ROHM BD79103 Analod to Digital Converter (ADC)

The ROHM BD79103 is a 8-channel, 12-bit ADC which is controlled over SPI.

Linux Driver:

Source Code:

The ROHM Finland SWDC has added support for the BD79103 in the existing Linux driver, in collaboration with the Linux kernel community. Driver is included in the Upstream Linux from v6.18-rc1 onwards.

The Linux kernel can be obtained from:

https://www.kernel.org/

or by cloning Linus Torvald’s official linux development tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux.git

The driver supports reading the ADC channels via the Linux IIO subsystem. SPI MODE 3 (CPOL=1, CPHA=1) should be used.

Linux subsystem:

IIO (Industrial input/output)

Devicetree example:

    spi {
        adc: adc@0 {
            compatible = "rohm,bd79103";
            reg = <0>;
            vdd-supply = <&dummyreg>; 
            iovdd-supply = <&dummyreg>;
            spi-cpha;
            spi-cpol;
            spi-max-frequency = <20000000>;
        };
    }

Known issues

We strongly recommend using the latest upstream version of the driver as plenty of fixes are done to the drivers by the Linux kernel community and there is no database for all known issues. Issues spotted by us during development (like adding support for new hardware or improving feature coverage) may have been reported to the issue tracker.