usb: musb: Check devctl status again for a spurious session request

On start-up, we can get a spurious session request interrupt with nothing
connected. After that the devctl session bit will silently clear, but the
musb hardware is never idled until a cable is plugged in, or the glue
layer module is reloaded.

Let's just check the session bit again in 3 seconds in peripheral mode
to catch the issue.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20210518150615.53464-1-tony@atomide.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -2055,6 +2055,15 @@ static void musb_pm_runtime_check_session(struct musb *musb)
 			dev_err(musb->controller, "Could not enable: %i\n",
 				error);
 		musb->quirk_retries = 3;
+
+		/*
+		 * We can get a spurious MUSB_INTR_SESSREQ interrupt on start-up
+		 * in B-peripheral mode with nothing connected and the session
+		 * bit clears silently. Check status again in 3 seconds.
+		 */
+		if (devctl & MUSB_DEVCTL_BDEVICE)
+			schedule_delayed_work(&musb->irq_work,
+					      msecs_to_jiffies(3000));
 	} else {
 		musb_dbg(musb, "Allow PM with no session: %02x", devctl);
 		pm_runtime_mark_last_busy(musb->controller);