On Thu, Dec 21, 2023 at 02:59:58PM -0600, Rob Herring wrote: > On Thu, Dec 21, 2023 at 07:50:47AM +0100, Christoph Winklhofer wrote: > > Add device tree binding for UART 1-wire bus. > > > > Signed-off-by: Christoph Winklhofer <cj.winklhofer@xxxxxxxxx> > > --- > > .../devicetree/bindings/w1/w1-uart.yaml | 44 +++++++++++++++++++ > > 1 file changed, 44 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/w1/w1-uart.yaml > > > > diff --git a/Documentation/devicetree/bindings/w1/w1-uart.yaml b/Documentation/devicetree/bindings/w1/w1-uart.yaml > > new file mode 100644 > > index 000000000000..93d83c42c407 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/w1/w1-uart.yaml > > @@ -0,0 +1,44 @@ > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/w1/w1-uart.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: UART 1-Wire Bus > > + > > +maintainers: > > + - Christoph Winklhofer <cj.winklhofer@xxxxxxxxx> > > + > > +description: | > > + UART 1-wire bus. Utilizes the UART interface via the Serial Device Bus > > + to create the 1-Wire timing patterns. > > + > > + The UART peripheral must support full-duplex and operate in open-drain > > + mode. The timing patterns are generated by a specific combination of > > + baud-rate and transmitted byte, which corresponds to a 1-Wire read bit, > > + write bit or reset pulse. > > + > > + The default baud-rate for reset and presence detection is 9600 and for > > + a 1-Wire read or write operation 115200. In case the actual baud-rate > > + is different from the requested one, the transmitted byte is adapted > > + to generate the 1-Wire timing patterns. > > + > > + https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html > > + > > + > > +properties: > > + compatible: > > + const: w1-uart > > + > > +required: > > + - compatible > > + > > +additionalProperties: false > > + > > +examples: > > + - | > > + serial { > > + onewire { > > Have you tried this in an actual DT? Assuming the UART node has a > schema, it should be a warning because child node names are explicit in > serial.yaml unfortunately. IOW, you need to add "onewire" to > serial.yaml. > Thank you! It was tested on an older DT with the wildcard pattern. I updated my test-system and now get the warning. On the Raspberry PI, a DT overlay was used, in this case there is no warning with: make CHECK_DTBS=y overlays/w1-uart.dtbo ARCH=arm Is it possible to do a validation for a DT overlay? Since the overlay may be incomplete, only existing nodes or properties could be checked. Thanks! Christoph
