/*
   * Driver for AMD7930 sound chips found on Sparcs.
   * Copyright (C) 2002 David S. Miller <davem@redhat.com>
   *
   * Based entirely upon drivers/sbus/audio/amd7930.c which is:
   * Copyright (C) 1996,1997 Thomas K. Dyas (tdyas@eden.rutgers.edu)
   *
   * --- Notes from Thomas's original driver ---
   * This is the lowlevel driver for the AMD7930 audio chip found on all
   * sun4c machines and some sun4m machines.
   *
   * The amd7930 is actually an ISDN chip which has a very simple
   * integrated audio encoder/decoder. When Sun decided on what chip to
   * use for audio, they had the brilliant idea of using the amd7930 and
   * only connecting the audio encoder/decoder pins.
   *
   * Thanks to the AMD engineer who was able to get us the AMD79C30
   * databook which has all the programming information and gain tables.
   *
   * Advanced Micro Devices' Am79C30A is an ISDN/audio chip used in the
   * SparcStation 1+.  The chip provides microphone and speaker interfaces
   * which provide mono-channel audio at 8K samples per second via either
   * 8-bit A-law or 8-bit mu-law encoding.  Also, the chip features an
   * ISDN BRI Line Interface Unit (LIU), I.430 S/T physical interface,
   * which performs basic D channel LAPD processing and provides raw
   * B channel data.  The digital audio channel, the two ISDN B channels,
   * and two 64 Kbps channels to the microprocessor are all interconnected
   * via a multiplexer.
   * --- End of notes from Thoamas's original driver ---
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/moduleparam.h>
  
  #include <sound/driver.h>
  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/info.h>
  #include <sound/control.h>
  #include <sound/initval.h>
  
  #include <asm/io.h>
  #include <asm/irq.h>
  #include <asm/sbus.h>

  #include <asm/prom.h>

  
  static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
  static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
  static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;	/* Enable this card */
  
  module_param_array(index, int, NULL, 0444);
  MODULE_PARM_DESC(index, "Index value for Sun AMD7930 soundcard.");
  module_param_array(id, charp, NULL, 0444);
  MODULE_PARM_DESC(id, "ID string for Sun AMD7930 soundcard.");
  module_param_array(enable, bool, NULL, 0444);
  MODULE_PARM_DESC(enable, "Enable Sun AMD7930 soundcard.");
  MODULE_AUTHOR("Thomas K. Dyas and David S. Miller");
  MODULE_DESCRIPTION("Sun AMD7930");
  MODULE_LICENSE("GPL");
  MODULE_SUPPORTED_DEVICE("{{Sun,AMD7930}}");
  
  /* Device register layout.  */
  
  /* Register interface presented to the CPU by the amd7930. */
  #define AMD7930_CR	0x00UL		/* Command Register (W) */
  #define AMD7930_IR	AMD7930_CR	/* Interrupt Register (R) */
  #define AMD7930_DR	0x01UL		/* Data Register (R/W) */
  #define AMD7930_DSR1	0x02UL		/* D-channel Status Register 1 (R) */
  #define AMD7930_DER	0x03UL		/* D-channel Error Register (R) */
  #define AMD7930_DCTB	0x04UL		/* D-channel Transmit Buffer (W) */
  #define AMD7930_DCRB	AMD7930_DCTB	/* D-channel Receive Buffer (R) */
  #define AMD7930_BBTB	0x05UL		/* Bb-channel Transmit Buffer (W) */
  #define AMD7930_BBRB	AMD7930_BBTB	/* Bb-channel Receive Buffer (R) */
  #define AMD7930_BCTB	0x06UL		/* Bc-channel Transmit Buffer (W) */
  #define AMD7930_BCRB	AMD7930_BCTB	/* Bc-channel Receive Buffer (R) */
  #define AMD7930_DSR2	0x07UL		/* D-channel Status Register 2 (R) */
  
  /* Indirect registers in the Main Audio Processor. */
  struct amd7930_map {
  	__u16	x[8];
  	__u16	r[8];
  	__u16	gx;
  	__u16	gr;
  	__u16	ger;
  	__u16	stgr;
  	__u16	ftgr;
  	__u16	atgr;
  	__u8	mmr1;
  	__u8	mmr2;
  };
  
  /* After an amd7930 interrupt, reading the Interrupt Register (ir)
   * clears the interrupt and returns a bitmask indicating which
   * interrupt source(s) require service.
   */
  
  #define AMR_IR_DTTHRSH			0x01 /* D-channel xmit threshold */
  #define AMR_IR_DRTHRSH			0x02 /* D-channel recv threshold */
  #define AMR_IR_DSRI			0x04 /* D-channel packet status */
  #define AMR_IR_DERI			0x08 /* D-channel error */
  #define AMR_IR_BBUF			0x10 /* B-channel data xfer */
  #define AMR_IR_LSRI			0x20 /* LIU status */
  #define AMR_IR_DSR2I			0x40 /* D-channel buffer status */
  #define AMR_IR_MLTFRMI			0x80 /* multiframe or PP */
  
  /* The amd7930 has "indirect registers" which are accessed by writing
   * the register number into the Command Register and then reading or
   * writing values from the Data Register as appropriate. We define the
   * AMR_* macros to be the indirect register numbers and AM_* macros to
   * be bits in whatever register is referred to.
   */
  
  /* Initialization */
  #define	AMR_INIT			0x21
  #define		AM_INIT_ACTIVE			0x01
  #define		AM_INIT_DATAONLY		0x02
  #define		AM_INIT_POWERDOWN		0x03
  #define		AM_INIT_DISABLE_INTS		0x04
  #define AMR_INIT2			0x20
  #define		AM_INIT2_ENABLE_POWERDOWN	0x20
  #define		AM_INIT2_ENABLE_MULTIFRAME	0x10
  
