本文基于RockPi 4A Debian系統介紹i2c設備的調試工具i2c-tools。
i2c-tools的相關命令常用于linux系統讀寫i2c設備寄存器的在線調試。
安裝命令：
apt-get updateapt-get install i2c-toolslinux版本代碼下載路徑：
https://mirrors.edge.kernel.org/pub/software/utils/i2c-tools/一、i2cdetect
1、命令
root@linaro-alip:/# i2cdetectError: No i2c-bus specified!Usage: i2cdetect [-y] [-a] [-q|-r] I2CBUS [FIRST LAST] i2cdetect -F I2CBUS i2cdetect -l I2CBUS is an integer or an I2C bus name If provided, FIRST and LAST limit the probing range.2、用法
## 列出i2c總線root@linaro-alip:/# i2cdetect -li2c-0 i2c rk3x-i2c I2C adapteri2c-1 i2c rk3x-i2c I2C adapteri2c-9 i2c DesignWare HDMI I2C adapter## 列出某個i2c總線上的i2c設備root@linaro-alip:/# i2cdetect -y 0 0 1 2 3 4 5 6 7 8 9 a b c d e f00: -- -- -- -- -- -- -- -- -- -- -- -- --10: -- -- -- -- -- -- -- -- -- -- -- UU -- -- -- --20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --40: UU UU -- -- -- -- -- -- -- -- -- -- -- -- -- --50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --70: -- -- -- -- -- -- -- --root@linaro-alip:/#RockPi 4A原理圖中，I2C0總線掛載I2C設備地址如下：
RockPi 4A單板 I2C 0總線I2C設備
二、i2cdump
1、命令
root@linaro-alip:~# i2cdumpError: No i2c-bus specified!Usage: i2cdump [-f] [-y] [-r first-last] I2CBUS ADDRESS [MODE [BANK [BANKREG]]] I2CBUS is an integer or an I2C bus name ADDRESS is an integer (0x03 - 0x77) MODE is one of: b (byte, default) w (word) W (word on even register addresses) s (SMBus block) i (I2C block) c (consecutive byte) Append p for SMBus PEC2、用法
## 顯示I2C 0號總線上0x1b設備的寄存器值。MODE為byte，可省略。root@linaro-alip:~# i2cdump -f -y 0 0x1b b 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef00: 12 50 08 21 01 13 01 00 00 00 00 01 01 00 00 00 ?P?!???....??...10: 80 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ??..............20: 01 17 00 6f ff 00 00 00 10 00 ff 0f ff 02 19 0f ??.o....?..?.???30: 00 00 19 07 00 00 02 03 00 00 09 00 00 00 00 0a ..??..??..?....?40: 00 0c 00 0c 00 07 00 01 00 0c 00 00 00 5f 00 03 .?.?.?.?.?..._.?50: 06 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ??..............60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................70: 00 cf 03 00 28 00 0c 1c 80 19 00 34 12 00 71 00 .??.(.????.4?.q.80: 10 50 1f ac 00 40 10 01 40 00 08 00 09 09 00 00 ?P??.@??@.?.??..90: 55 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 U...............a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................三、i2cget
1、命令
root@linaro-alip:~# i2cgetUsage: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS [DATA-ADDRESS [MODE]] I2CBUS is an integer or an I2C bus name ADDRESS is an integer (0x03 - 0x77) MODE is one of: b (read byte data, default) w (read word data) c (write byte/read byte) Append p for SMBus PEC2、用法
## 顯示I2C 0號總線上0x1b設備0x0和0x1寄存器地址，按字節讀取root@linaro-alip:~# i2cget -f -y 0 0x1b 0x00x12root@linaro-alip:~# i2cget -f -y 0 0x1b 0x10x50## 按字讀取root@linaro-alip:~# i2cget -f -y 0 0x1b 0x0 w0x5012四、i2cset
1、命令
root@linaro-alip:~# i2csetUsage: i2cset [-f] [-y] [-m MASK] [-r] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] ... [MODE] I2CBUS is an integer or an I2C bus name ADDRESS is an integer (0x03 - 0x77) MODE is one of: c (byte, no value) b (byte data, default) w (word data) i (I2C block data) s (SMBus block data) Append p for SMBus PEC2、用法
root@linaro-alip:/sys/rk8xx# i2cget -f -y 0 0x1b 0x100x80root@linaro-alip:/sys/rk8xx# i2cset -f -y 0 0x1b 0x10 0x0root@linaro-alip:/sys/rk8xx# i2cget -f -y 0 0x1b 0x100x00注：RK808-D 是PMIC芯片，如果沒有芯片手冊，建議慎重使用i2cset命令設置RK808-D寄存器的值。
五、i2ctransfer
i2c-tools-4.0及以后版本添加了i2ctransfer命令。
i2cget和i2cset可以讀寫的i2c設備的寄存器地址小于0xff，即寄存器是8位地址。
如果i2c設備寄存器是16位地址，可使用i2ctransfer命令，該命令同樣可用在寄存器地址是8位的設備。
1、命令
"Usage: i2ctransfer [-f] [-y] [-v] [-V] [-a] I2CBUS DESC [DATA] [DESC [DATA]]...\n"" I2CBUS is an integer or an I2C bus name\n"" DESC describes the transfer in the form: {r|w}LENGTH[@address]\n"" 1) read/write-flag 2) LENGTH (range 0-65535, or '?')\n"" 3) I2C address (use last one if omitted)\n"" DATA are LENGTH bytes for a write message. They can be shortened by a suffix:\n"" = (keep value constant until LENGTH)\n"" + (increase value by 1 until LENGTH)\n"" - (decrease value by 1 until LENGTH)\n"" p (use pseudo random generator until LENGTH with value as seed)\n\n""Example (bus 0, read 8 byte at offset 0x64 from EEPROM at 0x50):\n"" # i2ctransfer 0 w1@0x50 0x64 r8\n""Example (same EEPROM, at offset 0x42 write 0xff 0xfe ... 0xf0):\n"" # i2ctransfer 0 w17@0x50 0x42 0xff-\n");2、用法
## 從i2c 4號總線0x38設備的0x3a01寄存器開始讀16個字節的數據,w2：表示寄存器0x3a01的長度為2個字節i2ctransfer -y -f 4 w2@0x38 0x3a 0x01 r16## 向i2c 4號總線0x38設備的0x3a01寄存器寫0x10,w3：表示寄存器0x3a01和寫入值0x10的長度為3字節i2ctransfer -y -f 4 w3@0x38 0x3a 0x01 0x10