patch-2.2.16 linux/drivers/sound/ac97_codec.c

• Lines: 635
• Date: Wed Jun 7 14:26:43 2000
• Orig file: v2.2.15/linux/drivers/sound/ac97_codec.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN v2.2.15/linux/drivers/sound/ac97_codec.c linux/drivers/sound/ac97_codec.c
@@ -0,0 +1,634 @@
+/*
+ * ac97_codec.c: Generic AC97 mixer/modem module
+ *
+ * Derived from ac97 mixer in maestro and trident driver.
+ *
+ * Copyright 2000 Silicon Integrated System Corporation
+ *
+ *	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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * History
+ * v0.4 Mar 15 2000 Ollie Lho
+ *	dual codecs support verified with 4 channels output
+ * v0.3 Feb 22 2000 Ollie Lho
+ *	bug fix for record mask setting
+ * v0.2 Feb 10 2000 Ollie Lho
+ *	add ac97_read_proc for /proc/driver/{vendor}/ac97
+ * v0.1 Jan 14 2000 Ollie Lho <ollie@sis.com.tw> 
+ *	Isolated from trident.c to support multiple ac97 codec
+ */
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/bitops.h>
+#include <linux/ac97_codec.h>
+#include <asm/uaccess.h>
+
+static int ac97_read_mixer(struct ac97_codec *codec, int oss_channel);
+static void ac97_write_mixer(struct ac97_codec *codec, int oss_channel, 
+			     unsigned int left, unsigned int right);
+static void ac97_set_mixer(struct ac97_codec *codec, unsigned int oss_mixer, unsigned int val );
+static int ac97_recmask_io(struct ac97_codec *codec, int rw, int mask);
+static int ac97_mixer_ioctl(struct ac97_codec *codec, unsigned int cmd, unsigned long arg);
+
+static int ac97_init_mixer(struct ac97_codec *codec);
+
+static int sigmatel_init(struct ac97_codec *codec);
+
+#define arraysize(x)   (sizeof(x)/sizeof((x)[0]))
+
+static struct {
+	unsigned int id;
+	char *name;
+	int  (*init)  (struct ac97_codec *codec);
+} ac97_codec_ids[] = {
+	{0x414B4D00, "Asahi Kasei AK4540"     , NULL},
+	{0x41445340, "Analog Devices AD1881"  , NULL},
+	{0x43525900, "Cirrus Logic CS4297"    , NULL},
+	{0x43525903, "Cirrus Logic CS4297"  ,	NULL},
+	{0x43525913, "Cirrus Logic CS4297A"   , NULL},
+	{0x43525923, "Cirrus Logic CS4298"    , NULL},
+	{0x43525931, "Cirrus Logic CS4299"    , NULL},
+	{0x4e534331, "National Semiconductor LM4549" ,	NULL},
+	{0x53494c22, "Silicon Laboratory Si3036"     ,	NULL},
+	{0x53494c23, "Silicon Laboratory Si3038"     ,  NULL},
+	{0x83847600, "SigmaTel STAC????"      , NULL},
+	{0x83847604, "SigmaTel STAC9701/3/4/5", NULL},
+	{0x83847605, "SigmaTel STAC9704"      , NULL},
+	{0x83847608, "SigmaTel STAC9708"      , NULL},
+	{0x83847609, "SigmaTel STAC9721/23"   , sigmatel_init},
+	{0x54524106, "TriTech TR28026"        , NULL},
+	{0x54524108, "TriTech TR28028"        , NULL},
+	{0x574D4C00, "Wolfson WM9704"         , NULL},
+	{0x00000000, NULL, NULL}
+};
+
+static const char *ac97_stereo_enhancements[] =
+{
+	/*   0 */ "No 3D Stereo Enhancement",
+	/*   1 */ "Analog Devices Phat Stereo",
+	/*   2 */ "Creative Stereo Enhancement",
