设备树添加版本信息

一、 参考文章

Linux设备树相关操作

Linux内核/设备树version

二、添加

在 linux-4.11.y 版本的时候，在 arch/arm/boot/dts/include 目录下有 dt-bindings 文件链接到了 include/dt-bindings 目录；

可以用相同的方法，添加链接文件，链接到 include/子目录；

liangtao:include$ls -al
total 148
drwxrwxr-x 2 liangtao liangtao   4096 Jul 21 21:55 .
drwxrwxr-x 3 liangtao liangtao 147456 Sep  3 04:44 ..
lrwxrwxrwx 1 liangtao liangtao     34 Jul 21 21:55 dt-bindings -> ../../../../../include/dt-bindings

在 linux-4.12.y 版本的时候，将 arch/arm/boot/dts/include/dt-bindings 目录，移动到了 scripts/dtc/include-prefixes/dt-bindings 目录；

对应的 commit 为：d5d332d3f7e8435e264a71b90178dee69428d630

liangtao:dts$git whatchanged d5d332d3f7e8435e264a71b90178dee69428d630
commit d5d332d3f7e8435e264a71b90178dee69428d630
Author: Olof Johansson 
Date:   Fri May 12 20:13:26 2017 -0700
 
    devicetree: Move include prefixes from arch to separate directory
    
    We use a directory under arch/$ARCH/boot/dts as an include path
    that has links outside of the subtree to find dt-bindings from under
    include/dt-bindings. That's been working well, but new DT architectures
    haven't been adding them by default.
    
    Recently there's been a desire to share some of the DT material between
    arm and arm64, which originally caused developers to create symlinks or
    relative includes between the subtrees. This isn't ideal -- it breaks
    if the DT files aren't stored in the exact same hierarchy as the kernel
    tree, and generally it's just icky.
    
    As a somewhat cleaner solution we decided to add a $ARCH/ prefix link
    once, and allow DTS files to reference dtsi (and dts) files in other
    architectures that way.
    
    Original approach was to create these links under each architecture,
    but it lead to the problem of recursive symlinks.
    
    As a remedy, move the include link directories out of the architecture
    trees into a common location. At the same time, they can now share one
    directory and one dt-bindings/ link as well.
    
    Fixes: 4027494ae6e3 ('ARM: dts: add arm/arm64 include symlinks')
    Reported-by: Russell King 
    Reported-by: Omar Sandoval 
    Reviewed-by: Heiko Stuebner 
    Reviewed-by: Masahiro Yamada 
    Tested-by: Heiko Stuebner 
    Acked-by: Rob Herring 
    Cc: Heiko Stuebner 
    Cc: Mark Rutland 
    Cc: Russell King 
    As a remedy, move the include link directories out of the architecture
    trees into a common location. At the same time, they can now share one
    directory and one dt-bindings/ link as well.
    
    Fixes: 4027494ae6e3 ('ARM: dts: add arm/arm64 include symlinks')
    Reported-by: Russell King 
    Reported-by: Omar Sandoval 
    Reviewed-by: Heiko Stuebner 
    Reviewed-by: Masahiro Yamada 
    Tested-by: Heiko Stuebner 
    Acked-by: Rob Herring 
    Cc: Heiko Stuebner 
    Cc: Mark Rutland 
    Cc: Russell King 
    Cc: Catalin Marinas 
    Cc: Will Deacon 
    Cc: Mikael Starvik 
    Cc: Jesper Nilsson 
    Cc: James Hogan 
    Cc: Ralf Baechle 
    Cc: Benjamin Herrenschmidt 
    Cc: Paul Mackerras 
    Cc: Michael Ellerman 
    Cc: Frank Rowand 
    Cc: linux-arch 
    Signed-off-by: Olof Johansson 
 
