Marcus Folkesson [off-list ref] writes:

Chip Card Interface Device (CCID) protocol is a USB protocol that
allows a smartcard device to be connected to a computer via a card
reader using a standard USB interface, without the need for each manufacturer
of smartcards to provide its own reader or protocol.

This gadget driver makes Linux show up as a CCID device to the host and let a
userspace daemon act as the smartcard.

This is useful when the Linux gadget itself should act as a cryptographic
device or forward APDUs to an embedded smartcard device.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>

I still don't see the benefit of having this in the kernel when
functionfs would do just fine.