Add two macros that facilitate printing V4L fourcc values with printf
family of functions. v4l2_fourcc_conv provides the printf conversion
specifier for printing formats and v4l2_fourcc_to_conv provides the actual
arguments for that conversion specifier.
These macros are useful in both user and kernel code, therefore put them
into videodev2.h.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
include/uapi/linux/videodev2.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index caec178..93184929 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -82,6 +82,31 @@
((__u32)(a) | ((__u32)(b) << 8) | ((__u32)(c) << 16) | ((__u32)(d) << 24))
#define v4l2_fourcc_be(a, b, c, d) (v4l2_fourcc(a, b, c, d) | (1 << 31))
+/**
+ * v4l2_fourcc_conv - Printf fourcc conversion specifiers for V4L2 formats
+ *
+ * Use as part of the format string. The values are obtained using
+ * @v4l2_fourcc_to_conv macro.
+ *
+ * Example ("format" is the V4L2 pixelformat in __u32):
+ *
+ * printf("V4L2 format is: " v4l2_fourcc_conv "\n", v4l2_fourcc_to_conv(format);
+ */
+#define v4l2_fourcc_conv "%c%c%c%c%s"
+
+/**
+ * v4l2_fourcc_to_conv - Arguments for V4L2 fourcc format conversion
+ *
+ * @fourcc: V4L2 pixelformat, as in __u32
+ *
+ * Yields to a comma-separated list of arguments for printf that matches with
+ * conversion specifiers provided by @v4l2_fourcc_conv.
+ */
+#define v4l2_fourcc_to_conv(fourcc) \
+ (fourcc) & 0x7f, ((fourcc) >> 8) & 0x7f, ((fourcc) >> 16) & 0x7f, \
+ ((fourcc) >> 24) & 0x7f, (fourcc) & (1 << 31) ? "-BE" : ""
+
+
/*
* E N U M S
*/
--
2.7.4