+	/*   3 */ "National Semi 3D Stereo Enhancement",
+	/*   4 */ "YAMAHA Ymersion",
+	/*   5 */ "BBE 3D Stereo Enhancement",
+	/*   6 */ "Crystal Semi 3D Stereo Enhancement",
+	/*   7 */ "Qsound QXpander",
+	/*   8 */ "Spatializer 3D Stereo Enhancement",
+	/*   9 */ "SRS 3D Stereo Enhancement",
+	/*  10 */ "Platform Tech 3D Stereo Enhancement",
+	/*  11 */ "AKM 3D Audio",
+	/*  12 */ "Aureal Stereo Enhancement",
+	/*  13 */ "Aztech 3D Enhancement",
+	/*  14 */ "Binaura 3D Audio Enhancement",
+	/*  15 */ "ESS Technology Stereo Enhancement",
+	/*  16 */ "Harman International VMAx",
+	/*  17 */ "Nvidea 3D Stereo Enhancement",
+	/*  18 */ "Philips Incredible Sound",
+	/*  19 */ "Texas Instruments 3D Stereo Enhancement",
+	/*  20 */ "VLSI Technology 3D Stereo Enhancement",
+	/*  21 */ "TriTech 3D Stereo Enhancement",
+	/*  22 */ "Realtek 3D Stereo Enhancement",
+	/*  23 */ "Samsung 3D Stereo Enhancement",
+	/*  24 */ "Wolfson Microelectronics 3D Enhancement",
+	/*  25 */ "Delta Integration 3D Enhancement",
+	/*  26 */ "SigmaTel 3D Enhancement",
+	/*  27 */ "Reserved 27",
+	/*  28 */ "Rockwell 3D Stereo Enhancement",
+	/*  29 */ "Reserved 29",
+	/*  30 */ "Reserved 30",
+	/*  31 */ "Reserved 31"
+};
+
+/* this table has default mixer values for all OSS mixers. */
+static struct mixer_defaults {
+	int mixer;
+	unsigned int value;
+} mixer_defaults[SOUND_MIXER_NRDEVICES] = {
+	/* all values 0 -> 100 in bytes */
+	{SOUND_MIXER_VOLUME,	0x3232},
+	{SOUND_MIXER_BASS,	0x3232},
+	{SOUND_MIXER_TREBLE,	0x3232},
+	{SOUND_MIXER_PCM,	0x3232},
+	{SOUND_MIXER_SPEAKER,	0x3232},
+	{SOUND_MIXER_LINE,	0x3232},
+	{SOUND_MIXER_MIC,	0x3232},
+	{SOUND_MIXER_CD,	0x3232},
+	{SOUND_MIXER_ALTPCM,	0x3232},
+	{SOUND_MIXER_IGAIN,	0x3232},
+	{SOUND_MIXER_LINE1,	0x3232},
+	{SOUND_MIXER_PHONEIN,	0x3232},
+	{SOUND_MIXER_PHONEOUT,	0x3232},
+	{SOUND_MIXER_VIDEO,	0x3232},
+	{-1,0}
+};
+
+/* table to scale scale from OSS mixer value to AC97 mixer register value */	
+static struct ac97_mixer_hw {
+	unsigned char offset;
+	int scale;
+} ac97_hw[SOUND_MIXER_NRDEVICES]= {
+	[SOUND_MIXER_VOLUME]	=	{AC97_MASTER_VOL_STEREO,63},
+	[SOUND_MIXER_BASS]	=	{AC97_MASTER_TONE,	15},
+	[SOUND_MIXER_TREBLE]	=	{AC97_MASTER_TONE,	15},
+	[SOUND_MIXER_PCM]	=	{AC97_PCMOUT_VOL,	31},
+	[SOUND_MIXER_SPEAKER]	=	{AC97_PCBEEP_VOL,	15},
+	[SOUND_MIXER_LINE]	=	{AC97_LINEIN_VOL,	31},
+	[SOUND_MIXER_MIC]	=	{AC97_MIC_VOL,		31},
+	[SOUND_MIXER_CD]	=	{AC97_CD_VOL,		31},
+	[SOUND_MIXER_ALTPCM]	=	{AC97_HEADPHONE_VOL,	63},
+	[SOUND_MIXER_IGAIN]	=	{AC97_RECORD_GAIN,	31},
+	[SOUND_MIXER_LINE1]	=	{AC97_AUX_VOL,		31},
+	[SOUND_MIXER_PHONEIN]	= 	{AC97_PHONE_VOL,	15},
+	[SOUND_MIXER_PHONEOUT]	= 	{AC97_MASTER_VOL_MONO,	63},
+	[SOUND_MIXER_VIDEO]	=	{AC97_VIDEO_VOL,	31},
+};
+
+/* the following tables allow us to go from OSS <-> ac97 quickly. */
+enum ac97_recsettings {
+	AC97_REC_MIC=0,
+	AC97_REC_CD,
+	AC97_REC_VIDEO,
+	AC97_REC_AUX,
+	AC97_REC_LINE,
