g. base register address) and have potential bugs. So even though all tests may be overkill I don't agree that there shouldn't be any testing at all of the same IP on multiple different targets.

Martinhoff-maker · 2025-10-03T15:28:35Z

V5:

In order to be compliant with futur PR of @JarmouniA, remove all new sample overlays and instead introduce io-channels in some boards.dts
Still a little bit confused about how we handle tests overlays since we have "differences" between SoC even if it's the "same" IP as Johan said.

JarmouniA · 2025-10-03T16:44:12Z

Still a little bit confused about how we handle tests overlays since we have "differences" between SoC even if it's the "same" IP as Johan said

Different revisions of an IP should have different compatibles, see STM32 ADC for ex.

This commit updates the adc_raw_to_millivolts function to use 64-bit arithmetic. It is necessary when the intermediate result is higher than the maximum value of uint32_t. It also adds a range check to ensure the conversion result does not exceed the limits of int32_t, providing an assertion message for out-of-range values. Signed-off-by: Martin Hoff <[email protected]>

This commit introduces a new driver for the silabs Incremental ADC (IADC). Signed-off-by: Martin Hoff <[email protected]>

Martinhoff-maker · 2025-10-08T07:49:26Z

Rebased for merge conflict with migration guide.

tests/drivers/adc/adc_api/testcase.yaml

doc/releases/migration-guide-4.3.rst

Update compatibility from "silabs,gecko-iadc" to "silabs,iadc". It allows to use the new driver which are more custom to series 2 boards. Signed-off-by: Martin Hoff <[email protected]>

The goal to add the zephyr,user io-channels is to be able to run the ADC samples without having an overlays for each boards. Signed-off-by: Martin Hoff <[email protected]>

This commit introduces a new Kconfig option for oversampling in the ADC sequence sample. It allows to test oversampling for IADC sequences. Signed-off-by: Martin Hoff <[email protected]>

This commit updates the ADC sequence sample to improve handling of differential mode readings. It modifies the conversion logic to correctly interpret 16-bit/32-bit signed values and adjusts the resolution accordingly. This ensures accurate millivolt conversion for both differential and single-ended configurations. Signed-off-by: Martin Hoff <[email protected]>

This commit introduces/updates overlays for multiple silabs boards for ADC samples and ADC tests. Signed-off-by: Martin Hoff <[email protected]>

This commit introduces DMA support for the Silabs IADC driver. A new Kconfig option is added to enable DMA support, ensuring compatibility with the existing ADC configuration. DMA can be used for synch/asynch operation. Signed-off-by: Martin Hoff <[email protected]>

This commit introduces a new configuration file for DMA support specific to the Silabs IADC, along with updates to the test case YAML and device tree overlay for the xg29_rb4412a board. The changes ensure that the ADC driver can utilize DMA operations effectively. Signed-off-by: Martin Hoff <[email protected]>

Martinhoff-maker · 2025-10-08T12:54:31Z

V6: Add the deprecation of the old IADC driver

JarmouniA · 2025-10-08T13:05:28Z

drivers/adc/Kconfig.gecko

 	depends on DT_HAS_SILABS_GECKO_IADC_ENABLED
 	select SOC_GECKO_IADC
 	select ADC_CONFIGURABLE_INPUTS
+	select DEPRECATED


Add [deprecated] in the prompt as well, and direct the user in the help to the driver that shall be used.
And the driver should be disabled by default.

I think it could stay on enabled by default because if a user don't explicitly return to the old bindings, the symbol will not be selected.

JarmouniA · 2025-10-08T13:08:01Z

dts/arm/silabs/xg29/xg29.dtsi


 		adc0: adc@5a004000 {
-			compatible = "silabs,gecko-iadc";
+			compatible = "silabs,iadc";


Since all instances of silabs,gecko-iadc have been replaced, shouldn't the new driver be enabled by default for nodes with silabs,gecko-iadc compatible (downstream) ?

I want to get rid of the "gecko" naming so I want to have silabs,iadc, but yeah, no soc will use the old driver now. But i would like to let the possibility to the user to return back to the old driver for 1 release cycle before completely removed the old driver and compatible associated.

The driver can stay, it just will not be enabled by default, the newer one will instead for all nodes with new or old compatible.

So if I understand right, removed default=y in the old Kconfig and add:
depends on (DT_HAS_SILABS_IADC_ENABLED || DT_HAS_SILABS_GECKO_IADC_ENABLED) in the the new Kconfig ?
With that conf, the old binding will use the new driver but how can a user decide to go back to the old ? selecting the old Kconfig symbol will create a conflict. Or will the user needs to do:

CONFIG_ADC_SILABS_IADC=n CONFIG_ADC_GECKO_IADC=y

and change the binding ?
It makes me thinking that I might prefer to add a binding than replace it like:
compatible = "silabs,iadc", "silabs,gecko-iadc";

So if I understand right, removed default=y in the old Kconfig and add: depends on (DT_HAS_SILABS_IADC_ENABLED || DT_HAS_SILABS_GECKO_IADC_ENABLED) in the the new Kconfig ?

