[OLPC-devel] Re: ALSA interface for the analog input

[Tom Sylla]

Jim Gettys wrote:

>> *a- tell the EC to turn on MIC_AC (ie: bypass C35 and R25) [ OLPC specific ]

>> Details on *a:
>> Based on the port IO sequence that Ray sent, I guess talking to the EC
>> will be through cs5536 GPIO (LPC). There's a cs5536 gpio driver that
>> shows up as a character device. The userspace app could use that
>> interface to talk to the EC.
> 
> Ah, I didn't understand how that worked.  Thanks.  I haven't gone
> through the 5536 manual in that level of detail.

Just to clarify, 5536 GPIOs are not used for any of this. The Quanta 
design uses a GPIO on the EC to control the coupling. I still haven't 
seen an ENE EC spec, but I assume that the system talks to the GPIO 
function of the EC through I/O space. Probably the normal EC location of 
62/66, or maybe there is a way to map the GPIO block in the EC somewhere 
else in I/O space (through 62/66).

The point is that the 5536 GPIO block is not really involved. The 
confusion may have arisen since the pins of the LPC bus on 5536 can 
actually be muxed to be GPIOs if you wish.

Tom