Commit def6f8b9 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman

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
......@@ -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",
......
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