:120000 000000 a96aa0ea9d8c 000000000000 D      arch/arm/boot/dts/include/arm
:120000 000000 074a835fca3e 000000000000 D      arch/arm/boot/dts/include/arm64
:120000 000000 08c00e4972fa 000000000000 D      arch/arm/boot/dts/include/dt-bindings
:120000 000000 cf63d80e2b93 000000000000 D      arch/arm64/boot/dts/include/arm
:120000 000000 a96aa0ea9d8c 000000000000 D      arch/arm64/boot/dts/include/arm64
:120000 000000 08c00e4972fa 000000000000 D      arch/arm64/boot/dts/include/dt-bindings
:120000 000000 08c00e4972fa 000000000000 D      arch/cris/boot/dts/include/dt-bindings
:120000 000000 08c00e4972fa 000000000000 D      arch/metag/boot/dts/include/dt-bindings
:120000 000000 08c00e4972fa 000000000000 D      arch/mips/boot/dts/include/dt-bindings
:120000 000000 08c00e4972fa 000000000000 D      arch/powerpc/boot/dts/include/dt-bindings
:100644 100644 6dc1eda13b8e 58c05e5d9870 M      scripts/Makefile.lib
:000000 120000 000000000000 5d21b5a69a11 A      scripts/dtc/include-prefixes/arc
:000000 120000 000000000000 eb14d4515a57 A      scripts/dtc/include-prefixes/arm
:000000 120000 000000000000 275c42c21d71 A      scripts/dtc/include-prefixes/arm64
:000000 120000 000000000000 49ded4cae2be A      scripts/dtc/include-prefixes/c6x
:000000 120000 000000000000 736d998ba506 A      scripts/dtc/include-prefixes/cris
:000000 120000 000000000000 04fdbb3af016 A      scripts/dtc/include-prefixes/dt-bindings
:000000 120000 000000000000 3bdaa332c54c A      scripts/dtc/include-prefixes/h8300
:000000 120000 000000000000 87a3c847db8f A      scripts/dtc/include-prefixes/metag
:000000 120000 000000000000 d9830330a21d A      scripts/dtc/include-prefixes/microblaze
:000000 120000 000000000000 ae8d4948dc8d A      scripts/dtc/include-prefixes/mips
:000000 120000 000000000000 51772336d13f A      scripts/dtc/include-prefixes/nios2
:000000 120000 000000000000 71c3bc75c560 A      scripts/dtc/include-prefixes/openrisc
:000000 120000 000000000000 7cd6ec16e899 A      scripts/dtc/include-prefixes/powerpc
:000000 120000 000000000000 67d37808c599 A      scripts/dtc/include-prefixes/sh
:000000 120000 000000000000 d1eaf6ec7a2b A      scripts/dtc/include-prefixes/xtensa

我使用的是 linux-5.4.70 版本；使用的是 #include 文件中的 UTS_RELEASE 宏；

2.1 在 dtsi 文件中添加一个节点如下；

//包含自动生成的头文件
#include 
 
 / {
	
    //在根节点添加一个 version 节点
    version {
		model = UTS_RELEASE;
	};
 
};

2.2 在 scripts/dtc/include-prefixes/ 创建一个软链接文件

# 进入 include-prefixes 目录
cd scripts/dtc/include-prefixes/
 
# 创建软链接文件
ln -s ../../../include/generated/ generated

2.3 烧录之后，可以用以下命令查看

root@freescale ~$ cat /sys/firmware/devicetree/base/version/model 
5.4.70-svn122root@freescale ~$ 
root@freescale ~$ 

2.4 编写脚本，version，放入 /usr/bin/ 目录下；这样即可使用 version 命令来查看版本；

#!/bin/sh
 
echo ""
echo "kernel version"
uname -a
echo ""
 
echo "dtb version"
if [ -f /sys/firmware/devicetree/base/version/model ] ; then
	cat /sys/firmware/devicetree/base/version/model
	echo ""
else
	echo "No't found dtb version model node"
fi
echo ""