ipa: ipu3: agc: Introduce lineDuration in IPASessionConfiguration

Instead of having a local cached value for line duration, store it in
the IPASessionConfiguration::sensor structure.
While at it, configure the default analogue gain and shutter speed to
controlled fixed values.

The latter is set to be 10ms as it will in most cases be close to the
one needed, making the AGC faster to converge.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>

src/ipa/ipu3/ipa_context.cpp

@@ -86,6 +86,14 @@ namespace libcamera::ipa::ipu3 {
  * \brief Maximum analogue gain supported with the configured sensor
  */
 
+/**
+ * \var IPASessionConfiguration::sensor
+ * \brief Sensor-specific configuration of the IPA
+ *
+ * \var IPASessionConfiguration::sensor.lineDuration
+ * \brief Line duration in microseconds
+ */
+
 /**
  * \var IPAFrameContext::agc
  * \brief Context for the Automatic Gain Control algorithm