[PATCH 04/13] media: v4l2-subdev: Add a helper to figure out the pad streaming state

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Add a helper, v4l2_subdev_state_streams_enabled(), to tell which streams
are enabled on a pad. This is useful to e.g. figure out in a driver
whether a hardware configuration change is necessary to enable a given
stream.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 17 +++++++++++++++++
 include/media/v4l2-subdev.h           |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index a3074f469b15..60b8febd3339 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -2453,6 +2453,23 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_disable_streams);
 
+u64 v4l2_subdev_state_streams_enabled(struct v4l2_subdev *sd,
+				      struct v4l2_subdev_state *state, u32 pad)
+{
+	u64 streams_mask = 0;
+
+	for (unsigned int i = 0; i < state->stream_configs.num_configs; i++) {
+		struct v4l2_subdev_stream_config *cfg =
+			&state->stream_configs.configs[i];
+
+		if (cfg->pad == pad && cfg->enabled)
+			streams_mask |= BIT_ULL(cfg->stream);
+	}
+
+	return streams_mask;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_state_streams_enabled);
+
 int v4l2_subdev_s_stream_helper(struct v4l2_subdev *sd, int enable)
 {
 	struct v4l2_subdev_state *state;
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 57f2bcb4eb16..deab128a4779 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1731,6 +1731,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
 int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
 				u64 streams_mask);
 
+u64 v4l2_subdev_state_streams_enabled(struct v4l2_subdev *sd,
+				      struct v4l2_subdev_state *state, u32 pad);
+
 /**
  * v4l2_subdev_s_stream_helper() - Helper to implement the subdev s_stream
  *	operation using enable_streams and disable_streams
-- 
2.39.5