Commit 05e11a45 authored Mar 24, 2014 by Manu Gautam

USB: ci13xxx_msm: Clear LINK's SW_VBUS state in USBCMD on DISCONNECT



Most platforms typically rely on USB PHY for sess_vld signal inside
the Link Controller. In case VBUS is not fed to PHY, software can
configure LINK to rely on software controlled bit in USBCMD register
(USBCMD_SESS_VLD_CTRL) for sess_valid. LINK pulls DP HIGH when
running in peripheral mode and sess_valid signal is present.
On VBUS DISCONNET, software currently stops LINK without clearing
sess_valid bit. And it is noticed that USB LINK continues to pull
DP high even after stopping if USBCMD_SESS_VLD_CTRL is not cleared.
This results in charger compliance tests failing renegotiation tests
where CDP --> SDP transition is checked by removing and reapplying
VBUS within 100 msec. Failure happens as compliance tester finds
DP at way too high level (~2.8v) during primary detection stage.

CRs-fixed: 633479
Change-Id: I883867e39e4d1a306e5e63ec1da445a3aede1585
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>

parent 71ee1119

drivers/usb/gadget/ci13xxx_msm.c

+17 −1

Original line number	Diff line number	Diff line
		@@ -64,11 +64,27 @@ static void ci13xxx_msm_disconnect(void)
		struct ci13xxx *udc = _udc;
		struct usb_phy *phy = udc->transceiver;

		if (phy && (phy->flags & ENABLE_DP_MANUAL_PULLUP))
		if (phy && (phy->flags & ENABLE_DP_MANUAL_PULLUP)) {
		u32 temp;

		usb_phy_io_write(phy,
		ULPI_MISC_A_VBUSVLDEXT \|
		ULPI_MISC_A_VBUSVLDEXTSEL,
		ULPI_CLR(ULPI_MISC_A));

		/* Notify LINK of VBUS LOW */
		temp = readl_relaxed(USB_USBCMD);
		temp &= ~USBCMD_SESS_VLD_CTRL;
		writel_relaxed(temp, USB_USBCMD);

		/*
		* Add memory barrier as it is must to complete
		* above USB PHY and Link register writes before
		* moving ahead with USB peripheral mode enumeration,
		* otherwise USB peripheral mode may not work.
		*/
		mb();
		}
		}

		/* Link power management will reduce power consumption by