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

Mika Westerberg
2017-06-13T08:48:31Z

On Mon, Jun 12, 2017 at 04:57:00PM +0100, Lorenzo Pieralisi wrote:
> I had a more in-depth look at this series and from my understanding
> the problem are the following to manage the LPC bindings in ACPI.
>
> (1) Child devices of an LPC controller require special handling when
> filling their resources (ie they need to be translated - in DT
> that's guaranteed by the "isa" binding, in ACPI it has to be
> done by new code)
> (2) In DT systems, LPC child devices are created by the LPC bus
> controller driver through an of_platform_populate() call with
> the LPC controller node as the fwnode root. For ACPI to work
> the same way there must be a way to prevent LPC children to
> be enumerated in acpi_default_enumeration() something like
> I2C does (and then the LPC driver would enumerate its children as
> DT does)
>
> I am not sure how (1) and (2) can be managed with current ACPI bindings
> and kernel code - I suspect it may be done by mirroring what's done
> for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC adapter
> is matched as a platform device and it takes care of enumerating its
> children - problem though is preventing enumeration from core ACPI code).

Is there an example ASL showing how these LPC devices are
currently presented in ACPI?