101 lines
3.5 KiB
Plaintext
101 lines
3.5 KiB
Plaintext
STMicroelectronics STM32 Serial Audio Interface (SAI).
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The SAI interface (Serial Audio Interface) offers a wide set of audio protocols
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as I2S standards, LSB or MSB-justified, PCM/DSP, TDM, and AC'97.
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The SAI contains two independent audio sub-blocks. Each sub-block has
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its own clock generator and I/O lines controller.
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Required properties:
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- compatible: Should be "st,stm32f4-sai" or "st,stm32h7-sai"
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- reg: Base address and size of SAI common register set.
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- clocks: Must contain phandle and clock specifier pairs for each entry
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in clock-names.
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- clock-names: Must contain "pclk" "x8k" and "x11k"
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"pclk": Clock which feeds the peripheral bus interface.
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Mandatory for "st,stm32h7-sai" compatible.
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Not used for "st,stm32f4-sai" compatible.
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"x8k": SAI parent clock for sampling rates multiple of 8kHz.
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"x11k": SAI parent clock for sampling rates multiple of 11.025kHz.
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- interrupts: cpu DAI interrupt line shared by SAI sub-blocks
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Optional properties:
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- resets: Reference to a reset controller asserting the SAI
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SAI subnodes:
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Two subnodes corresponding to SAI sub-block instances A et B can be defined.
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Subnode can be omitted for unsused sub-block.
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SAI subnodes required properties:
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- compatible: Should be "st,stm32-sai-sub-a" or "st,stm32-sai-sub-b"
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for SAI sub-block A or B respectively.
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- reg: Base address and size of SAI sub-block register set.
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- clocks: Must contain one phandle and clock specifier pair
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for sai_ck which feeds the internal clock generator.
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- clock-names: Must contain "sai_ck".
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- dmas: see Documentation/devicetree/bindings/dma/stm32-dma.txt
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- dma-names: identifier string for each DMA request line
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"tx": if sai sub-block is configured as playback DAI
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"rx": if sai sub-block is configured as capture DAI
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- pinctrl-names: should contain only value "default"
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- pinctrl-0: see Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt
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SAI subnodes Optional properties:
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- st,sync: specify synchronization mode.
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By default SAI sub-block is in asynchronous mode.
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This property sets SAI sub-block as slave of another SAI sub-block.
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Must contain the phandle and index of the sai sub-block providing
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the synchronization.
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- st,iec60958: support S/PDIF IEC6958 protocol for playback
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IEC60958 protocol is not available for capture.
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By default, custom protocol is assumed, meaning that protocol is
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configured according to protocol defined in related DAI link node,
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such as i2s, left justified, right justified, dsp and pdm protocols.
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Note: ac97 protocol is not supported by SAI driver
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The device node should contain one 'port' child node with one child 'endpoint'
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node, according to the bindings defined in Documentation/devicetree/bindings/
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graph.txt.
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Example:
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sound_card {
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compatible = "audio-graph-card";
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dais = <&sai1b_port>;
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};
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sai1: sai1@40015800 {
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compatible = "st,stm32h7-sai";
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#address-cells = <1>;
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#size-cells = <1>;
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ranges = <0 0x40015800 0x400>;
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reg = <0x40015800 0x4>;
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clocks = <&rcc SAI1_CK>, <&rcc PLL1_Q>, <&rcc PLL2_P>;
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clock-names = "pclk", "x8k", "x11k";
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interrupts = <87>;
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sai1a: audio-controller@40015804 {
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compatible = "st,stm32-sai-sub-a";
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reg = <0x4 0x1C>;
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clocks = <&rcc SAI1_CK>;
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clock-names = "sai_ck";
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dmas = <&dmamux1 1 87 0x400 0x0>;
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dma-names = "tx";
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pinctrl-names = "default";
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pinctrl-0 = <&pinctrl_sai1a>;
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sai1b_port: port {
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cpu_endpoint: endpoint {
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remote-endpoint = <&codec_endpoint>;
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format = "i2s";
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};
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};
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};
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};
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audio-codec {
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codec_port: port {
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codec_endpoint: endpoint {
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remote-endpoint = <&cpu_endpoint>;
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};
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};
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};
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