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Re: Interrupts on GPIO (on RPI, specifically, but also in general)

On Apr 19, 2018, at 9:40 AM, Manuel Bouyer <> wrote:

The DTB is here to describe the hardware; with hardware such as RPIs
we indeed change the hardware when connecting something to the GPIOs or
i2c/spi busses. Both sides needs to cooperate and the device tree is there
to make the link between the different elements.

Fair enough, although with something like i2c, I think of it more like “connecting something to a traditional serial port”.  Is there a tutorial on this that I can read?

Extending and rebuilding a fdt is easy in our tree.

Well, that’s good to know :-)

I'm not sure you can do something general enough this way. For example
you may need to configure pullup/pulldown state of the GPIO, and some
controllers may allow different pull levels. The FDT can address this,
with MD-specific nodes under a MI node. For example look at allwinner,*
properties in our fdt trees.

Yah, but I can already set up the GPIO itself with /etc/gpio.conf.

BTW I just noticed we have fdt gpiokeys driver, which looks like what you

Well, hey now.  Ok, I guess I’ll now go off and figure out how FDT works.


-- thorpej

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