drivers: sensor: add support for ALS31300 3D Hall Effect Sensor #94248

fabocode · 2025-08-07T21:49:26Z

Overview

This PR adds driver support for the Allegro Microsystems ALS31300 3-axis linear Hall Effect sensor with I2C interface.

Features Implemented

3-axis magnetic field measurement (X, Y, Z axes)
I2C communication interface
Device temperature readings
Standard Zephyr sensor API (sample_fetch/channel_get)
Add driver support for one-shot sensor reads (Read/Decode Sensor API)
Device tree integration with proper bindings

Hardware Details

The ALS31300 is a 3D linear Hall Effect sensor that provides 12-bit digital output proportional to the magnetic field strength in each axis. The sensor communicates via I2C and is commonly used in:

3D position sensing applications
Joystick implementations
Linear motion detection
Angle sensing applications

Testing

Driver builds successfully
Follows Zephyr sensor API conventions
Device tree bindings validated

Files Modified/Added

drivers/sensor/als31300/ - Driver implementation
dts/bindings/sensor/allegromicro,als31300.yaml - Device tree bindings
drivers/sensor/CMakeLists.txt - Build integration
drivers/sensor/Kconfig - Configuration options

References

ALS31300 Product Page
Datasheet: Available on manufacturer website

sonarqubecloud · 2025-08-07T23:29:55Z

Quality Gate passed

Issues
2 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud

tests/drivers/build_all/sensor/i2c.dtsi

drivers/sensor/als31300/als31300.c

ubieda · 2025-08-08T17:58:26Z

Also, please address the Issues raised by SonarQube

Copilot

Pull Request Overview

This PR adds driver support for the Allegro Microsystems ALS31300 3-axis linear Hall Effect sensor with I2C interface. The implementation provides both synchronous sensor API and asynchronous RTIO API support for magnetic field measurements on X, Y, and Z axes along with device temperature readings.

Complete driver implementation for ALS31300 3D Hall Effect sensor with I2C communication
Standard Zephyr sensor API support for sample_fetch/channel_get operations
RTIO-based asynchronous API implementation with proper encoding/decoding functions

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
`tests/drivers/build_all/sensor/i2c.dtsi`	Adds test device tree node for build verification
`dts/bindings/sensor/allegro,als31300.yaml`	Device tree binding definition for the sensor
`drivers/sensor/als31300/als31300.h`	Header file with register definitions, bit masks, and data structures
`drivers/sensor/als31300/als31300.c`	Main driver implementation with sensor API and RTIO support
`drivers/sensor/als31300/Kconfig`	Configuration options for the driver
`drivers/sensor/als31300/CMakeLists.txt`	Build configuration for the driver
`drivers/sensor/Kconfig`	Integration of driver configuration into main sensor Kconfig
`drivers/sensor/CMakeLists.txt`	Integration of driver build into main sensor CMakeLists

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Copilot · 2025-09-01T13:01:53Z

dts/bindings/sensor/allegro,als31300.yaml

+
+description: Allegro ALS31300 3D Linear Hall Effect Sensor
+
+compatible: "allegro,als31300"


The compatible string uses 'allegro' vendor prefix, but the expected format should be 'allegromicro' to match the company name Allegro Microsystems. This should be consistent with other Allegro device bindings.

Suggested change

compatible: "allegro,als31300"

compatible: "allegromicro,als31300"

This is not applicable, after checking this will break build

Copilot · 2025-09-01T13:01:54Z

drivers/sensor/als31300/als31300.c

+	 * Bits [6:4] = 0 → Low-power count = 0.5ms (doesn't matter in Active Mode)
+	 * Bits [31:7] = 0 → Reserved (should be 0)
+	 */
+	ret = i2c_reg_write_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, reg27_value);


The function i2c_reg_write_byte_dt() expects a uint8_t value but reg27_value is declared as uint32_t. This will only write the lowest byte and ignore the upper 24 bits, which may not configure the device correctly.

Suggested change

ret = i2c_reg_write_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, reg27_value);

ret = i2c_reg_write_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, (uint8_t *)&reg27_value, sizeof(reg27_value));

Is required i2c_reg_write_byte_dt

Copilot · 2025-09-01T13:01:54Z

drivers/sensor/als31300/als31300.c

+	uint8_t test_val[4];
+
+	ret = i2c_reg_read_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, test_val);


The function i2c_reg_read_byte_dt() expects a uint8_t* parameter but test_val is declared as uint8_t[4]. This function only reads a single byte, not 4 bytes as the array suggests.

Suggested change

uint8_t test_val[4];

ret = i2c_reg_read_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, test_val);

uint8_t test_val;

ret = i2c_reg_read_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, &test_val);

Got it, now I am following your suggestion

drivers/sensor/als31300/CMakeLists.txt

drivers/sensor/als31300/als31300.c

ubieda

Looks good to me. Thanks!

MaureenHelm · 2025-09-29T22:28:07Z

drivers/sensor/als31300/als31300.c

+ * @param raw_value Signed 12-bit magnetic field value
+ * @return Magnetic field in microgauss
+ */
+int32_t als31300_convert_to_gauss(const struct device *dev, int16_t raw_value)


Why does this function take a device pointer argument?

