How to put sensors into the ObjectMapper

Mike Jones proclivis at
Tue Aug 4 04:03:39 AEST 2020

My RaspPi work has progressed but I don’t know how to get sensors in the ObjectMapper, which I hope will mean sensors end up in webui.


At this point, I have my PMbus devices in the device tree like this path:

/sys/firmware/devicetree/base/soc/i2c at 7e804000/ltc2974 at 32/regulators/vout0 to vout3

And the config files like this path:

/etc/default/obmc/hwmon/soc/i2c#7e804000/ltc2974 at 32/reg1 at 32.conf <mailto:32/reg1 at 32.conf>

The sensors show up here:


Indicating that the device tree is causing hwmon to offer its telemetry nodes.

From my reading of the docs, it seems like the ObjectMapper keeps an inventory of sensors.

So to search, I did something like:

dbus-send —system -print-reply \
—dest=xyz.openbmc_project.ObjectMapper \
/xyz/openbmc_project/object_mapper \
xyz.openbmc_project.ObjectMapper.GetAncestors \
string:”/xyz/openbmc_project/inventory.system” array:string: | grep ltc2974

But none of my devices are there.

I looked at meta-ibm and meta-hxt and could not see how to get the devices into the ObjectMapper.


So I have these questions:

- What it the mechanism for getting these into the ObjectMapper?
- Once there, will they show up in webui without any other files and recipes?
- What docs might describe what I need to know to connect the hwmon devices to the ObjectMapper?
- Is there something I have to do to start the ObjectMapper service? I don’t see it with a grep through systemctl.
- Is there an existing meta layer that would be a good example and a pointer to the proper bb files to look at?


My work so far is here: <>

Configured by: <>

Thanks, and sorry I am a newbie without tribal knowledge. I am trying to find solutions on my own and only ask for help when stuck. Unfortunately, I’m stuck.

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