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 -- balbi
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