On Fri, 4 Jul 2014, Tuomas Tynkkynen wrote: > The Tegra USB complex has a particularly annoying misdesign: some of the > UTMI pad configuration registers are global for all the 3 USB controllers > on the chip, but those registers are located in the first controller's > register space and will be cleared when the reset to the first > controller is asserted. Currently, this means that if the 1st controller > were to finish probing after the 2nd or 3rd controller, USB would not > work at all. > > Fix this situation by always resetting the 1st controller before doing > any other setup to any of the controllers, and then never ever reset the > first controller again. As the UTMI registers are related to the PHY, > the PHY driver should probably reset the Tegra controllers instead, > but since old device trees only have reset phandles in the EHCI nodes, > do it here, which means a bit of device tree groveling. Those old DTs > also won't get the reset fix from this commit, so we'll dev_warn() them, > but the driver will still keep probing successfully. > > Signed-off-by: Tuomas Tynkkynen <ttynkkynen@xxxxxxxxxx> > --- > v2 changes: assume we can find the usb1 reset from the PHY DT node, > don't fail if it's not found but just issue a warning > drivers/usb/host/ehci-tegra.c | 62 +++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 59 insertions(+), 3 deletions(-) Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> -- 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
