From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Li Subject: Re: [PATCH 1/2] usb: dwc2: optionally assert phy "full reset" when waking up Date: Wed, 20 Jul 2016 10:54:33 +0800 Message-ID: <0c61cf90-6fea-19ce-ce74-91648cb2d921@rock-chips.com> References: <1446236275-12698-2-git-send-email-dianders@chromium.org> <1468929933-6971-1-git-send-email-randy.li@rock-chips.com> <20160720013614.GA12210@rob-hp-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160720013614.GA12210@rob-hp-laptop> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rob Herring Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org, eddie.cai-TNX95d0MmH7DzftRWevZcw@public.gmane.org List-Id: devicetree@vger.kernel.org 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 >> >> 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 >> Signed-off-by: Yunzhi Li >> Reviewed-by: Randy Li >> --- >> 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). > > Rob > -- Randy Li The third produce department -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html