Re: I2C: can't detect Adafruit Mini I2C Gamepad on Linux - other devices detected

[Michael Opdenacker <michael.opdenacker@rootcommit.com>]

Hi Wolfram

Thanks for your help!

On 4/11/25 17:57, Wolfram Sang wrote:
>> Plus "i2cdetect -r <num>" shows the device as UU for address 0x50, as
>> usually happens with a driver is loaded.
> Always. The address is blocked for userspace in any case.
>
>> I thought that connected I2C devices always showed in i2cdetect output,
>> whether they are declared in the device tree and have a driver or not.
> This is a valid expectation. Since you used 'i2cdetect -r', it means
> that the device does not react to the read_byte method. Very strange (if
> not even against the specs). Did you try without '-r' to use
> SMBUS_QUICK? What driver are we talking about anyhow?


Without the driver loaded, I get this...

~ # i2cdetect 5
i2cdetect: warning: can't use SMBus quick write command, will skip some 
addresses
i2cdetect: WARNING! This program can confuse your I2C bus
Continue? [y/N] y
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:
10:
20:
30: -- -- -- -- -- -- -- --
40:
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60:
70:
~ #
~ # i2cdetect -r 5
i2cdetect: WARNING! This program can confuse your I2C bus
Continue? [y/N] y
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

When the driver is loaded, there's UU as expected for address 0x50.

The driver is drivers/input/joystick/adafruit-seesaw.c
Cheers
Michael.

-- 
Michael Opdenacker
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