> From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Friday, May 30, 2014 4:42 PM > > On Fri, May 23, 2014 at 11:39:24AM -0700, Paul Zimmerman wrote: > > Newer DWC3 controllers can be built for USB 2.0-only mode, where > > most of the USB 3.0 circuitry is left out. To support this mode, > > the driver must limit the speed programmed into the DCFG register > > to Hi-Speed or lower. > > > > Reads and writes to the PIPECTL register are left as-is, since > > they should be no-ops in USB 2.0-only mode. Calls to phy_init() > > etc. for the USB3 phy are also left as-is, since the no-op USB3 > > phy should be used for USB 2.0-only mode controllers. > > > > Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx> > > --- > > Hi Felipe, > > > > Does this look OK to you? I think it is fine to leave the PIPECTL > > accesses and the phy_init() calls as-is, but if you would prefer > > that I also conditionalize those I can do that. We have at least > > one customer who will need this feature fairly soon, so we would > > like to get this in without too much delay, although I guess we > > missed the 3.16 merge window. > > I like this a lot :-) Very nice of Synopsys to support this > configuration. Could you just let me know which versions of the core > support this configuration ? We have AM437x which has this sort of > "quirk" although, I think it's done using a TI-specific "modification", > perhaps ? It has been officially supported since 2.60a. But it's possible that customers have hacked up something like this on their own with previous versions, so the exact version number might not mean much. The patch should work for all versions of the core, because the DWC_USB3_SSPHY_INTERFACE bits have always been there, going back to preproduction versions of the core. It has been pointed out to me that DT can already be used to limit the max speed, using the 'maximum-speed' property (duh). But I think we still want the patch for non-DT platforms like dwc3-pci. -- Paul -- 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