+	AC97_REC_STEREO, /* combination of all enabled outputs..  */
+	AC97_REC_MONO,	      /*.. or the mono equivalent */
+	AC97_REC_PHONE	      
+};
+
+static unsigned int ac97_rm2oss[] = {
+	[AC97_REC_MIC] 	 = SOUND_MIXER_MIC,
+	[AC97_REC_CD] 	 = SOUND_MIXER_CD,
+	[AC97_REC_VIDEO] = SOUND_MIXER_VIDEO,
+	[AC97_REC_AUX] 	 = SOUND_MIXER_LINE1,
+	[AC97_REC_LINE]  = SOUND_MIXER_LINE,
+	[AC97_REC_STEREO]= SOUND_MIXER_IGAIN,
+	[AC97_REC_PHONE] = SOUND_MIXER_PHONEIN
+};
+
+/* indexed by bit position */
+static unsigned int ac97_oss_rm[] = {
+	[SOUND_MIXER_MIC] 	= AC97_REC_MIC,
+	[SOUND_MIXER_CD] 	= AC97_REC_CD,
+	[SOUND_MIXER_VIDEO] 	= AC97_REC_VIDEO,
+	[SOUND_MIXER_LINE1] 	= AC97_REC_AUX,
+	[SOUND_MIXER_LINE] 	= AC97_REC_LINE,
+	[SOUND_MIXER_IGAIN]	= AC97_REC_STEREO,
+	[SOUND_MIXER_PHONEIN] 	= AC97_REC_PHONE
+};
+
+/* reads the given OSS mixer from the ac97 the caller must have insured that the ac97 knows
+   about that given mixer, and should be holding a spinlock for the card */
+static int ac97_read_mixer(struct ac97_codec *codec, int oss_channel) 
+{
+	u16 val;
+	int ret = 0;
+	struct ac97_mixer_hw *mh = &ac97_hw[oss_channel];
+
+	val = codec->codec_read(codec , mh->offset);
+
+	if (AC97_STEREO_MASK & (1 << oss_channel)) {
+		/* nice stereo mixers .. */
+		int left,right;
+
+		left = (val >> 8)  & 0x7f;
+		right = val  & 0x7f;
+
+		if (oss_channel == SOUND_MIXER_IGAIN) {
+			right = (right * 100) / mh->scale;
+			left = (left * 100) / mh->scale;
+		} else {
+			right = 100 - ((right * 100) / mh->scale);
+			left = 100 - ((left * 100) / mh->scale);
+		}
+		ret = left | (right << 8);
+	} else if (oss_channel == SOUND_MIXER_SPEAKER) {
+		ret = 100 - ((((val & 0x1e)>>1) * 100) / mh->scale);
+	} else if (oss_channel == SOUND_MIXER_PHONEIN) {
+		ret = 100 - (((val & 0x1f) * 100) / mh->scale);
+	} else if (oss_channel == SOUND_MIXER_PHONEOUT) {
+		ret = 100 - (((val & 0x1f) * 100) / mh->scale);
+	} else if (oss_channel == SOUND_MIXER_MIC) {
+		ret = 100 - (((val & 0x1f) * 100) / mh->scale);
+		/*  the low bit is optional in the tone sliders and masking
+		    it lets us avoid the 0xf 'bypass'.. */
+	} else if (oss_channel == SOUND_MIXER_BASS) {
+		ret = 100 - ((((val >> 8) & 0xe) * 100) / mh->scale);
+	} else if (oss_channel == SOUND_MIXER_TREBLE) {
+		ret = 100 - (((val & 0xe) * 100) / mh->scale);
+	}
+
+#ifdef DEBUG
+	printk("ac97_codec: read OSS mixer %2d (%s ac97 register 0x%02x), "
+	       "0x%04x -> 0x%04x\n",
+	       oss_channel, codec->id ? "Secondary" : "Primary",
+	       mh->offset, val, ret);
+#endif
+
+	return ret;
+}
+
+/* write the OSS encoded volume to the given OSS encoded mixer, again caller's job to
+   make sure all is well in arg land, call with spinlock held */
+static void ac97_write_mixer(struct ac97_codec *codec, int oss_channel,
+		      unsigned int left, unsigned int right)
+{
+	u16 val = 0;
+	struct ac97_mixer_hw *mh = &ac97_hw[oss_channel];
+
+#ifdef DEBUG
