Hello Bastien Nocera, I'm not the best person to answer your questions but I will try and help. The best people to talk to would be Jonathan Cameron, the IIO maintainer, and Srinivas Pandruvada, the author of the hid-sensor-hub device drivers. I have CC'ed them for you to hopefully get a better response than what I can offer. Your device uses the same sensor hub, over usb, as my device does. I have a Microsoft Surface and it also uses many of the sensors found on the Lenovo Yoga. > So, my question regarding the IIO user-space API is: > is it possible to make the IIO accelerometer send out a kevent when the > orientation changes in a major way (using triggers?) or does user-space > need to poll the device instead? Of course it's possible but this does not occur in the current hid sensor hub drivers, from my understanding of the code. You should probably check out the current documentation on the IIO sysfs user interface: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio These outline the possible attributes sysfs offers. As of now the only ones that are found on the hid sensor hub devices is _raw as of 3.16 and _scale, _offset, _sampling_frequency, _hysteresis. The raw attribute lets you read the data that is at the top of the iio buffer. As you can see in the documentation there are many events support by other drivers that could possible be implemented by the hid-sensor-hub devices. IIO devices use a buffer that have a fixed size. It can be enabled with the sysfs interface. An example of this can be found in the kernel (drivers/staging/iio/iio_simple_dummy_buffer.c) there is also additional documentation there as well as dummy drivers. To use these interfaces in user space, or in the context of GNOME desktop, I think you would need to poll the iio buffer for new data and calculate the changes that way. The iio subsystem does support events but you would need to add these to the hid-sensor-hub devices and do the calculations for each event. This would allow you to poll for these iio events instead of polling the buffer. Hope this helps, Reyad Attiyat -- 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