I will delete it, I thought it might be used in the future, but this will simplify it

MaureenHelm · 2025-09-29T22:29:56Z

drivers/sensor/als31300/als31300.c

+		/* Convert microcelsius to sensor_value format */
+		val->val1 = converted_val / 1000000;
+		val->val2 = converted_val % 1000000;
+
+		/* Handle negative temperatures properly */
+		if (converted_val < 0 && val->val2 != 0) {
+			val->val1 -= 1;
+			val->val2 = 1000000 + val->val2;
+		}


Use sensor_value_from_micro

Thanks, I added this as well

MaureenHelm · 2025-09-29T22:30:17Z

drivers/sensor/als31300/als31300.c

+	/* Convert microgauss to sensor_value format */
+	val->val1 = converted_val / 1000000;
+	val->val2 = converted_val % 1000000;
+	/* Handle negative values properly */
+	if (converted_val < 0 && val->val2 != 0) {
+		val->val1 -= 1;
+		val->val2 = 1000000 + val->val2;
+	}


MaureenHelm · 2025-09-29T22:30:45Z

drivers/sensor/als31300/als31300.c

+	return 0;
+}
+
+static const struct sensor_driver_api als31300_api = {


Use DEVICE_API

Sure, I included it

MaureenHelm · 2025-09-29T22:31:22Z

drivers/sensor/als31300/als31300.c

+	/* Small delay to ensure the mode change takes effect */
+	k_msleep(10);


Why this particular value for the delay?

It was meant for testing at first. I tested and functionality is not affected, so I will delete it.

Add driver for Allegro Microsystems ALS31300 3-axis linear Hall Effect sensor. The driver supports: - I2C communication interface - X, Y, Z magnetic field measurements - Device temperature readings Signed-off-by: Fabian Barraez <fabianbarraez@gmail.com>

sonarqubecloud · 2025-10-05T00:29:45Z

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
7.6% Duplication on New Code

See analysis details on SonarQube Cloud

fabocode force-pushed the sensor/add-als31300 branch from 56c4273 to 04ceaf7 Compare August 7, 2025 23:04

fabocode marked this pull request as ready for review August 7, 2025 23:33

zephyrbot added the area: Sensors Sensors label Aug 7, 2025

zephyrbot requested review from MaureenHelm, asemjonovs, avisconti, jeppenodgaard, teburd, tristan-google, ubieda and yperess August 7, 2025 23:34

zephyrbot assigned MaureenHelm Aug 7, 2025

ubieda reviewed Aug 8, 2025

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fabocode force-pushed the sensor/add-als31300 branch 7 times, most recently from cbd86fa to eb0c088 Compare September 24, 2025 00:10

fabocode requested review from kartben and ubieda September 24, 2025 00:54

fabocode force-pushed the sensor/add-als31300 branch 3 times, most recently from 9aa1e02 to e58b74c Compare September 24, 2025 18:15

ubieda reviewed Sep 24, 2025

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fabocode force-pushed the sensor/add-als31300 branch 2 times, most recently from f73cde1 to 518883a Compare September 25, 2025 01:47

fabocode requested a review from ubieda September 25, 2025 02:25

ubieda previously approved these changes Sep 25, 2025

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MaureenHelm requested changes Sep 29, 2025

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fabocode dismissed ubieda’s stale review via 0e14a50 October 5, 2025 00:03

fabocode force-pushed the sensor/add-als31300 branch from 518883a to 0e14a50 Compare October 5, 2025 00:03

zephyrbot added area: Boards/SoCs area: Tests Issues related to a particular existing or missing test area: Devicetree Bindings labels Oct 5, 2025

zephyrbot requested a review from nashif October 5, 2025 00:05

fabocode requested review from MaureenHelm and ubieda October 6, 2025 01:14

MaureenHelm approved these changes Oct 17, 2025

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ubieda approved these changes Oct 17, 2025

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jhedberg merged commit 6b8fcae into zephyrproject-rtos:main Oct 17, 2025
32 checks passed

fabocode deleted the sensor/add-als31300 branch October 17, 2025 19:10


		description: Allegro ALS31300 3D Linear Hall Effect Sensor

		compatible: "allegro,als31300"

	compatible: "allegro,als31300"
	compatible: "allegromicro,als31300"

	ret = i2c_reg_write_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, reg27_value);
	ret = i2c_reg_write_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, (uint8_t *)&reg27_value, sizeof(reg27_value));

		uint8_t test_val[4];

		ret = i2c_reg_read_byte_dt(&cfg->i2c, ALS31300_REG_VOLATILE_27, test_val);

		/* Small delay to ensure the mode change takes effect */
		k_msleep(10);

drivers: sensor: add support for ALS31300 3D Hall Effect Sensor #94248

drivers: sensor: add support for ALS31300 3D Hall Effect Sensor #94248

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fabocode commented Aug 7, 2025

Overview

Features Implemented

Hardware Details

Testing

Files Modified/Added

References

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sonarqubecloud bot commented Aug 7, 2025

Quality Gate passed

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ubieda commented Aug 8, 2025

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