On Thu, Feb 11, 2021 at 6:13 AM Rob Herring [off-list ref] wrote:

On Sun, Feb 07, 2021 at 06:23:51PM +0800, Shengjiu Wang wrote:

quoted

fsl_rpmsg cpu dai driver is driver for rpmsg audio, which 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.

Signed-off-by: Shengjiu Wang <redacted>
---
 .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 80 +++++++++++++++++++
 1 file changed, 80 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..2d3ce10d42fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml

@@ -0,0 +1,80 @@
+# 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>
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx7ulp-rpmsg
+      - fsl,imx8mn-rpmsg
+      - fsl,imx8mm-rpmsg
+      - fsl,imx8mp-rpmsg

rpmsg is a protocol. What's the h/w block?

On Linux side this driver is a virtual driver, it is running
on Arm Cortex-A core. The h/w block is controlled by
another core (cortex-M core). so this driver actually
doesn't touch any hardware, it just does configuration
for rpmsg channel.

quoted

+
+  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
+
+  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
+    description: instance index for rpmsg image
+
+  fsl,version:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: rpmsg image version index

What are these 2 used for?

fsl,audioindex: As we may support multiple instance, for example
two sound card with one rpmsg channel, this is the instance index.

fsl,version: There are maybe different image running on M core, this
is the image version, different image has different function.

quoted

+
+  fsl,buffer-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: pre allocate dma buffer size
+
+  fsl,enable-lpa:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: enable low power audio path.
+
+  fsl,codec-type:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Sometimes the codec is registered by
+                 driver not the device tree, this items
+                 can be used to distinguish codecs

0-2^32 are valid values?

I should add range for it.

quoted

+
+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;
+        status = "okay";

Don't show status in examples.

ok, will remove it.

quoted

+    };
--
2.27.0