+	printk("ac97_codec: wrote OSS mixer %2d (%s ac97 register 0x%02x), "
+	       "left vol:%2d, right vol:%2d:",
+	       oss_channel, codec->id ? "Secondary" : "Primary",
+	       mh->offset, left, right);
+#endif
+
+	if (AC97_STEREO_MASK & (1 << oss_channel)) {
+		/* stereo mixers */
+		if (oss_channel == SOUND_MIXER_IGAIN) {
+			right = (right * mh->scale) / 100;
+			left = (left * mh->scale) / 100;
+		} else {
+			right = ((100 - right) * mh->scale) / 100;
+			left = ((100 - left) * mh->scale) / 100;
+		}			
+		val = (left << 8) | right;
+	} else if (oss_channel == SOUND_MIXER_SPEAKER) {
+		val = (((100 - left) * mh->scale) / 100) << 1;
+	} else if (oss_channel == SOUND_MIXER_PHONEIN) {
+		val = (((100 - left) * mh->scale) / 100);
+	} else if (oss_channel == SOUND_MIXER_PHONEOUT) {
+		val = (((100 - left) * mh->scale) / 100);
+	} else if (oss_channel == SOUND_MIXER_MIC) {
+		val = codec->codec_read(codec , mh->offset) & ~0x801f;
+		val |= (((100 - left) * mh->scale) / 100);
+		/*  the low bit is optional in the tone sliders and masking
+		    it lets us avoid the 0xf 'bypass'.. */
+	} else if (oss_channel == SOUND_MIXER_BASS) {
+		val = codec->codec_read(codec , mh->offset) & ~0x0f00;
+		val |= ((((100 - left) * mh->scale) / 100) << 8) & 0x0e00;
+	} else if (oss_channel == SOUND_MIXER_TREBLE) {
+		val = codec->codec_read(codec , mh->offset) & ~0x000f;
+		val |= (((100 - left) * mh->scale) / 100) & 0x000e;
+	}
+#ifdef DEBUG
+	printk(" 0x%04x", val);
+#endif
+
+	codec->codec_write(codec, mh->offset, val);
+
+#ifdef DEBUG
+	val = codec->codec_read(codec, mh->offset);
+	printk(" -> 0x%04x\n", val);
+#endif
+}
+
+/* a thin wrapper for write_mixer */
+static void ac97_set_mixer(struct ac97_codec *codec, unsigned int oss_mixer, unsigned int val ) 
+{
+	unsigned int left,right;
+
+	/* cleanse input a little */
+	right = ((val >> 8)  & 0xff) ;
+	left = (val  & 0xff) ;
+
+	if (right > 100) right = 100;
+	if (left > 100) left = 100;
+
+	codec->mixer_state[oss_mixer] = (right << 8) | left;
+	codec->write_mixer(codec, oss_mixer, left, right);
+}
+
+/* read or write the recmask, the ac97 can really have left and right recording
+   inputs independantly set, but OSS doesn't seem to want us to express that to
+   the user. the caller guarantees that we have a supported bit set, and they
+   must be holding the card's spinlock */
+static int ac97_recmask_io(struct ac97_codec *codec, int rw, int mask) 
+{
+	unsigned int val;
+
+	if (rw) {
+		/* read it from the card */
+		val = codec->codec_read(codec, AC97_RECORD_SELECT);
+#ifdef DEBUG
+		printk("ac97_codec: ac97 recmask to set to 0x%04x\n", val);
+#endif
+		return (1 << ac97_rm2oss[val & 0x07]);
+	}
+
+	/* else, write the first set in the mask as the
+	   output */	
+	/* clear out current set value first (AC97 supports only 1 input!) */
+	val = (1 << ac97_rm2oss[codec->codec_read(codec, AC97_RECORD_SELECT) & 0x07]);
+	if (mask != val)
+	    mask &= ~val;
+       
