This version (19 Jan 2018 09:22) was approved by Alexandru Ardelean.The Previously approved version (08 Jun 2016 18:15) is available.
Table of Contents
HDL AXI SPIDF Linux Driver
Supported Devices
- HDL AXI SPDIF
Source Code
Status
Files
| Function | File |
|---|---|
| driver | sound/soc/adi/axi-spdif.c |
Example device initialization
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The AXI SPDIF driver is a platform driver and can currently only be instantiated via device tree.
Required devicetree properties:
- compatible: Should always be “adi,axi-spdif-tx-1.00.a”
- reg: Base address and register area size
- clock-frequency: Clock frequency applied at the spdif_data_clk pin in HZ
Example:
axi_spdif_tx_0: axi-spdif-tx@75c00000 {
compatible = "adi,axi-spdif-tx-1.00.a";
reg = <0x75c00000 0x1000>;
clock-frequency = <12288000>;
};
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 | no | 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 | yes | 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 hdmi_dai_link = { .name = "HDMI", .stream_name = "HDMI", .cpu_dai_name = "75c00000.axi-spdif-tx", .platform_name = "xilinx_pcm_audio.2", .codec_name = "adv7511.0-0039", .codec_dai_name = "adv7511", .dai_fmt = SND_SOC_DAIFMT_SPDIF | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBS_CFS, }; static struct snd_soc_card hdmi_card = { .name = "HDMI monitor", .owner = THIS_MODULE, .dai_link = &hdmi_dai_link, .num_links = 1, };
ADV7511 HDMI + SPDIF board driver
The HDL AXI SPDIF driver is currently used in conjunction with the ADV7511 HDMI transmitter on various FPGA platforms. For these platforms 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? |
|---|---|
| In progress | In progress |
Files
| Function | File |
|---|---|
| driver | sound/soc/adi/adv7511_hdmi.c |
Kernel configuration
Enable ALSA SoC evaluation board driver:
Device Drivers ---> <*> Sound card support ---> <*> Advanced Linux Sound Architecture ---> <*> ALSA for SoC audio support ---> <*> SoC Audio for Xilinx based boards <*> ADV7511 HDMI transmitter sound support
Example device initialization
The ADV7511 HDMI 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”
- cpu-dai: Phandle to the SPDIF device devicetree entry
- pcm: Phandle to the PCM device devicetree entry
Example:
axi_dma_0: axidma@40400000 {
#address-cells = <1>;
#size-cells = <1>;
#dma-cells = <1>;
compatible = "xlnx,axi-dma";
reg = <0x40400000 0x1000>;
xlnx,sg-include-stscntrl-strm = <0x0>;
dma-channel@40400000 {
compatible = "xlnx,axi-dma-mm2s-channel";
interrupts = <0 58 0x4>;
xlnx,datawidth = <0x20>;
xlnx,include-dre = <0x0>;
};
};
xilinx_pcm_audio: xilinx_pcm_audio {
compatible = "xilinx-pcm-audio";
#size-cells = <0>;
#address-cells = <1>;
playback: stream@0 {
reg = <0>;
dma-request = <&axi_dma_0 0>;
};
};
axi_spdif_tx_0: axi-spdif-tx@0x75c00000 {
compatible = "adi,axi-spdif-tx-1.00.a";
reg = <0x75c00000 0x1000>;
clock-frequency = <12288000>;
};
adv7511_hdmi_snd: adv7511_hdmi_snd {
compatible = "adv7511-hdmi-snd";
cpu-dai = <&axi_spdif_tx_0>;
pcm = <&xilinx_pcm_audio>;
};
Driver testing
Make sure the sound card is properly instantiated.
This specifies any shell prompt running on the target
root:/> aplay -l card 0: monitor [HDMI monitor], device 0: HDMI adv7511-0 [] Subdevices: 1/1 Subdevice #0: subdevice #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:/> speaker-test -c 2 speaker-test 1.0.24.2 Playback device is default Stream parameters are 48000Hz, S16_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 S16 -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 S16 -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-spidf.txt · Last modified: 19 Jan 2018 09:22 by Alexandru Ardelean