[PATCH v3 10/12] media: ov5640: Make the FPS clamping / rounding more extendable

[Maxime Ripard <maxime.ripard@bootlin.com>]

The current code uses an algorithm to clamp the FPS values and round them
to the closest supported one that isn't really allows to be extended to
more than two values.

Rework it a bit to make it much easier to extend the amount of FPS options
we support.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 drivers/media/i2c/ov5640.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
index b9a8f3feed74..0f6c39080d69 100644
--- a/drivers/media/i2c/ov5640.c
+++ b/drivers/media/i2c/ov5640.c
@@ -1890,7 +1890,8 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
 {
 	const struct ov5640_mode_info *mode;
 	enum ov5640_frame_rate rate = OV5640_30_FPS;
-	u32 minfps, maxfps, fps;
+	int minfps, maxfps, best_fps, fps;
+	int i;
 
 	minfps = ov5640_framerates[OV5640_15_FPS];
 	maxfps = ov5640_framerates[OV5640_30_FPS];
@@ -1901,19 +1902,21 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
 		return OV5640_30_FPS;
 	}
 
-	fps = DIV_ROUND_CLOSEST(fi->denominator, fi->numerator);
+	fps = clamp_val(DIV_ROUND_CLOSEST(fi->denominator, fi->numerator),
+			minfps, maxfps);
+
+	best_fps = minfps;
+	for (i = 0; i < ARRAY_SIZE(ov5640_framerates); i++) {
+		int curr_fps = ov5640_framerates[i];
+
+		if (abs(curr_fps - fps) < abs(best_fps - fps)) {
+			best_fps = curr_fps;
+			rate = i;
+		}
+	}
 
 	fi->numerator = 1;
-	if (fps > maxfps)
-		fi->denominator = maxfps;
-	else if (fps < minfps)
-		fi->denominator = minfps;
-	else if (2 * fps >= 2 * minfps + (maxfps - minfps))
-		fi->denominator = maxfps;
-	else
-		fi->denominator = minfps;
-
-	rate = (fi->denominator == minfps) ? OV5640_15_FPS : OV5640_30_FPS;
+	fi->denominator = best_fps;
 
 	mode = ov5640_find_mode(sensor, rate, width, height, false);
 	return mode ? rate : -EINVAL;
-- 
2.17.0