Messages in this thread | | | Date | Wed, 22 Sep 2010 07:56:07 -0700 | From | Greg KH <> | Subject | Re: Regarding USB-to-serial device driver |
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On Wed, Sep 22, 2010 at 11:02:46AM +0530, Raju Rameshwar Uprade wrote: > > > Greg, > I am facing some problem in data copying. > I am having a const unsigned char *buf which contains 02 08 00 00 00 00 00 00 f8. > which is copied in port->write_urb->transfer_buffer and sent on ttyUSB0 using > usb_submit_urb(port->write_urb, GFP_ATOMIC).
For what driver?
> But I want to send the data bytes is a particular fashion. > > 1. I want to Add Mark parity.
That's a control signal and is independant of the data payload, right?
> 2. Send the data byte 02 ( Address of a device )
That means you need to modify the data. Why not do that in userspace?
> 3. Add Space parity .
Again, control signal.
> 4. send the data byte 08 00 00 00 00 00 00 f8 ( Null cmd + check sum )
Should be fine.
> Kindly help me.I am facing the problem in separating the data bytes so > that I can send the data bytes separately using usb_submit_urb.
It all depends on the driver you are using. Why not do all of this from userspace? That way it works on any device you are talking to.
good luck,
greg k-h
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