drivers/gp8xxx: add initial support #21182

basilfx · 2025-02-02T13:53:17Z

Contribution description

This adds support for the Guestgood GP8xxx I2C voltage and current DACs. The following variations are supported.

GP8503: 2-channel 12-bit VDAC with 0-2.5/VCC V output range
GP8512: 1-channel 15-bit VDAC with 0-2.5/VCC V output range
GP8211S: 1-channel 15-bit VDAC with 0-5/10 V output range
GP8403: 2-channel 12-bit VDAC with 0-5/10 V output range
GP8413: 2-channel 15-bit VDAC with 0-5/10 V output range
GP8302: 1-channel 12-bit IDAC with 0-25 mA output range

Although Guestgood is Chinese and doesn't offer English datasheets, small and well-documented development boards are produced by DFRobot, which are distributed by several known distributors such as Mouser and Digikey.

The 0-10V VDACs had my particular interest, because several home automation appliances can be controlled using 0-10V signals. These single-chip solutions are very ideal for this purpose.

SAUL was extended to support voltage and current actuators.

Testing procedure

A test application is provided in tests/drivers/gp8xxx. By default, it will select the GP8403, but additional actuators can be specified using USEMODULE. I tested the GP8403 and GP8302 only, but the others will probably work out of the box (my driver is largely based on DFRobot's Arduino version).

SAUL integration can be tested with examples/basic/saul. Note that when using this application, the arguments are parsed as Volts or Amperes. Unfortunately, the SAUL shell does not support fractional numbers, so testing the full range is not really possible for the 0-25 mA IDAC.

I have created three videos to show the driver in action:

https://youtu.be/4KP5KcsVPYA - tests/drivers/gp8xxx with only GP8403
https://youtu.be/1veRyRUucIw - tests/drivers/gp8xxx with both GP8302 + GP8403
https://youtu.be/a-7JHC5piZs - examples/basic/saul with both GP8302 + GP8403

My test setup:

Issues/PRs references

None

riot-ci · 2025-02-04T16:42:23Z

Murdock results

✔️ PASSED

47a53e8 tests/drivers/saul_drivers: enable gp8403 and 8302

Success	Failures	Total	Runtime
11000	0	11001	09m:22s

Artifacts

Documentation preview

basilfx · 2026-01-05T22:56:19Z

I took the liberty of rebasing this PR and adapt it to meet the conventions since last push.

Tested this once more using the SLSTK3401A with the GP8302 + GP8403 combination.

drivers/gp8xxx/gp8xxx.c

crasbe · 2026-01-06T13:59:38Z

drivers/gp8xxx/gp8xxx.c

+{
+    assert(dev->params.info->type == GP8XXX_INFO_TYPE_VDAC);
+
+    /* only the 5 V/10 V models have a customizable range */


Wouldn't it make sense to return an error when the range wasn't actually set because the device doesn't support it? -ENOSUP for example?

I decided that wrong use would fall in the use of programming errors, and that an assert would be sufficient alternative to another return value or making it type safer.

drivers/gp8xxx/gp8xxx.c

drivers/gp8xxx/include/gp8xxx_params.h

tests/drivers/gp8xxx/main.c

crasbe · 2026-01-06T14:14:11Z

dist/tools/doccheck/exclude_simple

+warning: Member GP8211S_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8211S_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8211S_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8302_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8302_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8302_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8403_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8403_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8403_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8413_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8413_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8413_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8503_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8503_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8503_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8512_INFO_CHANNELS (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8512_INFO_RANGE (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8512_INFO_RESOLUTION (macro definition) of file gp8xxx_info.h is not documented.
+warning: Member GP8XXX_REG_CHANNEL (macro definition) of file gp8xxx_constants.h is not documented.
+warning: Member GP8XXX_REG_OUTPUT (macro definition) of file gp8xxx_constants.h is not documented.


I would much prefer if you instead documented the macros.

Documented them, so this commit will be removed.

crasbe · 2026-01-06T14:15:41Z

tests/drivers/saul_drivers/Makefile

+ifneq (,$(filter gp8xxx,$(DRIVERS)))
+  USEMODULE += gp8403
+  USEMODULE += gp8302
+endif


Would this also work when selecting gp8512 module in the test application?

Tested this by only selecting gp8512 AND including gp8512, which compiled fine.

basilfx · 2026-01-06T16:03:07Z

Thanks @crasbe, I will take care of the comments tonight (hopefully).

basilfx · 2026-01-06T22:44:37Z

@crasbe I have addressed all comments. I commented on the ones still unresolved, to check if you agree.

Did another round of testing with the SLSTK3401a (as in the videos) and it still works.

basilfx · 2026-01-12T16:21:47Z

@crasbe anything I need to address, or can I squash?

crasbe

Just some super small nitpicks, you can squash the changes directly I think.

drivers/gp8xxx/Makefile.dep

drivers/gp8xxx/gp8xxx.c

drivers/gp8xxx/include/gp8xxx_params.h

drivers/include/gp8xxx.h

crasbe · 2026-01-13T15:22:37Z

The test needs a Makefile.ci file to exclude devices that don't have enough memory, I'll run make generate-Makefile.ci locally and post the results here shortly.

crasbe · 2026-01-13T15:32:15Z

Here you go:

BOARD_INSUFFICIENT_MEMORY := \
    atmega8 \
    nucleo-l011k4 \
    #

To add support for voltage and current DACs, add additional SAUL actuators.

