Currently if we want to read the status of the PINs on a serial port, I
need to open the file (e.g. /dev/ttyUSB0) unfortunately in doing so we
*change* RTS/DTR
How difficult would it be to extent the usb_serial driver to expose the
pin status like this:
/sys/class/tty/ttyUSB0/device/RTS (rw, Request To Send)
/sys/class/tty/ttyUSB0/device/CTS (r, Clear To Send)
/sys/class/tty/ttyUSB0/device/DSR (r, Data Set Ready)
/sys/class/tty/ttyUSB0/device/DCD (r, Data Carrier Detect)
/sys/class/tty/ttyUSB0/device/DTR (rw, Data Terminal Ready)
/sys/class/tty/ttyUSB0/device/RI (r, Ring Indicator)
We could then simply read the file /sys/class/tty/ttyUSB0/device/DCD and
get a 1 if it is high.
We could also control RTS/DTS by using something like:
echo 1 > /sys/class/tty/ttyUSB0/device/DTR
I realize that if we LIMIT our usage of the serial port to ONLY serial
communication then there is not value is this extension. But the moment
you start using it to drive DIY electronics it would be a VERY welcomed
addition.
Thanks,
Gérald
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