This version (06 Jan 2021 13:39) was approved by Robin Getz.The Previously approved version (19 Jan 2018 10:23) is available.
Table of Contents
HDL AXI I2S Linux Driver
Supported Devices
- HDL AXI I2S
Source Code
Status
Files
| Function | File |
|---|---|
| driver | sound/soc/adi/axi-i2s.c |
Example device initialization
The AXI I2S driver is a platform driver and can currently only be instantiated via device tree.
Required devicetree properties:
- compatible : Must be “adi,axi-i2s-1.00.a”
- reg : Must contain I2S registers location and length
- clocks : Clock specifier providing a handle to the controllers clocks. The controller expects two clocks, the clock used for the AXI interface and the clock used for the sample rate base frequency.
- clock-names : “axi” for the clock to the AXI interface, “i2s” for the sample rate base clock.
- dma : Specifiers for the DMA channels that are used by the core.
- dma-names : “tx” for the transmit channel, “rx” for the receive channel.
Example:
axi_i2s_0: axi-i2s@77600000 {
compatible = "adi,axi-i2s-1.00.a";
reg = <0x77600000 0x1000>;
clocks = <&fpga_clock &audio_clock>;
clock-names = "axi", "ref";
dmas = <&ps7_dma 0 &ps7_dma 1>;
dma-names = "tx", "rx";
};
DAI configuration
The driver will register one CPU-DAI named after the device itself.
Supported DAI formats
| Name | Supported by driver | Description |
|---|---|---|
| SND_SOC_DAIFMT_I2S | yes | I2S mode |
| SND_SOC_DAIFMT_RIGHT_J | no | Right Justified mode |
| SND_SOC_DAIFMT_LEFT_J | no | Left Justified mode |
| SND_SOC_DAIFMT_DSP_A | no | data MSB after FRM LRC |
| SND_SOC_DAIFMT_DSP_B | no | data MSB during FRM LRC |
| SND_SOC_DAIFMT_AC97 | no | AC97 mode |
| SND_SOC_DAIFMT_PDM | no | Pulse density modulation |
| SND_SOC_DAIFMT_SPDIF | no | SPDIF mode |
| SND_SOC_DAIFMT_NB_NF | yes | Normal bit- and frameclock |
| SND_SOC_DAIFMT_NB_IF | no | Normal bitclock, inverted frameclock |
| SND_SOC_DAIFMT_IB_NF | no | Inverted frameclock, normal bitclock |
| SND_SOC_DAIFMT_IB_IF | no | Inverted bit- and frameclock |
| SND_SOC_DAIFMT_CBM_CFM | no | Codec bit- and frameclock master |
| SND_SOC_DAIFMT_CBS_CFM | no | Codec bitclock slave, frameclock master |
| SND_SOC_DAIFMT_CBM_CFS | no | Codec bitclock master, frameclock slave |
| SND_SOC_DAIFMT_CBS_CFS | yes | Codec bit- and frameclock slave |
Example DAI configuration
static struct snd_soc_dai_link zed_adau1761_dai_link = { .name = "adau1761", .stream_name = "adau1761", .codec_dai_name = "adau-hifi", .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBS_CFS, .ops = &zed_adau1761_ops, }; static struct snd_soc_card zed_adau1761_card = { .name = "ZED ADAU161", .owner = THIS_MODULE, .dai_link = &zed_adau1761_dai_link, .num_links = 1, .dapm_widgets = zed_adau1761_widgets, .num_dapm_widgets = ARRAY_SIZE(zed_adau1761_widgets), .dapm_routes = zed_adau1761_routes, .num_dapm_routes = ARRAY_SIZE(zed_adau1761_routes), .fully_routed = true, };
I2S + ADAU1761 ZED board driver
The HDL I2S SPDIF driver is currently used in conjunction with the ADAU1761 audio codec on the ZED board. For this platform there exist a ASoC board driver which provides the necessary information on how both device are interconnected, so that a ALSA sound card can be instantiated.
Source
Status
| Source | Mainlined? |
|---|---|
| git | In progress |
Files
| Function | File |
|---|---|
| driver | sound/soc/adi/zed_adau1761.c |
Kernel configuration
Enable ALSA SoC evaluation board driver:
Device Drivers ---> <*> Sound card support ---> <*> Advanced Linux Sound Architecture ---> <*> ALSA for SoC audio support ---> <*> Audio support for Analog Devices reference designs <*> ZED board sound support
Example device initialization
The ZED board ADAU1761 sound board driver is a platform driver and can currently only be instantiated via device tree.
Required devicetree properties:
- compatible: Should always be “adv7511-hdmi-snd”
- audio-codec: Phandle to the ADAU1761 device devicetree entry
- cpu-dai: Phandle to the I2S device devicetree entry
Example:
axi_iic_0: i2c@41600000 {
compatible = "xlnx,axi-iic-1.01.b", "xlnx,xps-iic-2.00.a";
interrupt-parent = <&gic>;
interrupts = <0 57 0x4>;
reg = <0x41600000 0x10000>;
#size-cells = <0>;
#address-cells = <1>;
adau1761: adau1761@3b {
compatible = "adi,adau1761";
reg = <0x3b>;
};
};
axi_i2s: axi-i2s@0x77600000 {
compatible = "adi,axi-i2s-1.00.a";
reg = <0x77600000 0x1000>;
clocks = <&fpga_clock &audio_clock>;
clock-names = "axi", "ref";
dmas = <&ps7_dma 0 &ps7_dma 1>;
dma-names = "tx", "rx";
};
zed_adau1761_snd: zed_adau1761_snd {
compatible = "zed-adau1761-snd";
audio-codec = <&adau1761>;
cpu-dai = <&axi_i2s>;
};
Driver testing
Make sure the sound card is properly instantiated.
This specifies any shell prompt running on the target
root:/> aplay -l card 0: ...
To test audio playback you can use the speaker test utility, which allows to playback several different test patterns. For a extensive description on the speaker-test utility and the different options it supports please refer to the speaker-test man page.
This specifies any shell prompt running on the target
root:/> speakertest -c 2 speaker-test 1.0.24.2 Playback device is default Stream parameters are 48000Hz, S32_LE, 2 channels Using 16 octaves of pink noise Rate set to 48000Hz (requested 48000Hz) Buffer size range from 512 to 2097152 Period size range from 256 to 262143 Requested buffer time 20000 us Periods = 4 was set period_size = 320 was set buffer_size = 960 0 - Front Left 1 - Front Right ....
To test audio record you can use the arecord utility. arecord will record the incoming audio signal and write it to a wav file.
This specifies any shell prompt running on the target
root:/> arecord -f S32 -r 48000 -c 2 > test.wav ...
To playback a wav file you can use the aplay utility. You can also create a audio loop-back by sending the output of arecord to aplay. This will send the incoming audio stream back via the outgoing audio stream.
This specifies any shell prompt running on the target
root:/> arecord -f S32 -r 48000 -c 2 | aplay ...
For more information on the the aplay and arecord utilities please refer to the aplay and arecord man page.
More information
resources/tools-software/linux-drivers/sound/hdl-axi-i2s.txt · Last modified: 06 Jan 2021 13:39 by Robin Getz