Il giorno mar 10 dic 2024 alle ore 16:28 Marc Kleine-Budde
<mkl@xxxxxxxxxxxxxx> ha scritto:
>
> On 10.12.2024 16:18:07, Stefano Offredi wrote:
> > > > Even with those lines of code, If I print spi->irq before the call
> > > > to request_threaded_irq() it keeps different error codes
> > > > values (-19, -22, depending on whether I set the gpio controller
> > > > values in ACPI table).
> > >
> > > Just to clarify: from the Linux point of view "rx-int" is a GPIO, not an
> > > interrupt. It's connected to the "nINT1/GPIO1" pin of the mcp251xfd and
> > > this is optional. The IRQ which is available under spi->irq is connected
> > > to the "nINT" pin of the mcp251xfd.
> > >
> > > > Even If I remove in ACPI table all the gpio references listed
> > > > here below:
> > > >
> > > > - GpioInt (Edge, ActiveLow, ExclusiveAndWake, PullDefault...
> > > > - Package () {"rx-int-gpios", Package () { ^CAN0, 0, 0, 0 } }
> > > >
> > > > the spi->irq keeps error value -2.
> > >
> > > I suggest to first remove all "rx-int" related stuff from your ACPI
> > > table and concentrate that "spi->irq" has a proper value.
> > >
> > > The relevant code is in acpi_status acpi_register_spi_device():
> > >
> > > | https://elixir.bootlin.com/linux/v5.15/source/drivers/spi/spi.c#L2294
> > >
> >
> > Ok thanks I will investigate on it.
> >
> > Just to be sure, will the driver, if rx-int and interrupt logic is not
>
> "rx-int" is not used as an interrupt source. To keep things simple
> forget about "rx-int" for now.
>
> > used, perform a polling on the spi bus to check for messages incoming
> > on the can controller?
>
> No - polling is not implemented and makes IMHO no sense, as it's quite
> some overhead.
>
Ok, now it's clear, rx-int (INT0) is not necessary, but nINT is necessary.
I will investigate starting from acpi_register_spi_device.
I think that the problem depends on the fact that my gpio controller is not
described in the ACPI table, (is loaded as an external module after the boot),
and the reference from the ACPI mcp descriptor fails.
Thanks again for your support. I'll be back when I have solved it.
regards
Stefano
> > So I should see in this operating mode
> > continuous spi communication on the bus, right?
>
> If there's no traffic on the bus, you should only see very little SPI
> communication. Just a read of the timestamp every 30s or so.
>
> regards,
> Marc
>
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