Hi,

This series adds initial Industrial I/O subsystem support for the
Melexis MLX90393 3-axis magnetometer and temperature sensor.

The MLX90393 supports both I2C and SPI interfaces. This series
implements support for the I2C interface while keeping the driver
structure transport-independent to simplify future SPI support.

Currently supported features:

* Raw magnetic field measurements for X/Y/Z axes
* Raw temperature measurements
* Configurable gain/scale selection
* Configurable oversampling ratio
* Direct mode operation through the IIO subsystem
* I2C interface support

The driver has been tested on Raspberry Pi 5 hardware using an
MLX90393 sensor connected over I2C. Magnetic field and temperature
measurements were verified through the IIO sysfs interface.

Previous Submission:
Link: https://lore.kernel.org/linux-iio/20260510191010.155380-1-nikhilgtr@gmail.com/

Changes in v2:
[DT]
- Extended the DT binding to document power supply regulators and
  optional interrupt and trigger GPIOs.
[IIO]
- Removed the RFC tag based on reviewer feedback.
- Added a MAINTAINERS entry as part of the initial submission and
  expanded it in the driver patch.
- Reworked the scale availability implementation to simplify the
  data layout and eliminate the need for constructing a temporary
  table, avoiding potential race conditions.
- Replaced usleep_range() with fsleep() where appropriate and
  documented initialization delays.
- Simplified helper functions and improved error handling by
  returning directly where appropriate.
- Reduced unnecessary local variables and line wrapping to improve
  readability and align with kernel coding style.
- Added comments for lock protection and command definitions to
  improve code clarity.
- Switched to devm_mutex_init() and cleaned up include usage in
  accordance with the "include what you use" principle.
- Improved consistency across the driver, including conditional
  handling, switch statements, formatting, and general code style.
- Addressed all review comments from Jonathan Cameron.

I would like to thank Jonathan Cameron for the prompt and thorough
review of the previous revision. The detailed feedback on both the
submission process and the implementation has significantly improved
the quality and maintainability of this series.

Further review and comments are greatly appreciated.

Thanks,
Nikhil Gautam

Nikhil Gautam (2):
  dt-bindings: iio: magnetometer: add Melexis MLX90393
  iio: magnetometer: add support for Melexis MLX90393

 .../iio/magnetometer/melexis,mlx90393.yaml    |  55 ++
 MAINTAINERS                                   |   7 +
 drivers/iio/magnetometer/Kconfig              |  10 +
 drivers/iio/magnetometer/Makefile             |   2 +
 drivers/iio/magnetometer/mlx90393.h           |  74 ++
 drivers/iio/magnetometer/mlx90393_core.c      | 681 ++++++++++++++++++
 drivers/iio/magnetometer/mlx90393_i2c.c       |  72 ++
 7 files changed, 901 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/melexis,mlx90393.yaml
 create mode 100644 drivers/iio/magnetometer/mlx90393.h
 create mode 100644 drivers/iio/magnetometer/mlx90393_core.c
 create mode 100644 drivers/iio/magnetometer/mlx90393_i2c.c

-- 
2.39.5

On Thu, Jun 18, 2026 at 09:31:39PM +0530, Nikhil Gautam wrote:
> Hi,
> 
> This series adds initial Industrial I/O subsystem support for the
> Melexis MLX90393 3-axis magnetometer and temperature sensor.
> 
> The MLX90393 supports both I2C and SPI interfaces. This series
> implements support for the I2C interface while keeping the driver
> structure transport-independent to simplify future SPI support.
> 
> Currently supported features:
> 
> * Raw magnetic field measurements for X/Y/Z axes
> * Raw temperature measurements
> * Configurable gain/scale selection
> * Configurable oversampling ratio
> * Direct mode operation through the IIO subsystem
> * I2C interface support
> 
> The driver has been tested on Raspberry Pi 5 hardware using an
> MLX90393 sensor connected over I2C. Magnetic field and temperature
> measurements were verified through the IIO sysfs interface.

This doesn't answer to two important questions:
- why do we need a brand new driver?
  Can't one of the existing be updated to cover this HW?

- where to find the datasheet? Any Links or other means to get it?

-- 
With Best Regards,
Andy Shevchenko

On 19-06-2026 12:29 am, Andy Shevchenko wrote:
> On Thu, Jun 18, 2026 at 09:31:39PM +0530, Nikhil Gautam wrote:
>> Hi,
>>
>> This series adds initial Industrial I/O subsystem support for the
>> Melexis MLX90393 3-axis magnetometer and temperature sensor.
>>
>> The MLX90393 supports both I2C and SPI interfaces. This series
>> implements support for the I2C interface while keeping the driver
>> structure transport-independent to simplify future SPI support.
>>
>> Currently supported features:
>>
>> * Raw magnetic field measurements for X/Y/Z axes
>> * Raw temperature measurements
>> * Configurable gain/scale selection
>> * Configurable oversampling ratio
>> * Direct mode operation through the IIO subsystem
>> * I2C interface support
>>
>> The driver has been tested on Raspberry Pi 5 hardware using an
>> MLX90393 sensor connected over I2C. Magnetic field and temperature
>> measurements were verified through the IIO sysfs interface.
> This doesn't answer to two important questions:
> - why do we need a brand new driver?
>    Can't one of the existing be updated to cover this HW?
>
> - where to find the datasheet? Any Links or other means to get it?

Hi Andy,

I looked at the existing magnetometer drivers in the IIO subsystem,
but none support the MLX90393 or a sufficiently similar register map and 
command protocol.
The MLX90393 uses its own command-based interface and device-specific 
configuration and conversion logic,
so extending an existing driver would require substantial changes with 
little code reuse.
Therefore, I chose to implement it as a separate driver.

The datasheet is publicly available from Melexis:
Link: 
https://media.melexis.com/-/media/files/documents/datasheets/mlx90393-datasheet-melexis.pdf

I'll include the datasheet link and clarify the rationale for introducing
a new driver in the cover letter of the next revision.

Thanks,
Nikhil