Enable Zynq Temperature Monitoring

[josephnobes-stfc]

Added recipe for lmsensors to the project, which should enable the use of the sensors command to read data about the system.

This should enable the system to read its own temperature.

[josephnobes-stfc]

Before merging, I need to verify that this allows the desired temperatures to be read. The aim is to be able to read internal temperatures from the Zynq. This is likely to come from UltraScale SYSMON, which should provide temperature and voltage readings.

[josephnobes-stfc]

After uploading the image, the response from the sensors command (having run through all detections with sensors-detect) is as follows:

root@petalinux-custom:~# sensors
ff0e0000ethernetffffffff01-mdio-1
Adapter: MDIO adapter
temp1:        +34.0 C  (crit = +100.0 C)

root@petalinux-custom:~#

This sensor would appear to be the MDIO adapter (Alaska 88E1512), which has its own temperature sensor. The Zynq's own temperature has not been exposed.

[josephnobes-stfc]

Note for later: needs driver?
https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/sysmonpsu/src

[josephnobes-stfc]

See this:
https://support.xilinx.com/s/question/0D52E00006iHv06SAC/zynqmpsoc-ultrascale-sysfs-onchip-temperature-sensor-pl-ps-and-other-voltage-sensors?language=en_US

Temperatures are available as part of sysfs. Is there a better way of getting to them? Is this what the driver latches onto?

[josephnobes-stfc]

This interface is called ZynqMP AMS.
For reference: https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842163/Zynq+UltraScale+MPSoC+AMS

According to Xilinx, this is in the Xilinx kernel only, not mainline.