drivers: sensor: add bma400 accelerometer driver by lucagessi · Pull Request #104178 · zephyrproject-rtos/zephyr

lucagessi · 2026-02-17T18:25:28Z

Add initial support for the Bosch BMA400 accelerometer. The existing bma4xx driver is not compatible with the BMA400 due to significant register map differences.

Supported features:

On-motion auto wakeup
Inactivity auto low-power mode
Motion detection trigger (normal mode)
FIFO data streaming (normal mode)

#85462 highlights that bma4xx driver is not compatible with bma400.

#8139 asks for bma400 driver implementation

github-actions · 2026-02-17T18:26:11Z

Hello @lucagessi, and thank you very much for your first pull request to the Zephyr project!
Our Continuous Integration pipeline will execute a series of checks on your Pull Request commit messages and code, and you are expected to address any failures by updating the PR. Please take a look at our commit message guidelines to find out how to format your commit messages, and at our contribution workflow to understand how to update your Pull Request. If you haven't already, please make sure to review the project's Contributor Expectations and update (by amending and force-pushing the commits) your pull request if necessary.
If you are stuck or need help please join us on Discord and ask your question there. Additionally, you can escalate the review when applicable. 😊

lucagessi · 2026-02-23T09:57:03Z

Hi! Following up on this PR since all CI checks are green. Let me know if you have any questions.

lucagessi · 2026-03-11T06:09:24Z

Hi @MaureenHelm,

Just a quick follow-up since the CI checks are all green. Is there anything else you need me to address before review? I'm also happy to split this into smaller commits if the current one is too large.

Let me know what you think—I'm open to any changes. Thanks!

MaureenHelm · 2026-03-11T14:25:02Z

Hi @MaureenHelm,

Just a quick follow-up since the CI checks are all green. Is there anything else you need me to address before review? I'm also happy to split this into smaller commits if the current one is too large.

Let me know what you think—I'm open to any changes. Thanks!

I took a quick look and saw two things:

We're trying to avoid introducing new device-specific sensor samples. Would like to see you use one of the existing accel samples rather than introducing a new one
Please add the new sensor to tests/drivers/build_all/sensor so it gets covered in CI/CD build testing

I'll try to come back soon and do a more in-depth review.

lucagessi · 2026-03-24T05:42:23Z

@MaureenHelm I made the changes you suggested.
Hope is fine.
Thank you

sonarqubecloud · 2026-03-24T06:09:14Z

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.5% Duplication on New Code

See analysis details on SonarQube Cloud

lucagessi · 2026-03-31T14:58:45Z

Hi @MaureenHelm @teburd, I implemented the requested changes. All checks are green. Let me know if everything is ok now!🙏

ubieda

First-pass review.

sonarqubecloud · 2026-04-23T14:36:51Z

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.5% Duplication on New Code

See analysis details on SonarQube Cloud

lucagessi · 2026-04-28T05:22:53Z

@ubieda I made the changes you asked. Are ok for you?
Thank you

ubieda · 2026-04-28T13:45:53Z

Hi, @lucagessi I'll take another look in the next couple of days! Thanks for your patience.

ubieda · 2026-04-30T18:47:32Z

+	depends on SENSOR_ASYNC_API
+	select SPI if $(dt_compat_on_bus,$(DT_COMPAT_BOSCH_BMA400),spi)
+	select SPI_RTIO if $(dt_compat_on_bus,$(DT_COMPAT_BOSCH_BMA400),spi)
+	select RTIO_WORKQ


Let's drop this as it isn't required

ubieda · 2026-04-30T18:54:34Z

+	struct bma400_decoder_header header;
+	uint8_t int_status;
+	uint16_t accel_odr: 4;
+	uint16_t fifo_count: 10;


IIUC from the datasheet - The FIFO can hold 1024 bytes. Don't we, then, need 11-bits to hold the max value?

You are right my fault

ubieda · 2026-04-30T19:02:21Z

+		const bool has_accel = (BMA400_FIFO_EMPTY_FRAME & buffer[0]) != 0;
+		const bool is_empty = (BMA400_FIFO_EMPTY_FRAME == buffer[0]);


I'm confused because I'm failing to see how has_accel can be false and is_empty true at the same time (See if-elseif-else branching below). Please explain the intend.

In general: please double-check the header classification and properly handle the flags critical for the features supported.

ubieda · 2026-04-30T19:05:21Z

+	struct rtio_iodev_sqe *streaming_sqe = drv_data->streaming_sqe;
+
+	ARG_UNUSED(sqe);
+	ARG_UNUSED(result);


Handle result, as it may indicate a failure (applies to all completion cb's)

ubieda · 2026-04-30T19:19:17Z

+	uint8_t value;
+	uint8_t power_mode_conf = 0;
+
+	/* If ODR is greater than 25Hz, enable normal mode */


Would you mind clarifying how we enforce this comment? Is it stale?

I Will remove It. The sensor works only in normal mode or low power with auto sleep.

Ok - In general: I advise to look over the driver and simplify it to cover the features that are supported. I'd rather work with a driver that is limited functionality but reliable than one that has many features but not sure what is well-supported and what isn't.

