i2ctool i2cget读取16位地址的寄存器值的方法

梦里梦外; 2022-11-12 13:50 737阅读 0赞

ASUS的i2cdetect tool放在device/asus/Z00L/i2c-tools目录下，用mmm device/asus/Z00L/i2c-tools就会生成相应的bin文件，push到机台的system/bin文件目录下

root@ASUS\_Z00L\_63:/system/bin \# ./i2cdetect  -l

i2c-0 i2c      MSM-I2C-v2-adapter              I2C adapter  
i2c-4 i2c        MSM-I2C-v2-adapter               I2C adapter  
i2c-5 i2c        MSM-I2C-v2-adapter               I2C adapter  
i2c-6 i2c        MSM-I2C-v2-adapter               I2C adapter

root@ASUS\_Z00L\_63:/system/bin \# ./i2cdetect  -y -r 0                             
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  
00: -- -- -- -- -- -- -- -- -- -- -- -- UU -- -- --   
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
60: UU -- -- -- -- -- -- -- UU -- -- -- -- -- -- --   
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
root@ASUS\_Z00L\_63:/system/bin \# ./i2cdetect  -y -r 4                             
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
60: -- -- -- -- -- -- -- -- -- -- UU -- -- -- -- --   
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
root@ASUS\_Z00L\_63:/system/bin \# ./i2cdetect  -y -r 5                             
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
30: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --   
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
root@ASUS\_Z00L\_63:/system/bin \# ./i2cdetect  -y -r 6                             
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --   
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

上面每一个 UU都是一个i2c设备的挂载点，对应的就是在这个bus上的slave address。

如果想要看某个设备里的register的内容则

1|root@ASUS\_Z00L\_63:/system/bin \# ./i2cdump  -f -y 5 0x38                        
No size specified (using byte-data access)  
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef  
00: 00 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
40: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
60: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................  
80: 57 50 19 19 19 70 01 05 0b 1e 00 01 00 00 00 00    WP???p????.?....  
90: 00 89 00 00 00 00 09 00 00 00 00 00 00 00 00 22    .?....?........"  
a0: 01 0a 10 54 01 01 b1 01 61 01 08 00 00 6f 01 09    ???T????a??..o??  
b0: 00 05 00 00 00 00 00 00 00 00 00 00 00 00 00 55    .?.............U  
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................  
d0: 01 30 1a 00 ff 40 10 20 00 00 64 00 00 05 64 00    ?0?..@? ..d..?d.  
e0: 6c 02 20 10 51 06 8a 00 00 0f 1c eb 08 00 00 00    l? ?Q??..????...  
f0: ff ff ff ff ff ff ff ff ff ff ff ff 01 00 41 ff    ............?.A.

————————————————  
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原文链接：https://blog.csdn.net/u013308744/article/details/50128651

///读16bit 地址/

# NAME #

i2cget - read from I2C/SMBus chip registers

# SYNOPSIS #

**i2cget** \[**-f**\] \[**-y**\] \[**-a**\] *i2cbus* *chip-address* \[*data-address *\[*mode*\]\]  
**i2cget** **-V**

# DESCRIPTION #

i2cget is a small helper program to read registers visible through the I2C bus (or SMBus).

# OPTIONS #

**-V**

Display the version and exit.

**-f**

Force access to the device even if it is already busy. By default, i2cget will refuse to access a device which is already under the control of a kernel driver. Using this flag is dangerous, it can seriously confuse the kernel driver in question. It can also cause i2cget to return an invalid value. So use at your own risk and only if you know what you're doing.

**-y**

Disable interactive mode. By default, i2cget will wait for a confirmation from the user before messing with the I2C bus. When this flag is used, it will perform the operation directly. This is mainly meant to be used in scripts. Use with caution.

**-a**

Allow using addresses between 0x00 - 0x07 and 0x78 - 0x7f. Not recommended.

There are two required options to i2cget. *i2cbus* indicates the number or name of the I2C bus to be scanned. This number should correspond to one of the busses listed by *i2cdetect -l*. *chip-address* specifies the address of the chip on that bus, and is an integer between 0x08 and 0x77.

*data-address* specifies the address on that chip to read from, and is an integer between 0x00 and 0xFF. If omitted, the currently active register will be read (if that makes sense for the considered chip).

The *mode* parameter, if specified, is one of the letters **b**, **w** or **c**, corresponding to a read byte data, a read word data or a write byte/read byte transaction, respectively. A **p** can also be appended to the *mode* parameter to enable PEC. If the *mode* parameter is omitted, i2cget defaults to a read byte data transaction, unless *data-address* is also omitted, in which case the default (and only valid) transaction is a single read byte.

