DESK-MX6-L/Pheripherals/Audio
| History | |||
|---|---|---|---|
| ID# | Issue Date | Notes | |
| 14/07/2021 | First DESK release | ||
| 03/03/2022 | DESK 3.0.0 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 the AXEL Lite SOM:
From imx6qdl-sbcx-revb-common.dtsi it is possible to find the codec SSI interface configuration:
sound {
compatible = "fsl,imx-audio-tlv320aic31xx";
model = "sbcx-audio-tlv320aic3100";
ssi-controller = <&ssi1>;
audio-codec = <&codec>;
audio-routing =
"Speaker", "SPK",
"Headphone Jack", "HPL",
"Headphone Jack", "HPR",
"MIC1LP", "Line In",
"MIC1LM", "Line In",
"MIC1RP", "Mic Jack",
"Mic Jack", "MICBIAS";
mux-int-port = <1>;
mux-ext-port = <3>;
status = "okay";
};
...
...
&audmux {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_tlv320aic3x_1>;
status = "okay";
};
&ssi1 {
status = "okay";
};
...
...
&iomuxc {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_hog_sbcx &pinctrl_hog_sbcx_one_piece>;
...
...
tlv320aic3x {
pinctrl_tlv320aic3x_1: tlv320aic3x_codecgrp-1{
fsl,pins = <
MX6QDL_PAD_CSI0_DAT5__AUD3_TXD 0x130b0
MX6QDL_PAD_CSI0_DAT6__AUD3_TXFS 0x130b0
MX6QDL_PAD_CSI0_DAT7__AUD3_RXD 0x130b0
MX6QDL_PAD_CSI0_DAT4__AUD3_TXC 0x130b0
MX6QDL_PAD_GPIO_3__XTALOSC_REF_CLK_24M 0x130b0
MX6QDL_PAD_GPIO_4__GPIO1_IO04 0x130b0
>;
};
};
Accessing the peripheral[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.
Linux messages at boot time[edit | edit source]
... ... [ 5.071782] fsl-ssi-dai 2028000.ssi: No cache defaults, reading back from HW ... ... [ 5.624473] ALSA device list: [ 5.635031] #0: sbcx-audio-tlv320aic3100
To list the audio sound cards just use the aplay utility:
root@desk-mx6:~# aplay -l **** List of PLAYBACK Hardware Devices **** card 0: sbcxaudiotlv320 [sbcx-audio-tlv320aic3100], device 0: HiFi tlv320aic31xx-hifi-0 [HiFi tlv320aic31xx-hifi-0] Subdevices: 1/1 Subdevice #0: subdevice #0
Usage alsa-utils[edit | edit source]
root@desk-mx6:~# aplay /home/root/rootfs/unit_tests/ASRC/audio8k16S.wav Playing WAVE '/home/root/rootfs/unit_tests/ASRC/audio8k16S.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
In order to unmute the speaker the alsamixer utility can be used.
Additional information[edit | edit source]
Information about alsa-utils can be found on ALSA project wiki pages
