i.MX ProcessorsのトピックRe: iMX8MM SAI I2S with dummy codec

iMX8MM SAI I2S with dummy codec

jonver — Wed, 23 Oct 2019 11:24:30 GMT

Hi,

I trying to make the imx8mm board output audio via I2S. The chip that decodes the audio is CS4344, which has no config so no I2C is present.

I made the following changes to the dts file:

    sound {
        compatible = "simple-audio-card";
        simple-audio-card,name = "CS4344";
        simple-audio-card,format = "i2s";
        simple-audio-card,widgets =
            "Line", "Line Out";
        simple-audio-card,routing =
            "Line Out", "LLOUT",
            "Line Out", "RLOUT";
        simple-audio-card,cpu {
            sound-dai = <&sai5>;
        };
        simple-audio-card,codec {
         sound-dai = <&codec1>;
        };
    };

    codec1: codec1 {
         compatible = "linux,snd-soc-dummy";
         #sound-dai-cells = <0>;
         status = "okay";
     };
        pinctrl_sai5: sai5grp {
            fsl,pins = <
                MX8MM_IOMUXC_SAI2_MCLK_SAI5_MCLK        0xd6
                MX8MM_IOMUXC_SAI1_TXFS_SAI5_TX_SYNC     0xd6
                MX8MM_IOMUXC_SAI5_RXD2_SAI5_TX_BCLK     0xd6
                MX8MM_IOMUXC_SAI1_TXD1_SAI5_TX_DATA1    0xd6
                MX8MM_IOMUXC_SAI1_TXD3_SAI5_TX_DATA3    0xd6
            >;
        };
&sai5 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_sai5>;
    assigned-clocks = <&clk IMX8MM_CLK_SAI5_SRC>,
            <&clk IMX8MM_CLK_SAI5_DIV>;
    assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
    assigned-clock-rates = <0>, <1536000>;
    #sound-dai-cells = <0>;
    status = "okay";
};

The CONFIG_SND_SIMPLE_CARD option is enabled when compiling the kernel.

I see no sound card in my boot logs or with the following commands `dmesg | grep sai` or `cat /proc/asound/cards`.

Any ideas? Thanks.

Re: iMX8MM SAI I2S with dummy codec

igorpadykov — Wed, 23 Oct 2019 23:10:30 GMT

Hi Jonathan

one can check solution provided on

SAI on i.MX8M Mini

Best regards
igor
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Re: iMX8MM SAI I2S with dummy codec

maxipenna — Mon, 29 Mar 2021 15:09:00 GMT

@igorpadykov why are you linking a solution where an i2c codec is used and binded into the dts? The user asked a question about interfacing a codec that is NOT managed on i2c. So your solution isn't applicable...I've just tried the approach provided by @jonver and I confirm it's not working altought I think it's very likely to be correct...

Re: iMX8MM SAI I2S with dummy codec

igorpadykov — Mon, 29 Mar 2021 15:24:15 GMT

Hi Massimo

one can try to remove i2c codes, if they are not used.

Best regards
igor

Re: iMX8MM SAI I2S with dummy codec

maxipenna — Mon, 29 Mar 2021 17:10:10 GMT

Sorry but have you tried to do that and confirm it's working or not? If I open simple-card.txt in a more or less recent kernel I see

Required dai-link subnodes:

- cpu : CPU sub-node
- codec : CODEC sub-node

You have to define a codec subnode since on dts you're describing a "link" between your i2s interface and what's outside. Without this quirk alsa won't work. That's why they introduced the dummy codec module inside kernel. The problem is that this module is not working properly on imx8mm. I'm using 5.4.97 linux-fslc-imx and the following dts config on an imx8mm processor.

