media: rcar-vin: Add support for V4L2_FIELD_ALTERNATE

The hardware is capable to passing V4L2_FIELD_ALTERNATE to user-space.
Allow users to request this field format but still default to using the
hardware interlacer if alternating is not explicitly requested.

Before this change a sensor providing data using alternate would be
always combined to an interlaced frame. After this change the user can
request to receive frames as alternate if the sensor provides it.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/rcar-vin/rcar-dma.c

@@ -529,12 +529,17 @@ static void rvin_set_coeff(struct rvin_dev *vin, unsigned short xs)
 
 static void rvin_crop_scale_comp_gen2(struct rvin_dev *vin)
 {
+	unsigned int crop_height;
 	u32 xs, ys;
 
 	/* Set scaling coefficient */
+	crop_height = vin->crop.height;
+	if (V4L2_FIELD_IS_INTERLACED(vin->format.field))
+		crop_height *= 2;
+
 	ys = 0;
-	if (vin->crop.height != vin->compose.height)
-		ys = (4096 * vin->crop.height) / vin->compose.height;
+	if (crop_height != vin->compose.height)
+		ys = (4096 * crop_height) / vin->compose.height;
 	rvin_write(vin, ys, VNYS_REG);
 
 	xs = 0;
@@ -578,21 +583,9 @@ void rvin_crop_scale_comp(struct rvin_dev *vin)
 	/* Set Start/End Pixel/Line Pre-Clip */
 	rvin_write(vin, vin->crop.left, VNSPPRC_REG);
 	rvin_write(vin, vin->crop.left + vin->crop.width - 1, VNEPPRC_REG);
+	rvin_write(vin, vin->crop.top, VNSLPRC_REG);
+	rvin_write(vin, vin->crop.top + vin->crop.height - 1, VNELPRC_REG);
 
-	switch (vin->format.field) {
-	case V4L2_FIELD_INTERLACED:
-	case V4L2_FIELD_INTERLACED_TB:
-	case V4L2_FIELD_INTERLACED_BT:
-		rvin_write(vin, vin->crop.top / 2, VNSLPRC_REG);
-		rvin_write(vin, (vin->crop.top + vin->crop.height) / 2 - 1,
-			   VNELPRC_REG);
-		break;
-	default:
-		rvin_write(vin, vin->crop.top, VNSLPRC_REG);
-		rvin_write(vin, vin->crop.top + vin->crop.height - 1,
-			   VNELPRC_REG);
-		break;
-	}
 
 	/* TODO: Add support for the UDS scaler. */
 	if (vin->info->model != RCAR_GEN3)
@@ -636,6 +629,9 @@ static int rvin_setup(struct rvin_dev *vin)
 		vnmc = VNMC_IM_ODD_EVEN;
 		progressive = true;
 		break;
+	case V4L2_FIELD_ALTERNATE:
+		vnmc = VNMC_IM_ODD_EVEN;
+		break;
 	default:
 		vnmc = VNMC_IM_ODD;
 		break;
@@ -794,6 +790,18 @@ static bool rvin_capture_active(struct rvin_dev *vin)
 	return rvin_read(vin, VNMS_REG) & VNMS_CA;
 }
 
+static enum v4l2_field rvin_get_active_field(struct rvin_dev *vin, u32 vnms)
+{
+	if (vin->format.field == V4L2_FIELD_ALTERNATE) {
+		/* If FS is set it is an Even field. */
+		if (vnms & VNMS_FS)
+			return V4L2_FIELD_BOTTOM;
+		return V4L2_FIELD_TOP;
+	}
+
+	return vin->format.field;
+}
+
 static void rvin_set_slot_addr(struct rvin_dev *vin, int slot, dma_addr_t addr)
 {
 	const struct rvin_video_format *fmt;
@@ -943,7 +951,7 @@ static irqreturn_t rvin_irq(int irq, void *data)
 
 	/* Capture frame */
 	if (vin->queue_buf[slot]) {
-		vin->queue_buf[slot]->field = vin->format.field;
+		vin->queue_buf[slot]->field = rvin_get_active_field(vin, vnms);
 		vin->queue_buf[slot]->sequence = vin->sequence;
 		vin->queue_buf[slot]->vb2_buf.timestamp = ktime_get_ns();
 		vb2_buffer_done(&vin->queue_buf[slot]->vb2_buf,
@@ -1070,6 +1078,7 @@ static int rvin_mc_validate_format(struct rvin_dev *vin, struct v4l2_subdev *sd,
 		case V4L2_FIELD_TOP:
 		case V4L2_FIELD_BOTTOM:
 		case V4L2_FIELD_NONE:
+		case V4L2_FIELD_ALTERNATE:
 			break;
 		case V4L2_FIELD_INTERLACED_TB:
 		case V4L2_FIELD_INTERLACED_BT:

drivers/media/platform/rcar-vin/rcar-v4l2.c

@@ -117,15 +117,7 @@ static void rvin_format_align(struct rvin_dev *vin, struct v4l2_pix_format *pix)
 	case V4L2_FIELD_INTERLACED_TB:
 	case V4L2_FIELD_INTERLACED_BT:
 	case V4L2_FIELD_INTERLACED:
-		break;
 	case V4L2_FIELD_ALTERNATE:
-		/*
-		 * Driver does not (yet) support outputting ALTERNATE to a
-		 * userspace. It does support outputting INTERLACED so use
-		 * the VIN hardware to combine the two fields.
-		 */
-		pix->field = V4L2_FIELD_INTERLACED;
-		pix->height *= 2;
 		break;
 	default:
 		pix->field = RVIN_DEFAULT_FIELD;
@@ -164,15 +156,25 @@ static int rvin_reset_format(struct rvin_dev *vin)
 
 	v4l2_fill_pix_format(&vin->format, &fmt.format);
 
-	rvin_format_align(vin, &vin->format);
-
 	vin->src_rect.top = 0;
 	vin->src_rect.left = 0;
 	vin->src_rect.width = vin->format.width;
 	vin->src_rect.height = vin->format.height;
 
+	/*  Make use of the hardware interlacer by default. */
+	if (vin->format.field == V4L2_FIELD_ALTERNATE) {
+		vin->format.field = V4L2_FIELD_INTERLACED;
+		vin->format.height *= 2;
+	}
+
+	rvin_format_align(vin, &vin->format);
+
 	vin->crop = vin->src_rect;
-	vin->compose = vin->src_rect;
+
+	vin->compose.top = 0;
+	vin->compose.left = 0;
+	vin->compose.width = vin->format.width;
+	vin->compose.height = vin->format.height;
 
 	return 0;
 }
@@ -217,13 +219,6 @@ static int rvin_try_format(struct rvin_dev *vin, u32 which,
 		crop->left = 0;
 		crop->width = pix->width;
 		crop->height = pix->height;
-
-		/*
-		 * If source is ALTERNATE the driver will use the VIN hardware
-		 * to INTERLACE it. The crop height then needs to be doubled.
-		 */
-		if (pix->field == V4L2_FIELD_ALTERNATE)
-			crop->height *= 2;
 	}
 
 	if (field != V4L2_FIELD_ANY)