[RFC PATCH v2 4/5] media: vsp1: Split out pre-filter multiplier

[Kieran Bingham <kieran.bingham@ideasonboard.com>]

From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

The 'mp' value is used through many calculations in determining the scaling
factors of the UDS. Factor this out so that it can be reused in further
calculations, and also ensure that if the BLADV control is ever changed only a
single function needs to be modified.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 drivers/media/platform/vsp1/vsp1_uds.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/vsp1/vsp1_uds.c b/drivers/media/platform/vsp1/vsp1_uds.c
index 27012af973b2..c71c24363d54 100644
--- a/drivers/media/platform/vsp1/vsp1_uds.c
+++ b/drivers/media/platform/vsp1/vsp1_uds.c
@@ -46,6 +46,18 @@ void vsp1_uds_set_alpha(struct vsp1_entity *entity, struct vsp1_dl_body *dlb,
 		       alpha << VI6_UDS_ALPVAL_VAL0_SHIFT);
 }
 
+/*
+ * Determine the pre-filter multiplication value.
+ *
+ * This calculation assumes that the BLADV control is unset.
+ */
+static unsigned int uds_multiplier(int ratio)
+{
+	unsigned int mp = ratio / 4096;
+
+	return mp < 4 ? 1 : (mp < 8 ? 2 : 4);
+}
+
 /*
  * uds_output_size - Return the output size for an input size and scaling ratio
  * @input: input size in pixels
@@ -55,10 +67,7 @@ static unsigned int uds_output_size(unsigned int input, unsigned int ratio)
 {
 	if (ratio > 4096) {
 		/* Down-scaling */
-		unsigned int mp;
-
-		mp = ratio / 4096;
-		mp = mp < 4 ? 1 : (mp < 8 ? 2 : 4);
+		unsigned int mp = uds_multiplier(ratio);
 
 		return (input - 1) / mp * mp * 4096 / ratio + 1;
 	} else {
@@ -88,10 +97,7 @@ static unsigned int uds_passband_width(unsigned int ratio)
 {
 	if (ratio >= 4096) {
 		/* Down-scaling */
-		unsigned int mp;
-
-		mp = ratio / 4096;
-		mp = mp < 4 ? 1 : (mp < 8 ? 2 : 4);
+		unsigned int mp = uds_multiplier(ratio);
 
 		return 64 * 4096 * mp / ratio;
 	} else {
-- 
2.19.1