ipa: ipu3: awb: Clamp gain values

The gain values are coded as u3.13 fixed point values, ie they can not
be more than 8. Clamp the values in order to avoid any off limits value
which could make the IPU3 behave in a weird manner.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
index 1dc27fc..87a6cc7 100644
--- a/src/ipa/ipu3/algorithms/awb.cpp
+++ b/src/ipa/ipu3/algorithms/awb.cpp
@@ -353,6 +353,14 @@
 
 	/* Color temperature is not relevant in Grey world but still useful to estimate it :-) */
 	asyncResults_.temperatureK = estimateCCT(sumRed.R, sumRed.G, sumBlue.B);
+
+	/*
+	 * Gain values are unsigned integer value ranging [0, 8) with 13 bit
+	 * fractional part.
+	 */
+	redGain = std::clamp(redGain, 0.0, 65535.0 / 8192);
+	blueGain = std::clamp(blueGain, 0.0, 65535.0 / 8192);
+
 	asyncResults_.redGain = redGain;
 	/* Hardcode the green gain to 1.0. */
 	asyncResults_.greenGain = 1.0;