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Commit def6f8b9 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
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USB: twl4030-usb: fix minor reporting goofage 



Fix a reporting glitch in the twl4030 USB transceiver code.
It wasn't properly distinguishing the two types of active
USB link:  ID grounded, vs not.  In the current code that
distinction doesn't much matter; in the future this bugfix
should help support better USB controller communications.

Provide a comment sorting out some of the cryptic bits of
the manual:  different sections use different names for
key signals, and the register definitions don't help much
without the explanations and diagrams.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent dc2f2b75

drivers/usb/otg/twl4030-usb.c

+19 −7
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ 


/* In module TWL4030_MODULE_PM_MASTER */

#define PROTECT_KEY			0x0E

#define STS_HW_CONDITIONS		0x0F



/* In module TWL4030_MODULE_PM_RECEIVER */

#define VUSB_DEDICATED1			0x7D
@@ -351,15 +352,26 @@ static enum linkstat twl4030_usb_linkstat(struct twl4030_usb *twl) 
	int	status;

	int	linkstat = USB_LINK_UNKNOWN;



	/* STS_HW_CONDITIONS */

	status = twl4030_readb(twl, TWL4030_MODULE_PM_MASTER, 0x0f);

	/*

	 * For ID/VBUS sensing, see manual section 15.4.8 ...

	 * except when using only battery backup power, two

	 * comparators produce VBUS_PRES and ID_PRES signals,

	 * which don't match docs elsewhere.  But ... BIT(7)

	 * and BIT(2) of STS_HW_CONDITIONS, respectively, do

	 * seem to match up.  If either is true the USB_PRES

	 * signal is active, the OTG module is activated, and

	 * its interrupt may be raised (may wake the system).

	 */

	status = twl4030_readb(twl, TWL4030_MODULE_PM_MASTER,

			STS_HW_CONDITIONS);

	if (status < 0)

		dev_err(twl->dev, "USB link status err %d\n", status);

	else if (status & BIT(7))

		linkstat = USB_LINK_VBUS;

	else if (status & BIT(2))

	else if (status & (BIT(7) | BIT(2))) {

		if (status & BIT(2))

			linkstat = USB_LINK_ID;

		else

			linkstat = USB_LINK_VBUS;

	} else

		linkstat = USB_LINK_NONE;



	dev_dbg(twl->dev, "HW_CONDITIONS 0x%02x/%d; link %d\n",