ALSA: ALSA driver for SGI O2 audio board

This patch adds a new ALSA driver for the audio device found inside
most of the SGI O2 workstation. The hardware uses a SGI custom chip,
which feeds a AD codec chip.
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>

include/sound/ad1843.h

+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright 2003 Vivien Chappelier <vivien.chappelier@linux-mips.org>
+ * Copyright 2008 Thomas Bogendoerfer <tsbogend@franken.de>
+ */
+
+#ifndef __SOUND_AD1843_H
+#define __SOUND_AD1843_H
+
+struct snd_ad1843 {
+	void *chip;
+	int (*read)(void *chip, int reg);
+	int (*write)(void *chip, int reg, int val);
+};
+
+#define AD1843_GAIN_RECLEV 0
+#define AD1843_GAIN_LINE   1
+#define AD1843_GAIN_LINE_2 2
+#define AD1843_GAIN_MIC    3
+#define AD1843_GAIN_PCM_0  4
+#define AD1843_GAIN_PCM_1  5
+#define AD1843_GAIN_SIZE   (AD1843_GAIN_PCM_1+1)
+
+int ad1843_get_gain_max(struct snd_ad1843 *ad1843, int id);
+int ad1843_get_gain(struct snd_ad1843 *ad1843, int id);
+int ad1843_set_gain(struct snd_ad1843 *ad1843, int id, int newval);
+int ad1843_get_recsrc(struct snd_ad1843 *ad1843);
+int ad1843_set_recsrc(struct snd_ad1843 *ad1843, int newsrc);
+void ad1843_setup_dac(struct snd_ad1843 *ad1843,
+		      unsigned int id,
+		      unsigned int framerate,
+		      snd_pcm_format_t fmt,
+		      unsigned int channels);
+void ad1843_shutdown_dac(struct snd_ad1843 *ad1843,
+			 unsigned int id);
+void ad1843_setup_adc(struct snd_ad1843 *ad1843,
+		      unsigned int framerate,
+		      snd_pcm_format_t fmt,
+		      unsigned int channels);
+void ad1843_shutdown_adc(struct snd_ad1843 *ad1843);
+int ad1843_init(struct snd_ad1843 *ad1843);
+
+#endif /* __SOUND_AD1843_H */

sound/mips/Kconfig

@@ -9,6 +9,12 @@ menuconfig SND_MIPS
 
 if SND_MIPS
 
+config SND_SGI_O2
+	tristate "SGI O2 Audio"
+	depends on SGI_IP32
+        help
+                Sound support for the SGI O2 Workstation. 
+
 config SND_SGI_HAL2
         tristate "SGI HAL2 Audio"
         depends on SGI_HAS_HAL2

sound/mips/Makefile

@@ -3,8 +3,10 @@
 #
 
 snd-au1x00-objs := au1x00.o
+snd-sgi-o2-objs := sgio2audio.o ad1843.o
 snd-sgi-hal2-objs := hal2.o
 
 # Toplevel Module Dependency
 obj-$(CONFIG_SND_AU1X00) += snd-au1x00.o
+obj-$(CONFIG_SND_SGI_O2) += snd-sgi-o2.o
 obj-$(CONFIG_SND_SGI_HAL2) += snd-sgi-hal2.o

