tree b04c392c99c3fb4989820423e938e93e7791c558
parent 9a7db6af2010ce9ca6ca9e1e53850aa6456b6b38
author Chau Ly <chaul@amperecomputing.com> 1681897495 +0000
committer Chau Ly <chaul@amperecomputing.com> 1687403140 +0000

intrusionsensor: Add hwmon reading method

This commit adds a new reading method for intrusionsensor, which reads
the chassis intrusion status from hwmon.

Example:
    {
         "Class": "Aspeed2600_Hwmon",
         "Name": "Chassis_Intrusion_Status",
         "Type": "ChassisIntrusionSensor"
    }

intrusionsensor will search for the sysfs hwmon name string in the
compatibleHwmonNames map using the Class string (e.g intrusion0_alarm
for Aspeed2600_Hwmon class) and read the chassis intrusion status from
it. This currently just supports Aspeed2600_Hwmon class which is based
on the aspeed-chassis driver from Aspeed SDK. The driver reads the
Intrusion Status bit in the CHAI10 register from AST2600. This bit
needs to be cleared every read in order to get the current state (which
means to write 0 to the hwmon file). In the condition of being cleared
every read, it will show 0 in hwmon for the normal state, and 1 for the
intrusion state.

Tested:

$ busctl get-property xyz.openbmc_project.IntrusionSensor \
 /xyz/openbmc_project/Chassis/Intrusion \
 xyz.openbmc_project.Chassis.Intrusion Status

If the chassis cover is closed: "Normal"
If the chassis cover is open: "HardwareIntrusion"

Signed-off-by: Chau Ly <chaul@amperecomputing.com>
Change-Id: I6f6a42592c8acae7be4f10e65a8b52ee30a4bd4f