[libcamera-devel] [PATCH 6/9] libcamera: v4l2_controls: Add V4L2ControlId

[Laurent Pinchart]

Add a V4L2 specialisation of the ControlId class, in order to construct
a ControlId from a v4l2_query_ext_ctrl. This is needed in order to use
ControlList for V4L2 controls.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/include/v4l2_controls.h | 12 +++--
 src/libcamera/v4l2_controls.cpp       | 67 +++++++++++++++++++++++----
 src/libcamera/v4l2_device.cpp         |  4 +-
 3 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/src/libcamera/include/v4l2_controls.h b/src/libcamera/include/v4l2_controls.h
index b39370b2e90e..71ce377fe4c5 100644
--- a/src/libcamera/include/v4l2_controls.h
+++ b/src/libcamera/include/v4l2_controls.h
@@ -20,23 +20,27 @@
 
 namespace libcamera {
 
+class V4L2ControlId : public ControlId
+{
+public:
+	V4L2ControlId(const struct v4l2_query_ext_ctrl &ctrl);
+};
+
 class V4L2ControlInfo
 {
 public:
 	V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl);
 
-	unsigned int id() const { return id_; }
+	const ControlId &id() const { return id_; }
 	unsigned int type() const { return type_; }
 	size_t size() const { return size_; }
-	const std::string &name() const { return name_; }
 
 	const ControlRange &range() const { return range_; }
 
 private:
-	unsigned int id_;
+	V4L2ControlId id_;
 	unsigned int type_;
 	size_t size_;
-	std::string name_;
 
 	ControlRange range_;
 };
diff --git a/src/libcamera/v4l2_controls.cpp b/src/libcamera/v4l2_controls.cpp
index 6f5f1578b139..a630a2583d33 100644
--- a/src/libcamera/v4l2_controls.cpp
+++ b/src/libcamera/v4l2_controls.cpp
@@ -7,6 +7,8 @@
 
 #include "v4l2_controls.h"
 
+#include <string.h>
+
 /**
  * \file v4l2_controls.h
  * \brief Support for V4L2 Controls using the V4L2 Extended Controls APIs
@@ -47,6 +49,60 @@
 
 namespace libcamera {
 
+namespace {
+
+std::string v4l2_ctrl_name(const struct v4l2_query_ext_ctrl &ctrl)
+{
+	size_t len = strnlen(ctrl.name, sizeof(ctrl.name));
+	return std::string(static_cast<const char *>(ctrl.name), len);
+}
+
+ControlType v4l2_ctrl_type(const struct v4l2_query_ext_ctrl &ctrl)
+{
+	switch (ctrl.type) {
+	case V4L2_CTRL_TYPE_BOOLEAN:
+		return ControlTypeBool;
+
+	case V4L2_CTRL_TYPE_INTEGER:
+		return ControlTypeInteger32;
+
+	case V4L2_CTRL_TYPE_INTEGER64:
+		return ControlTypeInteger64;
+
+	case V4L2_CTRL_TYPE_MENU:
+	case V4L2_CTRL_TYPE_BUTTON:
+	case V4L2_CTRL_TYPE_BITMASK:
+	case V4L2_CTRL_TYPE_INTEGER_MENU:
+		/*
+		 * More precise types may be needed, for now use a 32-bit
+		 * integer type.
+		 */
+		return ControlTypeInteger32;
+
+	default:
+		return ControlTypeNone;
+	}
+}
+
+} /* namespace */
+
+/**
+ * \class V4L2ControlId
+ * \brief V4L2 control static metadata
+ *
+ * The V4L2ControlId class is a specialisation of the ControlId for V4L2
+ * controls.
+ */
+
+/**
+ * \brief Construct a V4L2ControlId from a struct v4l2_query_ext_ctrl
+ * \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
+ */
+V4L2ControlId::V4L2ControlId(const struct v4l2_query_ext_ctrl &ctrl)
+	: ControlId(ctrl.id, v4l2_ctrl_name(ctrl), v4l2_ctrl_type(ctrl))
+{
+}
+
 /**
  * \class V4L2ControlInfo
  * \brief Information on a V4L2 control
@@ -66,13 +122,12 @@ namespace libcamera {
 
 /**
  * \brief Construct a V4L2ControlInfo from a struct v4l2_query_ext_ctrl
- * \param ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
+ * \param[in] ctrl The struct v4l2_query_ext_ctrl as returned by the kernel
  */
 V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
+	: id_(ctrl)
 {
-	id_ = ctrl.id;
 	type_ = ctrl.type;
-	name_ = static_cast<const char *>(ctrl.name);
 	size_ = ctrl.elem_size * ctrl.elems;
 
 	if (ctrl.type == V4L2_CTRL_TYPE_INTEGER64)
@@ -101,12 +156,6 @@ V4L2ControlInfo::V4L2ControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
  * \return The V4L2 control value data size
  */
 
-/**
- * \fn V4L2ControlInfo::name()
- * \brief Retrieve the control user readable name
- * \return The V4L2 control user readable name
- */
-
 /**
  * \fn V4L2ControlInfo::range()
  * \brief Retrieve the control value range
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 3bd82ff23212..466c3d41f6e3 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -184,7 +184,7 @@ int V4L2Device::getControls(V4L2ControlList *ctrls)
 
 		const V4L2ControlInfo *info = &iter->second;
 		controlInfo[i] = info;
-		v4l2Ctrls[i].id = info->id();
+		v4l2Ctrls[i].id = ctrl->id();
 	}
 
 	struct v4l2_ext_controls v4l2ExtCtrls = {};
@@ -259,7 +259,7 @@ int V4L2Device::setControls(V4L2ControlList *ctrls)
 
 		const V4L2ControlInfo *info = &iter->second;
 		controlInfo[i] = info;
-		v4l2Ctrls[i].id = info->id();
+		v4l2Ctrls[i].id = ctrl->id();
 
 		/* Set the v4l2_ext_control value for the write operation. */
 		switch (info->type()) {
-- 
Regards,

Laurent Pinchart