sound/mips/ad1843.c

+/*
+ *   AD1843 low level driver
+ *
+ *   Copyright 2003 Vivien Chappelier <vivien.chappelier@linux-mips.org>
+ *   Copyright 2008 Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+ *
+ *   inspired from vwsnd.c (SGI VW audio driver)
+ *     Copyright 1999 Silicon Graphics, Inc.  All rights reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/ad1843.h>
+
+/*
+ * AD1843 bitfield definitions.  All are named as in the AD1843 data
+ * sheet, with ad1843_ prepended and individual bit numbers removed.
+ *
+ * E.g., bits LSS0 through LSS2 become ad1843_LSS.
+ *
+ * Only the bitfields we need are defined.
+ */
+
+struct ad1843_bitfield {
+	char reg;
+	char lo_bit;
+	char nbits;
+};
+
+static const struct ad1843_bitfield
+	ad1843_PDNO   = {  0, 14,  1 },	/* Converter Power-Down Flag */
+	ad1843_INIT   = {  0, 15,  1 },	/* Clock Initialization Flag */
+	ad1843_RIG    = {  2,  0,  4 },	/* Right ADC Input Gain */
+	ad1843_RMGE   = {  2,  4,  1 },	/* Right ADC Mic Gain Enable */
+	ad1843_RSS    = {  2,  5,  3 },	/* Right ADC Source Select */
+	ad1843_LIG    = {  2,  8,  4 },	/* Left ADC Input Gain */
+	ad1843_LMGE   = {  2, 12,  1 },	/* Left ADC Mic Gain Enable */
+	ad1843_LSS    = {  2, 13,  3 },	/* Left ADC Source Select */
+	ad1843_RD2M   = {  3,  0,  5 },	/* Right DAC 2 Mix Gain/Atten */
+	ad1843_RD2MM  = {  3,  7,  1 },	/* Right DAC 2 Mix Mute */
+	ad1843_LD2M   = {  3,  8,  5 },	/* Left DAC 2 Mix Gain/Atten */
+	ad1843_LD2MM  = {  3, 15,  1 },	/* Left DAC 2 Mix Mute */
+	ad1843_RX1M   = {  4,  0,  5 },	/* Right Aux 1 Mix Gain/Atten */
+	ad1843_RX1MM  = {  4,  7,  1 },	/* Right Aux 1 Mix Mute */
+	ad1843_LX1M   = {  4,  8,  5 },	/* Left Aux 1 Mix Gain/Atten */
+	ad1843_LX1MM  = {  4, 15,  1 },	/* Left Aux 1 Mix Mute */
+	ad1843_RX2M   = {  5,  0,  5 },	/* Right Aux 2 Mix Gain/Atten */
+	ad1843_RX2MM  = {  5,  7,  1 },	/* Right Aux 2 Mix Mute */
+	ad1843_LX2M   = {  5,  8,  5 },	/* Left Aux 2 Mix Gain/Atten */
+	ad1843_LX2MM  = {  5, 15,  1 },	/* Left Aux 2 Mix Mute */
+	ad1843_RMCM   = {  7,  0,  5 },	/* Right Mic Mix Gain/Atten */
+	ad1843_RMCMM  = {  7,  7,  1 },	/* Right Mic Mix Mute */
+	ad1843_LMCM   = {  7,  8,  5 },	/* Left Mic Mix Gain/Atten */
+	ad1843_LMCMM  = {  7, 15,  1 },	/* Left Mic Mix Mute */
+	ad1843_HPOS   = {  8,  4,  1 },	/* Headphone Output Voltage Swing */
+	ad1843_HPOM   = {  8,  5,  1 },	/* Headphone Output Mute */
+	ad1843_MPOM   = {  8,  6,  1 },	/* Mono Output Mute */
+	ad1843_RDA1G  = {  9,  0,  6 },	/* Right DAC1 Analog/Digital Gain */
+	ad1843_RDA1GM = {  9,  7,  1 },	/* Right DAC1 Analog Mute */
+	ad1843_LDA1G  = {  9,  8,  6 },	/* Left DAC1 Analog/Digital Gain */
