[PATCH 013/108] acpi: Add a binding for ACPI settings in the device tree

[Simon Glass]

Hi Wolfgang,

On Fri, 31 Jan 2020 at 01:18, Wolfgang Wallner
<wolfgang.wallner at br-automation.com> wrote:
>
> Hi Simon,
>
> > +Devices
> > +=======
> > +
> > +Device bindings are described by their own individual binding files.
> > +
> > +U-Boot provides for some optional properties which are documented here.
> > +
> > + - acpi,has-power-resource : (boolean) true if this device has a power resource.
> > +    This causes a PRIC (ACPI PowerResource) to be written containing the
> > +    properties provided by this binding, to describe how to handle powering the
> > +    device up and down using GPIOs
> > + - acpi,cid : Contains the string to use as the compatible ID (_CID)
> > + - acpi,compatible : compatible string to report
> > + - acpi,desc : Contains the string to use as the _DDN (DOS (Disk Operating
> > +    System) Device Name)
> > + - acpi,hid : Contains the string to use as the HID (Human Interface Device)
> > +    identifier _HID
>
> Nit: "_HID" in ACPI stands for "Hardware ID"

OK thank you, will fix. I am trying to write things out in full since
it is very hard to find out what all these different things mean.

>
> > + - acpi,hid-desc-reg-offset : HID register offset (for Human Interface Devices)
> > + - acpi,probed : Tells U-Boot to add 'linux,probed' to the ACPI tables so that
> > +    Linux will not re-init the device
> > + - acpi,uid : _UID value for device
>
> Would it make sense to automatically infer ACPI properties from existing
> device tree properties?
>
> E.g. if the compatible string contains "hid-over-i2c", then _CID could be set
> to "PNP0C50".

Yes we could do that. So is that true for all devices that use this i2c driver?

> And a "hid-over-i2c" device would also have a "hid-descr-addr" device tree
> property for the offset of the HID descriptor register which could be passed
> on in ACPI as part of the _DSM method.

Are you suggesting renaming acpi,hid-desc-reg-offset to hid-descr-addr?

Regards,
Simon