imx8mm audio codec SGTL5000

Shao — Fri, 03 Feb 2023 06:06:45 GMT

Hi,

I use advantech-ROM5721 and I face a problem about porting audio codec SGTL5000.

I set the codec sys_mclk to 24,576,000Hz and use codec internal PLL function descripte in datasheet Figure 9.

Here is device tree and driver I use.
The HP_Out and Line_Out output with a lot of noise (sounds likewhite noise).

I try some modify to fix the problem but unfortunately.

What I try

1. regard frequecny(24,576,000Hz) as 22579200 to setup the CHIP_CLK_CTRL register (as attachment line 965)

The noise almost cancel, but the tone different about 10%

Ex I play 1KHz single tone sound, output 1.09KHz tone.

2. change sys_clk to 22,579,200 (44,100Hz*512) at the device tree as below.

&sai1 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_sai1>;
    assigned-clocks = <&clk IMX8MM_CLK_SAI1>;
    assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
    // assigned-clock-rates = <0>, <24576000>;
    assigned-clock-rates = <0>, <22579200>;
    status = "okay";
};

&i2c4{

    codec: sgtl5000@a {
       compatible = "fsl,sgtl5000";
       reg = <0x0a>;
       clocks = <&clk IMX8MM_CLK_SAI1_ROOT>;
       clock-names = "mclk";
       pinctrl-names = "default";
       pinctrl-0 = <&pinctrl_sai1_mclk>;
       assigned-clocks = <&clk IMX8MM_CLK_SAI1>;
       assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
       // assigned-clock-rates = <24576000>;
       assigned-clock-rates = <22579200>;
    };

};

The driver only apply frequency to 23,130,353 Hz
I use printk in the function "sgtl5000_set_dai_sysclk " to check sysclk

Since the mclk/sample_freq is not equal to 256, 384 or 512, driver use the PLL setting.

printk("%s:sgtl5000->sysclk:%d\n", __func__, freq);
// [ 6.262997] sgtl5000_set_dai_sysclk:sgtl5000->sysclk:23130353

What is the sysclk prefre for sgtl5000?

How to change the sysclk to specific frequency(ex:22,579,200 (44,100Hz*512) or 11,289,600(44,100Hz*256))?

Re: imx8mm audio codec SGTL5000

Harvey021 — Fri, 10 Feb 2023 06:36:17 GMT

Hi @Shao

If the audio quality sounds good after modification, it is okay to the tone difference shown.

Best regards

Harvey

topic imx8mm audio codec SGTL5000 in i.MX Processors

imx8mm audio codec SGTL5000

Re: imx8mm audio codec SGTL5000