On Thu, Aug 24, 2023 at 08:37:01AM -0500, Rob Herring wrote: > On Thu, Aug 24, 2023 at 01:10:12PM +0200, Martin Zaťovič wrote: > > Wiegand bus is defined by a Wiegand controller node. This node > > can contain one or more device nodes for devices attached to > > the controller(it is advised to only connect one device as Wiegand > > is a point-to-point bus). > > How would multiple devices work? Seems like you'd need some sort of mux > which would be another node. If there's not really any need, then I'd > just say it's only a single device. Either way the binding needs to > define this. > > > > > Wiegand controller needs to specify several attributes such as > > the pulse length in order to function properly. These attributes > > are documented here. > > > > Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > > Signed-off-by: Martin Zaťovič <m.zatovic1@xxxxxxxxx> > > --- > > .../bindings/wiegand/wiegand-controller.yaml | 39 +++++++++++++++++++ > > MAINTAINERS | 5 +++ > > 2 files changed, 44 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml > > > > diff --git a/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml b/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml > > new file mode 100644 > > index 000000000000..8f36287e4fed > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml > > @@ -0,0 +1,39 @@ > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/wiegand/wiegand-controller.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Wiegand Generic Controller Common Properties > > + > > +maintainers: > > + - Martin Zaťovič <m.zatovic1@xxxxxxxxx> > > + > > +description: > > + Wiegand busses can be described with a node for the Wiegand controller device > > + and a set of child nodes for each SPI slave on the bus. > > Some more detail on what Wiegand is would be useful. Link to spec? What > it is used for? There is no official Wiegand datasheet out there. I can include the summary of some proprietary documents about Wiegand, like the commit message of the second commit in the series. > > > + > > +properties: > > + $nodename: > > + pattern: "^wiegand(@.*|-[0-9a-f])?$" > > The '-[0-9a-f]' suffix should be decimal rather than hex. > > > + > > + pulse-len-us: > > + description: > > + Length of the low pulse in microseconds. > > + > > + interval-len-us: > > + description: > > + Length of a whole bit (both the pulse and the high phase) in microseconds. > > + > > + frame-gap-us: > > + description: > > + Length of the last bit of a frame (both the pulse and the high phase) in > > + microseconds. > > If you have multiple devices, you need to define the child node format. > Specifically, you need addresses for multiple devices. So you need to > define the unit-address format, #address-cells and #size-cells values, > and any constraints on 'reg' such as max address and/or number of entries. I see.. the bus should really only allow one device to be connected. That means, there is no need to define anything else in this file, right? I will explicitely mention it in the Description and I will add the unevaluatedPropertied: type: object to the wiegand-gpio.yaml file so that adding a child node is allowed. > > Rob With regards, Martin Zaťovič
