usb: otg: twl4030-usb: check if vbus is driven by twl itself

At least on pandora, STS_VBUS gets set even when VBUS is driven by twl
itself. Reporting VBUS in this case confuses OMAP musb glue and charger
driver, so check if OTG VBUS charge pump is on before reporting VBUS
event to avoid this problem.

diff --git a/drivers/usb/otg/twl4030-usb.c b/drivers/usb/otg/twl4030-usb.c
index f590476..3374fbe 100644 (file)
--- a/drivers/usb/otg/twl4030-usb.c
+++ b/drivers/usb/otg/twl4030-usb.c
@@ -246,10 +246,30 @@ twl4030_usb_clear_bits(struct twl4030_usb *twl, u8 reg, u8 bits)
 
 /*-------------------------------------------------------------------------*/
 
+static bool twl4030_is_driving_vbus(struct twl4030_usb *twl)
+{
+       int ret;
+
+       ret = twl4030_usb_read(twl, PHY_CLK_CTRL_STS);
+       if (ret < 0 || !(ret & PHY_DPLL_CLK))
+               /*
+                * if clocks are off, registers are not updated,
+                * but we can assume we don't drive VBUS in this case
+                */
+               return false;
+
+       ret = twl4030_usb_read(twl, ULPI_OTG_CTRL);
+       if (ret < 0)
+               return false;
+
+       return (ret & (ULPI_OTG_DRVVBUS | ULPI_OTG_CHRGVBUS)) ? true : false;
+}
+
 static enum usb_xceiv_events twl4030_usb_linkstat(struct twl4030_usb *twl)
 {
        int     status;
        int     linkstat = USB_EVENT_NONE;
+       bool    driving_vbus = false;
 
        twl->vbus_supplied = false;
 
@@ -268,18 +288,22 @@ static enum usb_xceiv_events twl4030_usb_linkstat(struct twl4030_usb *twl)
        if (status < 0)
                dev_err(twl->dev, "USB link status err %d\n", status);
        else if (status & (BIT(7) | BIT(2))) {
-               if (status & (BIT(7)))
-                        twl->vbus_supplied = true;
+               if (status & BIT(7)) {
+                       driving_vbus = twl4030_is_driving_vbus(twl);
+                       if (driving_vbus)
+                               status &= ~BIT(7);
+               }
 
                if (status & BIT(2))
                        linkstat = USB_EVENT_ID;
-               else
+               else if (status & BIT(7)) {
                        linkstat = USB_EVENT_VBUS;
-       } else
-               linkstat = USB_EVENT_NONE;
+                       twl->vbus_supplied = true;
+               }
+       }
 
-       dev_dbg(twl->dev, "HW_CONDITIONS 0x%02x/%d; link %d\n",
-                       status, status, linkstat);
+       dev_dbg(twl->dev, "HW_CONDITIONS 0x%02x; link %d, driving_vbus %d\n",
+                       status, linkstat, driving_vbus);
 
        if (twl->otg.last_event == linkstat)
                return linkstat;