On Sun, 2015-09-27 at 19:23 +0100, Jonathan Cameron wrote: > 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. OK > > +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_te > > mp_thresh_either_value > > +# echo 1 > > > /sys/devices/virtual/thermal/thermal_zone9/iio:device9/events/in_te > > mp_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! > Idea here is to just give pointers to the IIO documentation and examples to get developers to explore if they want to use this I/F. > 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. > Thanks for your reviews. -Srinivas > Jonathan > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" > in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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
