On Thu, Mar 16, 2017 at 5:50 AM, Olivier MOYSAN olivier.moysan@st.com wrote:
Hello Rob,
Thanks for your feedback.
On 03/15/2017 06:46 PM, Rob Herring wrote:
On Tue, Mar 07, 2017 at 10:44:31AM +0100, olivier moysan wrote:
This patch adds documentation of device tree bindings for the STM32 SAI ASoC driver.
Signed-off-by: olivier moysan olivier.moysan@st.com
.../devicetree/bindings/sound/st,stm32-sai.txt | 79 ++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 Documentation/devicetree/bindings/sound/st,stm32-sai.txt
diff --git a/Documentation/devicetree/bindings/sound/st,stm32-sai.txt b/Documentation/devicetree/bindings/sound/st,stm32-sai.txt new file mode 100644 index 0000000..b3be26d --- /dev/null +++ b/Documentation/devicetree/bindings/sound/st,stm32-sai.txt @@ -0,0 +1,79 @@ +STMicroelectronics STM32 Serial Audio Interface (SAI).
+The SAI interface (Serial Audio Interface) offers a wide set of audio protocols +as I2S standards, LSB or MSB-justified, PCM/DSP, TDM, and AC'97. +The SAI contains two independent audio sub-blocks. Each sub-block has +its own clock generator and I/O lines controller.
+Required properties:
- compatible: Should be "st,stm32f4-sai"
- reg: Base address and size of SAI common register set.
- clocks: Must contain phandle and clock specifier pairs for each entry
- in clock-names.
- clock-names: Must contain "clk_x8k" and "clk_x11k"
- "clk_x8k": SAI parent clock for sampling rates multiple of 8kHz.
- "clk_x11k": SAI parent clock for sampling rates multiple of 11.025kHz.
clk_ is redundant.
Do you mean, removing clk_ prefix ?
Yes.
- interrupts: cpu DAI interrupt line shared by SAI sub-blocks
+Note: Each SAI controller should have an alias correctly numbered +in "aliases" node, to provide explicit name to CPU DAI.
No, it shouldn't. Why do you need that?
Yes, this is not mandatory. This is convenient to identify sai controller, as we may have up to 8 instances. I can make it optional, or remove it if you think it is not relevant.
Remove it.
+Optional properties:
- resets: Reference to a reset controller asserting the SAI
+SAI subnodes: +Two subnodes corresponding to SAI sub-block instances A et B can be defined. +Subnode can be omitted for unsused sub-block.
+SAI subnodes required properties:
- compatible: Should be "st,stm32-sai-sub-a" or "st,stm32-sai-sub-b"
- for SAI sub-block A or B respectively.
- reg: Base address and size of SAI sub-block register set.
- clocks: Must contain one phandle and clock specifier pair
- for sai_ck which feeds the internal clock generator.
- clock-names: Must contain "sai_ck".
- dmas: see Documentation/devicetree/bindings/dma/stm32-dma.txt
- dma-names: identifier string for each DMA request line
- "tx": if sai sub-block is configured as playback DAI
- "rx": if sai sub-block is configured as capture DAI
- pinctrl-names: should contain only value "default"
- pinctrl-0: see Documentation/devicetree/bindings/pinctrl/pinctrl-stm32.txt
+Example: +sai1: sai1@40015800 {
- compatible = "st,stm32f4-sai";
- reg = <0x40015800 0x400>;
reg = <0x40015800 0x4>;
- clocks = <&rcc 1 CLK_SAIQ_PDIV>, <&rcc 1 CLK_I2SQ_PDIV>;
- clock-names = "clk_x8k", "clk_x11k";
- interrupts = <87>;
- resets = <&rcc 310>;
- sai1b: sai@1 {
unit address needs a reg property.
audio-controller@1
Right. This needs to be updated as follows: sai1b: sai1b@40015824 {
audio-controller@...
... reg = <0x40015824 0x1C>; ... };
#sound-dai-cells = <0>;compatible = "st,stm32-sai-sub-b";clocks = <&rcc 1 CLK_SAI2>;clock-names = "sai_ck";dmas = <&dma2 5 0 0x400 0x1>;dma-names = "tx";- };
+};
+sound {
- compatible = "simple-audio-card";
Perhaps you want to use the graph-card here. It's getting close to merging.
mclk-fs property is required when SAI is configured as master. It seems that mclk-fs is not supported in current version of audio graph card. So I thing I should keep simple card for the time being. Anyway, I plan further updates for SAI, so I will have opportunity to change to graph card at that time.
Well, it's not easy to switch later and maintain compatibility. Is it complicated to add mclk-fs property? The intent is graph-card supports everything simple-card supports.
Rob