  /* Line Interface Unit */
  #define	AMR_LIU_LSR			0xA1
  #define		AM_LIU_LSR_STATE		0x07
  #define		AM_LIU_LSR_F3			0x08
  #define		AM_LIU_LSR_F7			0x10
  #define		AM_LIU_LSR_F8			0x20
  #define		AM_LIU_LSR_HSW			0x40
  #define		AM_LIU_LSR_HSW_CHG		0x80
  #define	AMR_LIU_LPR			0xA2
  #define	AMR_LIU_LMR1			0xA3
  #define		AM_LIU_LMR1_B1_ENABL		0x01
  #define		AM_LIU_LMR1_B2_ENABL		0x02
  #define		AM_LIU_LMR1_F_DISABL		0x04
  #define		AM_LIU_LMR1_FA_DISABL		0x08
  #define		AM_LIU_LMR1_REQ_ACTIV		0x10
  #define		AM_LIU_LMR1_F8_F3		0x20
  #define		AM_LIU_LMR1_LIU_ENABL		0x40
  #define	AMR_LIU_LMR2			0xA4
  #define		AM_LIU_LMR2_DECHO		0x01
  #define		AM_LIU_LMR2_DLOOP		0x02
  #define		AM_LIU_LMR2_DBACKOFF		0x04
  #define		AM_LIU_LMR2_EN_F3_INT		0x08
  #define		AM_LIU_LMR2_EN_F8_INT		0x10
  #define		AM_LIU_LMR2_EN_HSW_INT		0x20
  #define		AM_LIU_LMR2_EN_F7_INT		0x40
  #define	AMR_LIU_2_4			0xA5
  #define	AMR_LIU_MF			0xA6
  #define	AMR_LIU_MFSB			0xA7
  #define	AMR_LIU_MFQB			0xA8
  
  /* Multiplexor */
  #define	AMR_MUX_MCR1			0x41
  #define	AMR_MUX_MCR2			0x42
  #define	AMR_MUX_MCR3			0x43
  #define		AM_MUX_CHANNEL_B1		0x01
  #define		AM_MUX_CHANNEL_B2		0x02
  #define		AM_MUX_CHANNEL_Ba		0x03
  #define		AM_MUX_CHANNEL_Bb		0x04
  #define		AM_MUX_CHANNEL_Bc		0x05
  #define		AM_MUX_CHANNEL_Bd		0x06
  #define		AM_MUX_CHANNEL_Be		0x07
  #define		AM_MUX_CHANNEL_Bf		0x08
  #define	AMR_MUX_MCR4			0x44
  #define		AM_MUX_MCR4_ENABLE_INTS		0x08
  #define		AM_MUX_MCR4_REVERSE_Bb		0x10
  #define		AM_MUX_MCR4_REVERSE_Bc		0x20
  #define	AMR_MUX_1_4			0x45
  
  /* Main Audio Processor */
  #define	AMR_MAP_X			0x61
  #define	AMR_MAP_R			0x62
  #define	AMR_MAP_GX			0x63
  #define	AMR_MAP_GR			0x64
  #define	AMR_MAP_GER			0x65
  #define	AMR_MAP_STGR			0x66
  #define	AMR_MAP_FTGR_1_2		0x67
  #define	AMR_MAP_ATGR_1_2		0x68
  #define	AMR_MAP_MMR1			0x69
  #define		AM_MAP_MMR1_ALAW		0x01
  #define		AM_MAP_MMR1_GX			0x02
  #define		AM_MAP_MMR1_GR			0x04
  #define		AM_MAP_MMR1_GER			0x08
  #define		AM_MAP_MMR1_X			0x10
  #define		AM_MAP_MMR1_R			0x20
  #define		AM_MAP_MMR1_STG			0x40
  #define		AM_MAP_MMR1_LOOPBACK		0x80
  #define	AMR_MAP_MMR2			0x6A
  #define		AM_MAP_MMR2_AINB		0x01
  #define		AM_MAP_MMR2_LS			0x02
  #define		AM_MAP_MMR2_ENABLE_DTMF		0x04
  #define		AM_MAP_MMR2_ENABLE_TONEGEN	0x08
  #define		AM_MAP_MMR2_ENABLE_TONERING	0x10
  #define		AM_MAP_MMR2_DISABLE_HIGHPASS	0x20
  #define		AM_MAP_MMR2_DISABLE_AUTOZERO	0x40
  #define	AMR_MAP_1_10			0x6B
  #define	AMR_MAP_MMR3			0x6C
  #define	AMR_MAP_STRA			0x6D
  #define	AMR_MAP_STRF			0x6E
  #define	AMR_MAP_PEAKX			0x70
  #define	AMR_MAP_PEAKR			0x71
  #define	AMR_MAP_15_16			0x72
  
