[alsa-devel] I2S driver for implants

[Matt Flax]

On 23/07/14 18:23, Vasily Khoruzhick wrote:
> On Wed, Jul 23, 2014 at 11:10 AM, Matt Flax <flatmax at flatmax.org> wrote:
>> Hi there,
> Hi Matt,
>
> I'd suggest you include alsa-devel ML next time (added it to CC)
>
>> I saw your driver sound/soc/samsung
>>
>> I am wanting to look into an I2S driver for the Exynos 5250 for eye
>> implants.
> Driver for I2S in Exynos 5 is already included in mainline kernel.
>
>> The implants use a serial bus and I am wanting to specify an I2S connection
>> to them.
>>
>> In order to do that I would need to write an I2S driver to talk to them.
>> Their bit rates are either 300 kbps or 600 kbps.
>> They only need I2S and not I2C ... there are not controls, simply serial
>> data in and out.
> Are you sure that your implants can talk over I2S?

Yes, we do/will have custom hardware to reconstruct the required signals 
from the I2S lines.
>> I am wondering if I can do something simple ... I notice that your driver
>> doesn't require too much code ...
>> Do you think it is possible for me to take a similar approach in writing my
>> implant driver ?
> Don't know, you didn't share much details on your hardware.

The hardware requires one I2S output line and one I2S input line + the 
clock line.

You say "Driver for I2S in Exynos 5 is already included in mainline 
kernel." ... do you mean that all I need is a device tree file to enable 
it ? If so, then can you please link me to an example device tree ... my 
assumption is that this I2S device will show up in alsa once the device 
tree is setup ?

>> Can you give me advice - how to start ?
> Start with reading specs and try to understand how your implants work,
> then look at existing code and try to adapt it for your usage.
> Then clean it up and prepare for submitting into mainline.

>> thanks
>> Matt
> Regards,
> Vasily