Documentation/devicetree/bindings/sound/st,stm32-sai.txt

   1 STMicroelectronics STM32 Serial Audio Interface (SAI).
   2
   3 The SAI interface (Serial Audio Interface) offers a wide set of audio protocols
   4 as I2S standards, LSB or MSB-justified, PCM/DSP, TDM, and AC'97.
   5 The SAI contains two independent audio sub-blocks. Each sub-block has
   6 its own clock generator and I/O lines controller.
   7
   8 Required properties:
   9   - compatible: Should be "st,stm32f4-sai" or "st,stm32h7-sai"
  10   - reg: Base address and size of SAI common register set.
  11   - clocks: Must contain phandle and clock specifier pairs for each entry
  12         in clock-names.
  13   - clock-names: Must contain "pclk" "x8k" and "x11k"
  14         "pclk": Clock which feeds the peripheral bus interface.
  15                 Mandatory for "st,stm32h7-sai" compatible.
  16                 Not used for "st,stm32f4-sai" compatible.
  17         "x8k": SAI parent clock for sampling rates multiple of 8kHz.
  18         "x11k": SAI parent clock for sampling rates multiple of 11.025kHz.
  19   - interrupts: cpu DAI interrupt line shared by SAI sub-blocks
  20
  21 Optional properties:
  22   - resets: Reference to a reset controller asserting the SAI
  23   - st,sync: specify synchronization mode.
  24         By default SAI sub-block is in asynchronous mode.
  25         This property sets SAI sub-block as slave of another SAI sub-block.
  26         Must contain the phandle and index of the sai sub-block providing
  27         the synchronization.
  28
  29 SAI subnodes:
  30 Two subnodes corresponding to SAI sub-block instances A et B can be defined.
  31 Subnode can be omitted for unsused sub-block.
  32
  33 SAI subnodes required properties:
  34   - compatible: Should be "st,stm32-sai-sub-a" or "st,stm32-sai-sub-b"
  35         for SAI sub-block A or B respectively.
  36   - reg: Base address and size of SAI sub-block register set.
  37   - clocks: Must contain one phandle and clock specifier pair
  38         for sai_ck which feeds the internal clock generator.
  39   - clock-names: Must contain "sai_ck".
  40   - dmas: see Documentation/devicetree/bindings/dma/stm32-dma.txt
  41   - dma-names: identifier string for each DMA request line
  42         "tx": if sai sub-block is configured as playback DAI
  43         "rx": if sai sub-block is configured as capture DAI
  44   - pinctrl-names: should contain only value "default"
  45   - pinctrl-0: see Documentation/devicetree/bindings/pinctrl/pinctrl-stm32.txt
  46
  47 The device node should contain one 'port' child node with one child 'endpoint'
  48 node, according to the bindings defined in Documentation/devicetree/bindings/
  49 graph.txt.
  50
  51 Example:
  52 sound_card {
  53         compatible = "audio-graph-card";
  54         dais = <&sai1b_port>;
  55 };
  56
  57 sai1: sai1@40015800 {
  58         compatible = "st,stm32h7-sai";
  59         #address-cells = <1>;
  60         #size-cells = <1>;
  61         ranges = <0 0x40015800 0x400>;
  62         reg = <0x40015800 0x4>;
  63         clocks = <&rcc SAI1_CK>, <&rcc PLL1_Q>, <&rcc PLL2_P>;
  64         clock-names = "pclk", "x8k", "x11k";
  65         interrupts = <87>;
  66
  67         sai1a: audio-controller@40015804 {
  68                 compatible = "st,stm32-sai-sub-a";
  69                 reg = <0x4 0x1C>;
  70                 clocks = <&rcc SAI1_CK>;
  71                 clock-names = "sai_ck";
  72                 dmas = <&dmamux1 1 87 0x400 0x0>;
  73                 dma-names = "tx";
  74                 pinctrl-names = "default";
  75                 pinctrl-0 = <&pinctrl_sai1a>;
  76
  77                 sai1b_port: port {
  78                         cpu_endpoint: endpoint {
  79                                 remote-endpoint = <&codec_endpoint>;
  80                                 format = "i2s";
  81                         };
  82                 };
  83         };
  84 };
  85
  86 audio-codec {
  87         codec_port: port {
  88                 codec_endpoint: endpoint {
  89                         remote-endpoint = <&cpu_endpoint>;
  90                 };
  91         };
  92 };