[PATCH v3 6/9] media: subdev: Add v4l2_subdev_is_streaming()

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

Add a helper function which returns whether the subdevice is streaming,
i.e. if .s_stream or .enable_streams has been called successfully.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 25 +++++++++++++++++++++++++
 include/media/v4l2-subdev.h           | 13 +++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 3d2c9c224b8f..20b5a00cbeeb 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -2419,6 +2419,31 @@ void v4l2_subdev_notify_event(struct v4l2_subdev *sd,
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_notify_event);
 
+bool v4l2_subdev_is_streaming(struct v4l2_subdev *sd)
+{
+	struct v4l2_subdev_state *state;
+
+	if (!v4l2_subdev_has_op(sd, pad, enable_streams))
+		return sd->streaming_enabled;
+
+	state = v4l2_subdev_get_locked_active_state(sd);
+
+	if (!(sd->flags & V4L2_SUBDEV_FL_STREAMS))
+		return !!sd->enabled_pads;
+
+	for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
+		const struct v4l2_subdev_stream_config *cfg;
+
+		cfg = &state->stream_configs.configs[i];
+
+		if (cfg->enabled)
+			return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_is_streaming);
+
 int v4l2_subdev_get_privacy_led(struct v4l2_subdev *sd)
 {
 #if IS_REACHABLE(CONFIG_LEDS_CLASS)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index d6867511e9cf..270a4dfa5663 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1914,4 +1914,17 @@ extern const struct v4l2_subdev_ops v4l2_subdev_call_wrappers;
 void v4l2_subdev_notify_event(struct v4l2_subdev *sd,
 			      const struct v4l2_event *ev);
 
+/**
+ * v4l2_subdev_is_streaming() - Returns if the subdevice is streaming
+ * @sd: The subdevice
+ *
+ * v4l2_subdev_is_streaming() tells if the subdevice is currently streaming.
+ * "Streaming" here means whether .s_stream() or .enable_streams() has been
+ * successfully called, and the streaming has not yet been disabled.
+ *
+ * If the subdevice implements .enable_streams() this function must be called
+ * while holding the active state lock.
+ */
+bool v4l2_subdev_is_streaming(struct v4l2_subdev *sd);
+
 #endif /* _V4L2_SUBDEV_H */

-- 
2.34.1