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@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