□︰今已有兩極四方，恐入八卦矣！

○︰所為何事？

□︰圍城而不攻？是何故耶？？

○︰是所謂碩果不食。能上不能下？窮之災！囧之禍乎？？

○︰《易》有剝極來復之道！！

與時並進者遭遇『困難』，面對『未知』是再自然不過的事。如之何『求解』正砥礪著學者的『百折不撓』之精神。『九天九地』的探尋，難到不會有『一陽來復』之時？深體自由軟體者之心？？

假使仔細閱讀《 Device Tree on ARCH_BCM2708 》，留心一下『那個人』── notro ── 與『那個時間』── on Jul 30, 2014 ──，也許我們不只對樹莓派『裝置樹』有更多的了解，更能明白許多的貢獻其來有自，正所謂『德不孤，必有鄰』乎！！

此處將僅簡單說說幾個工具程式，以及簡介它們的用法。

常用縮寫︰

【 DT 】︰  Device Tree
【 FDT 】︰ Flattended Device Tree: a DT representation used in the dtb blob.
【 .dtb 】︰ Device Tree Binary
【 .dts 】︰ Device Tree Source
【 .dtsi 】︰ Device Tree Source Include
【 dtc 】︰ Device Tree Compiler

# dtc 的用法說明

pi@raspberrypi ~  fdtdump -h
Usage: fdtdump [options] 

Options: -[dshV]
  -d, --debug   Dump debug information while decoding the file
  -s, --scan    Scan for an embedded fdt in file
  -h, --help    Print this help and exit
  -V, --version Print version and exit

# 範例︰顯示 dtb 內容
fdtdump /boot/overlays/lirc-rpi-overlay.dtb



# fdtget 的用法說明
pi@raspberrypi ~  fdtput -h
Usage: write a property value to a device tree
	fdtput 
   [...]
	fdtput -c 
 [...]

The command line arguments are joined together into a single value.
	s=string, i=int, u=unsigned, x=hex
	Optional modifier prefix:
		hh or b=byte, h=2 byte, l=4 byte (default)

Options: -[cpt:vhV]
  -c, --create     Create nodes if they don't already exist
  -p, --auto-path  Automatically create nodes as needed for the node path
  -t, --type  Type of data
  -v, --verbose    Display each value decoded from command line
  -h, --help       Print this help and exit
  -V, --version    Print version and exit

# 範例︰
cp /boot/bcm2709-rpi-2-b.dtb .
fdtput --type s bcm2709-rpi-2-b.dtb /soc/spi@7e204000 status "okay"
fdtget bcm2709-rpi-2-b.dtb /soc/spi@7e204000 status