Set GPIO bank number in device tree

Question

Do you know how to set the GPIO bank number in the device tree for an i2c gpio controller?

I tried with gpio-base (described in the gpio driver doc) but it was not very conclusive.

I have a device tree:

...
&i2c2 {
      pca9502: pca9502@4C {
        compatible = "nxp,pca9502";
        reg = <0x4C>;
        gpio-controller;
        /* HERE */
        gpio-base = <1>; 
     }
}
...

and the driver fetch the DT to find the gpio-base:

of_get_property(dev.of_node, "gpio-base", NULL);

In this case, a gpiochip is created with the number 2^32 giving: gpiochip16777216. And I can't access my GPIO using echo XX > export.

When I don't add gpio-base = <1>;, it works but the gpiochip number is 504 (with -1 as a default bank number) which I don't understand.

I don't know how to define the bank number into the device tree.

Answer 1

Well, my issue was not linked with the device tree structure but with the endianness of the processor.