Introduce a serial transport which undoes the Victor DMM cable's
obfuscation to the DMM chip's original data packet. Which allows to
re-use the existing FS9922 support code, obsoleting the victor-dmm
device driver.
The Brymen BU-86X infrared adapters are sold with BM869s meters. Raw
streams of data bytes get communicated by means of HID reports with
report number 0 and up to 8 data bytes each. Communication parameters
are fixed and need no configuration.
Do implement the transport methods for serial communication underneath
the common layer, by communicating HID requests and payload data by
means of HIDAPI library calls.
This commit adds the common logic of serial-over-HID communication and
implements the full internal serial transport API, including reception
in the background. But it does not yet support a single HID chip (which
each run their own proprietary protocol).
The implementation works with either hidapi-libusb or hidapi-hidraw
variant of the HIDAPI library, but was only tested on Linux.
Search for the optional HIDAPI library. Call the library's init and exit
routine, and print version information. Extend the common serial layer's
code paths for open, list, and find USB to also support serial over HID.
This commit prepares serial over HID, but the HIDAPI specific transport
for serial communication still is empty in this implementation.
Uwe Hermann
Gerhard Sittig