On 05/05/2020 18:51, Robin Murphy wrote: > On 2020-05-05 5:51 pm, Andre Przywara wrote: >> Date: Mon, 4 May 2020 12:43:18 +0100 >> Subject: [PATCH 03/16] dt-bindings: ehci/ohci: Allow iommus property >> >> A OHCI/EHCI controller could be behind an IOMMU, in which case an iommus >> property assigns the stream ID for this device. > > Hmm, pretty much any DMA master device could be behind an IOMMU, and in > a way that's basically entirely irrelevant to the device itself (and > thus the consumer of its binding). Is there a better way we can handle > this than repeating such "semi-standard" properties in individual > bindings for ever more? I was asking exactly the same question to Rob. Indeed this is more of a parent bus property, if at all, and individual drivers are not even aware of this. But what is a device property is the number of device IDs that the device uses and that would need to be translated into stream IDs. So I think this is merely saying: just a single device ID. And no, we couldn't come up with some more generic solution (yet). I think a similar problem comes up with power-domains and other properties handled by code in drivers/of. Cheers, Andre > > Robin. > >> Allow that property in the DT bindings to fix a complaint about the >> Arm Juno >> board's DTS file. >> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> >> --- >> Documentation/devicetree/bindings/usb/generic-ehci.yaml | 3 +++ >> Documentation/devicetree/bindings/usb/generic-ohci.yaml | 3 +++ >> 2 files changed, 6 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/usb/generic-ehci.yaml >> b/Documentation/devicetree/bindings/usb/generic-ehci.yaml >> index 10edd05872ea..20664c28bfb2 100644 >> --- a/Documentation/devicetree/bindings/usb/generic-ehci.yaml >> +++ b/Documentation/devicetree/bindings/usb/generic-ehci.yaml >> @@ -74,6 +74,9 @@ properties: >> phy-names: >> const: usb >> + iommus: >> + maxItems: 1 >> + >> required: >> - compatible >> - reg >> diff --git a/Documentation/devicetree/bindings/usb/generic-ohci.yaml >> b/Documentation/devicetree/bindings/usb/generic-ohci.yaml >> index bcffec1f1341..ff6c04cde695 100644 >> --- a/Documentation/devicetree/bindings/usb/generic-ohci.yaml >> +++ b/Documentation/devicetree/bindings/usb/generic-ohci.yaml >> @@ -73,6 +73,9 @@ properties: >> phy-names: >> const: usb >> + iommus: >> + maxItems: 1 >> + >> required: >> - compatible >> - reg >>