  /* Data Link Controller */
  #define	AMR_DLC_FRAR_1_2_3		0x81
  #define	AMR_DLC_SRAR_1_2_3		0x82
  #define	AMR_DLC_TAR			0x83
  #define	AMR_DLC_DRLR			0x84
  #define	AMR_DLC_DTCR			0x85
  #define	AMR_DLC_DMR1			0x86
  #define		AMR_DLC_DMR1_DTTHRSH_INT	0x01
  #define		AMR_DLC_DMR1_DRTHRSH_INT	0x02
  #define		AMR_DLC_DMR1_TAR_ENABL		0x04
  #define		AMR_DLC_DMR1_EORP_INT		0x08
  #define		AMR_DLC_DMR1_EN_ADDR1		0x10
  #define		AMR_DLC_DMR1_EN_ADDR2		0x20
  #define		AMR_DLC_DMR1_EN_ADDR3		0x40
  #define		AMR_DLC_DMR1_EN_ADDR4		0x80
  #define		AMR_DLC_DMR1_EN_ADDRS		0xf0
  #define	AMR_DLC_DMR2			0x87
  #define		AMR_DLC_DMR2_RABRT_INT		0x01
  #define		AMR_DLC_DMR2_RESID_INT		0x02
  #define		AMR_DLC_DMR2_COLL_INT		0x04
  #define		AMR_DLC_DMR2_FCS_INT		0x08
  #define		AMR_DLC_DMR2_OVFL_INT		0x10
  #define		AMR_DLC_DMR2_UNFL_INT		0x20
  #define		AMR_DLC_DMR2_OVRN_INT		0x40
  #define		AMR_DLC_DMR2_UNRN_INT		0x80
  #define	AMR_DLC_1_7			0x88
  #define	AMR_DLC_DRCR			0x89
  #define	AMR_DLC_RNGR1			0x8A
  #define	AMR_DLC_RNGR2			0x8B
  #define	AMR_DLC_FRAR4			0x8C
  #define	AMR_DLC_SRAR4			0x8D
  #define	AMR_DLC_DMR3			0x8E
  #define		AMR_DLC_DMR3_VA_INT		0x01
  #define		AMR_DLC_DMR3_EOTP_INT		0x02
  #define		AMR_DLC_DMR3_LBRP_INT		0x04
  #define		AMR_DLC_DMR3_RBA_INT		0x08
  #define		AMR_DLC_DMR3_LBT_INT		0x10
  #define		AMR_DLC_DMR3_TBE_INT		0x20
  #define		AMR_DLC_DMR3_RPLOST_INT		0x40
  #define		AMR_DLC_DMR3_KEEP_FCS		0x80
  #define	AMR_DLC_DMR4			0x8F
  #define		AMR_DLC_DMR4_RCV_1		0x00
  #define		AMR_DLC_DMR4_RCV_2		0x01
  #define		AMR_DLC_DMR4_RCV_4		0x02
  #define		AMR_DLC_DMR4_RCV_8		0x03
  #define		AMR_DLC_DMR4_RCV_16		0x01
  #define		AMR_DLC_DMR4_RCV_24		0x02
  #define		AMR_DLC_DMR4_RCV_30		0x03
  #define		AMR_DLC_DMR4_XMT_1		0x00
  #define		AMR_DLC_DMR4_XMT_2		0x04
  #define		AMR_DLC_DMR4_XMT_4		0x08
  #define		AMR_DLC_DMR4_XMT_8		0x0c
  #define		AMR_DLC_DMR4_XMT_10		0x08
  #define		AMR_DLC_DMR4_XMT_14		0x0c
  #define		AMR_DLC_DMR4_IDLE_MARK		0x00
  #define		AMR_DLC_DMR4_IDLE_FLAG		0x10
  #define		AMR_DLC_DMR4_ADDR_BOTH		0x00
  #define		AMR_DLC_DMR4_ADDR_1ST		0x20
  #define		AMR_DLC_DMR4_ADDR_2ND		0xa0
  #define		AMR_DLC_DMR4_CR_ENABLE		0x40
  #define	AMR_DLC_12_15			0x90
  #define	AMR_DLC_ASR			0x91
  #define	AMR_DLC_EFCR			0x92
  #define		AMR_DLC_EFCR_EXTEND_FIFO	0x01
  #define		AMR_DLC_EFCR_SEC_PKT_INT	0x02
  
  #define AMR_DSR1_VADDR			0x01
  #define AMR_DSR1_EORP			0x02
  #define AMR_DSR1_PKT_IP			0x04
  #define AMR_DSR1_DECHO_ON		0x08
  #define AMR_DSR1_DLOOP_ON		0x10
  #define AMR_DSR1_DBACK_OFF		0x20
  #define AMR_DSR1_EOTP			0x40
  #define AMR_DSR1_CXMT_ABRT		0x80
  
  #define AMR_DSR2_LBRP			0x01
  #define AMR_DSR2_RBA			0x02
  #define AMR_DSR2_RPLOST			0x04
  #define AMR_DSR2_LAST_BYTE		0x08
  #define AMR_DSR2_TBE			0x10
  #define AMR_DSR2_MARK_IDLE		0x20
  #define AMR_DSR2_FLAG_IDLE		0x40
  #define AMR_DSR2_SECOND_PKT		0x80
  
  #define AMR_DER_RABRT			0x01
  #define AMR_DER_RFRAME			0x02
  #define AMR_DER_COLLISION		0x04
  #define AMR_DER_FCS			0x08
  #define AMR_DER_OVFL			0x10
  #define AMR_DER_UNFL			0x20
  #define AMR_DER_OVRN			0x40
  #define AMR_DER_UNRN			0x80
  
  /* Peripheral Port */
  #define	AMR_PP_PPCR1			0xC0
  #define	AMR_PP_PPSR			0xC1
  #define	AMR_PP_PPIER			0xC2
  #define	AMR_PP_MTDR			0xC3
  #define	AMR_PP_MRDR			0xC3
  #define	AMR_PP_CITDR0			0xC4
  #define	AMR_PP_CIRDR0			0xC4
  #define	AMR_PP_CITDR1			0xC5
  #define	AMR_PP_CIRDR1			0xC5
  #define	AMR_PP_PPCR2			0xC8
  #define	AMR_PP_PPCR3			0xC9

  struct snd_amd7930 {

  	spinlock_t		lock;
  	void __iomem		*regs;
  	u32			flags;
  #define AMD7930_FLAG_PLAYBACK	0x00000001
  #define AMD7930_FLAG_CAPTURE	0x00000002
  
  	struct amd7930_map	map;

  	struct snd_card		*card;
  	struct snd_pcm		*pcm;
  	struct snd_pcm_substream	*playback_substream;
  	struct snd_pcm_substream	*capture_substream;

  
  	/* Playback/Capture buffer state. */
  	unsigned char		*p_orig, *p_cur;
  	int			p_left;
  	unsigned char		*c_orig, *c_cur;
  	int			c_left;
  
  	int			rgain;
  	int			pgain;
  	int			mgain;

  	unsigned int		irq;
  	unsigned int		regs_size;
  	struct snd_amd7930	*next;

  };

  static struct snd_amd7930 *amd7930_list;

  
  /* Idle the AMD7930 chip.  The amd->lock is not held.  */

  static __inline__ void amd7930_idle(struct snd_amd7930 *amd)

  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&amd->lock, flags);
  	sbus_writeb(AMR_INIT, amd->regs + AMD7930_CR);
  	sbus_writeb(0, amd->regs + AMD7930_DR);
  	spin_unlock_irqrestore(&amd->lock, flags);
  }
  
  /* Enable chip interrupts.  The amd->lock is not held.  */

  static __inline__ void amd7930_enable_ints(struct snd_amd7930 *amd)

