v4l2-ctrls: Add transaction support

Commit Message

Laurent Pinchart March 3, 2011, 3:13 p.m. UTC

None

Patch

diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index 2412f08..d0e6265 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -1264,13 +1264,22 @@  EXPORT_SYMBOL(v4l2_ctrl_handler_log_status);
 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
 {
 	struct v4l2_ctrl *ctrl;
+	unsigned int count = 0;
 	int ret = 0;
 
 	if (hdl == NULL)
 		return 0;
 	mutex_lock(&hdl->lock);
-	list_for_each_entry(ctrl, &hdl->ctrls, node)
+	list_for_each_entry(ctrl, &hdl->ctrls, node) {
 		ctrl->done = false;
+		count++;
+	}
+
+	if (hdl->begin) {
+		ret = hdl->begin(hdl, count == 1);
+		if (ret)
+			goto done;
+	}
 
 	list_for_each_entry(ctrl, &hdl->ctrls, node) {
 		struct v4l2_ctrl *master = ctrl->cluster[0];
@@ -1298,6 +1307,11 @@  int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
 			if (master->cluster[i])
 				master->cluster[i]->done = true;
 	}
+
+	if (hdl->commit)
+		hdl->commit(hdl, ret != 0);
+
+done:
 	mutex_unlock(&hdl->lock);
 	return ret;
 }
@@ -1717,6 +1731,12 @@  static int try_or_set_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 			return -EBUSY;
 	}
 
+	if (set && hdl->begin) {
+		ret = hdl->begin(hdl, cs->count == 1);
+		if (ret)
+			return ret;
+	}
+
 	for (i = 0; !ret && i < cs->count; i++) {
 		struct v4l2_ctrl *ctrl = helpers[i].ctrl;
 		struct v4l2_ctrl *master = ctrl->cluster[0];
@@ -1747,6 +1767,10 @@  static int try_or_set_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 		v4l2_ctrl_unlock(ctrl);
 		cluster_done(i, cs, helpers);
 	}
+
+	if (set && hdl->commit)
+		hdl->commit(hdl, ret == 0);
+
 	return ret;
 }
 
@@ -1842,8 +1866,20 @@  static int set_ctrl(struct v4l2_ctrl *ctrl, s32 *val)
 	ctrl->val = *val;
 	ctrl->is_new = 1;
 	ret = try_or_set_control_cluster(master, false);
-	if (!ret)
-		ret = try_or_set_control_cluster(master, true);
+	if (ret)
+		goto done;
+
+	if (master->handler->begin) {
+		ret = master->handler->begin(master->handler, true);
+		if (ret)
+			goto done;
+	}
+
+	ret = try_or_set_control_cluster(master, true);
+	if (master->handler->commit)
+		master->handler->commit(master->handler, ret != 0);
+
+done:
 	*val = ctrl->cur.val;
 	v4l2_ctrl_unlock(ctrl);
 	return ret;
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 97d0638..29acffc 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -157,6 +157,12 @@  struct v4l2_ctrl_ref {
   * @buckets:	Buckets for the hashing. Allows for quick control lookup.
   * @nr_of_buckets: Total number of buckets in the array.
   * @error:	The error code of the first failed control addition.
+  * @begin:	Begin a control set transaction. Called before the first control
+  *		in a group is set. The single argument is true if the group
+  *		contains a single control, and false otherwise.
+  * @commit:	End a control set transaction. Called after the last control
+  * 		in a group is set. The rollback argument is true if an error
+  * 		occured when setting the controls, and false otherwise.
   */
 struct v4l2_ctrl_handler {
 	struct mutex lock;
@@ -166,6 +172,8 @@  struct v4l2_ctrl_handler {
 	struct v4l2_ctrl_ref **buckets;
 	u16 nr_of_buckets;
 	int error;
+	int (*begin)(struct v4l2_ctrl_handler *hdl, bool single);
+	void (*commit)(struct v4l2_ctrl_handler *hdl, bool rollback);
 };
 
 /** struct v4l2_ctrl_config - Control configuration structure.