How to use soc API without codec driver

How to use soc API without codec driver

[Marc Garnier]

Hi,

I need to receive and transmit PCM data through SSC port of a sam9261 to 
a device which doesn't have any kind of I/O controls (neither i2c nor 
spi). So, I wonder how to deal with the codec driver side.
Someone could explain me what are the minimum requirements to write a 
Asoc driver of this kind?

Re: How to use soc API without codec driver

[Mark Brown]

On Tue, Dec 08, 2009 at 03:46:53PM +0100, Marc Garnier wrote:

> I need to receive and transmit PCM data through SSC port of a sam9261 to 
> a device which doesn't have any kind of I/O controls (neither i2c nor 
> spi). So, I wonder how to deal with the codec driver side.
> Someone could explain me what are the minimum requirements to write a 
> Asoc driver of this kind?

There's a couple of drivers for such CODECs in the tree already - have a
look at the wm8727 driver for one example.  You need to register at
least a DAI with whatever the capabilities of the hardware are and can
leave all the operations blank.

Re: How to use soc API without codec driver

[Marc Garnier]

You mean I just have to use snd_soc_register_dai()? Things like 
soc_init_card() and snd_soc_new_pcms() are not mandatory?
So, i think code like this one could be ok :

#define Q2686_RATES (SNDRV_PCM_RATE_8000_192000)

#define Q2686_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE |\
    SNDRV_PCM_FMTBIT_S24_LE)

static struct snd_soc_dai_ops q2686_dai_ops = {
};

struct snd_soc_dai q2686_dai = {
    .name = "Q2686",
    .playback = {
        .stream_name = "Playback",
        .channels_min = 2,
        .channels_max = 2,
        .rates = Q2686_RATES,
        .formats = Q2686_FORMATS,
    },
    .capture = {
        .stream_name = "Capture",
        .channels_min = 2,
        .channels_max = 2,
        .rates = Q2686_RATES,
        .formats = Q2686_FORMATS,},
    .ops = &wm8728_dai_ops,
};
EXPORT_SYMBOL_GPL(q2686_dai);

static int __init q2686_modinit(void)
{
    return snd_soc_register_dai(&q2686_dai);
}
module_init(q2686_modinit);

static void __exit q2686_exit(void)
{
    snd_soc_unregister_dai(&q2686_dai);
}
module_exit(q2686_exit);

MODULE_DESCRIPTION("ASoC Q2686 driver");
MODULE_AUTHOR("Marc Garnier");
MODULE_LICENSE("GPL");

Mark Brown wrote:
> On Tue, Dec 08, 2009 at 03:46:53PM +0100, Marc Garnier wrote:
>
>   
>> I need to receive and transmit PCM data through SSC port of a sam9261 to 
>> a device which doesn't have any kind of I/O controls (neither i2c nor 
>> spi). So, I wonder how to deal with the codec driver side.
>> Someone could explain me what are the minimum requirements to write a 
>> Asoc driver of this kind?
>>     
>
> There's a couple of drivers for such CODECs in the tree already - have a
> look at the wm8727 driver for one example.  You need to register at
> least a DAI with whatever the capabilities of the hardware are and can
> leave all the operations blank.
>   

Re: How to use soc API without codec driver

[Mark Brown]

On Wed, Dec 09, 2009 at 07:39:19AM +0100, Marc Garnier wrote:
> You mean I just have to use snd_soc_register_dai()? Things like  
> soc_init_card() and snd_soc_new_pcms() are not mandatory?

init_card() has been removed now, but new_pcms() is still required -
like I say, look at one of the existing drivers like the spdif
transciever driver for examples of drivers which do what you're trying
to do here.

> static int __init q2686_modinit(void)
> {
>    return snd_soc_register_dai(&q2686_dai);
> }
> module_init(q2686_modinit);

This should be done from a platform device, not from module init.

Re: capturing data from the microphone

[Mark Brown]

On Wed, Jan 06, 2010 at 11:44:04AM +0100, Marc Garnier wrote:
> OK, well, I work on a custom device platform based on an Atmel
> at91sam9261. I wrote an alsa driver composed of 2 files

CCing in the list and Sedji, who wrote the driver.  Please also try
avoid top posting - Linux lists generally intersperse replies with the
relevant context from the original message since it makes mails much
more legible.

> But when I want to record a pcm stream I have this error:
> # arecord -v -c 1 -t wav -f S16_LE -r 8000 -d 10 input.wav
> arecord: pcm_read:1629: read error: Input/output error

[With an AT91 in slave mode...]
> and actually no interrupt occur and I
> wonder why...

Can you see clocks on the audio interface?  Have you checked that the
pins on the processor are configured to route the signals to the correct
IP block?

Re: capturing data from the microphone

[Riccardo Magliocchetti]

Marc,

Mark Brown ha scritto:
> On Wed, Jan 06, 2010 at 11:44:04AM +0100, Marc Garnier wrote:
>> OK, well, I work on a custom device platform based on an Atmel
>> at91sam9261. I wrote an alsa driver composed of 2 files
> 
> CCing in the list and Sedji, who wrote the driver.  Please also try
> avoid top posting - Linux lists generally intersperse replies with the
> relevant context from the original message since it makes mails much
> more legible.

The next time please also try to avoid hijacking other people's threads.

thanks,
riccardo