I2C driver not load (Failed to register i2c client -16)

Question

I have some devices on i2c bus. I use DTS for probe driver, but I cannot probe one of driver. Device have address (0x20) kernel send me message:

i2c i2c-0: Failed to register i2c client mcp23017 at 0x20 (-16)

Device is mcp2301 and I can detect it

 i2cdetect -y 0
 0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
 00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
 10: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- 
 20: 20 UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
 30: -- -- -- -- UU -- -- -- -- -- UU -- -- -- -- -- 
 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU 
 50: -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- -- 
 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
 70: -- -- -- -- -- -- -- --  

As you can see, same device (0x21 also mcp2301) is working fine.

When I use i2cget/i2cset I can properly control this device (0x20). I also tried turn i2cdebug in kernel. But nothing interesting - because driver of 0x20 device not probe(not enter to probe function).

I tried mcp230xx driver and my own driver, both same behaviour.

Thanks

Update:

Complet dts is here.My dts overlayhere. And dmesg with initcall_debug here. Finaly here is my drive (but also I try gpio-mcp23s08.c driver with same error).

Kernel 3.10.17 CPU is arm-iMX6

Answer 1

either the DTS contain the driver inclusion for the same i2c address twice or the second time the driver was attempted to be assigned to this i2c address manually without unbinding it first. in both cases the error EBUSY (-16) will appear in the dmesg. also there is a possibility the driver will be assigned to the bus but not probed in case if some internal driver kernel expecting service structures were missing or incomplete. in such case the i2cdetect will show the i2c address on already assigned driver as a numbers instead of a busy sign UU and there will be no probe messages output.

Answer 2

I think You have multiple I2C clients with the same address (if I looked on the right DTS):

You have this client on address 0x20

adv7180@20 {
                compatible = "adv,adv7180";

And then again address 0x20:

encoder@20 {
                compatible = "bustec,bt125_exp";

Then you have client with address 0x18

tlv320aic3107@18 {
                compatible = "ti,tlv320aic3107";

and same address again:

            1w@18 {
                compatible = "dallas,ds2482";

That makes sense since you have errno 16

#define EBUSY           16      /* Device or resource busy */