DESK-MX9-L/Peripherals/Audio
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| 2024/01/31 | DESK-MX9-L 5.0.0 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-cb2001.dts 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 = <&codec_dai>;
simple-audio-card,frame-master = <&codec_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,cpu {
sound-dai = <&sai3>;
};
codec_dai: simple-audio-card,codec {
sound-dai = <&codec>;
system-clock-frequency = <24000000>;
};
};
...
};
...
&sai3 {
#sound-dai-cells = <0>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_sai3>;
pinctrl-1 = <&pinctrl_codec_en>;
assigned-clocks = <&clk IMX93_CLK_SAI3>;
assigned-clock-parents = <&clk IMX93_CLK_AUDIO_PLL>;
assigned-clock-rates = <12288000>;
fsl,sai-mclk-direction-output;
status = "okay";
};
...
&lpi2c1 {
...
codec: tlv320aic31xx@18 {
#sound-dai-cells = <0>;
compatible = "ti,tlv320aic3100";
reg = <0x18>;
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>;
};
...
};
...
&iomuxc {
...
pinctrl_sai3: sai3grp {
fsl,pins = <
MX93_PAD_GPIO_IO26__SAI3_TX_SYNC 0x31e
MX93_PAD_GPIO_IO16__SAI3_TX_BCLK 0x31e
MX93_PAD_GPIO_IO17__SAI3_MCLK 0x31e
MX93_PAD_GPIO_IO19__SAI3_TX_DATA00 0x31e
MX93_PAD_GPIO_IO20__SAI3_RX_DATA00 0x31e
>;
};
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:~# 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 root@desk-mx93:~#
Usage alsa-utils[edit | edit source]
In order to unmute the speaker the amixer utility can be used.
root@desk-mx93:~# amixer sset "Speaker" on Simple mixer control 'Speaker',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] root@desk-mx93:~# amixer sset "Speaker Analog" 100 Simple mixer control 'Speaker Analog',0 Capabilities: pvolume pvolume-joined Playback channels: Mono Limits: Playback 0 - 127 Mono: Playback 100 [79%] [-13.50dB] root@desk-mx93:~# 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 2 [67%] [18.00dB] [on] root@desk-mx93:~# amixer sset "DAC" 100 Simple mixer control 'DAC',0 Capabilities: pvolume Playback channels: Front Left - Front Right Limits: Playback 0 - 175 Mono: Front Left: Playback 100 [57%] [-13.50dB] Front Right: Playback 100 [57%] [-13.50dB] root@desk-mx93:~# 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] root@desk-mx93:~#
To perform a sound, execute the command:
root@desk-mx93:~# speaker-test sim speaker-test 1.2.8 Playback device is default Stream parameters are 48000Hz, S16_LE, 1 channels Using 16 octaves of pink noise Rate set to 48000Hz (requested 48000Hz) Buffer size range from 3848 to 5773 Period size range from 1924 to 1925 Using max buffer size 5772 Periods = 4 was set period_size = 1924 was set buffer_size = 5773 0 - Front Left
Additional information[edit | edit source]
Information about alsa-utils can be found on ALSA project wiki pages
