Re: Interrupt questions

[Vincent DEFERT <vincent.defert%posteo.net@localhost>]

What is PIO mode?

For the clock, I see in meson-gxbb.dts that i2c_A's clock is CLKID_I2C, 
and in gxbb-clkc.h that CLKID_I2C is 22, but I have no clue what it means.
At least, it appears to be in the correct domain (not the Always On domain).

I had to make device tree modifications because:

- i2c_A is enabled in meson-gxbb-odroidc2.dts but its interrupt number 
is incorrect (meson-gx.dts specifies the number for the S905X, not the S905)
- i2c_B was disabled and I wanted to test it.

I have made both modifications in meson-gxbb-odroidc2.dts.


On 25/06/2025 16:28, Robert Swindells wrote:
> Vincent DEFERT <vincent.defert%posteo.net@localhost> wrote:
> > > Do you need it to work in interrupt mode, or would it be enough to
> > > use PIO mode at first?
> > With a CPU running in the GHz range I didn't dare using polling, but
> > I'll give it a try.
> I meant PIO mode of the I2C controller, looking at the datasheet it
> supports both that and interrupt/DMA modes.
>
> You could also check that the clock definitions are correct.
>
> Have you made any local device tree modifications?
>
>  From a dump of the .dtb file that we build, the i2c controllers seem
> to be marked as disabled and don't have clock names defined for them.