[media] v4l2-ctrls: create type_ops

Since compound controls can have non-standard types we need to be able to do
type-specific checks etc. In order to make that easy type operations are added.
There are four operations:

- equal: check if two values are equal
- init: initialize a value
- log: log the value
- validate: validate a new value

The v4l2_ctrl struct adds p_new and p_cur unions at the end of the struct.
This union provides a standard way of accessing control types through a pointer,
which greatly simplifies internal control processing.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 9024daebdf3b..ddd9fdf1ac1a 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -36,6 +36,19 @@ struct v4l2_subscribed_event;
 struct v4l2_fh;
 struct poll_table_struct;
 
+/** union v4l2_ctrl_ptr - A pointer to a control value.
+ * @p_s32:      Pointer to a 32-bit signed value.
+ * @p_s64:      Pointer to a 64-bit signed value.
+ * @p_char:     Pointer to a string.
+ * @p:          Pointer to a compound value.
+ */
+union v4l2_ctrl_ptr {
+        s32 *p_s32;
+        s64 *p_s64;
+        char *p_char;
+        void *p;
+};
+
 /** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
   * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
   *             for volatile (and usually read-only) controls such as a control
@@ -54,6 +67,23 @@ struct v4l2_ctrl_ops {
         int (*s_ctrl)(struct v4l2_ctrl *ctrl);
 };
 
+/** struct v4l2_ctrl_type_ops - The control type operations that the driver has to provide.
+  * @equal: return true if both values are equal.
+  * @init: initialize the value.
+  * @log: log the value.
+  * @validate: validate the value. Return 0 on success and a negative value otherwise.
+  */
+struct v4l2_ctrl_type_ops {
+        bool (*equal)(const struct v4l2_ctrl *ctrl,
+                      union v4l2_ctrl_ptr ptr1,
+                      union v4l2_ctrl_ptr ptr2);
+        void (*init)(const struct v4l2_ctrl *ctrl,
+                     union v4l2_ctrl_ptr ptr);
+        void (*log)(const struct v4l2_ctrl *ctrl);
+        int (*validate)(const struct v4l2_ctrl *ctrl,
+                        union v4l2_ctrl_ptr ptr);
+};
+
 typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
 
 /** struct v4l2_ctrl - The control structure.
@@ -89,6 +119,7 @@ typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
   *             value, then the whole cluster is in manual mode. Drivers should
   *             never set this flag directly.
   * @ops:       The control ops.
+  * @type_ops:  The control type ops.
   * @id:        The control ID.
   * @name:      The control name.
   * @type:      The control type.
@@ -137,6 +168,7 @@ struct v4l2_ctrl {
         unsigned int manual_mode_value:8;
 
         const struct v4l2_ctrl_ops *ops;
+        const struct v4l2_ctrl_type_ops *type_ops;
         u32 id;
         const char *name;
         enum v4l2_ctrl_type type;
@@ -164,6 +196,9 @@ struct v4l2_ctrl {
                 char *string;
                 void *p;
         } cur;
+
+        union v4l2_ctrl_ptr p_new;
+        union v4l2_ctrl_ptr p_cur;
 };
 
 /** struct v4l2_ctrl_ref - The control reference.
@@ -217,6 +252,7 @@ struct v4l2_ctrl_handler {
 
 /** struct v4l2_ctrl_config - Control configuration structure.
   * @ops:       The control ops.
+  * @type_ops:  The control type ops. Only needed for compound controls.
   * @id:        The control ID.
   * @name:      The control name.
   * @type:      The control type.
@@ -241,6 +277,7 @@ struct v4l2_ctrl_handler {
   */
 struct v4l2_ctrl_config {
         const struct v4l2_ctrl_ops *ops;
+        const struct v4l2_ctrl_type_ops *type_ops;
         u32 id;
         const char *name;
         enum v4l2_ctrl_type type;