On 26/09/15 23:05, Srinivas Pandruvada wrote: > An overview document about thermal iio binding. > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> > --- > Documentation/thermal/thermal_iio_binding | 88 +++++++++++++++++++++++++++++++ > 1 file changed, 88 insertions(+) > create mode 100644 Documentation/thermal/thermal_iio_binding > > diff --git a/Documentation/thermal/thermal_iio_binding b/Documentation/thermal/thermal_iio_binding > new file mode 100644 > index 0000000..df501f1 > --- /dev/null > +++ b/Documentation/thermal/thermal_iio_binding > @@ -0,0 +1,88 @@ > + > +Thermal IIO Bindings > + > +When CONFIG_THERMAL_IIO is enabled, in addition to the regular thermal > +zone attributes, an additional entry for an IIO device is created. > +IIO sysfs ABI documents is available at Documentation/ABI/sysfs-bus-iio. > + > +The following example shows the contents of the IIO:device in a thermal > +zone. > + > +thermal_zoneX > +├── iio:device9 > +│ ├── buffer > +│ │ ├── enable > +│ │ ├── length > +│ │ └── watermark > +│ ├── events > +│ │ ├── in_temp_thresh_either_en > +│ │ └── in_temp_thresh_either_value > +│ ├── in_temp_raw > +│ ├── name > +│ ├── scan_elements > +│ │ ├── in_temp_en > +│ │ ├── in_temp_index > +│ │ ├── in_temp_type > +│ │ ├── in_timestamp_en > +│ │ ├── in_timestamp_index > +│ │ └── in_timestamp_type > +│ ├── subsystem -> ../../../../../bus/iio > +│ ├── trigger0 > +│ │ └── name > +│ ├── trigger > +│ │ └── current_trigger > +│ └── uevent > +├── integral_cutoff > +... > +... other thermal_zone attributes > +... > + > + > +IIO Attributes > + > +name: This shows iio device name, which will match thermal_zone/type attribute > +in_temp_raw: This will show raw temperature values same as thermal_zone/temp > +attribute. > + > +trigger/current_trigger: This is IIO way of specifying data ready indication. Kind of, given it's not exposed to userspace to read, but rather hooked directly to the filling of the buffer. You might want to reword to not imply userspace can discover that it has fired directly. > +If the thermal client can provide asynchronous notifications, then a iio trigger > +device is created under trigger0. The name of this trigger will be thermal > +device name suffixed with devX. To enable iio buffer notifications, > +trigger/current_trigger cab be updated with this trigger. For example > + > +#echo "x86_pkg_temp-dev9" > trigger/current_trigger > + > +In addition of samples can be pushed to iio buffers with external standard IIO > +device triggers, E.g. sysfs trigger. > + > +How to enable events? > +To enable events a suitable threshold temperature can be written to > +in_temp_thresh_either_value > +and enable by writing 1 to in_temp_thresh_either_en. > + > +To monitor events a good user space program is here: > +tools/iio/iio_event_monitor.c > + > +For example > +# echo 50000 > /sys/devices/virtual/thermal/thermal_zone9/iio:device9/events/in_temp_thresh_either_value > +# echo 1 > /sys/devices/virtual/thermal/thermal_zone9/iio:device9/events/in_temp_thresh_either_en > +# ./iio_event_monitor x86_pkg_temp > +Found IIO device with name x86_pkg_temp with device number 9 > +Event: time: 1443297126626859289, type: temp, channel: 0, evtype: thresh, direction: either > + > +How to read temperature samples? > +When thermal client or core driver calls thermal_zone_device_update, this will > +result in sample pushed to iio buffers. These samples can be read from > +/dev/iio:deviceX file. > + > +To enable buffer select scan_elements > +# echo 1 > scan_elements/in_temp_en > + > +Set buffer length to n samples and enable buffer. > +# echo 2 > buffer/length > +# echo 1 > buffer/enable > + > +Then user can poll/select or /dev/iio:deviceX (Here X correspond to iio device number), > +and read temperature samples. A good example is at tools/iio/generic_buffer.c. > + One too many blank lines at the end. > + Reasonable docs to get people started I think, but whether they are detailed enough is going to be a question for the thermal guys! Also, perhaps a cross reference to Daniel's doc book on IIO? Documentation/DocBook/iio/ As that expands in detail it might include lots of stuff that isn't relevant to thermal, but it might also fill in details that we don't want to explicitly layout here. Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