+	ad1843_LDA1GM = {  9, 15,  1 },	/* Left DAC1 Analog Mute */
+	ad1843_RDA2G  = { 10,  0,  6 },	/* Right DAC2 Analog/Digital Gain */
+	ad1843_RDA2GM = { 10,  7,  1 },	/* Right DAC2 Analog Mute */
+	ad1843_LDA2G  = { 10,  8,  6 },	/* Left DAC2 Analog/Digital Gain */
+	ad1843_LDA2GM = { 10, 15,  1 },	/* Left DAC2 Analog Mute */
+	ad1843_RDA1AM = { 11,  7,  1 },	/* Right DAC1 Digital Mute */
+	ad1843_LDA1AM = { 11, 15,  1 },	/* Left DAC1 Digital Mute */
+	ad1843_RDA2AM = { 12,  7,  1 },	/* Right DAC2 Digital Mute */
+	ad1843_LDA2AM = { 12, 15,  1 },	/* Left DAC2 Digital Mute */
+	ad1843_ADLC   = { 15,  0,  2 },	/* ADC Left Sample Rate Source */
+	ad1843_ADRC   = { 15,  2,  2 },	/* ADC Right Sample Rate Source */
+	ad1843_DA1C   = { 15,  8,  2 },	/* DAC1 Sample Rate Source */
+	ad1843_DA2C   = { 15, 10,  2 },	/* DAC2 Sample Rate Source */
+	ad1843_C1C    = { 17,  0, 16 },	/* Clock 1 Sample Rate Select */
+	ad1843_C2C    = { 20,  0, 16 },	/* Clock 2 Sample Rate Select */
+	ad1843_C3C    = { 23,  0, 16 },	/* Clock 3 Sample Rate Select */
+	ad1843_DAADL  = { 25,  4,  2 },	/* Digital ADC Left Source Select */
+	ad1843_DAADR  = { 25,  6,  2 },	/* Digital ADC Right Source Select */
+	ad1843_DAMIX  = { 25, 14,  1 },	/* DAC Digital Mix Enable */
+	ad1843_DRSFLT = { 25, 15,  1 },	/* Digital Reampler Filter Mode */
+	ad1843_ADLF   = { 26,  0,  2 }, /* ADC Left Channel Data Format */
+	ad1843_ADRF   = { 26,  2,  2 }, /* ADC Right Channel Data Format */
+	ad1843_ADTLK  = { 26,  4,  1 },	/* ADC Transmit Lock Mode Select */
+	ad1843_SCF    = { 26,  7,  1 },	/* SCLK Frequency Select */
+	ad1843_DA1F   = { 26,  8,  2 },	/* DAC1 Data Format Select */
+	ad1843_DA2F   = { 26, 10,  2 },	/* DAC2 Data Format Select */
+	ad1843_DA1SM  = { 26, 14,  1 },	/* DAC1 Stereo/Mono Mode Select */
+	ad1843_DA2SM  = { 26, 15,  1 },	/* DAC2 Stereo/Mono Mode Select */
+	ad1843_ADLEN  = { 27,  0,  1 },	/* ADC Left Channel Enable */
+	ad1843_ADREN  = { 27,  1,  1 },	/* ADC Right Channel Enable */
+	ad1843_AAMEN  = { 27,  4,  1 },	/* Analog to Analog Mix Enable */
+	ad1843_ANAEN  = { 27,  7,  1 },	/* Analog Channel Enable */
+	ad1843_DA1EN  = { 27,  8,  1 },	/* DAC1 Enable */
+	ad1843_DA2EN  = { 27,  9,  1 },	/* DAC2 Enable */
+	ad1843_DDMEN  = { 27, 12,  1 },	/* DAC2 to DAC1 Mix  Enable */
+	ad1843_C1EN   = { 28, 11,  1 },	/* Clock Generator 1 Enable */
+	ad1843_C2EN   = { 28, 12,  1 },	/* Clock Generator 2 Enable */
+	ad1843_C3EN   = { 28, 13,  1 },	/* Clock Generator 3 Enable */
+	ad1843_PDNI   = { 28, 15,  1 };	/* Converter Power Down */
+
+/*
+ * The various registers of the AD1843 use three different formats for
+ * specifying gain.  The ad1843_gain structure parameterizes the
+ * formats.
+ */
+
