On Tue, Jan 22, 2019 at 11:14:27AM +0000, Viorel Suman wrote:
Add the DT binding documentation for NXP Audio Mixer CPU DAI driver.
Signed-off-by: Viorel Suman viorel.suman@nxp.com
.../devicetree/bindings/sound/fsl,audmix.txt | 54 ++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/sound/fsl,audmix.txt
diff --git a/Documentation/devicetree/bindings/sound/fsl,audmix.txt b/Documentation/devicetree/bindings/sound/fsl,audmix.txt new file mode 100644 index 0000000..45f807e --- /dev/null +++ b/Documentation/devicetree/bindings/sound/fsl,audmix.txt @@ -0,0 +1,54 @@ +NXP Audio Mixer (AUDMIX).
+The Audio Mixer is a on-chip functional module that allows mixing of two +audio streams into a single audio stream. Audio Mixer has two input serial +audio interfaces. These are driven by two Synchronous Audio interface +modules (SAI). Each input serial interface carries 8 audio channels in its +frame in TDM manner. Mixer mixes audio samples of corresponding channels +from two interfaces into a single sample. Before mixing, audio samples of +two inputs can be attenuated based on configuration. The output of the +Audio Mixer is also a serial audio interface. Like input interfaces it has +the same TDM frame format. This output is used to drive the serial DAC TDM +interface of audio codec and also sent to the external pins along with the +receive path of normal audio SAI module for readback by the CPU.
+The output of Audio Mixer can be selected from any of the three streams
- serial audio input 1
- serial audio input 2
- mixed audio
+Mixing operation is independent of audio sample rate but the two audio +input streams must have same audio sample rate with same number of channels +in TDM frame to be eligible for mixing.
+Device driver required properties: +=================================
- compatible : Compatible list, contains "fsl,imx8qm-audmix"
- reg : Offset and length of the register set for the device.
- clocks : Must contain an entry for each entry in clock-names.
- clock-names : Must include the "ipg" for register access.
- power-domains : Must contain the phandle to AUDMIX power domain node
- dais : Must contain a list of phandles to AUDMIX connected
DAIs. The current implementation requires two phandlesto SAI interfaces to be provided, the first SAI in thelist being used to route the AUDMIX output.
- model : Must contain machine driver name which will configure
and instantiate the appropriate audio card.
I don't feel this is necessary for DT node. The driver should be able to figure out a proper name for the machine driver: it could use the compatible string to get "imx8qm-audmix" as the name like fsl_ssi; Or it could have built-in "imx-audmix" of_device_id data corresponding to "fsl,imx8qm-audmix" compatible string -- for any non-imx compatible in the future, use something else.
Thanks Nic
+Device driver configuration example: +======================================
- audmix: audmix@59840000 {
- compatible = "fsl,imx8qm-audmix";
- reg = <0x0 0x59840000 0x0 0x10000>;
- clocks = <&clk IMX8QXP_AUD_AUDMIX_IPG>;
- clock-names = "ipg";
- power-domains = <&pd_audmix>;
- dais = <&sai4>, <&sai5>;
- model = "imx-audmix";
- };
-- 2.7.4