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Table of Contents

ADAU1372 Sound CODEC Linux Driver

Supported Devices

Evaluation Boards

Source Code

Status

Source Mainlined?
git WIP

Files

Function File
driver sound/soc/codecs/adau1372.c
driver sound/soc/codecs/adau1372-i2c.c
driver sound/soc/codecs/adau1372-spi.c
include sound/soc/codecs/adau1372.h

Example device initialization

For compile time configuration, it’s common Linux practice to keep board- and application-specific configuration out of the main driver file, instead putting it into the board support file.

For devices on custom boards, as typical of embedded and SoC-(system-on-chip) based hardware, Linux uses platform_data to point to board-specific structures describing devices and how they are connected to the SoC. This can include available ports, chip variants, preferred modes, default initialization, additional pin roles, and so on. This shrinks the board-support packages (BSPs) and minimizes board and application specific #ifdefs in drivers.

21 Oct 2010 16:10

I2C

Declaring I2C devices

Unlike PCI or USB devices, I2C devices are not enumerated at the hardware level. Instead, the software must know which devices are connected on each I2C bus segment, and what address these devices are using. For this reason, the kernel code must instantiate I2C devices explicitly. There are different ways to achieve this, depending on the context and requirements. However the most common method is to declare the I2C devices by bus number.

This method is appropriate when the I2C bus is a system bus, as in many embedded systems, wherein each I2C bus has a number which is known in advance. It is thus possible to pre-declare the I2C devices that inhabit this bus. This is done with an array of struct i2c_board_info, which is registered by calling i2c_register_board_info().

So, to enable such a driver one need only edit the board support file by adding an appropriate entry to i2c_board_info.

For more information see: Documentation/i2c/instantiating-devices.rst

21 Oct 2010 16:10

The I2C device id depends on the ADDR0 and ADDR1 pin settings and needs to be set according to your board setup.

ADDR1 ADDR0 I2C device id
0 0 0x3c
0 1 0x3d
1 0 0x3e
1 1 0x3f

In this example we assume ADDR0=0 and ADDR1=0. 

static struct i2c_board_info __initdata bfin_i2c_board_info[] = {
 
	[--snip--]
	{
		I2C_BOARD_INFO("adau1372", 0x3c),
	},
	[--snip--]
}
static int __init stamp_init(void)
{
	[--snip--]
	i2c_register_board_info(0, bfin_i2c_board_info,
				ARRAY_SIZE(bfin_i2c_board_info));
	[--snip--]
 
	return 0;
}
arch_initcall(board_init);

SPI

Declaring SPI slave devices

Unlike PCI or USB devices, SPI devices are not enumerated at the hardware level. Instead, the software must know which devices are connected on each SPI bus segment, and what slave selects these devices are using. For this reason, the kernel code must instantiate SPI devices explicitly. The most common method is to declare the SPI devices by bus number.

This method is appropriate when the SPI bus is a system bus, as in many embedded systems, wherein each SPI bus has a number which is known in advance. It is thus possible to pre-declare the SPI devices that inhabit this bus. This is done with an array of struct spi_board_info, which is registered by calling spi_register_board_info().

For more information see: Documentation/spi/spi-summary.rst

21 Oct 2010 16:10

ASoC DAPM Widgets

The driver registers a set of input, output and supply DAPM widgets which represent the physical input and output signals of the device. For maximum power-saving these are widgets should be used in the machine driver DAPM routing to accurately model the external connections of the device.

Name Description
AIN0 ADC0 Single-ended Analog Input
AIN1 ADC1 Single-ended Analog Input
AIN2 ADC2 Single-ended Analog Input
AIN3 ADC3 Single-ended Analog Input
DMIC0_1 Digital Microphone Input Channel 0 and 1
DMIC2_3 Digital Microphone Input Channel 2 and 3
MICBIAS0 Bias Voltage for Electret Microphone
MICBIAS1 Bias Voltage for Electret Microphone
HPOUTL Left Headphone Output
HPOUTR Right Headphone Output