+struct ad1843_gain {
+	int	negative;		/* nonzero if gain is negative. */
+	const struct ad1843_bitfield *lfield;
+	const struct ad1843_bitfield *rfield;
+	const struct ad1843_bitfield *lmute;
+	const struct ad1843_bitfield *rmute;
+};
+
+static const struct ad1843_gain ad1843_gain_RECLEV = {
+	.negative = 0,
+	.lfield   = &ad1843_LIG,
+	.rfield   = &ad1843_RIG
+};
+static const struct ad1843_gain ad1843_gain_LINE = {
+	.negative = 1,
+	.lfield   = &ad1843_LX1M,
+	.rfield   = &ad1843_RX1M,
+	.lmute    = &ad1843_LX1MM,
+	.rmute    = &ad1843_RX1MM
+};
+static const struct ad1843_gain ad1843_gain_LINE_2 = {
+	.negative = 1,
+	.lfield   = &ad1843_LDA2G,
+	.rfield   = &ad1843_RDA2G,
+	.lmute    = &ad1843_LDA2GM,
+	.rmute    = &ad1843_RDA2GM
+};
+static const struct ad1843_gain ad1843_gain_MIC = {
+	.negative = 1,
+	.lfield   = &ad1843_LMCM,
+	.rfield   = &ad1843_RMCM,
+	.lmute    = &ad1843_LMCMM,
+	.rmute    = &ad1843_RMCMM
+};
+static const struct ad1843_gain ad1843_gain_PCM_0 = {
+	.negative = 1,
+	.lfield   = &ad1843_LDA1G,
+	.rfield   = &ad1843_RDA1G,
+	.lmute    = &ad1843_LDA1GM,
+	.rmute    = &ad1843_RDA1GM
+};
+static const struct ad1843_gain ad1843_gain_PCM_1 = {
+	.negative = 1,
+	.lfield   = &ad1843_LD2M,
+	.rfield   = &ad1843_RD2M,
+	.lmute    = &ad1843_LD2MM,
+	.rmute    = &ad1843_RD2MM
+};
+
+static const struct ad1843_gain *ad1843_gain[AD1843_GAIN_SIZE] =
+{
+	&ad1843_gain_RECLEV,
+	&ad1843_gain_LINE,
+	&ad1843_gain_LINE_2,
+	&ad1843_gain_MIC,
+	&ad1843_gain_PCM_0,
+	&ad1843_gain_PCM_1,
+};
+
+/* read the current value of an AD1843 bitfield. */
+
+static int ad1843_read_bits(struct snd_ad1843 *ad1843,
+			    const struct ad1843_bitfield *field)
+{
+	int w;
+
+	w = ad1843->read(ad1843->chip, field->reg);
+	return w >> field->lo_bit & ((1 << field->nbits) - 1);
+}
+
+/*
+ * write a new value to an AD1843 bitfield and return the old value.
+ */
+
+static int ad1843_write_bits(struct snd_ad1843 *ad1843,
+			     const struct ad1843_bitfield *field,
+			     int newval)
+{
+	int w, mask, oldval, newbits;
+
+	w = ad1843->read(ad1843->chip, field->reg);
+	mask = ((1 << field->nbits) - 1) << field->lo_bit;
+	oldval = (w & mask) >> field->lo_bit;
+	newbits = (newval << field->lo_bit) & mask;
+	w = (w & ~mask) | newbits;
+	ad1843->write(ad1843->chip, field->reg, w);
+
+	return oldval;
+}
+
+/*
+ * ad1843_read_multi reads multiple bitfields from the same AD1843
+ * register.  It uses a single read cycle to do it.  (Reading the
+ * ad1843 requires 256 bit times at 12.288 MHz, or nearly 20
+ * microseconds.)
+ *
+ * Called like this.
+ *
+ *  ad1843_read_multi(ad1843, nfields,
+ *		      &ad1843_FIELD1, &val1,
+ *		      &ad1843_FIELD2, &val2, ...);
