On Thu, May 20, 2010 at 03:10:42PM -0600, Steve McKown wrote: > On Thursday 20 May 2010 09:48:29 am Greg KH wrote: > > I'm confused, when would someone set the descriptor? Usually this > > happens at manufacturing time. Is that how you would be using this > > feature? > > Yes; I'm sorry I haven't been clear on this point. We have our own hardware > designs incorporating a cp210x. Each unit built needs its cp210x configured: > descriptors and port configuration. I worked with SiLabs to glean enough > information so I could add this functionality to the linux driver, since we > don't use Windows in our shop. Of course, no user needs these features, and > their post-mfg use would almost certainly prevent the device from operating > properly. > > What are going to be the sticking points to adding such features to the > driver? Based on our discussions thus far, I'm thinking that communicating > this information via sysfs using packed structures with CRC might be the way > to go. The binary structure would prevent the casual user from doing > something like: > echo 1234 | sudo tee /sys/blah/blah/VID > but the programmatic interface would still be pretty clean. > > A companion userspace library for mfg use would provide a lib and sample > program for setting descriptors and configurations via sysfs. > > Does this pass conceptual muster? Seems overly complicated. What's wrong with: echo 1 | sudo tee /sys/blah/blah/unlock cat binfile | sudo tee /sys/blah/blah/configuration echo 0 | sudo tee /sys/blah/blah/unlock Of course, hopefully "cat /sys/blah/blah/configuration" would give you back the same binfile you used for programming purposes. We use the default descriptors, but my understanding is that you're basically just programming an internal EEPROM, right? Seems like that would be the model to follow... but that's just my $0.02 Matt -- Matthew Dharm Home: mdharm-usb@xxxxxxxxxxxxxxxxxx Maintainer, Linux USB Mass Storage Driver Stef, you just got beaten by a ball of DIRT. -- Greg User Friendly, 12/7/1997
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