+	val = ffs(mask); 
+	val = ac97_oss_rm[val-1];
+	val |= val << 8;  /* set both channels */
+
+#ifdef DEBUG
+	printk("ac97_codec: setting ac97 recmask to 0x%04x\n", val);
+#endif
+
+	codec->codec_write(codec, AC97_RECORD_SELECT, val);
+
+	return 0;
+};
+
+static int ac97_mixer_ioctl(struct ac97_codec *codec, unsigned int cmd, unsigned long arg)
+{
+	int i, val = 0;
+
+	if (cmd == SOUND_MIXER_INFO) {
+		mixer_info info;
+		strncpy(info.id, codec->name, sizeof(info.id));
+		strncpy(info.name, codec->name, sizeof(info.name));
+		info.modify_counter = codec->modcnt;
+		if (copy_to_user((void *)arg, &info, sizeof(info)))
+			return -EFAULT;
+		return 0;
+	}
+	if (cmd == SOUND_OLD_MIXER_INFO) {
+		_old_mixer_info info;
+		strncpy(info.id, codec->name, sizeof(info.id));
+		strncpy(info.name, codec->name, sizeof(info.name));
+		if (copy_to_user((void *)arg, &info, sizeof(info)))
+			return -EFAULT;
+		return 0;
+	}
+
+	if (_IOC_TYPE(cmd) != 'M' || _IOC_SIZE(cmd) != sizeof(int))
+		return -EINVAL;
+
+	if (cmd == OSS_GETVERSION)
+		return put_user(SOUND_VERSION, (int *)arg);
+
+	if (_IOC_DIR(cmd) == _IOC_READ) {
+		switch (_IOC_NR(cmd)) {
+		case SOUND_MIXER_RECSRC: /* give them the current record source */
+			if (!codec->recmask_io) {
+				val = 0;
+			} else {
+				val = codec->recmask_io(codec, 1, 0);
+			}
+			break;
+
+		case SOUND_MIXER_DEVMASK: /* give them the supported mixers */
+			val = codec->supported_mixers;
+			break;
+
+		case SOUND_MIXER_RECMASK: /* Arg contains a bit for each supported recording source */
+			val = codec->record_sources;
+			break;
+
+		case SOUND_MIXER_STEREODEVS: /* Mixer channels supporting stereo */
+			val = codec->stereo_mixers;
+			break;
+
+		case SOUND_MIXER_CAPS:
+			val = SOUND_CAP_EXCL_INPUT;
+			break;
+
+		default: /* read a specific mixer */
+			i = _IOC_NR(cmd);
+
+			if (!supported_mixer(codec, i)) 
+				return -EINVAL;
+
+			/* do we ever want to touch the hardware? */
+		        /* val = codec->read_mixer(codec, i); */
+			val = codec->mixer_state[i];
+ 			break;
+		}
+		return put_user(val, (int *)arg);
+	}
+
+	if (_IOC_DIR(cmd) == (_IOC_WRITE|_IOC_READ)) {
+		codec->modcnt++;
+		get_user_ret(val, (int *)arg, -EFAULT);
+
+		switch (_IOC_NR(cmd)) {
+		case SOUND_MIXER_RECSRC: /* Arg contains a bit for each recording source */
+			if (!codec->recmask_io) return -EINVAL;
+			if (!val) return 0;
+			if (!(val &= codec->record_sources)) return -EINVAL;
+
+			codec->recmask_io(codec, 0, val);
+
+			return 0;
+		default: /* write a specific mixer */
+			i = _IOC_NR(cmd);
+
+			if (!supported_mixer(codec, i)) 
+				return -EINVAL;
+
+			ac97_set_mixer(codec, i, val);
+
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+/* entry point for /proc/driver/controller_vendor/ac97/%d */
+int ac97_read_proc (char *page, char **start, off_t off,
+		    int count, int *eof, void *data)
+{
+	int len = 0, cap, extid, val, id1, id2;
+	struct ac97_codec *codec;
