Q: define i2c nodes in device tree?

Albrecht Dreß albrecht.dress at arcor.de
Sat Mar 28 00:05:04 EST 2009


Hi Timur:

> You need to have a "gpio I2C" device driver that registers the same name as what's in the DTS, like this:

Thanks, that did the trick; a proper naming is apparently

pca8575:gpio at 20 {
        compatible = "nxp,pca8575";
        device_type = "gpio";
        reg = <0x20 1>;
};

Now the driver is called, but complains that no platform data is present.  Still have to figure out how to pass that... :-/

An other confusing thing: although the probe function fails with error -EINVAL, the device gets registered:

<7>[    0.801814] i2c 1-0020: uevent
<7>[    0.802213] pcf857x 1-0020: probe
<7>[    0.802236] pcf857x 1-0020: no platform data
<4>[    0.802265] pcf857x: probe of 1-0020 failed with error -22
<7>[    0.807980] i2c-adapter i2c-1: client [pca8575] registered with bus id 1-0020

# ls -al /sys/devices/f0000000.soc5200/f0003d40.i2c/i2c-adapter/i2c-1/
drwxr-xr-x    6 0        0               0 Jan  1 00:00 .
drwxr-xr-x    3 0        0               0 Jan  1 00:00 ..
drwxr-xr-x    2 0        0               0 Jan  1 00:00 1-0020
drwxr-xr-x    2 0        0               0 Jan  1 00:00 1-0021
drwxr-xr-x    2 0        0               0 Jan  1 00:00 1-0022
[...]

Is this the intended behaviour?

Thanks, Albrecht.

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