[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 3/5] dt-bindings: gpio: Add bindings for gpio-virtio

[Viresh Kumar]

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

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 .../devicetree/bindings/gpio/gpio-virtio.yaml | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-virtio.yaml

diff --git a/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
new file mode 100644
index 000000000000..96108cfb7a08
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/gpio-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtio GPIO controller
+
+maintainers:
+  - Viresh Kumar <viresh.kumar@linaro.org>
+
+allOf:
+  - $ref: /schemas/gpio/gpio.yaml#
+  - $ref: /schemas/virtio/virtio-device.yaml#
+
+description:
+  Virtio GPIO controller, see /schemas/virtio/virtio-device.yaml for more
+  details.
+
+properties:
+  $nodename:
+    pattern: '^gpio-virtio(-[a-z0-9]+)?$'
+
+  compatible:
+    const: virtio,29
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+required:
+  - compatible
+  - gpio-controller
+  - "#gpio-cells"
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    virtio@3000 {
+        compatible = "virtio,mmio";
+        reg = <0x3000 0x100>;
+        interrupts = <41>;
+
+        gpio: gpio-virtio {
+            compatible = "virtio,29";
+            gpio-controller;
+            #gpio-cells = <2>;
+            interrupt-controller;
+            #interrupt-cells = <2>;
+        };
+    };
+
+...
-- 
2.31.1.272.g89b43f80a514

Re: [PATCH V3 3/5] dt-bindings: gpio: Add bindings for gpio-virtio

[Arnd Bergmann]

On Mon, Jul 26, 2021 at 6:53 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> This patch adds binding for virtio GPIO controller, it is based on
> virtio-device bindings.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

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

> +
> +properties:
> +  $nodename:
> +    pattern: '^gpio-virtio(-[a-z0-9]+)?$'
> +
> +        gpio: gpio-virtio {
> +            compatible = "virtio,29";

The node name here does not appear to be mandated by the schema, but
most others name it "gpio", so I would do the same here instead of
"gpio-virtio".

       Arnd

Re: [PATCH V3 3/5] dt-bindings: gpio: Add bindings for gpio-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 GPIO controller, it is based on
> virtio-device bindings.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  .../devicetree/bindings/gpio/gpio-virtio.yaml | 60 +++++++++++++++++++
>  1 file changed, 60 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
> new file mode 100644
> index 000000000000..96108cfb7a08
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
> @@ -0,0 +1,60 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/gpio-virtio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Virtio GPIO controller
> +
> +maintainers:
> +  - Viresh Kumar <viresh.kumar@linaro.org>
> +
> +allOf:
> +  - $ref: /schemas/gpio/gpio.yaml#

You don't need to include this.

> +  - $ref: /schemas/virtio/virtio-device.yaml#
> +
> +description:
> +  Virtio GPIO controller, see /schemas/virtio/virtio-device.yaml for more
> +  details.
> +
> +properties:
> +  $nodename:
> +    pattern: '^gpio-virtio(-[a-z0-9]+)?$'
> +
> +  compatible:
> +    const: virtio,29
> +
> +  gpio-controller: true
> +
> +  "#gpio-cells":
> +    const: 2
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 2
> +
> +required:
> +  - compatible
> +  - gpio-controller
> +  - "#gpio-cells"
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    virtio@3000 {
> +        compatible = "virtio,mmio";
> +        reg = <0x3000 0x100>;
> +        interrupts = <41>;
> +
> +        gpio: gpio-virtio {
> +            compatible = "virtio,29";
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +            interrupt-controller;
> +            #interrupt-cells = <2>;
> +        };
> +    };
> +
> +...
> --
> 2.31.1.272.g89b43f80a514
>