I understand your point. I needed these features for a project so I tried to implement: auto wake up, auto sleep and motion event.

Is not clear how it works? Do I need to say it clearly?

No need to ellaborate: If you need all the features that's okay!

I'd simply suggest to step back, take another pass at the PR and address what you consider could use some improvement (e.g: const usage, error-handling, variables-sizing, etc).

Ok. I will do a review of the code by myself taking into account your suggestions. Thank you very much ubieda, I'll do my best ;)

ubieda · 2026-04-30T19:23:15Z

+/**
+ * Set the sensor's acceleration threshold for motion detection
+ */
+static int bma400_attr_set_motion_threshold(const struct sensor_value *val,


Should this be SI (e.g: the same unit as SENSOR_CHAN_ACCEL_XYZ)?

ubieda · 2026-04-30T19:24:11Z

+/**
+ * Set the sensor's acceleration motion event duration
+ */
+static int bma400_attr_set_motion_duration(const struct sensor_value *val,


Should this be SI (as in: Seconds)?

ubieda · 2026-04-30T19:29:59Z

+	int (*write_reg)(const struct device *dev, uint8_t reg_addr, uint8_t value);
+};
+
+struct bma400_runtime_config {


Please clairfy why the following fields should be constant:

auto_wakeup_en

auto_lowpower_en

int1_map

int2_map

The reason I ask is because this whole struct is updated at run-time.

ubieda · 2026-04-30T19:31:04Z

+			struct rtio_sqe *write_reset_fifo = rtio_sqe_acquire(r);
+			const uint8_t write_buffer[] = {
+				BMA400_REG_CMD,
+				0xb0, /* Reset FIFO */


Why not using BMA400_FIFO_FLUSH_CMD?

github-actions · 2026-06-01T01:29:26Z

This pull request has been marked as stale because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 7 days. Note, that you can always re-open a closed pull request at any time.

sonarqubecloud · 2026-06-09T03:00:47Z

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.5% Duplication on New Code

See analysis details on SonarQube Cloud

github-actions · 2026-07-11T00:53:56Z

This pull request has been marked as stale because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 7 days. Note that if it gets closed, you can ask someone to reopen it for you if you do not have the permissions to do so.

lucagessi · 2026-07-17T08:48:44Z

Sorry for the delay, been busy with work. I'm resuming work on the driver now.

github-actions · 2026-08-18T00:31:47Z

This pull request has been marked as stale because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 7 days. Note that if it gets closed, you can ask someone to reopen it for you if you do not have the permissions to do so.

Add initial support for the Bosch BMA400 accelerometer. The existing bma4xx driver is not compatible with the BMA400 due to significant register map differences. Supported features: - On-motion auto wakeup - Inactivity auto low-power mode - Motion detection trigger (normal mode) - FIFO data streaming (normal mode) Signed-off-by: Luca Gessi <lucagessi90@gmail.com>

Add bma400 sensor to build test. Signed-off-by: Luca Gessi <lucagessi90@gmail.com>

lucagessi · 2026-08-25T20:32:27Z

@ubieda I made some changes to the driver.

Below main changes:

Single interrupt line (INT1)

Dropped int2-gpios, fifo-pin-sel and motion-detect-pin-sel from the bindings. All sources (FIFO watermark, FIFO full, GEN2 motion) are mapped onto INT1 and served by one RTIO chain that reads the global INT_STAT0, so the second pin was redundant. Removed the second GPIO callback, the int1_map/int2_map config fields and the pending_gpio_interrupt state.
The line is disabled by the ISR and re-armed at the end of the chain, bounding it to one event per service window.

Sensor API conformance (review feedback)

SENSOR_ATTR_FULL_SCALE get/set now use m/s² (sensor_ms2_to_g/sensor_g_to_ms2) instead of raw g.
Motion threshold moved to SENSOR_ATTR_SLOPE_TH, converted from m/s² at 8 mg/LSB. SENSOR_ATTR_SLOPE_DUR is now expressed in samples/ticks (same convention as lis2dh/bma280) and writes the full 16-bit GEN2INT_CONFIG3:CONFIG31 field — it was truncated to 8 bits before.
Removed the bogus SENSOR_CHAN_DIE_TEMP support from the decoder, and the select RTIO_WORKQ.

FIFO decoding fixes

Frame classification rewritten: empty/sensortime/control headers are matched exactly before testing the axis-enable bits — the control frame (0x48) overlaps the Z-axis bit, so frames were mis-sized and the parse walked off.
fifo_count widened to 11 bits (FIFO is up to 1024 bytes); the decode buffer end now accounts for the SPI dummy byte.
Removed a sys_le16_to_cpu() applied to an already CPU-order sample.

RTIO error and lifecycle handling

SPI results are propagated from every stage (INT_STAT0, FIFO_LENGTH, FIFO_DATA) instead of ARG_UNUSED(result); every early return clears streaming_sqe and re-arms the GPIO so the stream cannot stall.
INT_STAT0 is decoded with the BMA400_ASSERTED_* status masks instead of the INT_CONFIG0 enable masks (they only matched by coincidence).
Terminal callback uses rtio_sqe_prep_callback_no_cqe(), the FIFO-flush write is null-checked and marked RTIO_SQE_NO_RESPONSE: no CQE/SQE pool leaks.
The streaming SQE is armed before the GPIO is re-enabled, so an event landing in that window is serviced.

