twl4030-usb: changes for VBUS/ID detection on OTG port

Some hackish code involving VUSB3V1 regulator power source
switching to get VBUS/ID detection working better.

diff --git a/drivers/i2c/chips/twl4030-usb.c b/drivers/i2c/chips/twl4030-usb.c
index 9ebdd13..5c0ff7a 100644 (file)
--- a/drivers/i2c/chips/twl4030-usb.c
+++ b/drivers/i2c/chips/twl4030-usb.c
@@ -269,6 +269,8 @@ struct twl4030_usb {
        u8                      linkstat;
        u8                      asleep;
        bool                    irq_enabled;
+
+       struct work_struct      change_mode_work;
 };
 
 /* internal define on top of container_of */
@@ -370,10 +372,10 @@ static enum linkstat twl4030_usb_linkstat(struct twl4030_usb *twl)
        status = twl4030_readb(twl, TWL4030_MODULE_PM_MASTER, 0x0f);
        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))
                linkstat = USB_LINK_ID;
+       else if (status & BIT(7))
+               linkstat = USB_LINK_VBUS;
        else
                linkstat = USB_LINK_NONE;
 
@@ -496,9 +498,6 @@ static void twl4030_usb_ldo_init(struct twl4030_usb *twl)
        /* put VUSB3V1 LDO in active state */
        twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB_DEDICATED2);
 
-       /* input to VUSB3V1 LDO is from VBAT, not VBUS */
-       twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x14, VUSB_DEDICATED1);
-
        /* turn on 3.1V regulator */
        twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x20, VUSB3V1_DEV_GRP);
        twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB3V1_TYPE);
@@ -531,21 +530,34 @@ static ssize_t twl4030_usb_vbus_show(struct device *dev,
 }
 static DEVICE_ATTR(vbus, 0444, twl4030_usb_vbus_show, NULL);
 
-static irqreturn_t twl4030_usb_irq(int irq, void *_twl)
+static void twl4030_change_mode_work(struct work_struct *work)
 {
-       struct twl4030_usb *twl = _twl;
-       int status;
+       struct twl4030_usb *twl = container_of(work,
+               struct twl4030_usb, change_mode_work);
+       u8 old_dedicated1, dedicated1;
 
-#ifdef CONFIG_LOCKDEP
-       /* WORKAROUND for lockdep forcing IRQF_DISABLED on us, which
-        * we don't want and can't tolerate.  Although it might be
-        * friendlier not to borrow this thread context...
-        */
-       local_irq_enable();
-#endif
+       if (twl->linkstat != USB_LINK_UNKNOWN) {
+               twl4030_i2c_read_u8(TWL4030_MODULE_PM_RECEIVER,
+                       &old_dedicated1, VUSB_DEDICATED1);
 
-       status = twl4030_usb_linkstat(twl);
-       if (status != USB_LINK_UNKNOWN) {
+               if (twl->linkstat == USB_LINK_ID)
+                       /* input to VUSB3V1 LDO is VBAT */
+                       dedicated1 = 0x14;
+               else
+                       /* input to VUSB3V1 LDO is VBUS */
+                       dedicated1 = 0x18;
+
+               if (dedicated1 != old_dedicated1) {
+                       dev_dbg(twl->dev, "VUSB_DEDICATED1 change %x -> %x\n",
+                               old_dedicated1, dedicated1);
+                       /* turn off VUSB3V1 input for a bit before change */
+                       twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER,
+                               0x10, VUSB_DEDICATED1);
+                       mdelay(50);
+                       twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER,
+                               dedicated1, VUSB_DEDICATED1);
+                       mdelay(50);
+               }
 
                /* FIXME add a set_power() method so that B-devices can
                 * configure the charger appropriately.  It's not always
@@ -558,12 +570,32 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl)
                 * USB_LINK_VBUS state.  musb_hdrc won't care until it
                 * starts to handle softconnect right.
                 */
-               twl4030charger_usb_en(status == USB_LINK_VBUS);
+               twl4030charger_usb_en(twl->linkstat == USB_LINK_VBUS);
+       }
+}
+
+static irqreturn_t twl4030_usb_irq(int irq, void *_twl)
+{
+       struct twl4030_usb *twl = _twl;
+       int status;
+
+#ifdef CONFIG_LOCKDEP
+       /* WORKAROUND for lockdep forcing IRQF_DISABLED on us, which
+        * we don't want and can't tolerate.  Although it might be
+        * friendlier not to borrow this thread context...
+        */
+       local_irq_enable();
+#endif
+
+       status = twl4030_usb_linkstat(twl);
+       if (status != USB_LINK_UNKNOWN) {
 
                if (status == USB_LINK_NONE)
                        twl4030_phy_suspend(twl, 0);
                else
                        twl4030_phy_resume(twl);
+
+               schedule_work(&twl->change_mode_work);
        }
        sysfs_notify(&twl->dev->kobj, NULL, "vbus");
 
@@ -644,6 +676,8 @@ static int __init twl4030_usb_probe(struct platform_device *pdev)
        if (device_create_file(&pdev->dev, &dev_attr_vbus))
                dev_warn(&pdev->dev, "could not create sysfs file\n");
 
+       INIT_WORK(&twl->change_mode_work, twl4030_change_mode_work);
+
        /* Our job is to use irqs and status from the power module
         * to keep the transceiver disabled when nothing's connected.
         *