ALSA Controls

Name Description Configuration
ADC 0 Capture Switch Digital mute control for the first ADC path.
ADC 0 Capture Volume Digital attenuation volume control for the first ADC path.
ADC 0+1 Bias ADC0 and ADC1 bias current setting. Possible values: “Normal operation”, “Enhanced performance”, “Power saving”.
ADC 0+1 High-Pass-Filter High-Pass-Filter configuration for the first and second ADC path. Possible values: “Off”, “1 Hz”, “4 Hz”, “8 Hz”.
ADC 1 Capture Switch Digital mute control for the second ADC path.
ADC 1 Capture Volume Digital attenuation volume control for the second ADC path.
ADC 2 Capture Switch Digital mute control for the third ADC path.
ADC 2 Capture Volume Digital attenuation volume control for the third ADC path.
ADC 2+3 Bias ADC2 and ADC3 bias current setting. Possible values: “Normal operation”, “Enhanced performance”, “Power saving”.
ADC 2+3 High-Pass-Filter High-Pass-Filter configuration for the third and fourth ADC path. Possible values: “Off”, “1 Hz”, “4 Hz”, “8 Hz”.
ADC 3 Capture Switch Digital mute control for the fourth ADC path.
ADC 3 Capture Volume Digital attenuation volume control for the fourth ADC path.
AFE 0+1 Bias Analog Front-End 0 and Analog Front-End 1 bias current setting. Possible values: “Normal operation”, “Extreme power saving”, “Enhanced performance”, “Power saving”.
AFE 2+3 Bias Analog Front-End 2 and Analog Front-End 3 bias current setting. Possible values: “Normal operation”, “Extreme power saving”, “Enhanced performance”, “Power saving”.
DAC 0 Mux Source select for the first DAC. Possible values: “Input ASRC0”, “Input ASRC1”
DAC 0 Playback Switch Digital mute control for the first DAC path.
DAC 0 Playback Volume Digital attenuation volume control for the first DAC path.
DAC 0+1 Bias DAC bias current setting. Possible values: “Normal operation”, “Power saving”, “Superior performance”, “Enhanced performance”
DAC 1 Mux Source select for the second DAC. Possible values: “Input ASRC0”, “Input ASRC1”
DAC 1 Playback Switch Digital mute control for the second DAC path.
DAC 1 Playback Volume Digital attenuation volume control for the second DAC path.
Decimator 0+1 Capture Mux
Decimator 2+3 Capture Mux
Headphone Bias Headphone output bias current setting. Possible values: “Normal operation”, “Extreme power saving”, “Enhanced performance”, “Power saving”.
Input ASRC Playback Mux
Microphone Bias Microphone input bias current setting. Possible values: “Normal operation”, “Extreme power saving”, “Enhanced performance”, “Power saving”.
Output ASRC0 Mux
Output ASRC1 Mux
Output ASRC2 Mux
Output ASRC3 Mux
PGA 0 Boost Capture Volume
PGA 0 Capture Switch
PGA 0 Capture Volume
PGA 1 Boost Capture Volume
PGA 1 Capture Switch
PGA 1 Capture Volume
PGA 2 Boost Capture Volume
PGA 2 Capture Switch
PGA 2 Capture Volume
PGA 3 Boost Capture Volume
PGA 3 Capture Switch
PGA 3 Capture Volume
Serial Output 0 Capture Mux Serial output channel 0 input select. Possible values: “Output ASRC0”, “Output ASRC1”, “Output ASRC2”, “Output ASRC3”, “Serial Input 0”, “Serial Input 1”, “Serial Input 2”, “Serial Input 3”, “Serial Input 4”, “Serial Input 5”, “Serial Input 6”, “Serial Input 7”.
Serial Output 1 Capture Mux Serial output channel 1 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 2 Capture Mux Serial output channel 2 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 3 Capture Mux Serial output channel 3 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 4 Capture Mux Serial output channel 4 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 5 Capture Mux Serial output channel 5 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 6 Capture Mux Serial output channel 6 input select. Possible values: See Serial Output 0 Capture Mux
Serial Output 7 Capture Mux Serial output channel 7 input select. Possible values: See Serial Output 0 Capture Mux

DAI configuration

The codec driver registers one DAI: adau1372

This DAI has a capture and a playback interface which share the clocking and are synchronous to each other. Which means they have to run in the same configuration.

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 yes Left Justified mode
SND_SOC_DAIFMT_DSP_A yes data MSB after FRM LRC
SND_SOC_DAIFMT_DSP_B yes data MSB during FRM LRC
SND_SOC_DAIFMT_AC97 no AC97 mode
SND_SOC_DAIFMT_PDM no Pulse density modulation
SND_SOC_DAIFMT_NB_NF yes Normal bit- and frameclock
SND_SOC_DAIFMT_NB_IF yes Normal bitclock, inverted frameclock
SND_SOC_DAIFMT_IB_NF yes Inverted frameclock, normal bitclock
SND_SOC_DAIFMT_IB_IF yes Inverted bit- and frameclock
SND_SOC_DAIFMT_CBM_CFM yes 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

DAI sysclk

Example DAI configuration

TDM configuration

The ADAU1372 has TDM support.

  • The number of slots can be either 2, 4 or 8.
  • The slot width can be 16 or 24.
  • The slot mask can select any combination of channels on both TX and RX

Example TDM configuration: 

	ret = snd_soc_dai_set_tdm_slot(codec_dai, 0x3, 0x3, 8, 24);

More information

Need Help?

31 Jul 2012 17:53 · Lars-Peter Clausen
resources/tools-software/linux-drivers/sound/adau1372.1465469843.txt.gz · Last modified: 09 Jun 2016 12:57 by Lars-Peter Clausen

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