[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>

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -531,13 +531,12 @@ static void v4l_print_query_ext_ctrl(const void *arg, bool write_only)
 
 	pr_cont("id=0x%x, type=%d, name=%.*s, min/max=%lld/%lld, "
 		"step=%lld, default=%lld, flags=0x%08x, elem_size=%u, elems=%u, "
-		"nr_of_dims=%u, dims=%u,%u,%u,%u,%u,%u,%u,%u\n",
+		"nr_of_dims=%u, dims=%u,%u,%u,%u\n",
 			p->id, p->type, (int)sizeof(p->name), p->name,
 			p->minimum, p->maximum,
 			p->step, p->default_value, p->flags,
 			p->elem_size, p->elems, p->nr_of_dims,
-			p->dims[0], p->dims[1], p->dims[2], p->dims[3],
-			p->dims[4], p->dims[5], p->dims[6], p->dims[7]);
+			p->dims[0], p->dims[1], p->dims[2], p->dims[3]);
 }
 
 static void v4l_print_querymenu(const void *arg, bool write_only)

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;