diff mbox

[RFC,2/3] v4l2-ctrls: add v4l2_ctrl_auto_cluster to simplify autogain/gain scenarios

Message ID ad0ec022eea20f19d3936a10268d429b1be57980.1295693790.git.hverkuil@xs4all.nl (mailing list archive)
State RFC
Headers show

Commit Message

Hans Verkuil Jan. 22, 2011, 11:06 a.m. UTC
None
diff mbox

Patch

diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index 983e287..b5da617 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -1178,6 +1178,25 @@  void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls)
 }
 EXPORT_SYMBOL(v4l2_ctrl_cluster);
 
+void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
+			    u8 manual_val, bool set_volatile)
+{
+	int i;
+
+	v4l2_ctrl_cluster(ncontrols, controls);
+	controls[0]->is_auto = true;
+	controls[0]->manual_mode_value = manual_val;
+
+	for (i = 1; i < ncontrols; i++) {
+		if (controls[i]) {
+			controls[i]->flags |= V4L2_CTRL_FLAG_UPDATE;
+			if (set_volatile)
+				controls[i]->is_volatile = true;
+		}
+	}
+}
+EXPORT_SYMBOL(v4l2_ctrl_auto_cluster);
+
 /* Activate/deactivate a control. */
 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active)
 {
@@ -1605,7 +1624,8 @@  int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs
 
 		v4l2_ctrl_lock(master);
 		/* g_volatile_ctrl will update the current control values */
-		if (ctrl->is_volatile && master->ops->g_volatile_ctrl)
+		if (ctrl->is_volatile && master->ops->g_volatile_ctrl &&
+		    (!master->is_auto || master->cur.val != master->manual_mode_value))
 			ret = master->ops->g_volatile_ctrl(master);
 		/* If OK, then copy the current control values to the caller */
 		if (!ret)
@@ -1717,6 +1737,11 @@  static int try_or_set_control_cluster(struct v4l2_ctrl *master, bool set)
 
 	/* Don't set if there is no change */
 	if (!ret && set && cluster_changed(master)) {
+		if (master->is_auto && !master->is_new &&
+		    master->cur.val != master->manual_mode_value) {
+			master->is_new = 1;
+			master->val = master->manual_mode_value;
+		}
 		ret = master->ops->s_ctrl(master);
 		/* If OK, then make the new values permanent. */
 		if (!ret)
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index a2b2d58..e715f4e 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -66,7 +66,16 @@  struct v4l2_ctrl_ops {
   *		retrieved through the g_volatile_ctrl op. Drivers can set
   *		this flag.
   * @is_enabled: If 0, then this control is disabled and will be hidden for
-  *		applications. Controls are always enabled by default.
+  *		applications. Controls are always enabled by default. Drivers
+  *		should never set this flag.
+  * @is_auto:   If set, then this control selects whether the other cluster
+  *		members are in 'automatic' mode or 'manual' mode. This is
+  *		used for autogain/gain type clusters. Drivers should never
+  *		set this flag.
+  * @manual_mode_value: If the is_auto flag is set, then this is the value
+  *		of the auto control that determines if that control is in
+  *		manual mode. So if the value of the auto control equals this
+  *		value, then the whole cluster is in manual mode.
   * @ops:	The control ops.
   * @id:	The control ID.
   * @name:	The control name.
@@ -108,6 +117,8 @@  struct v4l2_ctrl {
 	unsigned int is_private:1;
 	unsigned int is_volatile:1;
 	unsigned int is_enabled:1;
+	unsigned int is_auto:1;
+	unsigned int manual_mode_value:5;
 
 	const struct v4l2_ctrl_ops *ops;
 	u32 id;
@@ -366,6 +377,41 @@  int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
 void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
 
 
+/** v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
+  * that cluster and set it up for autofoo/foo-type handling.
+  * @ncontrols:	The number of controls in this cluster.
+  * @controls:	The cluster control array of size @ncontrols. The first control
+  *		must be the 'auto' control (e.g. autogain, autoexposure, etc.)
+  * @manual_val: The value for the first control in the cluster that equals the
+  *		manual setting.
+  * @set_volatile: If true, then all controls except the first auto control will
+  *		have is_volatile set to true. If false, then is_volatile will not
+  *		be touched.
+  *
+  * Use for control groups where one control selects some automatic feature and
+  * the other controls are only active whenever the automatic feature is turned
+  * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
+  * red and blue balance, etc.
+  *
+  * Using this function lets the framework take care of some of the actions
+  * related to such controls: whenever one of the manual controls are set
+  * without touching the auto control, then the auto control is set to
+  * manual mode. So in the s_ctrl op you can just set the new values. Also,
+  * g_volatile_ctrl is never called when in manual mode, since in that case
+  * the current control value can just be returned as is.
+  *
+  * This function also makes it easy to set all non-auto controls to volatile
+  * by setting the last argument to true. In most cases non-auto controls are
+  * volatile when in auto mode. E.g. if autogain is set, then the gain register
+  * usually reports the current automatically selected gain.
+  *
+  * This function also sets the V4L2_CTRL_FLAG_UPDATE for all the non-auto
+  * controls.
+  */
+void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
+			u8 manual_val, bool set_volatile);
+
+
 /** v4l2_ctrl_find() - Find a control with the given ID.
   * @hdl:	The control handler.
   * @id:	The control ID to find.