+	int is_ac97_20 = 0;
+
+	if ((codec = data) == NULL)
+		return -ENODEV;
+
+	id1 = codec->codec_read(codec, AC97_VENDOR_ID1);
+	id2 = codec->codec_read(codec, AC97_VENDOR_ID2);
+	len += sprintf (page+len, "Vendor name      : %s\n", codec->name);
+	len += sprintf (page+len, "Vendor id        : %04X %04X\n", id1, id2);
+
+	extid = codec->codec_read(codec, AC97_EXTENDED_ID);
+	extid &= ~((1<<2)|(1<<4)|(1<<5)|(1<<10)|(1<<11)|(1<<12)|(1<<13));
+	len += sprintf (page+len, "AC97 Version     : %s\n",
+			extid ? "2.0 or later" : "1.0");
+	if (extid) is_ac97_20 = 1;
+
+	cap = codec->codec_read(codec, AC97_RESET);
+	len += sprintf (page+len, "Capabilities     :%s%s%s%s%s%s\n",
+			cap & 0x0001 ? " -dedicated MIC PCM IN channel-" : "",
+			cap & 0x0002 ? " -reserved1-" : "",
+			cap & 0x0004 ? " -bass & treble-" : "",
+			cap & 0x0008 ? " -simulated stereo-" : "",
+			cap & 0x0010 ? " -headphone out-" : "",
+			cap & 0x0020 ? " -loudness-" : "");
+	val = cap & 0x00c0;
+	len += sprintf (page+len, "DAC resolutions  :%s%s%s\n",
+			" -16-bit-",
+			val & 0x0040 ? " -18-bit-" : "",
+			val & 0x0080 ? " -20-bit-" : "");
+	val = cap & 0x0300;
+	len += sprintf (page+len, "ADC resolutions  :%s%s%s\n",
+			" -16-bit-",
+			val & 0x0100 ? " -18-bit-" : "",
+			val & 0x0200 ? " -20-bit-" : "");
+	len += sprintf (page+len, "3D enhancement   : %s\n",
+			ac97_stereo_enhancements[(cap >> 10) & 0x1f]);
+
+	val = codec->codec_read(codec, AC97_GENERAL_PURPOSE);
+	len += sprintf (page+len, "POP path         : %s 3D\n"
+			"Sim. stereo      : %s\n"
+			"3D enhancement   : %s\n"
+			"Loudness         : %s\n"
+			"Mono output      : %s\n"
+			"MIC select       : %s\n"
+			"ADC/DAC loopback : %s\n",
+			val & 0x8000 ? "post" : "pre",
+			val & 0x4000 ? "on" : "off",
+			val & 0x2000 ? "on" : "off",
+			val & 0x1000 ? "on" : "off",
+			val & 0x0200 ? "MIC" : "MIX",
+			val & 0x0100 ? "MIC2" : "MIC1",
+			val & 0x0080 ? "on" : "off");
+
+	extid = codec->codec_read(codec, AC97_EXTENDED_ID);
+	cap = extid;
+	len += sprintf (page+len, "Ext Capabilities :%s%s%s%s%s%s%s\n",
+			cap & 0x0001 ? " -var rate PCM audio-" : "",
+			cap & 0x0002 ? " -2x PCM audio out-" : "",
+			cap & 0x0008 ? " -var rate MIC in-" : "",
+			cap & 0x0040 ? " -PCM center DAC-" : "",
+			cap & 0x0080 ? " -PCM surround DAC-" : "",
+			cap & 0x0100 ? " -PCM LFE DAC-" : "",
+			cap & 0x0200 ? " -slot/DAC mappings-" : "");
+	if (is_ac97_20) {
+		len += sprintf (page+len, "Front DAC rate   : %d\n",
+				codec->codec_read(codec, AC97_PCM_FRONT_DAC_RATE));
+	}
+
+	return len;
+}
+
+int ac97_probe_codec(struct ac97_codec *codec)
+{
+	u16 id1, id2;
+	u16 audio, modem;
+	int i;
+
+	/* probing AC97 codec, AC97 2.0 says that bit 15 of register 0x00 (reset) should 
+	   be read zero. Probing of AC97 in this way is not reliable, it is not even SAFE !! */
+	codec->codec_write(codec, AC97_RESET, 0L);
+	if ((audio = codec->codec_read(codec, AC97_RESET)) & 0x8000) {
