Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

[John Garry]

On 30/06/2017 10:05, Mika Westerberg wrote:
> On Thu, Jun 29, 2017 at 05:16:15PM +0100, John Garry wrote:
> > On 16/06/2017 12:24, Rafael J. Wysocki wrote:
> > > > > > > > > It causes acpi_default_enumeration() to be called but it should be fine
> > > > > > > > > as we are dealing with platform device anyway.
> > > > > > >
> > > > > > > I do not quite understand how declaring such MFD cell above would make sure
> > > > > > > that the LPC probe is called before the IPMI device is enumerated...
> > > > >
> > > > > In fact it may be that it is not sufficient in this case because the
> > > > > ACPI core might enumerate child devices before the LPC driver even gets
> > > > > a chance to probe so you would need to add also scan handler to the
> > > > > child devices and mark them already enumerated or something like that.
> > > Or extend the special I2C/SPI handling to them.
> >
> > For this, is it possible to just configure the ACPI table so we spoof that
> > the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a resource
> > of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus type i2c/spi to
> > solve this?
>
> But is the device connected to a I2C or SPI bus? If not, then it does
> not make much sense to declare it as I2C or SPI slave. Instead it should
> be platform device which is the type we use when there is no explicit
> bus specified in ACPI.

No, it's not a SPI nor an I2C bus. I actually would say that my idea is 
generally wrong, as the ACPI definition is not a real reflection of the 
bus/slave.

However, Rafael did suggest extending special I2C/SPI handling to them. 
In this case, I don't see how the LPC slave can be identified like an 
I2C or SPI slave is.

Thanks,
John

> .