[PATCH V3 0/5] virtio: Add virtio-device bindings

[PATCH V3 0/5] virtio: Add virtio-device bindings

[Viresh Kumar]

Hi,

Currently the DT only provides support for following node types for virtio-mmio
nodes:

        virtio_mmio@a000000 {
                dma-coherent;
                interrupts = <0x00 0x10 0x01>;
                reg = <0x00 0xa000000 0x00 0x200>;
                compatible = "virtio,mmio";
        };

Here, each virtio-mmio corresponds to a virtio-device. But there is no way for
other users in the DT to show their dependency on virtio devices.

This patchset provides that support.

The first patch adds virtio-device bindings to allow for device sub-nodes to be
present and the second patch updates the virtio core to update the of_node.

Other patches add bindings for i2c and gpio devices.

Tested on x86 with qemu for arm64.

Pending:
- Arnd suggested that "virtio,deviceXX" may be a better compatible string, while
  I used "virtio,XX" to match what PCI and USB do currently. I didn't change it
  yet to hear Rob's view on the same before making the change, in case he has
  any preferences.

V2/2.1->V3:
- Added review-tags from Arnd and Wolfram.
- Only the 5th patch changed otherwise:
  - Use of_device_is_compatible() instead of keeping a list of devices.
  - Use snprintf (with BUG_ON on return value) to create the compatible string,
    whose length is fixed using "virtio,XXXXXXXX".
  - Use dev_of_node().

V1->V2:
- The changes (both binding and code) are made at virtio level, instead of
  virtio-mmio. This allows the same to be used by all device types, irrespective
  of the transport mechanism.

- Dropped the reg property and used compatible in the form "virtio,<DID>".

- Dropped dt-bindings/virtio/virtio_ids.h.

- Add a patch to sync virtio-ids from spec, required for the last patch.

--
Viresh

Viresh Kumar (5):
  dt-bindings: virtio: Add binding for virtio devices
  dt-bindings: i2c: Add bindings for i2c-virtio
  dt-bindings: gpio: Add bindings for gpio-virtio
  uapi: virtio_ids: Sync ids with specification
  virtio: Bind virtio device to device-tree node

 .../devicetree/bindings/gpio/gpio-virtio.yaml | 60 +++++++++++++++++++
 .../devicetree/bindings/i2c/i2c-virtio.yaml   | 51 ++++++++++++++++
 .../devicetree/bindings/virtio/mmio.yaml      |  2 +-
 .../bindings/virtio/virtio-device.yaml        | 47 +++++++++++++++
 drivers/virtio/virtio.c                       | 57 +++++++++++++++++-
 include/uapi/linux/virtio_ids.h               | 12 ++++
 6 files changed, 225 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
 create mode 100644 Documentation/devicetree/bindings/virtio/virtio-device.yaml

-- 
2.31.1.272.g89b43f80a514

[PATCH V3 2/5] dt-bindings: i2c: Add bindings for i2c-virtio

[Viresh Kumar]

This patch adds binding for virtio I2C device, it is based on
virtio-device bindings.

Acked-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 .../devicetree/bindings/i2c/i2c-virtio.yaml   | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-virtio.yaml

diff --git a/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
new file mode 100644
index 000000000000..0381d9065287
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio I2C Adapter
+
+maintainers:
+  - Viresh Kumar <viresh.kumar@linaro.org>
+
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+  - $ref: /schemas/virtio/virtio-device.yaml#
+
+description:
+  Virtio I2C device, see /schemas/virtio/virtio-device.yaml for more details.
+
+properties:
+  $nodename:
+    pattern: '^i2c-virtio(-[a-z0-9]+)?$'
+
+  compatible:
+    const: virtio,22
+
+required:
+  - compatible
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    virtio@3000 {
+        compatible = "virtio,mmio";
+        reg = <0x3000 0x100>;
+        interrupts = <41>;
+
+        i2c-virtio {
+            compatible = "virtio,22";
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            light-sensor@1c {
+                compatible = "dynaimage,al3320a";
+                reg = <0x20>;
+            };
+        };
+    };
+
+...
-- 
2.31.1.272.g89b43f80a514

