Re: [PATCH 3/4] iio: accel: bmc150: Make it possible to configure INT2 instead of INT1

From: Stephan Gerhold <stephan@gerhold.net>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Rob Herring <robh+dt@kernel.org>,
	linux-iio <linux-iio@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>, Hans de Goede <hdegoede@redhat.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
	<devicetree@vger.kernel.org>, Hans de Goede <hdegoede@redhat.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>," 
	<~postmarketos/upstreaming@lists.sr.ht>,
	Nikita Travkin <nikita@trvn.ru>
Subject: Re: [PATCH 3/4] iio: accel: bmc150: Make it possible to configure INT2 instead of INT1
Date: Mon, 19 Jul 2021 19:26:28 +0200	[thread overview]
Message-ID: <YPW1xGtLyLNGKqjJ@gerhold.net> (raw)
In-Reply-To: <CAHp75Vdjotgi9RrmKQC4J_QQSYdRWwp+-8aHGkChx6VFLPDh-Q@mail.gmail.com>

On Mon, Jul 19, 2021 at 07:19:05PM +0300, Andy Shevchenko wrote:
> On Mon, Jul 19, 2021 at 6:11 PM Stephan Gerhold <stephan@gerhold.net> wrote:
> > On Mon, Jul 19, 2021 at 06:01:01PM +0300, Andy Shevchenko wrote:
> > > On Mon, Jul 19, 2021 at 5:07 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> > > > On Mon, Jul 19, 2021 at 1:26 PM Stephan Gerhold <stephan@gerhold.net> wrote:
> 
> ...
> 
> > > > >  #include <linux/acpi.h>
> > > > > +#include <linux/of_irq.h>
> > > > (...)
> > > > > +       irq_info = bmc150_accel_interrupts_int1;
> > > > > +       if (irq == of_irq_get_byname(dev->of_node, "INT2"))
> > > > > +               irq_info = bmc150_accel_interrupts_int2;
> > > >
> > > > This looks a bit DT-specific, but I don't see that ACPI has
> > > > named IRQs so I don't know what to do about it either.
> > >
> > > Yeah, we only have so far the (de facto) established way of naming
> > > GPIO based IRQs, and not IOxAPIC ones.
> > >
> > > > What does platform_get_irq_byname() do on ACPI systems?
> > >
> > > See above.
> > >
> > > > If there is no obvious fix I would leave it like this until the
> > > > first ACPI used needing this comes along, but I think maybe
> > > > Andy has suggestions.
> > >
> > > The platform_get_irq_byname() should do something similar that has
> > > been done in platform_get_irq() WRT ACPI.
> > > Here for sure the platform_get_irq_byname() or its optional variant
> > > should be used.
> >
> > I don't think there is a platform device here, we only have the
> > i2c_client or spi_device. That's why I didn't use
> > platform_get_irq_byname(). :)
> >
> > Is there something equivalent for I2C/SPI drivers?
> 
> Not yet. You probably need to supply some code there to allow
> multi-IRQ devices (in resource provider agnostic way).
> 
> You need to provide fwnode_get_irq_byname() to be similar with
> https://elixir.bootlin.com/linux/latest/source/drivers/base/property.c#L1010
> 
> Then use it in the drivers.
> 
> And/or integrate into frameworks somehow (something in between the
> lines: https://elixir.bootlin.com/linux/latest/source/drivers/i2c/i2c-core-base.c#L461).
> 

Well, I don't think anyone has an ACPI use case for this right now so
it's probably better if this is done by someone who actually needs this
and can test it somewhere. :)

I actually just "copied" this approach from some other IIO drivers where
this is done similarly (and additionally checked the source code to make
sure this won't break anything for ACPI platforms).

Stephan