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committed 3c6ee77088a/* * Driver for DBRI sound chip found on Sparcs. * Copyright (C) 2004, 2005 Martin Habets (mhabets@users.sourceforge.net) * * Converted to ring buffered version by Krzysztof Helt (krzysztof.h1@wp.pl) * * Based entirely upon drivers/sbus/audio/dbri.c which is: * Copyright (C) 1997 Rudolf Koenig (rfkoenig@immd4.informatik.uni-erlangen.de) * Copyright (C) 1998, 1999 Brent Baccala (baccala@freesoft.org) * * This is the low level driver for the DBRI & MMCODEC duo used for ISDN & AUDIO * on Sun SPARCStation 10, 20, LX and Voyager models. * * - DBRI: AT&T T5900FX Dual Basic Rates ISDN Interface. It is a 32 channel * data time multiplexer with ISDN support (aka T7259) * Interfaces: SBus,ISDN NT & TE, CHI, 4 bits parallel. * CHI: (spelled ki) Concentration Highway Interface (AT&T or Intel bus ?). * Documentation: * - "STP 4000SBus Dual Basic Rate ISDN (DBRI) Transceiver" from * Sparc Technology Business (courtesy of Sun Support) * - Data sheet of the T7903, a newer but very similar ISA bus equivalent * available from the Lucent (formerly AT&T microelectronics) home * page. * - http://www.freesoft.org/Linux/DBRI/ * - MMCODEC: Crystal Semiconductor CS4215 16 bit Multimedia Audio Codec * Interfaces: CHI, Audio In & Out, 2 bits parallel * Documentation: from the Crystal Semiconductor home page. * * The DBRI is a 32 pipe machine, each pipe can transfer some bits between * memory and a serial device (long pipes, no. 0-15) or between two serial * devices (short pipes, no. 16-31), or simply send a fixed data to a serial * device (short pipes). * A timeslot defines the bit-offset and no. of bits read from a serial device. * The timeslots are linked to 6 circular lists, one for each direction for * each serial device (NT,TE,CHI). A timeslot is associated to 1 or 2 pipes * (the second one is a monitor/tee pipe, valid only for serial input). * * The mmcodec is connected via the CHI bus and needs the data & some * parameters (volume, output selection) time multiplexed in 8 byte * chunks. It also has a control mode, which serves for audio format setting. * * Looking at the CS4215 data sheet it is easy to set up 2 or 4 codecs on * the same CHI bus, so I thought perhaps it is possible to use the on-board * & the speakerbox codec simultaneously, giving 2 (not very independent :-) * audio devices. But the SUN HW group decided against it, at least on my * LX the speakerbox connector has at least 1 pin missing and 1 wrongly * connected. * * I've tried to stick to the following function naming conventions: * snd_* ALSA stuff * cs4215_* CS4215 codec specific stuff * dbri_* DBRI high-level stuff * other DBRI low-level stuff */