[libcamera-devel] [PATCH v4 2/5] src: ipa: raspberrypi: agc: Make AGC handle Pause/Resume for itself

[David Plowman]

AGC, when paused, sets the last exposure/gain it wrote to be its
"fixed" values and will therefore continue to return them. When
resumed, we clear them so that both will float again.

This approach is better because AGC can be paused and we can
subsequently change (for example) the exposure and the gain won't
float again.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/ipa/raspberrypi/controller/rpi/agc.cpp | 24 ++++++++++++++++++++++
 src/ipa/raspberrypi/controller/rpi/agc.hpp |  4 ++++
 2 files changed, 28 insertions(+)

diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index 30a1c1c1..9da18c31 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -184,6 +184,26 @@ void Agc::Read(boost::property_tree::ptree const &params)
 	exposure_mode_ = &config_.exposure_modes[exposure_mode_name_];
 	constraint_mode_name_ = config_.default_constraint_mode;
 	constraint_mode_ = &config_.constraint_modes[constraint_mode_name_];
+	// Set up the "last shutter/gain" values, in case AGC starts "disabled".
+	status_.shutter_time = config_.default_exposure_time;
+	status_.analogue_gain = config_.default_analogue_gain;
+}
+
+bool Agc::IsPaused() const
+{
+	return false;
+}
+
+void Agc::Pause()
+{
+	fixed_shutter_ = status_.shutter_time;
+	fixed_analogue_gain_ = status_.analogue_gain;
+}
+
+void Agc::Resume()
+{
+	fixed_shutter_ = 0;
+	fixed_analogue_gain_ = 0;
 }
 
 void Agc::SetEv(double ev)
@@ -199,11 +219,15 @@ void Agc::SetFlickerPeriod(double flicker_period)
 void Agc::SetFixedShutter(double fixed_shutter)
 {
 	fixed_shutter_ = fixed_shutter;
+	// Set this in case someone calls Pause() straight after.
+	status_.shutter_time = fixed_shutter;
 }
 
 void Agc::SetFixedAnalogueGain(double fixed_analogue_gain)
 {
 	fixed_analogue_gain_ = fixed_analogue_gain;
+	// Set this in case someone calls Pause() straight after.
+	status_.analogue_gain = fixed_analogue_gain;
 }
 
 void Agc::SetMeteringMode(std::string const &metering_mode_name)
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.hpp b/src/ipa/raspberrypi/controller/rpi/agc.hpp
index 47ebb324..95db1812 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.hpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.hpp
@@ -70,6 +70,10 @@ public:
 	Agc(Controller *controller);
 	char const *Name() const override;
 	void Read(boost::property_tree::ptree const &params) override;
+	// AGC handles "pausing" for itself.
+	bool IsPaused() const override;
+	void Pause() override;
+	void Resume() override;
 	void SetEv(double ev) override;
 	void SetFlickerPeriod(double flicker_period) override;
 	void SetFixedShutter(double fixed_shutter) override; // microseconds
-- 
2.20.1