Antwort: [PATCH v3 13/29] dts: Add a binding for hid-over-i2c

Wolfgang Wallner
2020-04-01T07:39:26Z

Hi Simon,

-----"U-Boot" <u-boot-bounces@lists.denx.de> schrieb: -----

[snip]

>> + - acpi,ddn : Contains the string to use as the _DDN (DOS (Disk
>Operating
>> + System) Device Name)
>> + - acpi,hid : Contains the string to use as the HID (Hardware ID)
>> + identifier _HID
>> + - acpi,probed : Tells U-Boot to add 'linux,probed' to the ACPI
>tables so that
>> + Linux will only load the driver if the device can be detected
>(e.g. on I2C
>> + bus)
>
>Will support for 'linux,probed' be mainlined? Otherwise the
>description
>should IMHO mention that it is an out-of-tree feature.

I have thought some more about this property.
The Chromium discussions [1] mention that "linux,probed" is intended to be
a property in both Devicetree and ACPI, so a Linux kernel could handle the
device in the expected way whether it boots on a Devicetree platform or an
ACPI platform. The proposed "acpi,probed" property would only solve one such
use case (ACPI-based platforms): U-Boot boots, reads "acpi,probed" from
Devicetree, adds "linux,probed" to the ACPI description and hands that to the
Linux kernel.

Why would we not keep the name "linux,probed" for this property? U-Boot could
still do the same Devicetree -> ACPI translation, but the same property could
then also be useful for Devicetree-based platforms.

[snip]

regards, Wolfgang

[1] https://groups.google.com/a/chromium.org/forum/#!msg/chromium-os-reviews/4HTHl78IGHw/oz82uImnBgAJ