Hi Marek, > On Saturday, January 24, 2015 at 12:48:15 AM, Steve Rae wrote: > > On 15-01-21 11:05 PM, Marek Vasut wrote: > > > On Tuesday, January 20, 2015 at 11:42:08 PM, Steve Rae wrote: > > >> Implement the UDC support for the USB OTG interface. > > >> > > >> Signed-off-by: Steve Rae <s...@broadcom.com> > > >> --- > > > > > > General question -- this bcm controller you're adding here isn't > > > by any chance a DWC2 controller, or is it ? There's already a > > > driver for DWC2 in drivers/usb/gadget/s3c_udc_otg.c . This driver > > > should really be properly renamed though ;-/ > > > > > > If this is not DWC2, do you know what controller this is please ? > > > > yes -- it is a DWC2.... > > > > So, I have had a quick look at the s3c_udc_otg*.c code.... > > > > First observation is that there is a completely different > > philosophy in the implementation. For example, the the interrupt > > handler routine(s), Broadcom is using #defines (sysmap.h which BTW > > are autogenerated by our Device Team) whereas "S3C" is using a > > "s3c_usbotg_reg" structure for the 'address' and #defines for the > > 'data/masks'. I'm not suggesting that one is better than the other, > > they are just different. > > Hi! > > The later is accepted by U-Boot as the preferred way, so the s3c is > doing things right. > > > So, how do we proceed? > > At this point, the Altera SoCFPGA and Samsung Exynos both use this s3c > driver to operate the DWC2 core in gadget mode. It should be trivial > to add support for the boardcom SoC, just follow the Altera example. > > I would like to avoid situation where we have two drivers for a single > IP block. > > > - is the ultimate goal to get to a proper gadget driver for DWC2? (I > > don't really know enough about this yet, so I apologize for these > > questions....) > > Yes, but we already have one to my knowledge. > > > - is the "S3C" code a proper 'gadget' driver and/or is it a better > > starting point to get to a gadget driver? > > Yes, and it's thoroughly tested already. > > > - I don't have enough time right now to really investigate the > > existing "S3C" and implement it on our board(s); they are > > significantly different and it looks like it will take a lot of > > effort - is there someone (Denx or community) that could assist me? > > Sure, just start asking the questions. > > > - Could we continue to review this patchset and accept it; then > > establish a team to provide a "DWC2 gadget" that could be used going > > forward? > > No, unless there's a convincing technical argument that the currently > mainline DWC2 gadget driver (the s3c one) can absolutelly not be used > for the broadcom SoC, I want to avoid having two drivers for the same > IP core in mainline, sorry.
Maybe it is a highest time to think about renaming s3c_* to dwc2_* and avoid further confusion. > > [...] > > Sorry, at this point I have to push back a little. > > Best regards, > Marek Vasut -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
