On Tue, Sep 22, 2026 at 09:40:31AM -0600, Mathieu Poirier wrote:
> On Wed, Sep 16, 2026 at 11:10:53PM +0200, Francesco Valla wrote:
> > Add a new binding to describe remoteproc-provided virtio devices; while
> > these are discovered through a resource table parsed by the remoteproc
> > infrastructure at runtime, their description can be needed to probe
> > non-discoverable buses (such as I2C) or to link consumers and suppliers.
> >
> > Each vdev is described by a dedicated "group" node, which then includes
> > a virtio-device node, which binding is already existent and used by
> > virtio-mmio. Each vdev shall be stattically linked to a "group" node
> > using its index inside the resource table as the reg property of the
> > node; this permits to have multiple instances of the same type of
> > device.
> >
> > The binding is intended to be generic and adopted by any remoteproc
> > provider.
> >
> > Signed-off-by: Francesco Valla <[email protected]>
> > ---
> > .../bindings/remoteproc/remoteproc-virtio.yaml | 89
> > ++++++++++++++++++++++
> > 1 file changed, 89 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/remoteproc/remoteproc-virtio.yaml
> > b/Documentation/devicetree/bindings/remoteproc/remoteproc-virtio.yaml
> > new file mode 100644
> > index 000000000000..c4a0d84b1460
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/remoteproc/remoteproc-virtio.yaml
> > @@ -0,0 +1,89 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/remoteproc/remoteproc-virtio.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Virtio devices over remoteproc
> > +
> > +description: |
> > + Virtio devices ("vdevs") can be exposed using the remoteproc
> > infrastructure
> > + and its resource table. For some of them, a device tree node might be
> > needed
> > + to describe remote undiscoverable hardware and/or connect consumers and
> > + providers.
> > +
> > +maintainers:
> > + - Francesco Valla <[email protected]>
> > +
> > +properties:
> > + virtio:
> > + description: Contains a group of Virtio devices exposed by the
> > remoteproc.
> > +
> > + properties:
> > + '#address-cells':
> > + const: 1
> > +
> > + '#size-cells':
> > + const: 0
> > +
> > + patternProperties:
> > + "^vdev@[0-9a-f]+$":
> > + type: object
> > +
> > + properties:
> > + reg:
> > + description: Virtio device index inside the resource table.
> > + maxItems: 1
> > +
> > + additionalProperties:
> > + type: object
> > + $ref: /schemas/virtio/virtio-device.yaml
> > + maxItems: 1
> > +
> > + required:
> > + - reg
> > +
> > + additionalProperties: false
> > +
> > + required:
> > + - '#address-cells'
> > + - '#size-cells'
> > +
> > +additionalProperties: true
> > +
> > +examples:
> > + - |
> > + remoteproc-cm33 {
> > + virtio {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + vdev@0 {
> > + reg = <0>;
> > +
>
> Do we need the 'reg' since we already have vdev@X? I'll let the DT people
> provide their input on this.
>
AFAIK yes, because the rproc_get_vdev_fwnode() helpers search for indexed
child nodes using the 'reg' property, not the node name. This I believe
is the preferred way of doing things.
> > + gpio {
> > + compatible = "virtio,device29";
> > +
> > + gpio-controller;
> > + #gpio-cells = <2>;
> > + };
> > + };
> > +
> > + vdev@1 {
> > + reg = <1>;
> > +
> > + i2c {
> > + compatible = "virtio,device22";
> > +
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + eeprom@50 {
> > + compatible = "atmel,24c1025";
> > + reg = <0x50>;
> > + };
>
> The previous patch introduced bindings for virtio SPI while the above two are
> for GPIO and I2c, which is very confusing. I suggest you pick one and apply
> everywhere.
>
This is because both GPIO and I2C bindings are already defined - even if
not used in the devicetree files part of the kernel tree.
Moving forward, I plan to submit at least the spi-virtio bindings as a
separate patch set, as they can be used independently of this one.
> > + };
> > + };
> > + };
> > + };
> > +...
> >
> > --
> > 2.55.0
> >
Regards,
Francesco
