The Raspberry Pi hardware monitoring driver "RASPBERRYPI-HWMON" is being extended to allow exposing voltage measurements on these ARM single board computers.

The Raspberry Pi firmware provides a number of voltage measurements for the core and multiple SDRAM voltages. With a patch queued into hwmon-next, those voltage measurements are being propagated to the Linux user-space via the conventional HWMON sysfs interfaces.

This includes in0_input for the core voltage, in1_input as the SDRAM controller voltage, in2_input as the SDRAM I/O voltage, and in3_input as the SDRAM PHY voltage. All measurements are in millivolts.

With this patch making it into the hardware monitoring subsystem's hwmon-next Git branch, it should be submitted as part of the changes for the Linux 7.2 merge window in mid-June.