+		printk(KERN_ERR "ac97_codec: %s ac97 codec not present\n",
+		       codec->id ? "Secondary" : "Primary");
+		return 0;
+	}
+
+	/* probe for Modem Codec */
+	codec->codec_write(codec, AC97_EXTENDED_MODEM_ID, 0L);
+	modem = codec->codec_read(codec, AC97_EXTENDED_MODEM_ID);
+
+	codec->name = NULL;
+	codec->codec_init = NULL;
+
+	id1 = codec->codec_read(codec, AC97_VENDOR_ID1);
+	id2 = codec->codec_read(codec, AC97_VENDOR_ID2);
+	for (i = 0; i < arraysize(ac97_codec_ids); i++) {
+		if (ac97_codec_ids[i].id == ((id1 << 16) | id2)) {
+			codec->name = ac97_codec_ids[i].name;
+			codec->codec_init = ac97_codec_ids[i].init;
+			break;
+		}
+	}
+	if (codec->name == NULL)
+		codec->name = "Unknown";
+	printk(KERN_INFO "ac97_codec: AC97 %s codec, vendor id1: 0x%04x, "
+	       "id2: 0x%04x (%s)\n", audio ? "Audio" : (modem ? "Modem" : ""),
+	       id1, id2, codec->name);
+
+	return ac97_init_mixer(codec);
+}
+
+static int ac97_init_mixer(struct ac97_codec *codec)
+{
+	u16 cap;
+	int i;
+
+	cap = codec->codec_read(codec, AC97_RESET);
+
+	/* mixer masks */
+	codec->supported_mixers = AC97_SUPPORTED_MASK;
+	codec->stereo_mixers = AC97_STEREO_MASK;
+	codec->record_sources = AC97_RECORD_MASK;
+	if (!(cap & 0x04))
+		codec->supported_mixers &= ~(SOUND_MASK_BASS|SOUND_MASK_TREBLE);
+	if (!(cap & 0x10))
+		codec->supported_mixers &= ~SOUND_MASK_ALTPCM;
+
+	/* generic OSS to AC97 wrapper */
+	codec->read_mixer = ac97_read_mixer;
+	codec->write_mixer = ac97_write_mixer;
+	codec->recmask_io = ac97_recmask_io;
+	codec->mixer_ioctl = ac97_mixer_ioctl;
+
+	/* initialize volume level */
+	codec->codec_write(codec, AC97_MASTER_VOL_STEREO, 0L);
+	codec->codec_write(codec, AC97_PCMOUT_VOL, 0L);
+
+	/* codec specific initialization for 4-6 channel output or secondary codec stuff */
+	if (codec->id != 0 && codec->codec_init != NULL) {
+		codec->codec_init(codec);
+	}
+
+	/* initilize mixer channel volumes */
+	for (i = 0; i < SOUND_MIXER_NRDEVICES; i++) {
+		struct mixer_defaults *md = &mixer_defaults[i];
+		if (md->mixer == -1) 
+			break;
+		if (!supported_mixer(codec, md->mixer)) 
+			continue;
+		ac97_set_mixer(codec, md->mixer, md->value);
+	}
+
+	return 1;
+}
+
+static int ac97_init_modem(struct ac97_codec *codec)
+{
+	return 0;
+}
+
+static int sigmatel_init(struct ac97_codec * codec)
+{
+	codec->codec_write(codec, AC97_SURROUND_MASTER, 0L);
+
+	/* initialize SigmaTel STAC9721/23 as secondary codec, decoding AC link
+	   sloc 3,4 = 0x01, slot 7,8 = 0x00, */
+	codec->codec_write(codec, 0x74, 0x00);
+
+	/* we don't have the crystal when we are on an AMR card, so use
+	   BIT_CLK as our clock source. Write the magic word ABBA and read
+	   back to enable register 0x78 */
+	codec->codec_write(codec, 0x76, 0xabba);
+	codec->codec_read(codec, 0x76);
+
+	/* sync all the clocks*/
+	codec->codec_write(codec, 0x78, 0x3802);
+
+	return 1;
+}
+
+EXPORT_SYMBOL(ac97_read_proc);
+EXPORT_SYMBOL(ac97_probe_codec);