Yes, but you will have to add

#undef DT_DRV_COMPAT #define DT_DRV_COMPAT silabs_gecko_iadc DT_INST_FOREACH_STATUS_OKAY(IADC_INIT)

at the end of the new driver as well.

With that conf, the old binding will use the new driver but how can a user decide to go back to the old ? selecting the old Kconfig symbol will create a conflict. Or will the user needs to do:

CONFIG_ADC_SILABS_IADC=n CONFIG_ADC_GECKO_IADC=y

Yes, and ADC_GECKO_IADC should depend on ADC_SILABS_IADC=n

and change the binding ?

If you mean the compatible in device node? If they have the new compatible alone, yes they will have to put the old one (either alone, or with the new one)

It makes me thinking that I might prefer to add a binding than replace it like: compatible = "silabs,iadc", "silabs,gecko-iadc";

That's also a great option, this way switching drivers can be done with just

CONFIG_ADC_SILABS_IADC=n CONFIG_ADC_GECKO_IADC=y

sonarqubecloud · 2025-10-08T13:10:33Z

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
3.2% Duplication on New Code

See analysis details on SonarQube Cloud

Martinhoff-maker force-pushed the adc_series_2 branch 2 times, most recently from 65ca9a2 to ed1888b Compare August 8, 2025 13:03

Martinhoff-maker force-pushed the adc_series_2 branch 3 times, most recently from d9e92b0 to 5a91f78 Compare September 10, 2025 14:54

Martinhoff-maker marked this pull request as ready for review September 10, 2025 15:51

zephyrbot added Release Notes To be mentioned in the release notes area: Samples Samples platform: Silabs Silicon Labs area: ADC Analog-to-Digital Converter (ADC) labels Sep 10, 2025

zephyrbot requested review from anangl, asmellby, cfriedt, JarmouniA, jerome-pouiller, jhedberg, kartben, mnkp, nashif, rettichschnidi and yonsch September 10, 2025 15:52

zephyrbot assigned jhedberg and asmellby Sep 10, 2025

Martinhoff-maker mentioned this pull request Sep 11, 2025

Enables oversampling for the Gecko IADC #95823

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asmellby reviewed Sep 12, 2025

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Martinhoff-maker force-pushed the adc_series_2 branch 4 times, most recently from 396684b to 474f69c Compare September 19, 2025 15:05

Martinhoff-maker dismissed asmellby’s stale review via 3dced68 October 3, 2025 15:22

Martinhoff-maker force-pushed the adc_series_2 branch from bc0d950 to 3dced68 Compare October 3, 2025 15:22

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Martinhoff-maker requested review from asmellby and jerome-pouiller October 7, 2025 13:27

Martinhoff-maker added 2 commits October 8, 2025 09:46

drivers: adc: add IADC support for silabs series 2 boards

7739ebd

This commit introduces a new driver for the silabs Incremental ADC (IADC). Signed-off-by: Martin Hoff <[email protected]>

Martinhoff-maker dismissed JarmouniA’s stale review via c78d8b2 October 8, 2025 07:48

Martinhoff-maker force-pushed the adc_series_2 branch from a279105 to c78d8b2 Compare October 8, 2025 07:48

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Martinhoff-maker added 7 commits October 8, 2025 14:52

dts: arm: silabs: update IADC driver binding for all series 2 board

b1b80ac

Update compatibility from "silabs,gecko-iadc" to "silabs,iadc". It allows to use the new driver which are more custom to series 2 boards. Signed-off-by: Martin Hoff <[email protected]>

boards: silabs: add ADC io-channels on multiples boards

3c67ff1

The goal to add the zephyr,user io-channels is to be able to run the ADC samples without having an overlays for each boards. Signed-off-by: Martin Hoff <[email protected]>

samples: adc_sequence: add oversampling configuration option

a762b21

This commit introduces a new Kconfig option for oversampling in the ADC sequence sample. It allows to test oversampling for IADC sequences. Signed-off-by: Martin Hoff <[email protected]>

samples/tests: adc: silabs: add multiple device overlays.

0812b53

This commit introduces/updates overlays for multiple silabs boards for ADC samples and ADC tests. Signed-off-by: Martin Hoff <[email protected]>

Martinhoff-maker dismissed asmellby’s stale review via dc4d603 October 8, 2025 12:53

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Add silabs series 2 IADC driver with scan conversion and DMA support. #94264

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Add silabs series 2 IADC driver with scan conversion and DMA support. #94264

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