DESK-MX9-L/Peripherals/Audio
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| 2025/03/18 | DESK-MX9-L 5.2.0 release | ||
Contents
Peripheral Audio[edit | edit source]
Access to the audio interface is provided by ALSA (Advanced Linux Sound Architecture), which consists in a kernel driver and a users space library for application developers. A set of standard tools (alsa-utils) can be used for simple management of the audio codec.
Device tree configuration[edit | edit source]
Here below an example of device tree configuration used on standard DAVE's kit for AURA:
From imx93-aura-sbcx.dtsi it is possible to find the codec interface configuration:
/ {
...
sound {
compatible = "simple-audio-card";
simple-audio-card,format = "i2s";
simple-audio-card,name = "SBCX_TLV320";
simple-audio-card,bitclock-master = <&cpu_dai>;
simple-audio-card,frame-master = <&cpu_dai>;
simple-audio-card,widgets = "Headphone", "Headphone Jack",
"Line", "Line In",
"Microphone", "Mic Jack";
simple-audio-card,routing = "Speaker", "SPK",
"Headphone Jack", "HPL",
"Headphone Jack", "HPR",
"MIC1LP", "Line In",
"MIC1LM", "Line In",
"MIC1RP", "Mic Jack",
"Mic Jack", "MICBIAS";
simple-audio-card,mclk-fs = <256>;
cpu_dai: simple-audio-card,cpu {
sound-dai = <&sai3>;
};
codec_dai: simple-audio-card,codec {
sound-dai = <&codec>;
system-clock-frequency = <12288000>;
};
};
...
};
...
&sai3 {
#sound-dai-cells = <0>;
assigned-clock-rates = <24576000>;
status = "okay";
};
...
&lpi2c1 {
status = "okay";
codec: tlv320aic31xx@18 {
#sound-dai-cells = <0>;
compatible = "ti,tlv320aic3100";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_codec_en>;
reg = <0x18>;
clocks = <&clk IMX93_CLK_SAI3_GATE>;
clock-names = "mclk1";
reset-gpios = <&gpio2 21 GPIO_ACTIVE_LOW>;
HPVDD-supply = <&carrier_reg_3v3>;
SPRVDD-supply = <&carrier_reg_5v0>;
SPLVDD-supply = <&carrier_reg_5v0>;
AVDD-supply = <&carrier_reg_3v3>;
IOVDD-supply = <&carrier_reg_3v3>;
DVDD-supply = <&carrier_reg_1v8>;
status = "okay";
};
};
...
...
&iomuxc {
...
pinctrl_codec_en: codecen {
fsl,pins = <
MX93_PAD_GPIO_IO21__GPIO2_IO21 0x31e
>;
};
...
};
Accessing the peripheral[edit | edit source]
Linux messages at boot time[edit | edit source]
... [ 2.155123] ALSA device list: [ 2.162823] #0: SBCX_TLV320 ...
To list the audio sound cards just use the aplay utility:
root@desk-mx93-rev1:~# aplay -l **** List of PLAYBACK Hardware Devices **** card 0: SBCXTLV320 [SBCX_TLV320], device 0: 42660000.sai-tlv320aic31xx-hifi tlv320aic31xx-hifi-0 [42660000.sai-tlv320aic31xx-hifi tlv320aic31xx-hifi-0] Subdevices: 1/1 Subdevice #0: subdevice #0
Usage alsa-utils[edit | edit source]
In order to unmute the speaker the amixer utility can be used.
root@desk-mx93-rev1:~# amixer sset "Speaker" "on" Simple mixer control 'Speaker',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] root@desk-mx93-rev1:~# amixer sset "Speaker Analog" "108" Simple mixer control 'Speaker Analog',0 Capabilities: pvolume pvolume-joined Playback channels: Mono Limits: Playback 0 - 127 Mono: Playback 108 [85%] [-9.50dB] root@desk-mx93-rev1:~# amixer sset "Speaker Driver" "on 2" Simple mixer control 'Speaker Driver',0 Capabilities: pvolume pvolume-joined pswitch pswitch-joined Playback channels: Mono Limits: Playback 0 - 3 Mono: Playback 0 [0%] [6.00dB] [on] root@desk-mx93-rev1:~# amixer sset "DAC" "155" Simple mixer control 'DAC',0 Capabilities: pvolume Playback channels: Front Left - Front Right Limits: Playback 0 - 175 Mono: Front Left: Playback 155 [89%] [14.00dB] Front Right: Playback 155 [89%] [14.00dB] root@desk-mx93-rev1:~# amixer sset "Output Left From Left DAC" "on" Simple mixer control 'Output Left From Left DAC',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on]
To perform a sound, execute the command:
root@desk-mx93-rev1:~# speaker-test -c 1 -t wav speaker-test 1.2.8 Playback device is default Stream parameters are 48000Hz, S16_LE, 1 channels WAV file(s) Rate set to 48000Hz (requested 48000Hz) Buffer size range from 3840 to 5760 Period size range from 1920 to 1920 Using max buffer size 5760 Periods = 4 was set period_size = 1920 was set buffer_size = 5760 0 - Front Left Time per period = 1.395966 0 - Front Left
Additional information[edit | edit source]
Information about alsa-utils can be found on ALSA project wiki pages