Cancellation support (new)

Added a stream_busy atomic, claimed with atomic_cas(), so the GPIO ISR and the submitting thread can never service the same SQE.
Cancelled requests are retired with -ECANCELED (never 0: the executor reclaims the mempool block on a cancelled multishot) from the ISR path, from the FIFO-complete callback, and from a cancel-then-resubmit in bma400_submit_stream(), which takes over the service window, releases the parked SQE and reprograms the sensor. After a cancel the line is deliberately left disabled until a new submission arms it.
The trigger set is validated before any state is touched, so a rejected configuration never tears down a running stream.

Other

Motion and FIFO triggers in the same stream are rejected with -ENOTSUP: on a single edge-triggered line a persistent motion condition holds the line asserted and edges are lost.
The FIFO is flushed when stream configuration enables it, so no pre-config samples are delivered.

zephyrbot added area: Samples Samples area: Boards/SoCs area: Devicetree Binding PR modifies or adds a Device Tree binding area: Sensors Sensors labels Feb 17, 2026

zephyrbot requested review from JarmouniA, MaureenHelm, asemjonovs, avisconti, jeppenodgaard, kartben, nashif, teburd, tristan-google, ubieda and yperess February 17, 2026 18:27

zephyrbot assigned MaureenHelm Feb 17, 2026

lucagessi force-pushed the feature_driver_sensor_bma400 branch 4 times, most recently from fcdbb71 to 2f26e80 Compare February 19, 2026 06:29

lucagessi force-pushed the feature_driver_sensor_bma400 branch from 2f26e80 to 430dfd8 Compare March 14, 2026 14:53

zephyrbot added the area: Tests Issues related to a particular existing or missing test label Mar 14, 2026

lucagessi force-pushed the feature_driver_sensor_bma400 branch 2 times, most recently from 6b7d437 to 14ec47c Compare March 14, 2026 17:59

lucagessi marked this pull request as draft March 14, 2026 18:14

lucagessi marked this pull request as ready for review March 14, 2026 18:14

lucagessi requested a review from teburd March 24, 2026 05:42

ubieda requested changes Apr 20, 2026

View reviewed changes

lucagessi force-pushed the feature_driver_sensor_bma400 branch 2 times, most recently from e00c3c6 to 4a1706a Compare April 23, 2026 14:15

lucagessi requested a review from ubieda April 24, 2026 07:41

ubieda reviewed Apr 30, 2026

View reviewed changes

github-actions Bot added the Stale label Jun 1, 2026

github-actions Bot closed this Jun 9, 2026

teburd reopened this Jun 9, 2026

teburd removed the Stale label Jun 9, 2026

github-actions Bot added the Stale label Jul 11, 2026

parthitce mentioned this pull request Jul 17, 2026

Remove non-portable bit-field layout assumptions tree-wide #113762

Open

github-actions Bot removed the Stale label Jul 18, 2026

github-actions Bot added the Stale label Aug 18, 2026

lucagessi added 2 commits August 25, 2026 22:20

tests: drivers: build_all: add build test for BMA400

26d63e2

Add bma400 sensor to build test. Signed-off-by: Luca Gessi <lucagessi90@gmail.com>

lucagessi force-pushed the feature_driver_sensor_bma400 branch from 4a1706a to 26d63e2 Compare August 25, 2026 20:22

github-actions Bot removed the Stale label Aug 26, 2026

		const bool has_accel = (BMA400_FIFO_EMPTY_FRAME & buffer[0]) != 0;
		const bool is_empty = (BMA400_FIFO_EMPTY_FRAME == buffer[0]);

Uh oh!

Conversation

lucagessi commented Feb 17, 2026

Uh oh!

github-actions Bot commented Feb 17, 2026

Uh oh!

lucagessi commented Feb 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

lucagessi commented Mar 11, 2026

Uh oh!

MaureenHelm commented Mar 11, 2026

Uh oh!

lucagessi commented Mar 24, 2026

Uh oh!

sonarqubecloud Bot commented Mar 24, 2026

Quality Gate passed

Uh oh!

lucagessi commented Mar 31, 2026

Uh oh!

ubieda left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

sonarqubecloud Bot commented Apr 23, 2026

Quality Gate passed

Uh oh!

lucagessi commented Apr 28, 2026

Uh oh!

ubieda commented Apr 28, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

github-actions Bot commented Jun 1, 2026

Uh oh!

sonarqubecloud Bot commented Jun 9, 2026

Quality Gate passed

Uh oh!

github-actions Bot commented Jul 11, 2026

Uh oh!

lucagessi commented Jul 17, 2026

Uh oh!

github-actions Bot commented Aug 18, 2026

Uh oh!

lucagessi commented Aug 25, 2026

lucagessi commented Feb 23, 2026 •

edited

Loading