Implementing Top-Level Collections in Multi-touch Devices
The report descriptor for a multiple input device must include at least one top-level collection for the primary device and a separate top-level collection for the mouse.
Report descriptors for touch devices should use Finger (0x22) CL (Collection Logical) to group the data and control usages in the top-level collections, whereas the Stylus (0x20) CL should be used to group pen-related control and data usages.
The following report descriptor samples demonstrate the collection and usage settings for device type and mode.