# WARNING #

i2cget can be extremely dangerous if used improperly. I2C and SMBus are designed in such a way that an SMBus read transaction can be seen as a write transaction by certain chips. This is particularly true if setting *mode* to **cp** (write byte/read byte with PEC). Be extremely careful using this program.

# EXAMPLES #

Get the value of 8-bit register 0x11 of the I2C device at 7-bit address 0x2d on bus 1 (i2c-1), after user confirmation:

# i2cget 1 0x2d 0x11

Get the value of 16-bit register 0x00 of the I2C device at 7-bit address 0x48 on bus 1 (i2c-1), after user confirmation:

# i2cget 1 0x48 0x00 w

Set the internal pointer register of a 24C02 EEPROM at 7-bit address 0x50 on bus 9 (i2c-9) to 0x00, then read the first 2 bytes from that EEPROM:

# i2cset -y 9 0x50 0x00 ; i2cget -y 9 0x50 ; i2cget -y 9 0x50

This assumes that the device automatically increments its internal pointer register on every read, and supports read byte transactions (read without specifying the register address, "Receive Byte" in SMBus terminology.) Most EEPROM devices behave that way. Note that this is only safe as long as nobody else is accessing the I2C device at the same time. A safer approach would be to use a "Read Word" SMBus transaction instead, or an I2C Block Read transaction to read more than 2 bytes.

Set the internal pointer register of a 24C32 EEPROM at 7-bit address 0x53 on bus 9 (i2c-9) to 0x0000, then read the first 2 bytes from that EEPROM:

# i2cset -y 9 0x53 0x00 0x00 ; i2cget -y 9 0x53 ; i2cget -y 9 0x53

这里实际以读取ov7251的chip id 为例，实际操作如下：

1、查看我的7251挂载iic总线（实际是iic-2）及设备地址(实际读取是0x60)

[root@Pen-997:/]# i2cdetect -y -r 2
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00:          -- -- -- -- -- -- -- -- -- -- -- -- --
    10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    60: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    70: 70 -- -- -- -- -- -- --

根据数据手册可知：

\#define CHIP\_ID                0x007750  
\#define OV7251\_REG\_CHIP\_ID        0x300a

首先 设置要读取的地址 0x300a

[root@YoudaoDictionaryPen-997:/]# i2cset -y -f 2 0x60 0x30 0x0a

然后读取两个字节的数据：

[root@Pen-997:/]# i2cget -y -f 2 0x60
    0x77
    [root@Pen-997:/]# i2cget -y -f 2 0x60
    0x50

This again assumes that the device automatically increments its internal pointer register on every read, and supports read byte transactions. While the previous example was for a small EEPROM using 8-bit internal addressing, this example is for a larger EEPROM using 16-bit internal addressing. Beware that running this command on a small EEPROM using 8-bit internal addressing would actually *write* 0x00 to the first byte of that EEPROM. The safety concerns raised above still stand, however in this case there is no SMBus equivalent, so this is the only way to read data from a large EEPROM if your master isn't fully I2C capable. With a fully I2C capable master, you would use *i2ctransfer* to achieve the same in a safe and faster way.

# BUGS #

To report bugs or send fixes, please write to the Linux I2C mailing list <linux-i2c@vger.kernel.org> with Cc to the current maintainer: Jean Delvare <jdelvare@suse.de>.

# SEE ALSO[¶][Link 1] #

[i2cdetect(8)][i2cdetect_8], [i2cdump(8)][i2cdump_8], [i2cset(8)][i2cset_8], [i2ctransfer(8)][i2ctransfer_8]

# AUTHOR #

Jean Delvare

This manual page was strongly inspired from those written by David Z Maze for i2cset.

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   <td>October 2017</td> 
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[Link 1]: https://manpages.debian.org/unstable/i2c-tools/i2cget.8.en.html#SEE_ALSO
[i2cdetect_8]: https://manpages.debian.org/unstable/i2c-tools/i2cdetect.8.en.html
[i2cdump_8]: https://manpages.debian.org/unstable/i2c-tools/i2cdump.8.en.html
[i2cset_8]: https://manpages.debian.org/unstable/i2c-tools/i2cset.8.en.html
[i2ctransfer_8]: https://manpages.debian.org/unstable/i2c-tools/i2ctransfer.8.en.html