From 6195ecf605368d29a9ef684da387a6929845f925 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Tue, 24 Mar 2020 23:13:02 +0200
Subject: [PATCH] media: bcm2835-unicam: Add support for the FRAME_SYNC
 event

The FRAME_SYNC event is useful for userspace image processing algorithms
to program the camera sensor as early as possible after frame start.
Support it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
---
 drivers/media/platform/bcm2835/bcm2835-unicam.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/media/platform/bcm2835/bcm2835-unicam.c
+++ b/drivers/media/platform/bcm2835/bcm2835-unicam.c
@@ -772,6 +772,16 @@ static int unicam_all_nodes_disabled(str
 	       !dev->node[METADATA_PAD].streaming;
 }
 
+static void unicam_queue_event_sof(struct unicam_device *unicam)
+{
+	struct v4l2_event event = {
+		.type = V4L2_EVENT_FRAME_SYNC,
+		.u.frame_sync.frame_sequence = unicam->sequence,
+	};
+
+	v4l2_event_queue(&unicam->node[IMAGE_PAD].video_dev, &event);
+}
+
 /*
  * unicam_isr : ISR handler for unicam capture
  * @irq: irq number
@@ -853,6 +863,8 @@ static irqreturn_t unicam_isr(int irq, v
 			 */
 			unicam_schedule_dummy_buffer(&unicam->node[i]);
 		}
+
+		unicam_queue_event_sof(unicam);
 	}
 	/*
 	 * Cannot swap buffer at frame end, there may be a race condition
@@ -2022,6 +2034,8 @@ static int unicam_subscribe_event(struct
 				  const struct v4l2_event_subscription *sub)
 {
 	switch (sub->type) {
+	case V4L2_EVENT_FRAME_SYNC:
+		return v4l2_event_subscribe(fh, sub, 2, NULL);
 	case V4L2_EVENT_SOURCE_CHANGE:
 		return v4l2_event_subscribe(fh, sub, 4, NULL);
 	}
