Hi Mr. Kozlowski, > > + > > + vdevnum: > > + description: > > + virtual device number. > That's unusual property... Why numbering devices is part of DT (hardware description)? In HPE GXP virtual EHCI controller chipset, it can support up to 8 virtual devices(gadgets). Each device/gadget will be represented by a bit in 8 bits register. For example, the interrupt register bit 0 indicates the interrupt from device 0, bit 1 for device 1 ... so on. When a user defines a device/gadget, he/she can define the device number as between 0 and 7. Thus, the driver can look up to the bit position. That is why we have numbering devices as part of DT. > > + > > + fepnum: > > + description: > > + number of the flexible end-points this device is needed. > Similar question. In HPE GXP virtual EHCI Controller chipset, there is a flexible End-Point(EP) pool. Each flexible EP has its own mapping register. The mapping register bit 0 to 3 is for device number (vdevnum) and bit 4 to 7 is for EP number inside the device. The device driver configures the mapping register to assign a flexible EP to a specific device. Here, "fepnum" is the input letting the driver know how many EPs are needed for this device/gadget. Thanks Richard.
