On Wed, Jul 20, 2016 at 10:54:33AM +0800, Randy Li wrote: > Thank you for reviewing, if you agree with my opinion, I would implement a > new version as soon as possible. > > > On 07/20/2016 09:36 AM, Rob Herring wrote: > >On Tue, Jul 19, 2016 at 08:05:33PM +0800, Randy Li wrote: > >>From: Doug Anderson <dianders@xxxxxxxxxxxx> > >> > >>On the rk3288 USB host-only port (the one that's not the OTG-enabled > >>port) the PHY can get into a bad state when a wakeup is asserted (not > >>just a wakeup from full system suspend but also a wakeup from > >>autosuspend). The problem is caused by a design fault in IC, Rockchip > >>have confirmed it and fix this problem in the future IC model. > >> > >>We can get the PHY out of its bad state by asserting its "port reset", > >>but unfortunately that seems to assert a reset onto the USB bus so it > >>could confuse things if we don't actually deenumerate / reenumerate the > >>device. > >> > >>We can also get the PHY out of its bad state by fully resetting it using > >>the reset from the CRU (clock reset unit), which does a more full > >>reset. The CRU-based reset appears to actually cause devices on the bus > >>to be removed and reinserted, which fixes the problem (albeit in a hacky > >>way). > >> > >>It's unfortunate that we need to do a full re-enumeration of devices at > >>wakeup time, but this is better than alternative of letting the bus get > >>wedged. > >> > >>Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > >>Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx> > >>Reviewed-by: Randy Li <randy.li@xxxxxxxxxxxxxx> > >>--- > >> Documentation/devicetree/bindings/usb/dwc2.txt | 7 +++++++ > >> drivers/usb/dwc2/core.h | 5 +++++ > >> drivers/usb/dwc2/core_intr.c | 14 ++++++++++++++ > >> drivers/usb/dwc2/platform.c | 13 +++++++++++++ > >> 4 files changed, 39 insertions(+) > >> > >>diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt > >>index 20a68bf..40c63ae 100644 > >>--- a/Documentation/devicetree/bindings/usb/dwc2.txt > >>+++ b/Documentation/devicetree/bindings/usb/dwc2.txt > >>@@ -20,6 +20,13 @@ Refer to clk/clock-bindings.txt for generic clock consumer properties > >> Optional properties: > >> - phys: phy provider specifier > >> - phy-names: shall be "usb2-phy" > >>+- snps,need-phy-full-reset-on-wake: if present indicates that we need to reset > >Bikeshedding, but 'snps,full-phy-reset-on-wake' is slightly shorter. > > > >However, this isn't really even needed. It should be implied by the SoC > >specific compatible string. > I would. > > > >>+ the PHY when we detect a wakeup due to a hardware errata. If present you > >>+ must specify a "phy-full-reset" reset. > >>+ > >>+Resets: > >>+- phy-full-reset (optional): Fully resets the PHY (Only used by rk3288 Soc). > >This property belows in the phy node as that is where the reset is > >attached to and why is it not using the standard binding "resets"? > Because the struct phy_ops doesn't have something like reset method. It is > impossible to make a phy reset now. Also maybe it is not need to define a > reset at dts, just implied do that reset that in code(as the way to reset is > always same and only used by rk3288). Either the controller can retrieve the phy reset from the phy node or add a reset fn to struct phy_ops. The latter would be cleaner. If you don't put in DT at all and hard code in the driver, then I don't have an opinion. Rob -- 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
