Where I work we use this data to determine if there are broken traces between the touchscreen and the touchscreen controller. When a trace is broken, the absolute value of one of the 4 corners is a small fraction of the other three. With our flying systems, we have a shell script that reads the sysfs entry and writes it to the syslog on every system boot. With the sysfs entry, we are able to avoid dependency on any userspace utilities for accessing this data. On Wed, Jul 25, 2018 at 4:33 PM, Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: > Hi Nick, > > On Tue, Jul 03, 2018 at 09:47:29PM +0100, Nick Dyer wrote: >> With surface capacitance touchscreens the capacitance is measured >> through readings obtained from measurements taken at the four >> corners of the glass. These measurements are accessible in the I/Q >> modulation format from the the controller which becomes meaningful >> data when converted to an absolute value using the pythagorean >> theorem. > > What is the intended use of this data? Can it be fetched by an userspace > utility accessing device over usbfs? > > Thanks. > > -- > Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
