RFC: what do we do with system controllers?

[Russell King - ARM Linux]

On Wed, Feb 29, 2012 at 10:59:23AM +0100, Linus Walleij wrote:
> On Tue, Feb 28, 2012 at 9:38 AM, Russell King - ARM Linux
> <linux at arm.linux.org.uk> wrote:
> > On Tue, Feb 28, 2012 at 06:48:12AM +0100, Linus Walleij wrote:
> >> Mainly addressed to Greg but anyone is welcome to join the
> >> discussion...
> >>
> >> Several ARM platforms have system controllers. In this I
> >> include all custom terminology such as:
> >>
> >> - System Control
> >> - Chip Controller
> >> - Core Module control registers
> >> - Power Reset Control Management Units
> >> - Multimedia Communications Port
> >
> > Why do you include this?  If you include this, you should include things
> > like SSP/SPI ports, I2C and other such buses.
> 
> Mainly because it has these specific MCP controller oddity
> functions:
> 
> mcp_set_telecom_divisor()
> mcp_set_audio_divisor()
> 
> i.e. it has some "strangeness" of system controller type
> (telecom? que?) But it's quite little and no big deal, drop
> it off the list.

MCP = Multimedia Communication Port.  It is designed to work with the
UCB1200 and UCB1300 codec devices, which have two parts to them: a
telecom / pots interface and an audio interface.

The host side needs to be programmed with the appropriate sample rate -
it's the host side which controls the sample rate not the codec.