[MinnowBoard] [edk2] i2cdetect inconsistency/problem

[Gerard Bucas]

Hi All,

I have some problems and inconsistencies on i2c bus on my minnowBoard MAX.
Two problems:

1. When I run "i2cdetect -l"  on the same board with my yocto project build
and then again with running Ubuntu 14.04.3 LTS I get different listing for
i2c buses.

2. Even though I have no lures attached (so basic MinnowBoad MAX, "A2" with
0.81 or 0.82 firmware - same result), "i2cdetect -y N" (where N is different
for yocto & Ubuntu) shows a number of i2c devices detected which I assume
should not be there!?

I have two questions:

1. Where does i2cdetect get the "i2c adapter" bus names? How can they be
different with same firmware & hardware & linux kernel (between yocto &
Ubuntu)? Is this from some firmware or OS config?

2. Why are all those i2c devices detected by BOTH yocto linux and Ubuntu!?
Where do they come from? Is this due to some firmware or OS config? 

Below are the i2cdetect outputs from both my yocto and Ubuntu OS's (NOTE:
both are using the linux 3.19 kernel):

YOCTO:
# uname -a
Linux intel-corei7-64 3.19.5-yocto-standard #1 SMP PREEMPT Fri Aug 14
00:21:30 UTC 2015 x86_64 GNU/Linux

#modprobe i2c-dev
#i2cdetect -l
i2c-0	i2c       	i915 gmbus ssc                  	I2C adapter
i2c-1	i2c       	i915 gmbus vga                  	I2C adapter
i2c-2	i2c       	i915 gmbus panel                	I2C adapter
i2c-3	i2c       	i915 gmbus dpc                  	I2C adapter
i2c-4	i2c       	i915 gmbus dpb                  	I2C adapter
i2c-5	i2c       	i915 gmbus dpd                  	I2C adapter
i2c-6	i2c       	DPDDC-B                         	I2C adapter

#i2cdetect -y 4
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: 30 -- -- -- -- -- -- 37 -- -- 3a -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- 4a 4b -- -- -- -- 
50: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --                         

UBUNTU:
# uname -a
Linux tekmagic 3.19.0-26-generic #28~14.04.1-Ubuntu SMP Wed Aug 12 14:09:17
UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

# modprobe i2c-dev

# i2cdetect -l
i2c-0	i2c       	Synopsys DesignWare I2C adapter 	I2C adapter
i2c-1	i2c       	Synopsys DesignWare I2C adapter 	I2C adapter
i2c-2	i2c       	i915 gmbus ssc                  	I2C adapter
i2c-3	i2c       	i915 gmbus vga                  	I2C adapter
i2c-4	i2c       	i915 gmbus panel                	I2C adapter
i2c-5	i2c       	i915 gmbus dpc                  	I2C adapter
i2c-6	i2c       	i915 gmbus dpb                  	I2C adapter
i2c-7	i2c       	i915 gmbus dpd                  	I2C adapter
i2c-8	i2c       	DPDDC-B                         	I2C adapter

# i2cdetect -y 6
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: 30 -- -- -- -- -- -- 37 -- -- 3a -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- 4a 4b -- -- -- -- 
50: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --                         

Thanks!!

Gerard