Hi, On Mon, Apr 27, 2015 at 04:04:08PM +0100, Joao Pinto wrote: > Hi Filipe, that's Felipe (and yes, I know it's João, but you spelled it without ~) :-) > 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! you too, thanks -- balbi
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