[PATCH v5 05/16] media: sony-starvis2: Rework 2 lane support for higher link freqs

[Dave Stevenson]

With some Starvis 2 sensors, the link frequency on 2 lanes is sufficient
to achieve a lower line time than the 4 lane value divided by 2, as
the 4 lane value hits the minimum that the pixel array can handle.
That can't easily be handled with the way the values are currently stored.

Storing the 2 lane hmax alongside the pixel array's minimum allows the
4 lane support to divide the value by 2, and then clip to the pixel
array value as a minimum.

Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
---
 drivers/media/i2c/sony-starvis2.c | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/drivers/media/i2c/sony-starvis2.c b/drivers/media/i2c/sony-starvis2.c
index eb7662c43989..b0b1716a86e2 100644
--- a/drivers/media/i2c/sony-starvis2.c
+++ b/drivers/media/i2c/sony-starvis2.c
@@ -176,15 +176,15 @@ static const u64 link_freqs[] = {
 	[STARVIS2_LINK_FREQ_1188MHZ] = 1188000000,
 };
 
-static const u16 imx678_min_hmax_4lane[] = {
-	[STARVIS2_LINK_FREQ_297MHZ] = 1584,
-	[STARVIS2_LINK_FREQ_360MHZ] = 1320,
-	[STARVIS2_LINK_FREQ_445MHZ] = 1100,
-	[STARVIS2_LINK_FREQ_594MHZ] =  792,
-	[STARVIS2_LINK_FREQ_720MHZ] =  660,
-	[STARVIS2_LINK_FREQ_891MHZ] =  550,
-	[STARVIS2_LINK_FREQ_1039MHZ] = 550,
-	[STARVIS2_LINK_FREQ_1188MHZ] = 550,
+static const u16 imx678_min_hmax_2lane[] = {
+	[STARVIS2_LINK_FREQ_297MHZ]  = 3168,
+	[STARVIS2_LINK_FREQ_360MHZ]  = 2640,
+	[STARVIS2_LINK_FREQ_445MHZ]  = 2200,
+	[STARVIS2_LINK_FREQ_594MHZ]  = 1584,
+	[STARVIS2_LINK_FREQ_720MHZ]  = 1320,
+	[STARVIS2_LINK_FREQ_891MHZ]  = 1100,
+	[STARVIS2_LINK_FREQ_1039MHZ] = 1100,
+	[STARVIS2_LINK_FREQ_1188MHZ] = 1100,
 };
 
 struct starvis2_inck_cfg {
@@ -631,7 +631,8 @@ struct starvis2_variant {
 	const struct cci_reg_sequence *common_regs;
 	unsigned int num_common_regs;
 	unsigned int vmax_default;
-	const u16 *hmax_min;
+	const u16 *hmax_min_link_freq;
+	u16 hmax_min_pixel_array;
 };
 
 static const struct starvis2_variant imx678_variant_def = {
@@ -656,7 +657,8 @@ static const struct starvis2_variant imx678_variant_def = {
 	.common_regs = imx678_common_regs,
 	.num_common_regs = ARRAY_SIZE(imx678_common_regs),
 	.vmax_default = 2250,
-	.hmax_min = imx678_min_hmax_4lane,
+	.hmax_min_link_freq = imx678_min_hmax_2lane,
+	.hmax_min_pixel_array = 550,
 };
 
 struct starvis2_model_info {
@@ -1204,11 +1206,8 @@ static const struct v4l2_subdev_internal_ops starvis2_internal_ops = {
 static int starvis2_init_controls(struct starvis2 *starvis2)
 {
 	struct v4l2_ctrl_handler *ctrl_hdlr;
-	const u32 hmax_4lane =
-		starvis2->variant->hmax_min[__fls(starvis2->link_freq_bitmap)];
-	const u32 lane_scale =
-			starvis2->lane_mode == STARVIS2_LANEMODE_2L ? 2 : 1;
 	struct i2c_client *client = v4l2_get_subdevdata(&starvis2->sd);
+	const struct starvis2_variant *variant = starvis2->variant;
 	struct v4l2_fwnode_device_properties props;
 	struct v4l2_ctrl *link_freq;
 	s32 hblank, max_hblank, vblank, max_vblank;
@@ -1225,7 +1224,10 @@ static int starvis2_init_controls(struct starvis2 *starvis2)
 		return ret;
 
 	starvis2->vmax = starvis2->variant->vmax_default;
-	hmax = hmax_4lane * lane_scale;
+
+	hmax = variant->hmax_min_link_freq[__fls(starvis2->link_freq_bitmap)];
+	if (starvis2->lane_mode == STARVIS2_LANEMODE_4L)
+		hmax = max(hmax >> 1, variant->hmax_min_pixel_array);
 
 	/* PIXEL_RATE is fixed and read-only */
 	v4l2_ctrl_new_std(ctrl_hdlr, &starvis2_ctrl_ops, V4L2_CID_PIXEL_RATE,

-- 
2.34.1