V4L/DVB (12512): ov772x: implement a band-stop filter support

The V4L2_CID_BAND_STOP_FILTER control is used to switch the "Banding Filter" on
OV772x cameras on and off and to set the minimum AEC value in BDBASE register.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/ov772x.c

@@ -403,8 +403,9 @@ struct ov772x_priv {
 	const struct ov772x_color_format *fmt;
 	const struct ov772x_win_size     *win;
 	int                               model;
-	unsigned int                      flag_vflip:1;
-	unsigned int                      flag_hflip:1;
+	unsigned short                    flag_vflip:1;
+	unsigned short                    flag_hflip:1;
+	unsigned short                    band_filter;	/* 256 - BDBASE, 0 if (!COM8[5]) */
 };
 
 #define ENDMARKER { 0xff, 0xff }
@@ -569,6 +570,15 @@ static const struct v4l2_queryctrl ov772x_controls[] = {
 		.step		= 1,
 		.default_value	= 0,
 	},
+	{
+		.id		= V4L2_CID_BAND_STOP_FILTER,
+		.type		= V4L2_CTRL_TYPE_INTEGER,
+		.name		= "Band-stop filter",
+		.minimum	= 0,
+		.maximum	= 256,
+		.step		= 1,
+		.default_value	= 0,
+	},
 };
 
 
@@ -674,6 +684,9 @@ static int ov772x_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 	case V4L2_CID_HFLIP:
 		ctrl->value = priv->flag_hflip;
 		break;
+	case V4L2_CID_BAND_STOP_FILTER:
+		ctrl->value = priv->band_filter;
+		break;
 	}
 	return 0;
 }
@@ -700,6 +713,29 @@ static int ov772x_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
 			val ^= HFLIP_IMG;
 		ret = ov772x_mask_set(client, COM3, HFLIP_IMG, val);
 		break;
+	case V4L2_CID_BAND_STOP_FILTER:
+		if ((unsigned)ctrl->value > 256)
+			ctrl->value = 256;
+		if (ctrl->value == priv->band_filter)
+			break;
+		if (!ctrl->value) {
+			/* Switch the filter off, it is on now */
+			ret = ov772x_mask_set(client, BDBASE, 0xff, 0xff);
+			if (!ret)
+				ret = ov772x_mask_set(client, COM8,
+						      BNDF_ON_OFF, 0);
+		} else {
+			/* Switch the filter on, set AEC low limit */
+			val = 256 - ctrl->value;
+			ret = ov772x_mask_set(client, COM8,
+					      BNDF_ON_OFF, BNDF_ON_OFF);
+			if (!ret)
+				ret = ov772x_mask_set(client, BDBASE,
+						      0xff, val);
+		}
+		if (!ret)
+			priv->band_filter = ctrl->value;
+		break;
 	}
 
 	return ret;
@@ -893,6 +929,18 @@ static int ov772x_set_params(struct i2c_client *client,
 	if (ret < 0)
 		goto ov772x_set_fmt_error;
 
+	/*
+	 * set COM8
+	 */
+	if (priv->band_filter) {
+		ret = ov772x_mask_set(client, COM8, BNDF_ON_OFF, 1);
+		if (!ret)
+			ret = ov772x_mask_set(client, BDBASE,
+					      0xff, 256 - priv->band_filter);
+		if (ret < 0)
+			goto ov772x_set_fmt_error;
+	}
+
 	return ret;
 
 ov772x_set_fmt_error: