[media] ad9389b: retry setup if the state is inconsistent

Retry setup if the device is powered off when it should be powered on. This
state can be caused by rapid hotplug toggles.
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/ad9389b.c

@@ -904,7 +904,7 @@ static void ad9389b_notify_monitor_detect(struct v4l2_subdev *sd)
 	v4l2_subdev_notify(sd, AD9389B_MONITOR_DETECT, (void *)&mdt);
 }
 
-static void ad9389b_check_monitor_present_status(struct v4l2_subdev *sd)
+static void ad9389b_update_monitor_present_status(struct v4l2_subdev *sd)
 {
 	struct ad9389b_state *state = get_ad9389b_state(sd);
 	/* read hotplug and rx-sense state */
@@ -947,6 +947,31 @@ static void ad9389b_check_monitor_present_status(struct v4l2_subdev *sd)
 	ad9389b_s_ctrl(state->hdmi_mode_ctrl);
 }
 
+static void ad9389b_check_monitor_present_status(struct v4l2_subdev *sd)
+{
+	struct ad9389b_state *state = get_ad9389b_state(sd);
+	int retry = 0;
+
+	ad9389b_update_monitor_present_status(sd);
+
+	/*
+	 * Rapid toggling of the hotplug may leave the chip powered off,
+	 * even if we think it is on. In that case reset and power up again.
+	 */
+	while (state->power_on && (ad9389b_rd(sd, 0x41) & 0x40)) {
+		if (++retry > 5) {
+			v4l2_err(sd, "retried %d times, give up\n", retry);
+			return;
+		}
+		v4l2_dbg(1, debug, sd, "%s: reset and re-check status (%d)\n", __func__, retry);
+		ad9389b_notify_monitor_detect(sd);
+		cancel_delayed_work_sync(&state->edid_handler);
+		memset(&state->edid, 0, sizeof(struct ad9389b_state_edid));
+		ad9389b_s_power(sd, false);
+		ad9389b_update_monitor_present_status(sd);
+	}
+}
+
 static bool edid_block_verify_crc(u8 *edid_block)
 {
 	u8 sum = 0;