+ */
+
+static void ad1843_read_multi(struct snd_ad1843 *ad1843, int argcount, ...)
+{
+	va_list ap;
+	const struct ad1843_bitfield *fp;
+	int w = 0, mask, *value, reg = -1;
+
+	va_start(ap, argcount);
+	while (--argcount >= 0) {
+		fp = va_arg(ap, const struct ad1843_bitfield *);
+		value = va_arg(ap, int *);
+		if (reg == -1) {
+			reg = fp->reg;
+			w = ad1843->read(ad1843->chip, reg);
+		}
+
+		mask = (1 << fp->nbits) - 1;
+		*value = w >> fp->lo_bit & mask;
+	}
+	va_end(ap);
+}
+
+/*
+ * ad1843_write_multi stores multiple bitfields into the same AD1843
+ * register.  It uses one read and one write cycle to do it.
+ *
+ * Called like this.
+ *
+ *  ad1843_write_multi(ad1843, nfields,
+ *		       &ad1843_FIELD1, val1,
+ *		       &ad1843_FIELF2, val2, ...);
+ */
+
+static void ad1843_write_multi(struct snd_ad1843 *ad1843, int argcount, ...)
+{
+	va_list ap;
+	int reg;
+	const struct ad1843_bitfield *fp;
+	int value;
+	int w, m, mask, bits;
+
+	mask = 0;
+	bits = 0;
+	reg = -1;
+
+	va_start(ap, argcount);
+	while (--argcount >= 0) {
+		fp = va_arg(ap, const struct ad1843_bitfield *);
+		value = va_arg(ap, int);
+		if (reg == -1)
+			reg = fp->reg;
+		else
+			BUG_ON(reg != fp->reg);
+		m = ((1 << fp->nbits) - 1) << fp->lo_bit;
+		mask |= m;
+		bits |= (value << fp->lo_bit) & m;
+	}
+	va_end(ap);
+
+	if (~mask & 0xFFFF)
+		w = ad1843->read(ad1843->chip, reg);
+	else
+		w = 0;
+	w = (w & ~mask) | bits;
+	ad1843->write(ad1843->chip, reg, w);
+}
+
+int ad1843_get_gain_max(struct snd_ad1843 *ad1843, int id)
+{
+	const struct ad1843_gain *gp = ad1843_gain[id];
+	int ret;
+
+	ret = (1 << gp->lfield->nbits);
+	if (!gp->lmute)
+		ret -= 1;
+	return ret;
+}
+
+/*
+ * ad1843_get_gain reads the specified register and extracts the gain value
+ * using the supplied gain type.
+ */
+
+int ad1843_get_gain(struct snd_ad1843 *ad1843, int id)
+{
+	int lg, rg, lm, rm;
+	const struct ad1843_gain *gp = ad1843_gain[id];
+	unsigned short mask = (1 << gp->lfield->nbits) - 1;
+
+	ad1843_read_multi(ad1843, 2, gp->lfield, &lg, gp->rfield, &rg);
+	if (gp->negative) {
+		lg = mask - lg;
+		rg = mask - rg;
+	}
+	if (gp->lmute) {
+		ad1843_read_multi(ad1843, 2, gp->lmute, &lm, gp->rmute, &rm);
+		if (lm)
+			lg = 0;
+		if (rm)
+			rg = 0;
+	}
+	return lg << 0 | rg << 8;
+}
+
+/*
+ * Set an audio channel's gain.
+ *
+ * Returns the new gain, which may be lower than the old gain.
+ */
+
+int ad1843_set_gain(struct snd_ad1843 *ad1843, int id, int newval)
+{
+	const struct ad1843_gain *gp = ad1843_gain[id];
+	unsigned short mask = (1 << gp->lfield->nbits) - 1;
+
+	int lg = (newval >> 0) & mask;
+	int rg = (newval >> 8) & mask;
+	int lm = (lg == 0) ? 1 : 0;
