Re: Regarding USB-to-serial device driver

Greg KH
2010-09-22T15:06:38Z

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