usb: chipidea: imx: improve usbmisc_imx7d_pullup()

When add workaround for ERR051725, the usbmisc will put PHY to
Non-driving mode (OPMODE = 01) after stopping the device controller
and put PHY back to Normal mode (OPMODE = 00) after starting the device
controller.

However, this will bring issue for host controller. Because the PHY may
stay in Non-driving mode after switching the role from device to host.
Then the port will not work if USB device is attached. To fix this issue,
improving the workaround by putting PHY to Non-driving mode for a certain
period and back to Normal mode finally. To make host detect a disconnect
signal, the period should be at least 125us (a micro-frame time) for
high-speed link.

And only working as high-speed mode will need workaround for ERR051725.
So this will also filter the pullup event for high-speed.

Fixes: 11992b4 ("usb: chipidea: imx: implement workaround for ERR051725")
Reviewed-by: Jun Li <[email protected]>
Signed-off-by: Xu Yang <[email protected]>
Acked-by: Peter Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Xu Yang

drivers/usb/chipidea/ci_hdrc_imx.c

@@ -338,7 +338,8 @@ static int ci_hdrc_imx_notify_event(struct ci_hdrc *ci, unsigned int event)
 			schedule_work(&ci->usb_phy->chg_work);
 		break;
 	case CI_HDRC_CONTROLLER_PULLUP_EVENT:
-		if (ci->role == CI_ROLE_GADGET)
+		if (ci->role == CI_ROLE_GADGET &&
+		    ci->gadget.speed == USB_SPEED_HIGH)
 			imx_usbmisc_pullup(data->usbmisc_data,
 					   ci->gadget.connected);
 		break;

drivers/usb/chipidea/usbmisc_imx.c

@@ -1068,15 +1068,24 @@ static void usbmisc_imx7d_pullup(struct imx_usbmisc_data *data, bool on)
 	unsigned long flags;
 	u32 val;
 
+	if (on)
+		return;
+
 	spin_lock_irqsave(&usbmisc->lock, flags);
 	val = readl(usbmisc->base + MX7D_USBNC_USB_CTRL2);
-	if (!on) {
-		val &= ~MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_MASK;
-		val |= MX7D_USBNC_USB_CTRL2_OPMODE(1);
-		val |= MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_EN;
-	} else {
-		val &= ~MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_EN;
-	}
+	val &= ~MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_MASK;
+	val |= MX7D_USBNC_USB_CTRL2_OPMODE(1);
+	val |= MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_EN;
+	writel(val, usbmisc->base + MX7D_USBNC_USB_CTRL2);
+	spin_unlock_irqrestore(&usbmisc->lock, flags);
+
+	/* Last for at least 1 micro-frame to let host see disconnect signal */
+	usleep_range(125, 150);
+
+	spin_lock_irqsave(&usbmisc->lock, flags);
+	val &= ~MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_MASK;
+	val |= MX7D_USBNC_USB_CTRL2_OPMODE(0);
+	val &= ~MX7D_USBNC_USB_CTRL2_OPMODE_OVERRIDE_EN;
 	writel(val, usbmisc->base + MX7D_USBNC_USB_CTRL2);
 	spin_unlock_irqrestore(&usbmisc->lock, flags);
 }