  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&amd->lock, flags);
  	sbus_writeb(AMR_INIT, amd->regs + AMD7930_CR);
  	sbus_writeb(AM_INIT_ACTIVE, amd->regs + AMD7930_DR);
  	spin_unlock_irqrestore(&amd->lock, flags);
  }
  
  /* Disable chip interrupts.  The amd->lock is not held.  */

  static __inline__ void amd7930_disable_ints(struct snd_amd7930 *amd)

  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&amd->lock, flags);
  	sbus_writeb(AMR_INIT, amd->regs + AMD7930_CR);
  	sbus_writeb(AM_INIT_ACTIVE | AM_INIT_DISABLE_INTS, amd->regs + AMD7930_DR);
  	spin_unlock_irqrestore(&amd->lock, flags);
  }
  
  /* Commit amd7930_map settings to the hardware.
   * The amd->lock is held and local interrupts are disabled.
   */

  static void __amd7930_write_map(struct snd_amd7930 *amd)

  {
  	struct amd7930_map *map = &amd->map;
  
  	sbus_writeb(AMR_MAP_GX, amd->regs + AMD7930_CR);
  	sbus_writeb(((map->gx >> 0) & 0xff), amd->regs + AMD7930_DR);
  	sbus_writeb(((map->gx >> 8) & 0xff), amd->regs + AMD7930_DR);
  
  	sbus_writeb(AMR_MAP_GR, amd->regs + AMD7930_CR);
  	sbus_writeb(((map->gr >> 0) & 0xff), amd->regs + AMD7930_DR);
  	sbus_writeb(((map->gr >> 8) & 0xff), amd->regs + AMD7930_DR);
  
  	sbus_writeb(AMR_MAP_STGR, amd->regs + AMD7930_CR);
  	sbus_writeb(((map->stgr >> 0) & 0xff), amd->regs + AMD7930_DR);
  	sbus_writeb(((map->stgr >> 8) & 0xff), amd->regs + AMD7930_DR);
  
  	sbus_writeb(AMR_MAP_GER, amd->regs + AMD7930_CR);
  	sbus_writeb(((map->ger >> 0) & 0xff), amd->regs + AMD7930_DR);
  	sbus_writeb(((map->ger >> 8) & 0xff), amd->regs + AMD7930_DR);
  
  	sbus_writeb(AMR_MAP_MMR1, amd->regs + AMD7930_CR);
  	sbus_writeb(map->mmr1, amd->regs + AMD7930_DR);
  
  	sbus_writeb(AMR_MAP_MMR2, amd->regs + AMD7930_CR);
  	sbus_writeb(map->mmr2, amd->regs + AMD7930_DR);
  }
  
  /* gx, gr & stg gains.  this table must contain 256 elements with
   * the 0th being "infinity" (the magic value 9008).  The remaining
   * elements match sun's gain curve (but with higher resolution):
   * -18 to 0dB in .16dB steps then 0 to 12dB in .08dB steps.
   */
  static __const__ __u16 gx_coeff[256] = {
  	0x9008, 0x8b7c, 0x8b51, 0x8b45, 0x8b42, 0x8b3b, 0x8b36, 0x8b33,
  	0x8b32, 0x8b2a, 0x8b2b, 0x8b2c, 0x8b25, 0x8b23, 0x8b22, 0x8b22,
  	0x9122, 0x8b1a, 0x8aa3, 0x8aa3, 0x8b1c, 0x8aa6, 0x912d, 0x912b,
  	0x8aab, 0x8b12, 0x8aaa, 0x8ab2, 0x9132, 0x8ab4, 0x913c, 0x8abb,
  	0x9142, 0x9144, 0x9151, 0x8ad5, 0x8aeb, 0x8a79, 0x8a5a, 0x8a4a,
  	0x8b03, 0x91c2, 0x91bb, 0x8a3f, 0x8a33, 0x91b2, 0x9212, 0x9213,
  	0x8a2c, 0x921d, 0x8a23, 0x921a, 0x9222, 0x9223, 0x922d, 0x9231,
  	0x9234, 0x9242, 0x925b, 0x92dd, 0x92c1, 0x92b3, 0x92ab, 0x92a4,
  	0x92a2, 0x932b, 0x9341, 0x93d3, 0x93b2, 0x93a2, 0x943c, 0x94b2,
  	0x953a, 0x9653, 0x9782, 0x9e21, 0x9d23, 0x9cd2, 0x9c23, 0x9baa,
  	0x9bde, 0x9b33, 0x9b22, 0x9b1d, 0x9ab2, 0xa142, 0xa1e5, 0x9a3b,
  	0xa213, 0xa1a2, 0xa231, 0xa2eb, 0xa313, 0xa334, 0xa421, 0xa54b,
  	0xada4, 0xac23, 0xab3b, 0xaaab, 0xaa5c, 0xb1a3, 0xb2ca, 0xb3bd,
  	0xbe24, 0xbb2b, 0xba33, 0xc32b, 0xcb5a, 0xd2a2, 0xe31d, 0x0808,
  	0x72ba, 0x62c2, 0x5c32, 0x52db, 0x513e, 0x4cce, 0x43b2, 0x4243,
  	0x41b4, 0x3b12, 0x3bc3, 0x3df2, 0x34bd, 0x3334, 0x32c2, 0x3224,
  	0x31aa, 0x2a7b, 0x2aaa, 0x2b23, 0x2bba, 0x2c42, 0x2e23, 0x25bb,
  	0x242b, 0x240f, 0x231a, 0x22bb, 0x2241, 0x2223, 0x221f, 0x1a33,
  	0x1a4a, 0x1acd, 0x2132, 0x1b1b, 0x1b2c, 0x1b62, 0x1c12, 0x1c32,
  	0x1d1b, 0x1e71, 0x16b1, 0x1522, 0x1434, 0x1412, 0x1352, 0x1323,
  	0x1315, 0x12bc, 0x127a, 0x1235, 0x1226, 0x11a2, 0x1216, 0x0a2a,
  	0x11bc, 0x11d1, 0x1163, 0x0ac2, 0x0ab2, 0x0aab, 0x0b1b, 0x0b23,
  	0x0b33, 0x0c0f, 0x0bb3, 0x0c1b, 0x0c3e, 0x0cb1, 0x0d4c, 0x0ec1,
  	0x079a, 0x0614, 0x0521, 0x047c, 0x0422, 0x03b1, 0x03e3, 0x0333,
  	0x0322, 0x031c, 0x02aa, 0x02ba, 0x02f2, 0x0242, 0x0232, 0x0227,
  	0x0222, 0x021b, 0x01ad, 0x0212, 0x01b2, 0x01bb, 0x01cb, 0x01f6,
  	0x0152, 0x013a, 0x0133, 0x0131, 0x012c, 0x0123, 0x0122, 0x00a2,
  	0x011b, 0x011e, 0x0114, 0x00b1, 0x00aa, 0x00b3, 0x00bd, 0x00ba,
  	0x00c5, 0x00d3, 0x00f3, 0x0062, 0x0051, 0x0042, 0x003b, 0x0033,
  	0x0032, 0x002a, 0x002c, 0x0025, 0x0023, 0x0022, 0x001a, 0x0021,
  	0x001b, 0x001b, 0x001d, 0x0015, 0x0013, 0x0013, 0x0012, 0x0012,
  	0x000a, 0x000a, 0x0011, 0x0011, 0x000b, 0x000b, 0x000c, 0x000e,
  };
  
