Hi Filipe, On 4/27/2015 3:56 PM, Felipe Balbi wrote: > Hi Joao, > > On Mon, Apr 27, 2015 at 03:48:48PM +0100, Joao Pinto wrote: >>>> My name is Joao Pinto and I am working at Synopsys as a Software Engineer mainly >>>> in the USB Subsystem. >>>> >>>> I am sending you this email in order to know if someone is already working in >>>> the driver' development for Synopsys' USB 3.1 Host & Device and USB 2.0 OTG >>>> Controllers. >>> >>> Have you looked at the latest kernel tree to verify what is and is not >>> supported? That's your best source of information. >> >> I checked the USB Mailing List archive and the USB Git trees in order to find >> any reference of these drivers but nothing was found, so I would conclude that >> nothing was submitted about these 2 subjects. > > one of your colleagues maintains dwc2 which is the synopsys usb 2.0 otg > controller available on e.g. raspberry pi. > > For USB 3.1, nobody outside of synopsys (afaict) has access to any HW or > FPGA with USB 3.1, so there isn't much we can do without HW :-) In fact, > I don't know anybody, except for synopsys employees, with access to the > USB 3.1 documentation, but I would assume the core to be similar to the > current DWC USB3 (drivers/usb/dwc3) IP whose driver I maintain (please > confirm). > > If that's the case, then an incremental patch adding USB 3.1 support is > much more desirable than an entire new driver. > >>>> a) If no one is working, we have interest to start developing them >>> >>> Don't you already have internal code for these chips? Have you tested >>> Linux with them? >> >> As you know internal code is not always suitable for kernel submission >> and so sometimes it is better to upgrade a std kernel driver like dwc3 >> (USB 3.0 Device) in order to make it support 3.1 as well. > > yes, it's better to upgrade that driver, however, that driver is not > device only. I won't repeat myself trying to explain why we still don't > have DRD/OTG support, but it's coming. > >>>> b) If there is someone already developing them, we have interest in >>>> collaborating with the on going work >>> >>> Look at the changelog entries for the drivers for these chips, that >>> should give you the information you need here. >> >> I have checked the USB tree' logs as I said previously and nothing relevant was >> found. >> >>> >>> But really, running the latest kernel and seeing what doesn't work for >>> your hardware, and sending patches to fix this is the best way forward, >>> don't you agree? >> >> I agree with you if we are dealing with small improvements or bug fixes, but in >> this case we are dealing with new drivers or important updates on existing ones. > > I would assume that USB 3.1 itself is a very small change. The bulk of > the changes will probably come due to Type-C connector and USB Power > Delivery and Billboard classes, however, that's not coupled with USB 3.1 > at all. > >> One of the good practices I read about kernel development is to ask >> first if someone is already working in a particular subject to avoid >> work duplication and that's what I am doing in this email. > > that's correct, it's always good to ask and doesn't really hurt anybody, > but you also need to know who to ask :-) Greg can't know about > everything (although usually... well), and since you're talking about > changes to dwc2 and dwc3 it would be nice to Cc the maintainers for > those drivers, right ? ;-) > > cheers > Thank you very much for your inputs! When I have more details I will contact you about dwc3. Have a nice day! -- Joao -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
