libcamera: v4l2_subdevice: Inherit from Loggable

Prefix the V4L2Subdevice error messages with the name of the entity.
Remove the manually printed name from log messages where it was used and
standardize error messages while at there.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/include/v4l2_subdevice.h

@@ -9,6 +9,7 @@
 
 #include <string>
 
+#include "log.h"
 #include "media_object.h"
 
 namespace libcamera {
@@ -21,7 +22,7 @@ struct V4L2SubdeviceFormat {
 	uint32_t height;
 };
 
-class V4L2Subdevice
+class V4L2Subdevice : protected Loggable
 {
 public:
 	explicit V4L2Subdevice(const MediaEntity *entity);
@@ -41,6 +42,9 @@ public:
 	int getFormat(unsigned int pad, V4L2SubdeviceFormat *format);
 	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format);
 
+protected:
+	std::string logPrefix() const;
+
 private:
 	int setSelection(unsigned int pad, unsigned int target,
 			 Rectangle *rect);