[media] adv7511: disable register reset by HPD

Whenever the hotplug pin is pulled low the chip resets a whole bunch
of registers. It turns out that this can be turned off on the adv7511.
Do so, as this 'feature' introduces race conditions in setting up
registers, particular when the hotplug pin bounces a lot.

Signed-off-by: Martin Bugge <marbugge@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/i2c/adv7511.c

@@ -1038,6 +1038,12 @@ static void adv7511_init_setup(struct v4l2_subdev *sd)
 
 	/* clear all interrupts */
 	adv7511_wr(sd, 0x96, 0xff);
+	/*
+	 * Stop HPD from resetting a lot of registers.
+	 * It might leave the chip in a partly un-initialized state,
+	 * in particular with regards to hotplug bounces.
+	 */
+	adv7511_wr_and_or(sd, 0xd6, 0x3f, 0xc0);
 	memset(edid, 0, sizeof(struct adv7511_state_edid));
 	state->have_monitor = false;
 	adv7511_set_isr(sd, false);