  static __const__ __u16 ger_coeff[] = {
  	0x431f, /* 5. dB */
  	0x331f, /* 5.5 dB */
  	0x40dd, /* 6. dB */
  	0x11dd, /* 6.5 dB */
  	0x440f, /* 7. dB */
  	0x411f, /* 7.5 dB */
  	0x311f, /* 8. dB */
  	0x5520, /* 8.5 dB */
  	0x10dd, /* 9. dB */
  	0x4211, /* 9.5 dB */
  	0x410f, /* 10. dB */
  	0x111f, /* 10.5 dB */
  	0x600b, /* 11. dB */
  	0x00dd, /* 11.5 dB */
  	0x4210, /* 12. dB */
  	0x110f, /* 13. dB */
  	0x7200, /* 14. dB */
  	0x2110, /* 15. dB */
  	0x2200, /* 15.9 dB */
  	0x000b, /* 16.9 dB */
  	0x000f  /* 18. dB */
  };
  
  /* Update amd7930_map settings and program them into the hardware.
   * The amd->lock is held and local interrupts are disabled.
   */

  static void __amd7930_update_map(struct snd_amd7930 *amd)

  {
  	struct amd7930_map *map = &amd->map;
  	int level;
  
  	map->gx = gx_coeff[amd->rgain];
  	map->stgr = gx_coeff[amd->mgain];
  	level = (amd->pgain * (256 + ARRAY_SIZE(ger_coeff))) >> 8;
  	if (level >= 256) {
  		map->ger = ger_coeff[level - 256];
  		map->gr = gx_coeff[255];
  	} else {
  		map->ger = ger_coeff[0];
  		map->gr = gx_coeff[level];
  	}
  	__amd7930_write_map(amd);
  }

  static irqreturn_t snd_amd7930_interrupt(int irq, void *dev_id)

  {

  	struct snd_amd7930 *amd = dev_id;

  	unsigned int elapsed;
  	u8 ir;
  
  	spin_lock(&amd->lock);
  
  	elapsed = 0;
  
  	ir = sbus_readb(amd->regs + AMD7930_IR);
  	if (ir & AMR_IR_BBUF) {
  		u8 byte;
  
  		if (amd->flags & AMD7930_FLAG_PLAYBACK) {
  			if (amd->p_left > 0) {
  				byte = *(amd->p_cur++);
  				amd->p_left--;
  				sbus_writeb(byte, amd->regs + AMD7930_BBTB);
  				if (amd->p_left == 0)
  					elapsed |= AMD7930_FLAG_PLAYBACK;
  			} else
  				sbus_writeb(0, amd->regs + AMD7930_BBTB);
  		} else if (amd->flags & AMD7930_FLAG_CAPTURE) {
  			byte = sbus_readb(amd->regs + AMD7930_BBRB);
  			if (amd->c_left > 0) {
  				*(amd->c_cur++) = byte;
  				amd->c_left--;
  				if (amd->c_left == 0)
  					elapsed |= AMD7930_FLAG_CAPTURE;
  			}
  		}
  	}
  	spin_unlock(&amd->lock);
  
  	if (elapsed & AMD7930_FLAG_PLAYBACK)
  		snd_pcm_period_elapsed(amd->playback_substream);
  	else
  		snd_pcm_period_elapsed(amd->capture_substream);
  
  	return IRQ_HANDLED;
  }

  static int snd_amd7930_trigger(struct snd_amd7930 *amd, unsigned int flag, int cmd)

  {
  	unsigned long flags;
  	int result = 0;
  
  	spin_lock_irqsave(&amd->lock, flags);
  	if (cmd == SNDRV_PCM_TRIGGER_START) {
  		if (!(amd->flags & flag)) {
  			amd->flags |= flag;
  
  			/* Enable B channel interrupts.  */
  			sbus_writeb(AMR_MUX_MCR4, amd->regs + AMD7930_CR);
  			sbus_writeb(AM_MUX_MCR4_ENABLE_INTS, amd->regs + AMD7930_DR);
  		}
  	} else if (cmd == SNDRV_PCM_TRIGGER_STOP) {
  		if (amd->flags & flag) {
  			amd->flags &= ~flag;
  
  			/* Disable B channel interrupts.  */
  			sbus_writeb(AMR_MUX_MCR4, amd->regs + AMD7930_CR);
  			sbus_writeb(0, amd->regs + AMD7930_DR);
  		}
  	} else {
  		result = -EINVAL;
  	}
  	spin_unlock_irqrestore(&amd->lock, flags);
  
  	return result;
  }

  static int snd_amd7930_playback_trigger(struct snd_pcm_substream *substream,

  					int cmd)
  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  	return snd_amd7930_trigger(amd, AMD7930_FLAG_PLAYBACK, cmd);
  }

  static int snd_amd7930_capture_trigger(struct snd_pcm_substream *substream,

  				       int cmd)
  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  	return snd_amd7930_trigger(amd, AMD7930_FLAG_CAPTURE, cmd);
  }

  static int snd_amd7930_playback_prepare(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  	unsigned int size = snd_pcm_lib_buffer_bytes(substream);
  	unsigned long flags;
  	u8 new_mmr1;
  
  	spin_lock_irqsave(&amd->lock, flags);
  
  	amd->flags |= AMD7930_FLAG_PLAYBACK;
  
