[media] adv7604: Correct G/S_EDID behaviour

In order to have v4l2-compliance tool pass the G/S_EDID some modifications
where needed in the driver.
In particular, the edid.reserved zone must be blanked.

Based on a patch from Jean-Michel Hautbois <jean-michel.hautbois@vodalys.com>,
but reworked it a bit. It should use 'data' (which depends on edid.present)
instead of edid.blocks as the check whether edid data is present.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/i2c/adv7604.c

@@ -1997,19 +1997,7 @@ static int adv7604_get_edid(struct v4l2_subdev *sd, struct v4l2_edid *edid)
 	struct adv7604_state *state = to_state(sd);
 	u8 *data = NULL;
 
-	if (edid->pad > ADV7604_PAD_HDMI_PORT_D)
-		return -EINVAL;
-	if (edid->blocks == 0)
-		return -EINVAL;
-	if (edid->blocks > 2)
-		return -EINVAL;
-	if (edid->start_block > 1)
-		return -EINVAL;
-	if (edid->start_block == 1)
-		edid->blocks = 1;
-
-	if (edid->blocks > state->edid.blocks)
-		edid->blocks = state->edid.blocks;
+	memset(edid->reserved, 0, sizeof(edid->reserved));
 
 	switch (edid->pad) {
 	case ADV7604_PAD_HDMI_PORT_A:
@@ -2021,14 +2009,24 @@ static int adv7604_get_edid(struct v4l2_subdev *sd, struct v4l2_edid *edid)
 		break;
 	default:
 		return -EINVAL;
-		break;
 	}
-	if (!data)
+
+	if (edid->start_block == 0 && edid->blocks == 0) {
+		edid->blocks = data ? state->edid.blocks : 0;
+		return 0;
+	}
+
+	if (data == NULL)
 		return -ENODATA;
 
-	memcpy(edid->edid,
-	       data + edid->start_block * 128,
-	       edid->blocks * 128);
+	if (edid->start_block >= state->edid.blocks)
+		return -EINVAL;
+
+	if (edid->start_block + edid->blocks > state->edid.blocks)
+		edid->blocks = state->edid.blocks - edid->start_block;
+
+	memcpy(edid->edid, data + edid->start_block * 128, edid->blocks * 128);
+
 	return 0;
 }
 
@@ -2068,6 +2066,8 @@ static int adv7604_set_edid(struct v4l2_subdev *sd, struct v4l2_edid *edid)
 	int err;
 	int i;
 
+	memset(edid->reserved, 0, sizeof(edid->reserved));
+
 	if (edid->pad > ADV7604_PAD_HDMI_PORT_D)
 		return -EINVAL;
 	if (edid->start_block != 0)
@@ -2164,7 +2164,6 @@ static int adv7604_set_edid(struct v4l2_subdev *sd, struct v4l2_edid *edid)
 		return -EIO;
 	}
 
-
 	/* enable hotplug after 100 ms */
 	queue_delayed_work(state->work_queues,
 			&state->delayed_work_enable_hotplug, HZ / 10);