+	int rm = (rg == 0) ? 1 : 0;
+
+	if (gp->negative) {
+		lg = mask - lg;
+		rg = mask - rg;
+	}
+	if (gp->lmute)
+		ad1843_write_multi(ad1843, 2, gp->lmute, lm, gp->rmute, rm);
+	ad1843_write_multi(ad1843, 2, gp->lfield, lg, gp->rfield, rg);
+	return ad1843_get_gain(ad1843, id);
+}
+
+/* Returns the current recording source */
+
+int ad1843_get_recsrc(struct snd_ad1843 *ad1843)
+{
+	int val = ad1843_read_bits(ad1843, &ad1843_LSS);
+
+	if (val < 0 || val > 2) {
+		val = 2;
+		ad1843_write_multi(ad1843, 2,
+				   &ad1843_LSS, val, &ad1843_RSS, val);
+	}
+	return val;
+}
+
+/*
+ * Set recording source.
+ *
+ * Returns newsrc on success, -errno on failure.
+ */
+
+int ad1843_set_recsrc(struct snd_ad1843 *ad1843, int newsrc)
+{
+	if (newsrc < 0 || newsrc > 2)
+		return -EINVAL;
+
+	ad1843_write_multi(ad1843, 2, &ad1843_LSS, newsrc, &ad1843_RSS, newsrc);
+	return newsrc;
+}
+
+/* Setup ad1843 for D/A conversion. */
+
+void ad1843_setup_dac(struct snd_ad1843 *ad1843,
+		      unsigned int id,
+		      unsigned int framerate,
+		      snd_pcm_format_t fmt,
+		      unsigned int channels)
+{
+	int ad_fmt = 0, ad_mode = 0;
+
+	switch (fmt) {
+	case SNDRV_PCM_FORMAT_S8:
+		ad_fmt = 0;
+		break;
+	case SNDRV_PCM_FORMAT_U8:
+		ad_fmt = 0;
+		break;
+	case SNDRV_PCM_FORMAT_S16_LE:
+		ad_fmt = 1;
+		break;
+	case SNDRV_PCM_FORMAT_MU_LAW:
+		ad_fmt = 2;
+		break;
+	case SNDRV_PCM_FORMAT_A_LAW:
+		ad_fmt = 3;
+		break;
+	default:
+		break;
+	}
+
+	switch (channels) {
+	case 2:
+		ad_mode = 0;
+		break;
+	case 1:
+		ad_mode = 1;
+		break;
+	default:
+		break;
+	}
+
+	if (id) {
+		ad1843_write_bits(ad1843, &ad1843_C2C, framerate);
+		ad1843_write_multi(ad1843, 2,
+				   &ad1843_DA2SM, ad_mode,
+				   &ad1843_DA2F, ad_fmt);
+	} else {
+		ad1843_write_bits(ad1843, &ad1843_C1C, framerate);
+		ad1843_write_multi(ad1843, 2,
+				   &ad1843_DA1SM, ad_mode,
+				   &ad1843_DA1F, ad_fmt);
+	}
+}
+
+void ad1843_shutdown_dac(struct snd_ad1843 *ad1843, unsigned int id)
+{
+	if (id)
+		ad1843_write_bits(ad1843, &ad1843_DA2F, 1);
+	else
+		ad1843_write_bits(ad1843, &ad1843_DA1F, 1);
+}
+
+void ad1843_setup_adc(struct snd_ad1843 *ad1843,
+		      unsigned int framerate,
+		      snd_pcm_format_t fmt,
+		      unsigned int channels)
+{
+	int da_fmt = 0;
+
+	switch (fmt) {
+	case SNDRV_PCM_FORMAT_S8:	da_fmt = 0; break;
+	case SNDRV_PCM_FORMAT_U8:	da_fmt = 0; break;
+	case SNDRV_PCM_FORMAT_S16_LE:	da_fmt = 1; break;
+	case SNDRV_PCM_FORMAT_MU_LAW:	da_fmt = 2; break;
+	case SNDRV_PCM_FORMAT_A_LAW:	da_fmt = 3; break;
+	default:		break;
+	}
+
+	ad1843_write_bits(ad1843, &ad1843_C3C, framerate);
+	ad1843_write_multi(ad1843, 2,
+			   &ad1843_ADLF, da_fmt, &ad1843_ADRF, da_fmt);
+}
+
