Messages in this thread | | | Date | Tue, 01 Oct 2002 23:35:53 +0800 | From | Steve Underwood <> | Subject | Re: USB IEEE1284 gadgets and ppdev |
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Tim Waugh wrote:
>On Wed, Sep 25, 2002 at 08:01:29AM -0700, Greg KH wrote: > > > >>I understand that the uss720 driver should register with parport, as >>it is a USB to parallel port adapter, but the usblp driver should >>not, as it is just a pass-through to a printer. Do you see any >>advantage to having usblp registering with parport? >> >> > >Well, it would mean that ppdev could use it. I understand that only a >few functions of a normal parallel port could be implemented (read, >write, get status). > >Alternatively I suppose I could get libieee1284 to grok /dev/usb/lp*. >Steve---would that solve the problem that you're running into? > >Tim. >*/ > > Well, the application is this. A lot of industrial control, embedded processor development interfaces, and other stuff use a parallel port to connect to a PC. The parallel port has gone from some notebooks, and is soon to go from desktops too. I want to access some of those devices through a USB to IEEE1284 cable. If the programming interface is ppdev, that is great - no changes needed for code that already works with a real parallel port. If it requires a somewhat different API, that's no big deal. Being able to bit twiddle to the extent that ppdev allows is pretty important, though. I guess there may be some latency issues slowing the bit twiddling across a USB interface, but nothing's perfect.
Regards, Steve
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