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b=q7m5FpCSf0KtWKBUFio0+C5svc B43jcg/vGa6IV6vn0X4Ni476MudeYiILU4tCXZOaT5M8XS6vuYP8aPocatBzRjQnFAoz7hKcIPVys lVU0XVLKK5209DViqfD0nvLsBMKPeaycXLk8ojgY0QVwgyUIISyKtndZqb3UEsNZ04Yk=; Received: from [87.14.44.235] (port=60776 helo=bywater) by esm19.siteground.biz with essmtpa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.100.1) (envelope-from ) id 1xBx4H-00000000GOS-3C3X; Wed, 30 Sep 2026 16:22:05 +0000 Date: Wed, 30 Sep 2026 18:22:03 +0200 From: Francesco Valla To: Krzysztof Kozlowski Cc: "Michael S. Tsirkin" , Mark Brown , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Haixu Cui , Jason Wang , Viresh Kumar , Xuan Zhuo , Eugenio =?utf-8?B?UMOpcmV6?= , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux.dev Subject: Re: [PATCH 1/2] dt-bindings: spi: add bindings for spi-virtio Message-ID: References: <20260929-spi-virtio-bindings-v1-0-6a0eef3213b3@valla.it> <20260929-spi-virtio-bindings-v1-1-6a0eef3213b3@valla.it> <20260930-arcane-pheasant-of-infinity-ecff83@quoll> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260930-arcane-pheasant-of-infinity-ecff83@quoll> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - esm19.siteground.biz X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - valla.it X-Source: X-Source-Args: X-Source-Dir: X-SGantispam-id: 70bd9ea3b80416f81ac2f5224697ac6f X-AntiAbuse: ID - 70bd9ea3b80416f81ac2f5224697ac6f AntiSpam-DLS: false AntiSpam-DLSP: AntiSpam-DLSRS: AntiSpam-TS: 1.0 CFBL-Address: feedback@antispam.mailspamprotection.com; report=arf CFBL-Feedback-ID: 1xBx4a-00000004PEM-277H-feedback@antispam.mailspamprotection.com Authentication-Results: outgoing.instance-europe-west4-c54f.prod.antispam.mailspamprotection.com; iprev=pass (214.173.214.35.bc.googleusercontent.com) smtp.remote-ip=35.214.173.214; auth=pass (LOGIN) smtp.auth=esm19.siteground.biz; dkim=pass header.d=valla.it header.s=default header.a=rsa-sha256; arc=none 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 > > --- > > .../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 > > + > > +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