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author | Cédric Le Goater <clg@fr.ibm.com> | 2015-03-09 21:56:18 +0100 |
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committer | Stewart Smith <stewart@linux.vnet.ibm.com> | 2015-03-24 18:22:55 +1100 |
commit | a5413878280a0cccd58d76802beffcce95f15c89 (patch) | |
tree | 253012eadeb3e6af40112bbf710dbf67dffa76f5 /doc | |
parent | b9410dad08de7c91b9bb040f9bebee5c1a0c3bde (diff) | |
download | skiboot-a5413878280a0cccd58d76802beffcce95f15c89.zip skiboot-a5413878280a0cccd58d76802beffcce95f15c89.tar.gz skiboot-a5413878280a0cccd58d76802beffcce95f15c89.tar.bz2 |
dts: add device tree documentation
Let's document what has been done so far for DTS sensors in the device
tree under node ibm,opal/sensors/
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/device-tree/ibm,opal/sensors.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/doc/device-tree/ibm,opal/sensors.txt b/doc/device-tree/ibm,opal/sensors.txt new file mode 100644 index 0000000..81aeff8 --- /dev/null +++ b/doc/device-tree/ibm,opal/sensors.txt @@ -0,0 +1,67 @@ +ibm,opal/sensors/ device tree nodes +-------------------------------------- + +All sensors of a POWER8 system are made available to the OS in the +ibm,opal/sensors/ directory. Each sensor is identified with a node +which name follows this pattern : + + <resource class name>@<resource identifier>/ + +For example : + + core-temp@20/ + +Each node has a minimum set of properties describing the sensor : + + - a "compatible" property which should be "ibm,opal-sensor" + + - a "sensor-type" property, which can be "temp", "fan", "power". + More will be added when new resources are supported. This type + is used "as is" by the Linux driver to map sensors in the sysfs + interface of the hwmon framework of Linux. + + - a "sensor-data" property giving a unique handler for the + OPAL_SENSOR_READ call to be used by Linux to get the value of + a sensor attribute. A sensor handler has the following encoding : + + | Attr. | Res. | Resource | + | Number | Class | Id | + |--------|--------|----------------| + + - a "sensor-status" property giving the state of the sensor. The + status bits have the slightly meanings depending on the resource + type but testing against 0x6 should raise an alarm. + + - an optional "label" property + + +Each node can have some extra properties depending on the resource +they represent. See the tree below for more information. + +ibm,opal/sensors/ { + + /* + * Core temperatures (DTS) nodes. + * + * We use the PIR of the core as a resource identifier. + */ + core-temp@20 { + compatible = "ibm,opal-sensor"; + name = "core-temp"; + sensor-type = "temp"; + + /* Status bits : + * + * 0x0003 FATAL + * 0x0002 CRITICAL + * 0x0001 WARNING + */ + sensor-data = <0x00800020>; + + /* + * These are extra properties to help Linux output. + */ + ibm,pir = <0x20>; + label = "Core"; + }; +}; |