Merge pull request #20 from ajcasagrande/add-headers

Include local copy of v4l2 headers in project repository.

README.md

@@ -28,7 +28,6 @@ It hides all the complexities of working with V4L2 and provides idiomatic Go typ
 * Go compiler/tools
 * Kernel minimum v5.10.x
 * A locally configured C compiler (i.e. gcc)
-* Header files for V4L2 (i.e. /usr/include/linux/videodev2.h)
 
 All examples have been tested using a Raspberry PI 3, running 32-bit Raspberry PI OS.
 The package should work with no problem on your 64-bit Linux OS.
@@ -45,6 +44,11 @@ sudo apt update
 sudo apt full-upgrade
 ```
 
+Install the `build-essential` package to install required C compilers:
+```shell
+sudo apt install build-essential
+```
+
 ### Using the go4vl package
 
 To include `go4vl` in your own code, `go get` the package:

examples/cgo_types/README.md

@@ -6,8 +6,8 @@ to communicate to device using cgo-generated types.
 
 ## Do not use it ## 
 
-Use package `v4l2` to do realtime image capture, as shown in example
-[examples/capture](../capture).
+Use package `v4l2` to do realtime image capture, as shown in examples
+[capture0](../capture0) and [capture1](../capture1).
 
 :warning:
 

examples/cgo_types/cgo_capture.go

@@ -1,6 +1,7 @@
 package main
 
 /*
+#cgo linux CFLAGS: -I ${SRCDIR}/../../include/
 #include <linux/videodev2.h>
 */
 import "C"

examples/manual_types/README.md

@@ -8,7 +8,7 @@ cgo-generated types (see v4l2 package) for stability.
 Do not use it. 
 
 If you want to play around with image capture, use the 
-[examples/capture](../capture).
+[capture0](../capture0) or [capture1](../capture1) examples.
 
 :warning:
 

include/README.md

@@ -0,0 +1,11 @@
+# V4L2 Include Files
+
+Here we provide a copy of the v4l2 header files as per the 
+[kernel.org docs](https://docs.kernel.org/userspace-api/media/v4l/func-ioctl.html#description):
+
+> Macros and defines specifying V4L2 ioctl requests are located in the `videodev2.h` header file.
+> _**Applications should use their own copy, not include the version in the kernel sources on the system they compile on.**_
+
+This helps to reduce compilation errors due to outdated headers installed in the user's system.
+
+Headers have been obtained from `v4l-utils` repo as of commit [3b94a0ca4894d75de240b3ebb296071e551a261e](https://github.com/gjasny/v4l-utils/tree/3b94a0ca4894d75de240b3ebb296071e551a261e/include/linux)

include/linux/v4l2-common.h

@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) */
+/*
+ * include/linux/v4l2-common.h
+ *
+ * Common V4L2 and V4L2 subdev definitions.
+ *
+ * Users are advised to #include this file either through videodev2.h
+ * (V4L2) or through v4l2-subdev.h (V4L2 subdev) rather than to refer
+ * to this file directly.
+ *
+ * Copyright (C) 2012 Nokia Corporation
+ * Contact: Sakari Ailus <[email protected]>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  Alternatively you can redistribute this file under the terms of the
+ *  BSD license as stated below:
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *  3. The names of its contributors may not be used to endorse or promote
+ *     products derived from this software without specific prior written
+ *     permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __V4L2_COMMON__
+#define __V4L2_COMMON__
+
+#include <linux/types.h>
+
+/*
+ *
+ * Selection interface definitions
+ *
+ */
+
+/* Current cropping area */
+#define V4L2_SEL_TGT_CROP		0x0000
+/* Default cropping area */
+#define V4L2_SEL_TGT_CROP_DEFAULT	0x0001
+/* Cropping bounds */
+#define V4L2_SEL_TGT_CROP_BOUNDS	0x0002
+/* Native frame size */
+#define V4L2_SEL_TGT_NATIVE_SIZE	0x0003
+/* Current composing area */
+#define V4L2_SEL_TGT_COMPOSE		0x0100
+/* Default composing area */
+#define V4L2_SEL_TGT_COMPOSE_DEFAULT	0x0101
+/* Composing bounds */
+#define V4L2_SEL_TGT_COMPOSE_BOUNDS	0x0102
+/* Current composing area plus all padding pixels */
+#define V4L2_SEL_TGT_COMPOSE_PADDED	0x0103
+
+/* Selection flags */
+#define V4L2_SEL_FLAG_GE		(1 << 0)
+#define V4L2_SEL_FLAG_LE		(1 << 1)
+#define V4L2_SEL_FLAG_KEEP_CONFIG	(1 << 2)
+
+struct v4l2_edid {
+	__u32 pad;
+	__u32 start_block;
+	__u32 blocks;
+	__u32 reserved[5];
+	__u8  *edid;
+};
+
+/* Backward compatibility target definitions --- to be removed. */
+#define V4L2_SEL_TGT_CROP_ACTIVE	V4L2_SEL_TGT_CROP
+#define V4L2_SEL_TGT_COMPOSE_ACTIVE	V4L2_SEL_TGT_COMPOSE
+#define V4L2_SUBDEV_SEL_TGT_CROP_ACTUAL	V4L2_SEL_TGT_CROP
+#define V4L2_SUBDEV_SEL_TGT_COMPOSE_ACTUAL V4L2_SEL_TGT_COMPOSE
+#define V4L2_SUBDEV_SEL_TGT_CROP_BOUNDS	V4L2_SEL_TGT_CROP_BOUNDS
+#define V4L2_SUBDEV_SEL_TGT_COMPOSE_BOUNDS V4L2_SEL_TGT_COMPOSE_BOUNDS
+
+/* Backward compatibility flag definitions --- to be removed. */
+#define V4L2_SUBDEV_SEL_FLAG_SIZE_GE	V4L2_SEL_FLAG_GE
+#define V4L2_SUBDEV_SEL_FLAG_SIZE_LE	V4L2_SEL_FLAG_LE
+#define V4L2_SUBDEV_SEL_FLAG_KEEP_CONFIG V4L2_SEL_FLAG_KEEP_CONFIG
+
+#endif /* __V4L2_COMMON__ */