Re: [PATCH v4 3/6] ASoC: dt-bindings: fsl_rpmsg: Add binding doc for rpmsg cpu dai driver
From: Rob Herring <robh@kernel.org>
Date: 2021-03-10 02:49:33
Also in:
alsa-devel, linuxppc-dev, lkml
On Mon, Mar 08, 2021 at 09:22:27PM +0800, Shengjiu Wang wrote:
fsl_rpmsg cpu dai driver is driver for rpmsg audio, which is mainly used
Bindings describe h/w blocks, not drivers.
quoted hunk ↗ jump to hunk
for getting the user's configuration from device tree and configure the clocks which is used by Cortex-M core. So in this document define the needed property. Signed-off-by: Shengjiu Wang <redacted> --- .../devicetree/bindings/sound/fsl,rpmsg.yaml | 118 ++++++++++++++++++ 1 file changed, 118 insertions(+) create mode 100644 Documentation/devicetree/bindings/sound/fsl,rpmsg.yamldiff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml new file mode 100644 index 000000000000..5731c1fbc0a6 --- /dev/null +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml@@ -0,0 +1,118 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/sound/fsl,rpmsg.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: NXP Audio RPMSG CPU DAI Controller + +maintainers: + - Shengjiu Wang <shengjiu.wang@nxp.com> + +description: | + fsl_rpmsg cpu dai driver is virtual driver for rpmsg audio, which doesn't + touch hardware. It is mainly used for getting the user's configuration + from device tree and configure the clocks which is used by Cortex-M core. + So in this document define the needed property. + +properties: + compatible: + enum: + - fsl,imx7ulp-rpmsg + - fsl,imx8mn-rpmsg + - fsl,imx8mm-rpmsg + - fsl,imx8mp-rpmsg + + model: + $ref: /schemas/types.yaml#/definitions/string + description: User specified audio sound card name + + clocks: + items: + - description: Peripheral clock for register access + - description: Master clock + - description: DMA clock for DMA register access + - description: Parent clock for multiple of 8kHz sample rates + - description: Parent clock for multiple of 11kHz sample rates + minItems: 5
If this doesn't touch hardware, what are these clocks for? You don't need 'minItems' unless it's less than the number of 'items'.
+ + clock-names: + items: + - const: ipg + - const: mclk + - const: dma + - const: pll8k + - const: pll11k + minItems: 5 + + power-domains: + maxItems: 1 + + fsl,audioindex: + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [0, 1] + default: 0 + description: Instance index for sound card in + M core side, which share one rpmsg + channel.
We don't do indexes in DT. What's this numbering tied to?
+ + fsl,version:
version of what? This seems odd at best.
+ $ref: /schemas/types.yaml#/definitions/uint32 + enum: [1, 2]
You're going to update this with every new firmware version?
+ default: 2 + description: The version of M core image, which is + to make driver compatible with different image. + + fsl,buffer-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: pre allocate dma buffer size
How can you have DMA, this doesn't touch h/w?
+ + fsl,enable-lpa: + $ref: /schemas/types.yaml#/definitions/flag + description: enable low power audio path. + + fsl,rpmsg-out: + $ref: /schemas/types.yaml#/definitions/flag + description: | + This is a boolean property. If present, the transmitting function + will be enabled. + + fsl,rpmsg-in: + $ref: /schemas/types.yaml#/definitions/flag + description: | + This is a boolean property. If present, the receiving function + will be enabled. + + fsl,codec-type: + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [0, 1, 2] + default: 0 + description: Sometimes the codec is registered by + driver not by the device tree, this items + can be used to distinguish codecs.
How does one decide what value to use?
+ + audio-codec: + $ref: /schemas/types.yaml#/definitions/phandle + description: The phandle of the audio codec
The codec is controlled from the Linux side?
+
+ memory-region:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description: phandle to the reserved memory nodes
+
+required:
+ - compatible
+ - fsl,audioindex
+ - fsl,version
+ - fsl,buffer-size
+
+additionalProperties: false
+
+examples:
+ - |
+ rpmsg_audio: rpmsg_audio {
+ compatible = "fsl,imx8mn-rpmsg";
+ fsl,audioindex = <0> ;
+ fsl,version = <2>;
+ fsl,buffer-size = <0x6000000>;
+ fsl,enable-lpa;How does this work? Don't you need somewhere to put the 'rpmsg' data?
+ }; -- 2.27.0