Hello Krzysztof, On Wed, Sep 30, 2026 at 02:03:17PM +0200, Krzysztof Kozlowski wrote: > On Tue, Sep 29, 2026 at 06:41:55PM +0200, Francesco Valla wrote: > > Add bindings for spi-virtio based on virtio-device, reflecting what > > already exists for gpio-virtio and i2c-virtio. A node using the bindings > > Existing code is not a reason to add more code. Existing bugs are not a > reason to add more bugs. Please provide proper rationale why this suits > DT. >
When a non-discoverable bus (SPI in this case, but that's true also for e.g. the I2C and GPIO cases I mentioned) made available by a virtio transport is registered, the devicetree can be used to declare its child devices (if any) and/or other properties (say,i GPIOs tied to CS lines for the SPI usecase). The virtio framework already searches for a node with a suitable compatible when registering a device [1]; this binding is thus not introducing a new functionality, but allowing proper validation of nodes tied to spi-virtio devices. > > is not used to instantiate the device, which is registered by the > > transport (e.g.: virtio-mmio), but to define its properties and > > establish dependencies with other nodes. > > > > Add the new bindings inside the MAINTAINERS file. > > > > Signed-off-by: Francesco Valla <[email protected]> > > --- > > .../devicetree/bindings/spi/spi-virtio.yaml | 53 > > ++++++++++++++++++++++ > > MAINTAINERS | 1 + > > 2 files changed, 54 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/spi/spi-virtio.yaml > > b/Documentation/devicetree/bindings/spi/spi-virtio.yaml > > new file mode 100644 > > index 000000000000..5b8639dd2e1f > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/spi/spi-virtio.yaml > > @@ -0,0 +1,53 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/spi/spi-virtio.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Virtio SPI controller device > > + > > +maintainers: > > + - Francesco Valla <[email protected]> > > + > > +allOf: > > + - $ref: /schemas/spi/spi-controller.yaml# > > + - $ref: /schemas/virtio/virtio-device.yaml# > > + > > +description: > > + Virtio SPI controller device, see /schemas/virtio/virtio-device.yaml for > > + more details. > > + > > +properties: > > + $nodename: > > + const: spi > > + > > + compatible: > > + const: virtio,device2d > > From where does the compatible come from? > This is the compatible the virtio framework is expecting [1]; '2d' is the hexadecimal representation of 45, which is the virtio identifier for a SPI device [2]. > Best regards, > Krzysztof > Thank you Regards, Francesco [1] https://elixir.bootlin.com/linux/v7.2.8/source/drivers/virtio/virtio.c#L488 [2] https://docs.oasis-open.org/virtio/virtio/v1.4/virtio-v1.4.html @ 5.21.1
