On Sat, Mar 24, 2012 at 03:10:25PM +0100, Martin Fuzzey wrote: > Hi Derald, > > > On Fri, Mar 23, 2012 at 2:09 PM, Derald Woods <woods.rt@xxxxxxxxx> wrote: > > Hello Martin, > > > > I have an existing design that uses the i.MX21 ARM9 processor. The > > design currently uses an external USB OTG chip. The chip is now > > end-of-life. I know that this is an older ARM processor. It still meets > > most of the design needs. Is the i.MX21 OTG functionality considered > > reliable? I have not seen any real success stories with the i.MX21 USB > > OTG implementation. Our board currently utilizes the USB OTG chip at > > the bootloader and Linux kernel level. > > > > It depends what you mean by OTG. > > The i.MX21 silicon has 3 USB ports, two of which can only be used as > USB hosts and one which is configurable as host only, function > (device) only or OTG (dynamic switching). > Somewhat confusingly the Freescale documentation refers to the whole > module as "USB-OTG". > > However the mainline code only supports host mode (there is no > function driver nor OTG support) > > I mainlined the i.MX21 HCD driver for 2.6.34 and fixed a few bugs for > 2.6.37 (in particular problems with non aligned buffers causing usbnet > to fail). > > Since then I haven't had any bug reports, the driver also passes the > USB test suite (which I updated to check the buffer alignment > behaviour). > > > > I would appreciate being pointed in the right direction or warned of > > impending danger. Basically I want to know if the mx21 USB OTG has > > performed well for other embedded Linux designs. > > > Something very close to the original code on which I based the driver > was shipped with the Chumby (which uses a heavily patched 2.6.16 > kernel). However that code had quite a few bugs and didn't support > isochronous transfers at all. > > I don't have any direct feedback myself of real world use of the > driver however since we ended up not shipping an iMX21 based Linux > product for non technical reasons. > > > I had originally posted to the Barebox mailing list. > > > Ah I'm not subscribed to that list - adding it as a CC hoping it's not > subscriber only > > Cheers, > > Martin Fuzzey Hello Martin, Thanks for the detailed feedback. This information is consistent with what I have observed and followed with regard to the i.MX21. It will help us chart a meaningful development course. Best regards, Derald D. Woods _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