  	/* Setup the pseudo-dma transfer pointers.  */
  	amd->p_orig = amd->p_cur = runtime->dma_area;
  	amd->p_left = size;
  
  	/* Put the chip into the correct encoding format.  */
  	new_mmr1 = amd->map.mmr1;
  	if (runtime->format == SNDRV_PCM_FORMAT_A_LAW)
  		new_mmr1 |= AM_MAP_MMR1_ALAW;
  	else
  		new_mmr1 &= ~AM_MAP_MMR1_ALAW;
  	if (new_mmr1 != amd->map.mmr1) {
  		amd->map.mmr1 = new_mmr1;
  		__amd7930_update_map(amd);
  	}
  
  	spin_unlock_irqrestore(&amd->lock, flags);
  
  	return 0;
  }

  static int snd_amd7930_capture_prepare(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  	unsigned int size = snd_pcm_lib_buffer_bytes(substream);
  	unsigned long flags;
  	u8 new_mmr1;
  
  	spin_lock_irqsave(&amd->lock, flags);
  
  	amd->flags |= AMD7930_FLAG_CAPTURE;
  
  	/* Setup the pseudo-dma transfer pointers.  */
  	amd->c_orig = amd->c_cur = runtime->dma_area;
  	amd->c_left = size;
  
  	/* Put the chip into the correct encoding format.  */
  	new_mmr1 = amd->map.mmr1;
  	if (runtime->format == SNDRV_PCM_FORMAT_A_LAW)
  		new_mmr1 |= AM_MAP_MMR1_ALAW;
  	else
  		new_mmr1 &= ~AM_MAP_MMR1_ALAW;
  	if (new_mmr1 != amd->map.mmr1) {
  		amd->map.mmr1 = new_mmr1;
  		__amd7930_update_map(amd);
  	}
  
  	spin_unlock_irqrestore(&amd->lock, flags);
  
  	return 0;
  }

  static snd_pcm_uframes_t snd_amd7930_playback_pointer(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  	size_t ptr;
  
  	if (!(amd->flags & AMD7930_FLAG_PLAYBACK))
  		return 0;
  	ptr = amd->p_cur - amd->p_orig;
  	return bytes_to_frames(substream->runtime, ptr);
  }

  static snd_pcm_uframes_t snd_amd7930_capture_pointer(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  	size_t ptr;
  
  	if (!(amd->flags & AMD7930_FLAG_CAPTURE))
  		return 0;
  
  	ptr = amd->c_cur - amd->c_orig;
  	return bytes_to_frames(substream->runtime, ptr);
  }
  
  /* Playback and capture have identical properties.  */

  static struct snd_pcm_hardware snd_amd7930_pcm_hw =

  {
  	.info			= (SNDRV_PCM_INFO_MMAP |
  				   SNDRV_PCM_INFO_MMAP_VALID |
  				   SNDRV_PCM_INFO_INTERLEAVED |
  				   SNDRV_PCM_INFO_BLOCK_TRANSFER |
  				   SNDRV_PCM_INFO_HALF_DUPLEX),
  	.formats		= SNDRV_PCM_FMTBIT_MU_LAW | SNDRV_PCM_FMTBIT_A_LAW,
  	.rates			= SNDRV_PCM_RATE_8000,
  	.rate_min		= 8000,
  	.rate_max		= 8000,
  	.channels_min		= 1,
  	.channels_max		= 1,
  	.buffer_bytes_max	= (64*1024),
  	.period_bytes_min	= 1,
  	.period_bytes_max	= (64*1024),
  	.periods_min		= 1,
  	.periods_max		= 1024,
  };

  static int snd_amd7930_playback_open(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  
  	amd->playback_substream = substream;
  	runtime->hw = snd_amd7930_pcm_hw;
  	return 0;
  }

  static int snd_amd7930_capture_open(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  
  	amd->capture_substream = substream;
  	runtime->hw = snd_amd7930_pcm_hw;
  	return 0;
  }

  static int snd_amd7930_playback_close(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  
  	amd->playback_substream = NULL;
  	return 0;
  }

  static int snd_amd7930_capture_close(struct snd_pcm_substream *substream)

  {

  	struct snd_amd7930 *amd = snd_pcm_substream_chip(substream);

  
  	amd->capture_substream = NULL;
  	return 0;
  }

  static int snd_amd7930_hw_params(struct snd_pcm_substream *substream,
  				    struct snd_pcm_hw_params *hw_params)

  {
  	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
  }

  static int snd_amd7930_hw_free(struct snd_pcm_substream *substream)

  {
  	return snd_pcm_lib_free_pages(substream);
  }

  static struct snd_pcm_ops snd_amd7930_playback_ops = {

  	.open		=	snd_amd7930_playback_open,
  	.close		=	snd_amd7930_playback_close,
  	.ioctl		=	snd_pcm_lib_ioctl,
  	.hw_params	=	snd_amd7930_hw_params,
  	.hw_free	=	snd_amd7930_hw_free,
  	.prepare	=	snd_amd7930_playback_prepare,
  	.trigger	=	snd_amd7930_playback_trigger,
  	.pointer	=	snd_amd7930_playback_pointer,
  };

  static struct snd_pcm_ops snd_amd7930_capture_ops = {

  	.open		=	snd_amd7930_capture_open,
  	.close		=	snd_amd7930_capture_close,
  	.ioctl		=	snd_pcm_lib_ioctl,
  	.hw_params	=	snd_amd7930_hw_params,
  	.hw_free	=	snd_amd7930_hw_free,
  	.prepare	=	snd_amd7930_capture_prepare,
  	.trigger	=	snd_amd7930_capture_trigger,
  	.pointer	=	snd_amd7930_capture_pointer,
  };

  static int __devinit snd_amd7930_pcm(struct snd_amd7930 *amd)

