[PATCH RFC v2 3/6] media: v4l2-ctrls: add lens group status controls for zoom and focus

[Michael Riesch]

Add the controls V4L2_CID_{FOCUS,ZOOM}_{CURRENT,STATUS} that report the
current position and status, respectively, of the zoom lens group and
the focus lens group.

Signed-off-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxxx>
---
 .../userspace-api/media/v4l/ext-ctrls-camera.rst   | 46 ++++++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ctrls-defs.c          | 10 +++++
 include/uapi/linux/v4l2-controls.h                 |  9 +++++
 3 files changed, 65 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
index 42cf4c3cda0c..3ea4175f9619 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
@@ -150,6 +150,29 @@ enum v4l2_exposure_metering -
     write-only control. It should be implemented only if the device cannot
     handle absolute values.
 
+``V4L2_CID_FOCUS_CURRENT (integer)``
+    The current position of the focal point. The unit is undefined. Larger
+    values indicate that the focus is closer to the camera, smaller values
+    indicate that the focus is closer to infinity. This is a read-only control.
+
+``V4L2_CID_FOCUS_STATUS (bitmask)``
+    The status of the focus lens group. The possible flags are described in
+    the table below. This is a read-only control.
+
+.. tabularcolumns:: |p{6.8cm}|p{10.7cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+    * - ``V4L2_LENS_STATUS_IDLE``
+      - Focus lens group is at rest.
+    * - ``V4L2_LENS_STATUS_BUSY``
+      - Focus lens group is moving.
+    * - ``V4L2_LENS_STATUS_FAILED``
+      - Focus lens group has failed to reach its target position. The driver
+	will not transition from this state until another action is performed
+	by an application.
 
 ``V4L2_CID_FOCUS_AUTO (boolean)``
     Enables continuous automatic focus adjustments. The effect of manual
@@ -241,6 +264,29 @@ enum v4l2_auto_focus_range -
     movement. A negative value moves the zoom lens group towards the
     wide-angle direction. The zoom speed unit is driver-specific.
 
+``V4L2_CID_ZOOM_CURRENT (integer)``
+    The current objective lens focal length. The unit is undefined and
+    its value should be a positive integer. This is a read-only control.
+
+``V4L2_CID_ZOOM_STATUS (bitmask)``
+    The status of the zoom lens group. The possible flags are described in
+    the table below. This is a read-only control.
+
+.. tabularcolumns:: |p{6.8cm}|p{10.7cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+    * - ``V4L2_LENS_STATUS_IDLE``
+      - Zoom lens group is at rest.
+    * - ``V4L2_LENS_STATUS_BUSY``
+      - Zoom lens group is moving.
+    * - ``V4L2_LENS_STATUS_FAILED``
+      - Zoom lens group has failed to reach its target position. The driver will
+	not transition from this state until another action is performed by an
+	application.
+
 ``V4L2_CID_IRIS_ABSOLUTE (integer)``
     This control sets the camera's aperture to the specified value. The
     unit is undefined. Larger values open the iris wider, smaller values
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
index 564fedee2c88..794ef3ab0c02 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
@@ -1044,6 +1044,10 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_CAMERA_ORIENTATION:	return "Camera Orientation";
 	case V4L2_CID_CAMERA_SENSOR_ROTATION:	return "Camera Sensor Rotation";
 	case V4L2_CID_HDR_SENSOR_MODE:		return "HDR Sensor Mode";
+	case V4L2_CID_FOCUS_CURRENT:		return "Focus, Current";
+	case V4L2_CID_FOCUS_STATUS:		return "Focus, Status";
+	case V4L2_CID_ZOOM_CURRENT:		return "Zoom, Current";
+	case V4L2_CID_ZOOM_STATUS:		return "Zoom, Status";
 
 	/* FM Radio Modulator controls */
 	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
@@ -1593,6 +1597,12 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 		*flags |= V4L2_CTRL_FLAG_WRITE_ONLY |
 			  V4L2_CTRL_FLAG_EXECUTE_ON_WRITE;
 		break;
+	case V4L2_CID_FOCUS_CURRENT:
+	case V4L2_CID_FOCUS_STATUS:
+	case V4L2_CID_ZOOM_CURRENT:
+	case V4L2_CID_ZOOM_STATUS:
+		*flags |= V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_VOLATILE;
+		break;
 	case V4L2_CID_FLASH_STROBE_STATUS:
 	case V4L2_CID_AUTO_FOCUS_STATUS:
 	case V4L2_CID_FLASH_READY:
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 5e80daa4ffe0..793ee8c65e87 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -993,6 +993,15 @@ enum v4l2_auto_focus_range {
 
 #define V4L2_CID_HDR_SENSOR_MODE		(V4L2_CID_CAMERA_CLASS_BASE+36)
 
+#define V4L2_LENS_STATUS_IDLE			(0 << 0)
+#define V4L2_LENS_STATUS_BUSY			(1 << 0)
+#define V4L2_LENS_STATUS_FAILED			(1 << 2)
+
+#define V4L2_CID_FOCUS_CURRENT			(V4L2_CID_CAMERA_CLASS_BASE+37)
+#define V4L2_CID_FOCUS_STATUS			(V4L2_CID_CAMERA_CLASS_BASE+38)
+#define V4L2_CID_ZOOM_CURRENT			(V4L2_CID_CAMERA_CLASS_BASE+39)
+#define V4L2_CID_ZOOM_STATUS			(V4L2_CID_CAMERA_CLASS_BASE+40)
+
 /* FM Modulator class control IDs */
 
 #define V4L2_CID_FM_TX_CLASS_BASE		(V4L2_CTRL_CLASS_FM_TX | 0x900)

-- 
2.37.2