Hi Rob On Wed, Mar 10, 2021 at 10:49 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > 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. I will modify the descriptions. but here it is a virtual device. the mapping in real h/w is cortex M core, Cortex M core controls the SAI, DMA interface. What we see from Linux side is a audio service through rpmsg channel. > > > 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 <shengjiu.wang@xxxxxxx> > > --- > > .../devicetree/bindings/sound/fsl,rpmsg.yaml | 118 ++++++++++++++++++ > > 1 file changed, 118 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml > > > > diff --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@xxxxxxx> > > + > > +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? When the cortex-M core support audio service, these clock needed prepared & enabled by ALSA driver. > > You don't need 'minItems' unless it's less than the number of 'items'. Ok, I will remove this minItems. > > > + > > + 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? I will remove it. it is not necessary > > > + > > + fsl,version: > > version of what? > > This seems odd at best. > I will remove it. it is not necessary > > + $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? The DMA is handled by M core image for sound playback and capture. we need to allocated buffer in Linux side. here just make the buffer size to be configurable. > > > + > > + 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? I will add more description: 0: dummy codec 1: WM8960 codec 2: AK4497 codec > > > + > > + audio-codec: > > + $ref: /schemas/types.yaml#/definitions/phandle > > + description: The phandle of the audio codec > > The codec is controlled from the Linux side? yes. > > > + > > + 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? The rpmsg data is not handled in this "rpmsg_audio" device, it is just to prepare the resource for rpmsg audio function, the clock, the memory the power... The rpmsg data is handled in imx-pcm-rpmsg.c and imx-audio-rpmsg.c These devices is registered by imx remoteproc driver. I will update this document in v5 Best regards Wang Shengjiu