/dts-v1/; /plugin/; #include "imx8mm-pinfunc.h" #include <dt-bindings/clock/imx8mm-clock.h> / { compatible = "fsl,imx8mm-evk", "fsl,imx8mm"; fragment@0 { target = <&iomuxc>; __overlay__ { imx8mm { pinctrl_sai3: sai3grp { fsl,pins = < MX8MM_IOMUXC_SAI3_TXFS_SAI3_TX_SYNC 0xd6 MX8MM_IOMUXC_SAI3_TXC_SAI3_TX_BCLK 0xd6 MX8MM_IOMUXC_SAI3_TXD_SAI3_TX_DATA0 0xd6 MX8MM_IOMUXC_SAI3_RXD_SAI3_RX_DATA0 0xd6 >; }; }; }; }; fragment@1 { target = <&sai3>; __overlay__ { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_sai3>; assigned-clocks = <&clk IMX8MM_CLK_SAI3>; assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>; assigned-clock-rates = <24576000>; status = "okay"; }; }; fragment@2 { target-path = "/"; __overlay__ { sound-i2s { compatible = "simple-audio-card"; simple-audio-card,name = "i2s-audio"; simple-audio-card,format = "left_j"; simple-audio-card,bitclock-master = <&dailink0_master>; simple-audio-card,frame-master = <&dailink0_master>; simple-audio-card,widgets = "Microphone", "Microphone Jack", "Headphone", "Headphone Jack", "Speaker", "External Speaker"; simple-audio-card,routing = "MIC_IN", "Microphone Jack", "Headphone Jack", "HP_OUT", "External Speaker", "LINE_OUT"; dailink0_master: simple-audio-card,cpu { sound-dai = <&sai3>; dai-tdm-slot-num = <2>; dai-tdm-slot-width = <32>; }; simple-audio-card,codec { sound-dai = <&codecdummy1>; clocks = <&clk IMX8MM_CLK_SAI3_ROOT>; }; }; }; }; fragment@3 { target-path = "/"; __overlay__ { codecdummy1: codec1 { #sound-dai-cells = <0>; compatible = "linux,snd-soc-dummy"; status = "okay"; }; }; }; };

Re: iMX8MM SAI I2S with dummy codec

igorpadykov — Tue, 30 Mar 2021 00:57:57 GMT

also may be useful:

https://community.nxp.com/t5/i-MX-Processors/SAI-on-i-MX8M-Mini/m-p/959805

Best regards
igor

Re: iMX8MM SAI I2S with dummy codec

maxipenna — Tue, 30 Mar 2021 09:45:25 GMT

Hello @igorpadykov, your link contains another example that uses a real codec on i2c. So it's out of topic since we don't have a codec on i2c bus.

Re: iMX8MM SAI I2S with dummy codec

igorpadykov — Tue, 11 May 2021 23:16:52 GMT

Hi maxipenna

in general one can find many simple-audio-card examples, one more below

https://bootlin.com/blog/eight-channels-audio-on-i-mx7-with-pcm3168/

Regarding your specific case, unfortunately nxp does not "officially" support solution

(verified set of software configurations described in official documents:

i.MX Linux Release Notes , i.MX Linux Reference Manual ) without real codec, sorry.

For that reason may be recommended to proceed for further help using

https://contact.nxp.com/new-prof-svcs-sw-tech

Best regards
igor

Re: iMX8MM SAI I2S with dummy codec

amalle — Fri, 23 Apr 2021 09:08:59 GMT

Hi @maxipenna ,

I seams to have end up in the same rabbit hole as you.

An I2S microphone on an IMX8MM without the need of a codec. The dummy codec looks like the obvious solution here...

Did you found a solution ?

Regards

Re: iMX8MM SAI I2S with dummy codec

maxipenna — Tue, 11 May 2021 17:16:10 GMT

@igorpadykov it seems what you said was not true. Don't know the meaning of "nxp does not "officially" support solution without real codec" either. I was able to achieve required functionality by using bt-sco driver instead of snd-soc-dummy.

__overlay__ { codecdummy1: codec1 { #sound-dai-cells = <0>; - compatible = "linux,snd-soc-dummy"; + compatible = "linux,bt-sco"; status = "okay"; }; };

and by adding the corresponding module CONFIG_SND_SOC_BT_SCO=m to my kernel config.

Cheers,

Re: iMX8MM SAI I2S with dummy codec

maxipenna — Tue, 11 May 2021 17:19:42 GMT

Hello, I've found the solution by looking around for other stuff like always

https://community.nxp.com/t5/i-MX-Processors/iMX8MM-SAI-I2S-with-dummy-codec/m-p/1275118/highlight/true#M173883