  {

  	struct snd_pcm *pcm;

  	int err;
  
  	if ((err = snd_pcm_new(amd->card,
  			       /* ID */             "sun_amd7930",
  			       /* device */         0,
  			       /* playback count */ 1,
  			       /* capture count */  1, &pcm)) < 0)
  		return err;
  	snd_assert(pcm != NULL, return -EINVAL);
  
  	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_amd7930_playback_ops);
  	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_amd7930_capture_ops);
  
  	pcm->private_data = amd;

  	pcm->info_flags = 0;
  	strcpy(pcm->name, amd->card->shortname);
  	amd->pcm = pcm;
  
  	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
  					      snd_dma_continuous_data(GFP_KERNEL),
  					      64*1024, 64*1024);
  
  	return 0;
  }
  
  #define VOLUME_MONITOR	0
  #define VOLUME_CAPTURE	1
  #define VOLUME_PLAYBACK	2

  static int snd_amd7930_info_volume(struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)

  {
  	int type = kctl->private_value;
  
  	snd_assert(type == VOLUME_MONITOR ||
  		   type == VOLUME_CAPTURE ||
  		   type == VOLUME_PLAYBACK, return -EINVAL);
  	(void) type;
  
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
  	uinfo->count = 1;
  	uinfo->value.integer.min = 0;
  	uinfo->value.integer.max = 255;
  
  	return 0;
  }

  static int snd_amd7930_get_volume(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)

  {

  	struct snd_amd7930 *amd = snd_kcontrol_chip(kctl);

  	int type = kctl->private_value;
  	int *swval;
  
  	snd_assert(type == VOLUME_MONITOR ||
  		   type == VOLUME_CAPTURE ||
  		   type == VOLUME_PLAYBACK, return -EINVAL);
  
  	switch (type) {
  	case VOLUME_MONITOR:
  		swval = &amd->mgain;
  		break;
  	case VOLUME_CAPTURE:
  		swval = &amd->rgain;
  		break;
  	case VOLUME_PLAYBACK:
  	default:
  		swval = &amd->pgain;
  		break;
  	};
  
  	ucontrol->value.integer.value[0] = *swval;
  
  	return 0;
  }

  static int snd_amd7930_put_volume(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)

  {

  	struct snd_amd7930 *amd = snd_kcontrol_chip(kctl);

  	unsigned long flags;
  	int type = kctl->private_value;
  	int *swval, change;
  
  	snd_assert(type == VOLUME_MONITOR ||
  		   type == VOLUME_CAPTURE ||
  		   type == VOLUME_PLAYBACK, return -EINVAL);
  
  	switch (type) {
  	case VOLUME_MONITOR:
  		swval = &amd->mgain;
  		break;
  	case VOLUME_CAPTURE:
  		swval = &amd->rgain;
  		break;
  	case VOLUME_PLAYBACK:
  	default:
  		swval = &amd->pgain;
  		break;
  	};
  
  	spin_lock_irqsave(&amd->lock, flags);
  
  	if (*swval != ucontrol->value.integer.value[0]) {
  		*swval = ucontrol->value.integer.value[0];
  		__amd7930_update_map(amd);
  		change = 1;
  	} else
  		change = 0;
  
  	spin_unlock_irqrestore(&amd->lock, flags);
  
  	return change;
  }

  static struct snd_kcontrol_new amd7930_controls[] __devinitdata = {

  	{
  		.iface		=	SNDRV_CTL_ELEM_IFACE_MIXER,
  		.name		=	"Monitor Volume",
  		.index		=	0,
  		.info		=	snd_amd7930_info_volume,
  		.get		=	snd_amd7930_get_volume,
  		.put		=	snd_amd7930_put_volume,
  		.private_value	=	VOLUME_MONITOR,
  	},
  	{
  		.iface		=	SNDRV_CTL_ELEM_IFACE_MIXER,
  		.name		=	"Capture Volume",
  		.index		=	0,
  		.info		=	snd_amd7930_info_volume,
  		.get		=	snd_amd7930_get_volume,
  		.put		=	snd_amd7930_put_volume,
  		.private_value	=	VOLUME_CAPTURE,
  	},
  	{
  		.iface		=	SNDRV_CTL_ELEM_IFACE_MIXER,
  		.name		=	"Playback Volume",
  		.index		=	0,
  		.info		=	snd_amd7930_info_volume,
  		.get		=	snd_amd7930_get_volume,
  		.put		=	snd_amd7930_put_volume,
  		.private_value	=	VOLUME_PLAYBACK,
  	},
  };

  static int __devinit snd_amd7930_mixer(struct snd_amd7930 *amd)

  {

  	struct snd_card *card;

  	int idx, err;
  
  	snd_assert(amd != NULL && amd->card != NULL, return -EINVAL);
  
  	card = amd->card;
  	strcpy(card->mixername, card->shortname);
  
  	for (idx = 0; idx < ARRAY_SIZE(amd7930_controls); idx++) {
  		if ((err = snd_ctl_add(card,
  				       snd_ctl_new1(&amd7930_controls[idx], amd))) < 0)
  			return err;
  	}
  
  	return 0;
  }

  static int snd_amd7930_free(struct snd_amd7930 *amd)

  {
  	amd7930_idle(amd);
  
  	if (amd->irq)
  		free_irq(amd->irq, amd);
  
  	if (amd->regs)
  		sbus_iounmap(amd->regs, amd->regs_size);
  
  	kfree(amd);
  
  	return 0;
  }

  static int snd_amd7930_dev_free(struct snd_device *device)

  {

  	struct snd_amd7930 *amd = device->device_data;

  
  	return snd_amd7930_free(amd);
  }

  static struct snd_device_ops snd_amd7930_dev_ops = {

  	.dev_free	=	snd_amd7930_dev_free,
  };

  static int __devinit snd_amd7930_create(struct snd_card *card,
  					struct resource *rp,
  					unsigned int reg_size,
  					int irq, int dev,
  					struct snd_amd7930 **ramd)

  {
  	unsigned long flags;

  	struct snd_amd7930 *amd;

  	int err;
  
