i.MX8MM mini no sound issue

[KennyChu]

Hi Supporter,

We will using AD1933+TPA3116 for the audio DAC/Amp. We try to porting a machine layer driver and encounter some problems. 

1. We try to use "aplay" to playback a wav file and only hear "pop" in the speaker.

2. We try to measure wave form and found that only left channel has data. Can you advise why this will happen? Is this situation will cause the speaker output "pop" sound? 

Below is my board information and sw information for your reference.

1. Test process.

a. Using spi_devtest to initial and configure AD1933. Is this ok? We try to write value to register and read it back. It is as expected.

b. Using aplay to playback. (aplay -Dplughw:0,0 /usr/share/sounds/alsa/Front_Center.wav)

2. HW rework pins.

SAI3_TXD-> DSDATA1

SAI3_MCLK-> MCLK

SAI3_TXFS-> DLRCLK

SAI3_TXC-> DBCLK

3. SW modification.

SDK: imx-yocto-LF_L5.4.3_1.0.0

---codec: snd-soc-dummy

--Machine : imx-ad1933.c (Please check attachments)

4. Device Tree modification.

imx8mm-evk.dts

sound-ad1933 {
compatible = "fsl,AD1933";
model = "imx-audio-ad1933";
cpu-dai = <&sai3>;
};

&sai3 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_sai3>;
assigned-clocks = <&clk IMX8MM_CLK_SAI3>;
assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
assigned-clock-rates = <12288000>;

status = "okay";
};

5. Wave form. Can you advise why there is no data in right channel? Is something wrong in machine driver or?

Regards,
Kenny

[KennyChu]

@igorpadykov 

Hi Igor,

We change setting below. 

codec:  dummy to ad193x.c

machine driver: imx-ad1933.c  to simple-audio-card

We can playback .wav file now but only has sound in the first time. 

After first time, there is only "pop" in the speaker. Can you advise how to fix it? 

Regards,

Kenny

[igorpadykov]

Hi KennyChu

one can look at Figure 7-1. ALSA SoC Software Architecture,

sect.7.1.4.5 Source Code Structure for sound driver architecture,

seems there is no need for "snd-soc-dummy"

i.MX Linux Reference Manual​

For "no data in right channel" suggest to check sai settings,

one can debug it in driver sound/soc/fsl/fsl_sai.c

Best regards
igor