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

[Jordan Crouse]

On 11/07/06 09:44 -0600, Tom Sylla wrote:
> 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.

Thanks - Jim clarified this to me earlier.  He meant that the GPIO pins on
the EC will work in a similar way to the GPIO pins on the 5536, so the 
existing GPIO driver is a good example.

Jordan

-- 
Jordan Crouse
Senior Linux Engineer
Advanced Micro Devices, Inc.
<www.amd.com/embeddedprocessors>