  	*ramd = NULL;

  	amd = kzalloc(sizeof(*amd), GFP_KERNEL);

  	if (amd == NULL)
  		return -ENOMEM;
  
  	spin_lock_init(&amd->lock);
  	amd->card = card;

  	amd->regs_size = reg_size;
  
  	amd->regs = sbus_ioremap(rp, 0, amd->regs_size, "amd7930");
  	if (!amd->regs) {
  		snd_printk("amd7930-%d: Unable to map chip registers.
  ", dev);
  		return -EIO;
  	}
  
  	amd7930_idle(amd);

  	if (request_irq(irq, snd_amd7930_interrupt,

  			IRQF_DISABLED | IRQF_SHARED, "amd7930", amd)) {

  		snd_printk("amd7930-%d: Unable to grab IRQ %d
  ",

  			   dev, irq);

  		snd_amd7930_free(amd);
  		return -EBUSY;
  	}

  	amd->irq = irq;

  
  	amd7930_enable_ints(amd);
  
  	spin_lock_irqsave(&amd->lock, flags);
  
  	amd->rgain = 128;
  	amd->pgain = 200;
  	amd->mgain = 0;
  
  	memset(&amd->map, 0, sizeof(amd->map));
  	amd->map.mmr1 = (AM_MAP_MMR1_GX | AM_MAP_MMR1_GER |
  			 AM_MAP_MMR1_GR | AM_MAP_MMR1_STG);
  	amd->map.mmr2 = (AM_MAP_MMR2_LS | AM_MAP_MMR2_AINB);
  
  	__amd7930_update_map(amd);
  
  	/* Always MUX audio (Ba) to channel Bb. */
  	sbus_writeb(AMR_MUX_MCR1, amd->regs + AMD7930_CR);
  	sbus_writeb(AM_MUX_CHANNEL_Ba | (AM_MUX_CHANNEL_Bb << 4),
  		    amd->regs + AMD7930_DR);
  
  	spin_unlock_irqrestore(&amd->lock, flags);
  
  	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL,
  				  amd, &snd_amd7930_dev_ops)) < 0) {
  		snd_amd7930_free(amd);
  		return err;
  	}
  
  	*ramd = amd;
  	return 0;
  }

  static int __devinit amd7930_attach_common(struct resource *rp, int irq)

  {

  	static int dev_num;

  	struct snd_card *card;
  	struct snd_amd7930 *amd;

  	int err;

  	if (dev_num >= SNDRV_CARDS)

  		return -ENODEV;

  	if (!enable[dev_num]) {
  		dev_num++;

  		return -ENOENT;
  	}

  	card = snd_card_new(index[dev_num], id[dev_num], THIS_MODULE, 0);

  	if (card == NULL)
  		return -ENOMEM;
  
  	strcpy(card->driver, "AMD7930");
  	strcpy(card->shortname, "Sun AMD7930");

  	sprintf(card->longname, "%s at 0x%02lx:0x%08Lx, irq %d",

  		card->shortname,
  		rp->flags & 0xffL,

  		(unsigned long long)rp->start,

  		irq);

  	if ((err = snd_amd7930_create(card, rp,
  				      (rp->end - rp->start) + 1,
  				      irq, dev_num, &amd)) < 0)

  		goto out_err;
  
  	if ((err = snd_amd7930_pcm(amd)) < 0)
  		goto out_err;
  
  	if ((err = snd_amd7930_mixer(amd)) < 0)
  		goto out_err;
  
  	if ((err = snd_card_register(card)) < 0)
  		goto out_err;
  
  	amd->next = amd7930_list;
  	amd7930_list = amd;

  	dev_num++;

  	return 0;
  
  out_err:
  	snd_card_free(card);
  	return err;
  }

  static int __devinit amd7930_obio_attach(struct device_node *dp)

  {

  	const struct linux_prom_registers *regs;
  	const struct linux_prom_irqs *irqp;

  	struct resource res, *rp;
  	int len;
  
  	irqp = of_get_property(dp, "intr", &len);
  	if (!irqp) {
  		snd_printk("%s: Firmware node lacks IRQ property.
  ",
  			   dp->full_name);
  		return -ENODEV;
  	}
  
  	regs = of_get_property(dp, "reg", &len);
  	if (!regs) {
  		snd_printk("%s: Firmware node lacks register property.
  ",
  			   dp->full_name);
  		return -ENODEV;
  	}
  
  	rp = &res;
  	rp->start = regs->phys_addr;
  	rp->end = rp->start + regs->reg_size - 1;
  	rp->flags = IORESOURCE_IO | (regs->which_io & 0xff);
  
  	return amd7930_attach_common(rp, irqp->pri);
  }
  
  static int __devinit amd7930_sbus_probe(struct of_device *dev, const struct of_device_id *match)

  {

  	struct sbus_dev *sdev = to_sbus_device(&dev->dev);

  	return amd7930_attach_common(&sdev->resource[0], sdev->irqs[0]);
  }
  
  static struct of_device_id amd7930_match[] = {
  	{
  		.name = "audio",
  	},
  	{},
  };
  
  static struct of_platform_driver amd7930_sbus_driver = {
  	.name		= "audio",
  	.match_table	= amd7930_match,
  	.probe		= amd7930_sbus_probe,
  };
  
  static int __init amd7930_init(void)
  {
  	struct device_node *dp;

  
  	/* Try to find the sun4c "audio" node first. */

  	dp = of_find_node_by_path("/");
  	dp = dp->child;
  	while (dp) {
  		if (!strcmp(dp->name, "audio"))
  			amd7930_obio_attach(dp);

  		dp = dp->sibling;

  	}

  	/* Probe each SBUS for amd7930 chips. */
  	return of_register_driver(&amd7930_sbus_driver, &sbus_bus_type);

  }
  
  static void __exit amd7930_exit(void)
  {

  	struct snd_amd7930 *p = amd7930_list;

  
  	while (p != NULL) {

  		struct snd_amd7930 *next = p->next;

  
  		snd_card_free(p->card);
  
  		p = next;
  	}
  
  	amd7930_list = NULL;

  
  	of_unregister_driver(&amd7930_sbus_driver);

  }
  
  module_init(amd7930_init);
  module_exit(amd7930_exit);