Re: [PATCH] usb: cp210x: Added support for GPIO (CP2103/4/5)

[Xiaofan Chen]

On Sun, Apr 29, 2012 at 9:02 PM, Uwe Bonnes
<bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> most RS232/USB Adapter don't supply and most applications working with these
> adapters don't need hard realtime. So even writing and reading the serial
> lines can be handled with libusb, like libftdi does.
>
> But as soon as higher level protocols based on the serial line get involved,
> a kernel driver is needed...
>
> So when thinking some termiox, some thoughts for the FTDI special modes,
> like MPSSE or synchronous FIFO should be spent. It would come handy if I
> could open /dev/ttyUSBx, set som termiox and could use the kernel driver for
> sending and receiving MPSSE commands. MPSSE is e.g. used in OpenOCD and
> xc3sprog to talk e.g. JTAG to external devices.

On the other hand, OpenOCD and your xc3sprog will probably remain
to be cross-plattform and in that case libusb/libftdi is a good option
to go. There is a patch under review in OpenOCD where libusb-1.0
is used for the MPSSE engine instead of libftdi/ftd2xx and the
performance seems to be better.



-- 
Xiaofan
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