asoc : snd_soc_simple_card connection to AKM4556 codec (i2s) issue on arm64

[Markus Bollinger]

Hello,

I found what was missing: In the device-tree i2s0 parameters I had to 
add a reference to the sound-dai = <&ak4556_codec>;
&i2s0 {
     ......
     status = "okay";
     sound-dai = <&ak4556_codec>;
};

Now the drivers get loaded as expected (snd_soc_simple_card and 
snd_soc_ak4556),
I can aplay a sound file, but I have no sound.
With the oscilloscope I can see the generated LRCK clock, the SCLK clock 
and coherent SDO data, but the MCLK is constant zero.

My question now: Should the MCLK clock be handled automatically or do I 
have to initialize it in my driver ?
(I tried to do a snd_soc_dai_set_sysclk() in my hw_params fct, but it 
fails with -ENOTSUPP)

Best regards,
Markus


On 8/5/2020 12:52 PM, Markus Bollinger wrote:
> Hello,
>
> I try to get working an AKM4556 codec on the arm64 Rockchip RK3399 
> board under Linux 4.4.179
> The codec is a simple one (without i2c connection), similar to AKM4554 
> (but 24 bit instead of 16 bit audio) and hard configured to use i2s.
> I implemented the driver soc/codecs/ak4556.c which has only few 
> differences to ak4554.c.
> But when I try to get it working with the soc/general/simple-card.c, 
> the connection to the codec fails
> Both drivers (snd_soc_simple_card and snd_soc_ak4556) get loaded, the 
> call to
>
> asoc_simple_card_dai_link_of -> asoc_simple_card_sub_parse_of(cpu, ..)
>
> is OK, but the call to
>
> asoc_simple_card_dai_link_of -> asoc_simple_card_sub_parse_of(codec, 
> ..) -> snd_soc_of_get_dai_name
>
> fails with -EPROBE_DEFER.
>
> Now, i am not sure if it is a driver issue or rather a device-tree 
> one. I declared dt like this :
>
> / {
>
>     ak4556_card: ak4556-adc-dac {
>         status = "okay";
>         compatible = "simple-audio-card";
>
>         simple-audio-card,name = "ak4556";
>         simple-audio-card,format = "i2s";
>         simple-audio-card,mclk-fs = <256>;
>
>         simple-audio-card,widgets =
>             "Line", "Line In",
>             "Line", "Line Out";
>         simple-audio-card,routing =
>             "LIN", "Line In",
>             "RIN", "Line In",
>             "Line Out", "LOUT",
>             "Line Out", "ROUT";
>
>         simple-audio-card,cpu {
>             sound-dai = <&i2s0>;
>         };
>         simple-audio-card,codec {
>             sound-dai = <&ak4556_codec>;
>         };
>     };
>
>     ak4556_codec: ak4556-codec {
>         status = "okay";
>         compatible = "asahi-kasei,ak4556";
>         #sound-dai-cells = <0>;
>     };
>
>     i2s0: i2s at ff880000 {
>
>         compatible = "rockchip,rk3399-i2s", "rockchip,rk3066-i2s";
>         reg = <0x0 0xff880000 0x0 0x1000>;
>         rockchip,grf = <&grf>;
>         interrupts = <GIC_SPI 39 IRQ_TYPE_LEVEL_HIGH 0>;
>         dmas = <&dmac_bus 0>, <&dmac_bus 1>;
>         dma-names = "tx", "rx";
>         clock-names = "i2s_clk", "i2s_hclk";
>         clocks = <&cru SCLK_I2S0_8CH>, <&cru HCLK_I2S0_8CH>;
>         resets = <&cru SRST_I2S0_8CH>, <&cru SRST_H_I2S0_8CH>;
>         reset-names = "reset-m", "reset-h";
>         pinctrl-names = "default";
>         pinctrl-0 = <&i2s0_8ch_bus>;
>         power-domains = <&power RK3399_PD_SDIOAUDIO>;
>         status = "disabled";
>     };
>
> &i2s0 {
>     #sound-dai-cells = <0>;
>     assigned-clocks = <&cru SCLK_I2S0_DIV>;
>     assigned-clock-parents = <&cru PLL_GPLL>;
>     status = "okay";
> };
>
> Thank you in advance for your suggestions,
>
> Markus