[PATCH v2] media: v4l2-subdev.h: allow V4L2_FRMIVAL_TYPE_CONTINUOUS & _STEPWISE

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add V4L2_FRMIVAL_TYPE_CONTINUOUS and V4L2_FRMIVAL_TYPE_STEPWISE for
subdev's frame intervals in addition to implicit existing
V4L2_FRMIVAL_TYPE_DISCRETE type.  This needs three new fields in the
v4l2_subdev_frame_interval_enum struct :
- type
- max_interval
- step_interval

A helper function 'v4l2_fill_frmivalenum_from_subdev' is also added.

Subdevs must fill the 'type' field.  If they do not, the default
value (0) is used which is equal to V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE.

if type is set to V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE, or left untouched,
only the 'interval' field must be filled, just as before.

If type is set to V4L2_FRMIVAL_TYPE_CONTINUOUS, 'interval' must be set
to the minimum frame interval (highest framerate), and 'max_interval'
to the maximum frame interval.

If type is set to V4L2_FRMIVAL_TYPE_STEPWISE, 'step_interval' must be
set to the step between available intervals, in addition to 'interval'
and 'max_interval' which must be set as for V4L2_FRMIVAL_TYPE_CONTINUOUS

Old users which do not check the 'type' field will get the minimum frame
interval (highest framrate) just like before.

Callers who intend to check the 'type' field should zero it themselves,
in case an old subdev driver does not do zero it.

When filled correctly by the sensor driver, the new fields must be
used as follows by the caller :

	 struct v4l2_frmivalenum * fival;
	 struct v4l2_subdev_frame_interval_enum fie;

	 if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE) {
		 fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
		 fival->discrete = fie.interval;
	 } else if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_CONTINUOUS) {
		 fival->type = V4L2_FRMIVAL_TYPE_CONTINUOUS;
		 fival->stepwise.min = fie.interval;
		 fival->stepwise.max = fie.max_interval;
	 } else {
		 fival->type = V4L2_FRMIVAL_TYPE_STEPWISE;
		 fival->stepwise.min = fie.interval;
		 fival->stepwise.max = fie.max_interval;
		 fival->stepwise.step = fie.step_interval;
	 }

Kernel users should use the new 'v4l2_fill_frmivalenum_from_subdev'
helper function.

Signed-off-by: Philippe De Muyter <phdm@xxxxxxxxx>
---
v2:
	Add a 'type' field and a helper function, as asked by Hans

 .../uapi/v4l/vidioc-subdev-enum-frame-interval.rst | 46 +++++++++++++++++++++-
 drivers/media/v4l2-core/v4l2-common.c              | 32 +++++++++++++++
 include/media/v4l2-common.h                        | 12 ++++++
 include/uapi/linux/v4l2-subdev.h                   | 22 ++++++++++-
 4 files changed, 109 insertions(+), 3 deletions(-)

diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst
index 1bfe386..d3144b7 100644
--- a/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst
+++ b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst
@@ -51,6 +51,44 @@ EINVAL error code if one of the input fields is invalid. All frame
 intervals are enumerable by beginning at index zero and incrementing by
 one until ``EINVAL`` is returned.
 
+If the sub-device can work only at a fixed set of frame intervals,
+driver must enumerate them with increasing indexes, by setting the
+``type`` field to ``V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE`` and only filling
+the ``interval`` field .  If the sub-device can work with a continuous
+range of frame intervals, driver must only return success for index 0,
+set the ``type`` field to ``V4L2_SUBDEV_FRMIVAL_TYPE_CONTINUOUS``,
+fill ``interval`` with the minimum interval and ``max_interval`` with
+the maximum interval.  If it is worth mentionning the step in the
+continuous interval, the driver must set the ``type`` field to
+``V4L2_SUBDEV_FRMIVAL_TYPE_STEPWISE`` and fill also the ``step_interval``
+field with the step between the possible intervals.
+
+Callers are expected to use the returned information as follows :
+
+.. code-block:: c
+
+        struct v4l2_frmivalenum * fival;
+        struct v4l2_subdev_frame_interval_enum fie;
+
+        if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE) {
+                fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
+                fival->discrete = fie.interval;
+        } else if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_CONTINUOUS) {
+                fival->type = V4L2_FRMIVAL_TYPE_CONTINUOUS;
+                fival->stepwise.min = fie.interval;
+                fival->stepwise.max = fie.max_interval;
+        } else {
+                fival->type = V4L2_FRMIVAL_TYPE_STEPWISE;
+                fival->stepwise.min = fie.interval;
+                fival->stepwise.max = fie.max_interval;
+                fival->stepwise.step = fie.step_interval;
+        }
+
+.. code-block:: c
+
+Kernel users may use the ``v4l2_fill_frmivalenum_from_subdev`` helper
+function instead.
+
 Available frame intervals may depend on the current 'try' formats at
 other pads of the sub-device, as well as on the current active links.
 See :ref:`VIDIOC_SUBDEV_G_FMT` for more
@@ -92,8 +130,14 @@ multiple pads of the same sub-device is not defined.
       - ``which``
       - Frame intervals to be enumerated, from enum
 	:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
+    * - struct :c:type:`v4l2_fract`
+      - ``max_interval``
+      - Maximum period, in seconds, between consecutive video frames, or 0.
+    * - struct :c:type:`v4l2_fract`
+      - ``step_interval``
+      - Frame interval step size, in seconds, or 0.
     * - __u32
-      - ``reserved``\ [8]
+      - ``reserved``\ [4]
       - Reserved for future extensions. Applications and drivers must set
 	the array to zero.
 
diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index b062111..d652dd3 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -445,3 +445,35 @@ int v4l2_s_parm_cap(struct video_device *vdev,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(v4l2_s_parm_cap);
+
+int v4l2_fill_frmivalenum_from_subdev(struct v4l2_subdev *sd, struct v4l2_frmivalenum *fival, int code)
+{
+	struct v4l2_subdev_frame_interval_enum fie;
+	int ret;
+
+	fie.index = fival->index;
+	fie.code = code;
+	fie.width = fival->width;
+	fie.height = fival->height;
+	fie.type = V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE; /* for old subdev drivers */
+
+	ret = v4l2_subdev_call(sd, pad, enum_frame_interval, NULL, &fie);
+
+	if (!ret) {
+		if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE) {
+			fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
+			fival->discrete = fie.interval;
+		} else if (fie.type == V4L2_SUBDEV_FRMIVAL_TYPE_CONTINUOUS) {
+			fival->type = V4L2_FRMIVAL_TYPE_CONTINUOUS;
+			fival->stepwise.min = fie.interval;
+			fival->stepwise.max = fie.max_interval;
+		} else {
+			fival->type = V4L2_FRMIVAL_TYPE_STEPWISE;
+			fival->stepwise.min = fie.interval;
+			fival->stepwise.max = fie.max_interval;
+			fival->stepwise.step = fie.step_interval;
+		}
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_fill_frmivalenum_from_subdev);
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index cdc87ec..3c62403 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -384,4 +384,16 @@ int v4l2_g_parm_cap(struct video_device *vdev,
 int v4l2_s_parm_cap(struct video_device *vdev,
 		    struct v4l2_subdev *sd, struct v4l2_streamparm *a);
 
+/**
+ * v4l2_fill_frmivalenum_from_subdev - helper for vidioc_enum_frameintervals
+ *      calling the enum_frame_interval op of the given subdev.
+ *
+ * @sd: the sub-device pointer.
+ * @fival: the VIDIOC_ENUM_FRAMEINTERVALS argument.
+ * @code: the MEDIA_BUS_FMT_ code (not fival->pixel_format !)
+ */
+int v4l2_fill_frmivalenum_from_subdev(struct v4l2_subdev *sd,
+	       			      struct v4l2_frmivalenum *fival,
+				      int code);
+
 #endif /* V4L2_COMMON_H_ */
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index 03970ce..3faae35 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -100,6 +100,16 @@ struct v4l2_subdev_frame_size_enum {
 };
 
 /**
+ * enum v4l2_subdev_frmival_type - Frame interval type
+ */
+enum v4l2_subdev_frmival_type {
+	V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE = 0,
+	V4L2_SUBDEV_FRMIVAL_TYPE_CONTINUOUS = 1,
+	V4L2_SUBDEV_FRMIVAL_TYPE_STEPWISE = 2,
+};
+
+
+/**
  * struct v4l2_subdev_frame_interval - Pad-level frame rate
  * @pad: pad number, as reported by the media API
  * @interval: frame interval in seconds
@@ -117,8 +127,13 @@ struct v4l2_subdev_frame_interval {
  * @code: format code (MEDIA_BUS_FMT_ definitions)
  * @width: frame width in pixels
  * @height: frame height in pixels
- * @interval: frame interval in seconds
+ * @interval: minimum frame interval in seconds
  * @which: format type (from enum v4l2_subdev_format_whence)
+ * @type: frame interval type (from enum v4l2_subdev_frmival_type)
+ * @max_interval: maximum frame interval in seconds,
+ *                if type != V4L2_SUBDEV_FRMIVAL_TYPE_DISCRETE
+ * @step_interval: step between frame intervals, in seconds,
+ *                 if type == V4L2_SUBDEV_FRMIVAL_TYPE_STEPWISE
  */
 struct v4l2_subdev_frame_interval_enum {
 	__u32 index;
@@ -128,7 +143,10 @@ struct v4l2_subdev_frame_interval_enum {
 	__u32 height;
 	struct v4l2_fract interval;
 	__u32 which;
-	__u32 reserved[8];
+	__u32 type;
+	struct v4l2_fract max_interval;
+	struct v4l2_fract step_interval;
+	__u32 reserved[3];
 };
 
 /**
-- 
1.8.4




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