The Guestgood GP8xxx I2C DACs are easy-to-use voltage and current DACs with standardized output ranges. All supported variants have very similar I2C protocol. This commit adds support for a generic driver (gp8xxx) and uses a information structure to record capabilities. Multiple driver instances can work simultaneously on the same I2C bus. SAUL support is also added.

These two drivers ensure that a VDAC and IDAC capabilities are included.

basilfx · 2026-01-13T15:38:01Z

Thanks. I took the liberty to immediately squash that into the commit for the test application.

basilfx · 2026-01-13T22:15:16Z

Thank you @crasbe for the review and help to get this merged!

github-actions bot added Area: doc Area: Documentation Area: tests Area: tests and testing framework Area: drivers Area: Device drivers Area: SAUL Area: Sensor/Actuator Uber Layer labels Feb 2, 2025

basilfx force-pushed the driver-gp8xxx branch 3 times, most recently from 8643628 to c59968c Compare February 2, 2025 21:18

github-actions bot added the Area: tools Area: Supplementary tools label Feb 2, 2025

basilfx marked this pull request as ready for review February 2, 2025 21:37

basilfx requested review from MichelRottleuthner, aabadie and leandrolanzieri as code owners February 2, 2025 21:37

basilfx force-pushed the driver-gp8xxx branch from c59968c to 6fe9152 Compare February 2, 2025 22:26

basilfx added Type: new feature The issue requests / The PR implemements a new feature for RIOT CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR labels Feb 4, 2025

basilfx force-pushed the driver-gp8xxx branch from 6fe9152 to 5fac517 Compare February 4, 2025 20:10

basilfx force-pushed the driver-gp8xxx branch from 5fac517 to 2a20deb Compare April 11, 2025 21:34

basilfx force-pushed the driver-gp8xxx branch 2 times, most recently from b5824f6 to c13315e Compare January 5, 2026 22:41

crasbe requested changes Jan 6, 2026

View reviewed changes

github-actions bot removed the Area: tools Area: Supplementary tools label Jan 6, 2026

basilfx force-pushed the driver-gp8xxx branch 2 times, most recently from 1f60595 to 9a4f7cc Compare January 6, 2026 22:41

crasbe reviewed Jan 12, 2026

View reviewed changes

basilfx force-pushed the driver-gp8xxx branch from 9a4f7cc to ee3150a Compare January 13, 2026 12:20

crasbe approved these changes Jan 13, 2026

View reviewed changes

crasbe enabled auto-merge January 13, 2026 14:11

crasbe added this pull request to the merge queue Jan 13, 2026

crasbe removed this pull request from the merge queue due to a manual request Jan 13, 2026

basilfx added 4 commits January 13, 2026 16:36

saul: add voltage and current actuators

9c86a70

To add support for voltage and current DACs, add additional SAUL actuators.

tests/drivers/gp8xxx: add test application

7e5a767

tests/drivers/saul_drivers: enable gp8403 and 8302

47a53e8

These two drivers ensure that a VDAC and IDAC capabilities are included.

basilfx force-pushed the driver-gp8xxx branch from ee3150a to 47a53e8 Compare January 13, 2026 15:37

crasbe enabled auto-merge January 13, 2026 15:38

crasbe added this pull request to the merge queue Jan 13, 2026

github-merge-queue bot removed this pull request from the merge queue due to failed status checks Jan 13, 2026

crasbe added this pull request to the merge queue Jan 13, 2026

Merged via the queue into RIOT-OS:master with commit aab9636 Jan 13, 2026
25 checks passed

basilfx deleted the driver-gp8xxx branch January 13, 2026 22:14

drivers/gp8xxx: add initial support #21182

drivers/gp8xxx: add initial support #21182

Conversation

basilfx commented Feb 2, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Contribution description

Testing procedure

Issues/PRs references

Uh oh!

riot-ci commented Feb 4, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Murdock results

Artifacts

Uh oh!

basilfx commented Jan 5, 2026

Uh oh!

Uh oh!

crasbe Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

basilfx Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

crasbe Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

basilfx Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

crasbe Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

basilfx Jan 6, 2026

Choose a reason for hiding this comment

Uh oh!

basilfx commented Jan 6, 2026

Uh oh!

basilfx commented Jan 6, 2026

Uh oh!

basilfx commented Jan 12, 2026

Uh oh!

crasbe left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

crasbe commented Jan 13, 2026

Uh oh!

crasbe commented Jan 13, 2026

Uh oh!

basilfx commented Jan 13, 2026

Uh oh!

Uh oh!

Uh oh!

basilfx commented Jan 13, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

basilfx commented Feb 2, 2025 •

edited

Loading

riot-ci commented Feb 4, 2025 •

edited

Loading