libcamera: ipa: rkisp1: Add basic control of auto exposure

Add an IPA which controls the exposure time and analog gain for a sensor
connected to the rkisp1 pipeline. The IPA supports turning AE on and off
and informing the camera of the status of the AE control loop.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/ipa/rkisp1.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * rkisp1.h - Image Processing Algorithm interface for RkISP1
+ */
+#ifndef __LIBCAMERA_IPA_INTERFACE_RKISP1_H__
+#define __LIBCAMERA_IPA_INTERFACE_RKISP1_H__
+
+enum RkISP1Operations {
+	RKISP1_IPA_ACTION_V4L2_SET = 1,
+	RKISP1_IPA_ACTION_PARAM_FILLED = 2,
+	RKISP1_IPA_ACTION_METADATA = 3,
+	RKISP1_IPA_EVENT_SIGNAL_STAT_BUFFER = 4,
+	RKISP1_IPA_EVENT_QUEUE_REQUEST = 5,
+};
+
+#endif /* __LIBCAMERA_IPA_INTERFACE_RKISP1_H__ */