+void ad1843_shutdown_adc(struct snd_ad1843 *ad1843)
+{
+	/* nothing to do */
+}
+
+/*
+ * Fully initialize the ad1843.  As described in the AD1843 data
+ * sheet, section "START-UP SEQUENCE".  The numbered comments are
+ * subsection headings from the data sheet.  See the data sheet, pages
+ * 52-54, for more info.
+ *
+ * return 0 on success, -errno on failure.  */
+
+int ad1843_init(struct snd_ad1843 *ad1843)
+{
+	unsigned long later;
+
+	if (ad1843_read_bits(ad1843, &ad1843_INIT) != 0) {
+		printk(KERN_ERR "ad1843: AD1843 won't initialize\n");
+		return -EIO;
+	}
+
+	ad1843_write_bits(ad1843, &ad1843_SCF, 1);
+
+	/* 4. Put the conversion resources into standby. */
+	ad1843_write_bits(ad1843, &ad1843_PDNI, 0);
+	later = jiffies + msecs_to_jiffies(500);
+
+	while (ad1843_read_bits(ad1843, &ad1843_PDNO)) {
+		if (time_after(jiffies, later)) {
+			printk(KERN_ERR
+			       "ad1843: AD1843 won't power up\n");
+			return -EIO;
+		}
+		schedule_timeout_interruptible(5);
+	}
+
+	/* 5. Power up the clock generators and enable clock output pins. */
+	ad1843_write_multi(ad1843, 3,
+			   &ad1843_C1EN, 1,
+			   &ad1843_C2EN, 1,
+			   &ad1843_C3EN, 1);
+
+	/* 6. Configure conversion resources while they are in standby. */
+
+	/* DAC1/2 use clock 1/2 as source, ADC uses clock 3.  Always. */
+	ad1843_write_multi(ad1843, 4,
+			   &ad1843_DA1C, 1,
+			   &ad1843_DA2C, 2,
+			   &ad1843_ADLC, 3,
+			   &ad1843_ADRC, 3);
+
+	/* 7. Enable conversion resources. */
+	ad1843_write_bits(ad1843, &ad1843_ADTLK, 1);
+	ad1843_write_multi(ad1843, 7,
+			   &ad1843_ANAEN, 1,
+			   &ad1843_AAMEN, 1,
+			   &ad1843_DA1EN, 1,
+			   &ad1843_DA2EN, 1,
+			   &ad1843_DDMEN, 1,
+			   &ad1843_ADLEN, 1,
+			   &ad1843_ADREN, 1);
+
+	/* 8. Configure conversion resources while they are enabled. */
+
+	/* set gain to 0 for all channels */
+	ad1843_set_gain(ad1843, AD1843_GAIN_RECLEV, 0);
+	ad1843_set_gain(ad1843, AD1843_GAIN_LINE, 0);
+	ad1843_set_gain(ad1843, AD1843_GAIN_LINE_2, 0);
+	ad1843_set_gain(ad1843, AD1843_GAIN_MIC, 0);
+	ad1843_set_gain(ad1843, AD1843_GAIN_PCM_0, 0);
+	ad1843_set_gain(ad1843, AD1843_GAIN_PCM_1, 0);
+
+	/* Unmute all channels. */
+	/* DAC1 */
+	ad1843_write_multi(ad1843, 2, &ad1843_LDA1GM, 0, &ad1843_RDA1GM, 0);
+	/* DAC2 */
+	ad1843_write_multi(ad1843, 2, &ad1843_LDA2GM, 0, &ad1843_RDA2GM, 0);
+
+	/* Set default recording source to Line In and set
+	 * mic gain to +20 dB.
+	 */
+	ad1843_set_recsrc(ad1843, 2);
+	ad1843_write_multi(ad1843, 2, &ad1843_LMGE, 1, &ad1843_RMGE, 1);
+
+	/* Set Speaker Out level to +/- 4V and unmute it. */
+	ad1843_write_multi(ad1843, 3,
+			   &ad1843_HPOS, 1,
+			   &ad1843_HPOM, 0,
+			   &ad1843_MPOM, 0);
+
+	return 0;
+}