Re: [PATCH V3 2/5] dt-bindings: i2c: Add bindings for i2c-virtio

[Arnd Bergmann]

On Mon, Jul 26, 2021 at 6:52 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> This patch adds binding for virtio I2C device, it is based on
> virtio-device bindings.
>
> Acked-by: Wolfram Sang <wsa@kernel.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH V3 2/5] dt-bindings: i2c: Add bindings for i2c-virtio

[Arnd Bergmann]

On Mon, Jul 26, 2021 at 10:06 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> On Mon, Jul 26, 2021 at 6:52 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> >
> > This patch adds binding for virtio I2C device, it is based on
> > virtio-device bindings.
> >
> > Acked-by: Wolfram Sang <wsa@kernel.org>
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Too quick, after seeing the same issue in the gpio binding I saw it here too:

> +        i2c-virtio {
> +            compatible = "virtio,22";

The node name "i2c-virtio" looks wrong. According to
https://github.com/devicetree-org/dt-schema/blob/master/schemas/i2c/i2c-controller.yaml,
this needs to be plain "i2c".

       Arnd

Re: [PATCH V3 2/5] dt-bindings: i2c: Add bindings for i2c-virtio

[Viresh Kumar]

On 26-07-21, 10:11, Arnd Bergmann wrote:
> On Mon, Jul 26, 2021 at 10:06 AM Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > On Mon, Jul 26, 2021 at 6:52 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > >
> > > This patch adds binding for virtio I2C device, it is based on
> > > virtio-device bindings.
> > >
> > > Acked-by: Wolfram Sang <wsa@kernel.org>
> > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> >
> > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> 
> Too quick, after seeing the same issue in the gpio binding I saw it here too:
> 
> > +        i2c-virtio {
> > +            compatible = "virtio,22";
> 
> The node name "i2c-virtio" looks wrong. According to
> https://github.com/devicetree-org/dt-schema/blob/master/schemas/i2c/i2c-controller.yaml,
> this needs to be plain "i2c".

Okay, I will move back to simple node names then.

Thanks.

-- 
viresh

Re: [PATCH V3 2/5] dt-bindings: i2c: Add bindings for i2c-virtio

[Rob Herring]

On Sun, Jul 25, 2021 at 10:52 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> This patch adds binding for virtio I2C device, it is based on
> virtio-device bindings.
>
> Acked-by: Wolfram Sang <wsa@kernel.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  .../devicetree/bindings/i2c/i2c-virtio.yaml   | 51 +++++++++++++++++++
>  1 file changed, 51 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
> new file mode 100644
> index 000000000000..0381d9065287
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-virtio.yaml
> @@ -0,0 +1,51 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/i2c/i2c-virtio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Virtio I2C Adapter
> +
> +maintainers:
> +  - Viresh Kumar <viresh.kumar@linaro.org>
> +
> +allOf:
> +  - $ref: /schemas/i2c/i2c-controller.yaml#
> +  - $ref: /schemas/virtio/virtio-device.yaml#
> +
> +description:
> +  Virtio I2C device, see /schemas/virtio/virtio-device.yaml for more details.
> +
> +properties:
> +  $nodename:
> +    pattern: '^i2c-virtio(-[a-z0-9]+)?$'

i2c-controller.yaml already defines the node name. In this case
though, it can be restricted a bit more to be just 'i2c' as there's
only a single instance.

> +
> +  compatible:
> +    const: virtio,22
> +
> +required:
> +  - compatible
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    virtio@3000 {
> +        compatible = "virtio,mmio";
> +        reg = <0x3000 0x100>;
> +        interrupts = <41>;
> +
> +        i2c-virtio {
> +            compatible = "virtio,22";
> +
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            light-sensor@1c {
> +                compatible = "dynaimage,al3320a";
> +                reg = <0x20>;
> +            };
> +        };
> +    };
> +
> +...
> --
> 2.31.1.272.g89b43f80a514
>