Date: Tue, 17 Oct 1995 13:32:00 -0700
From: vicky@atlas.West.Sun.COM (Vicki Abe)
Subject: Item #294: Dev Ext: Create CS423x Device Support Extension

P1275 Open Firmware Working Group Proposal -- Proposal #294
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Title:		CS423x Device Support Extension

Author:		Vicki.Abe@West.Sun.COM

Date:		October 13, 1995

Ed/Tech:	Technical

Synopsis:	CS423x device-specific extension needed for chip-specific
		features.

Doc & Version:	Device Support Extensions to IEEE1275-1994 Draft 0.3 08/17/95

Problem:	The CS423x family of audio devices provides two general
		purpose external control lines that are peculiar to this
		chip, and so cannot be included among generic properties
		for sound devices.

Proposal:	Add a device-specific extension to describe properties
		needed for CS423x auto-configuration.

		Implement the following as a device-specific extension for
		the Crystal Semiconductor CS423x Sound Device.
======================================================================
CS423x Device Support Extension to:

IEEE 1275-1994
Standard for Boot (Initialization, Configuration) Firmware

Revision 0.0

13 October 1995
Prepared by Vicki Abe, SunSoft Inc.


Overview

The CS423x implements two general-purpose external control lines.
Proper setting of these lines may be critical to device operation.
The following properties describe how these lines are used in the
particular implementation, allowing implementation-dependent support
for the device.

Additional Device-specific Properties

The following standard properties, as defined in Open Firmware, shall be
implemented:

"XCTL0"

	Standard property, encoded as with encode-string, that describes
	the function that occurs when external control line 0 
	(indirect register 10, bit 6) is set to 1.  Valid values for
	this property shall be one of "internal_speaker_enable",
	"internal_speaker_mute", "headphone_mute", "headphone_enable",
	"lineout_mute", "lineout_enable", "interrupt_enable",
	"interrupt_disable", "DMA_enable", "DMA_disable", or "not_connected".

"XCTL1"

	Standard property, encoded as with encode-string, that describes
	the function that occurs when external control line 1
	(indirect register 10, bit 7) is set to 1.  Valid values for
	this property are as for "XCTL0".

Rationale

The list of valid values for these proposed properties reflect the diverse
wiring implementations seen on various platforms.  We recognize that this
may not be a definitive list, but contains all currently known functionality.

References

[1] IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration)
Firmware, Core Practices and Requirements

[2] Device Support Extensions to: IEEE Std 1275-1994 Standard for Boot
(Initialization, Configuration) Firmware

[3] Crystal Semiconductor CS4231A Product Information Document, DS139PP1

[ P1275 Item #294 -- Received: Tue Oct 17 13:29:18 PDT 1995 ]