[alsa-devel] [PATCH 0/3] ASoC: Enable a new IC master mode: bcm2835<=>IC<=>cs42xx8

[Emmanuel Fusté]

Le 26/02/2017 à 22:44, Matt Flax a écrit :
>
>
> On 27/02/17 07:41, Emmanuel Fusté wrote:
>>
>>
>> I'm a complete newbie to ASoC  but I take part to this tread to learn 
>> as I hate to see how badly all diy and amateur audio hw are 
>> integrated with Alsa/ASoC/Linux and so never go upstream. On a 
>> professional/commercial dev, you would never take this ... convoluted 
>> I2S multi channel path.
>>
>
> Hey Emmanuel,
>
> We now know that we can retrofit legacy I2S silicon for multichannel, 
> in a very direct manner.
>
> If you were a chip manufacturer and you could potentially increase 
> your market take up by hundreds of millions of new potential low power 
> devices, wouldn't you manufacture ALL new chips with these minor 
> modifications ?
>
> Matt
Hi,

No, because this is a hack. There is established an more importantly  
interoperable bus standards to do multichannel digital audio : TDM/DSP 
A/DSP B
As today standards, even ultra low power and low powerfull IC are able 
to do standard multichannel serial audio. Atmel AT & ARM cortex  M µC, 
STMicro STM32 family etc ...
I2S signaling is only part of the equation, fifo, DMA handling, etc... 
of the multichannel part could be important depending of the implementation.
And the FPGA glue logic is way more costly than choosing a SOC / µC with 
a properly designed multichannel serial audio IP.
The real question is why this SOC so poorly endowed with bad device IP 
is so popular... but this is another story...

Don't get me wrong. I'm nevertheless a real supporter of this "hack". 
But it should be done the "right" way.

Emmanuel.