usb: musb: Disable pullup at init

BugLink: https://bugs.launchpad.net/bugs/1859865

commit 96a0c128 upstream.

The pullup may be already enabled before the driver is initialized. This
happens for instance on JZ4740.

It has to be disabled at init time, as we cannot guarantee that a gadget
driver will be bound to the UDC.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Suggested-by: Bin Liu <b-liu@ti.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200107152625.857-3-b-liu@ti.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/usb/musb/musb_core.c

@@ -2132,6 +2132,9 @@ musb_init_controller(struct device *dev, int nIrq, void __iomem *ctrl)
 	musb_platform_disable(musb);
 	musb_generic_disable(musb);
 
+	/* MUSB_POWER_SOFTCONN might be already set, JZ4740 does this. */
+	musb_writeb(musb->mregs, MUSB_POWER, 0);
+
 	/* Init IRQ workqueue before request_irq */
 	INIT_WORK(&musb->irq_work, musb_irq_work);
 	INIT_DELAYED_WORK(&musb->deassert_reset_work, musb_deassert_reset);