cx25821-alsa.c

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/*
 *  Driver for the Conexant CX25821 PCIe bridge
 *
 *  Copyright (C) 2009 Conexant Systems Inc.
 *  Authors  <[email protected]>, <[email protected]>
 *  Based on SAA713x ALSA driver and CX88 driver
 *
 *   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, version 2
 *
 *   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
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/vmalloc.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include <linux/delay.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/control.h>
#include <sound/initval.h>
#include <sound/tlv.h>

#include "cx25821.h"
#include "cx25821-reg.h"

#define AUDIO_SRAM_CHANNEL  SRAM_CH08

#define dprintk(level, fmt, arg...)             \
do {                                \
    if (debug >= level)                 \
        pr_info("%s/1: " fmt, chip->dev->name, ##arg);  \
} while (0)
#define dprintk_core(level, fmt, arg...)                \
do {                                    \
    if (debug >= level)                     \
        printk(KERN_DEBUG "%s/1: " fmt, chip->dev->name, ##arg); \
} while (0)

/****************************************************************************
    Data type declarations - Can be moded to a header file later
 ****************************************************************************/

static struct snd_card *snd_cx25821_cards[SNDRV_CARDS];
static int devno;

struct cx25821_audio_buffer {
    unsigned int bpl;
    struct btcx_riscmem risc;
    struct videobuf_dmabuf dma;
};

struct cx25821_audio_dev {
    struct cx25821_dev *dev;
    struct cx25821_dmaqueue q;

    /* pci i/o */
    struct pci_dev *pci;

    /* audio controls */
    int irq;

    struct snd_card *card;

    unsigned long iobase;
    spinlock_t reg_lock;
    atomic_t count;

    unsigned int dma_size;
    unsigned int period_size;
    unsigned int num_periods;

    struct videobuf_dmabuf *dma_risc;

    struct cx25821_audio_buffer *buf;

    struct snd_pcm_substream *substream;
};


/****************************************************************************
            Module global static vars
 ****************************************************************************/

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;  /* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;   /* ID for this card */
static bool enable[SNDRV_CARDS] = { 1, [1 ... (SNDRV_CARDS - 1)] = 1 };

module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable cx25821 soundcard. default enabled.");

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for cx25821 capture interface(s).");

/****************************************************************************
                Module macros
 ****************************************************************************/

MODULE_DESCRIPTION("ALSA driver module for cx25821 based capture cards");
MODULE_AUTHOR("Hiep Huynh");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Conexant,25821}");   /* "{{Conexant,23881}," */

static unsigned int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "enable debug messages");

/****************************************************************************
            Module specific funtions
 ****************************************************************************/
/* Constants taken from cx88-reg.h */
#define AUD_INT_DN_RISCI1       (1 <<  0)
#define AUD_INT_UP_RISCI1       (1 <<  1)
#define AUD_INT_RDS_DN_RISCI1   (1 <<  2)
#define AUD_INT_DN_RISCI2       (1 <<  4)   /* yes, 3 is skipped */
#define AUD_INT_UP_RISCI2       (1 <<  5)
#define AUD_INT_RDS_DN_RISCI2   (1 <<  6)
#define AUD_INT_DN_SYNC         (1 << 12)
#define AUD_INT_UP_SYNC         (1 << 13)
#define AUD_INT_RDS_DN_SYNC     (1 << 14)
#define AUD_INT_OPC_ERR         (1 << 16)
#define AUD_INT_BER_IRQ         (1 << 20)
#define AUD_INT_MCHG_IRQ        (1 << 21)
#define GP_COUNT_CONTROL_RESET  0x3

#define PCI_MSK_AUD_EXT   (1 <<  4)
#define PCI_MSK_AUD_INT   (1 <<  3)
/*
 * BOARD Specific: Sets audio DMA
 */

static int _cx25821_start_audio_dma(struct cx25821_audio_dev *chip)
{
    struct cx25821_audio_buffer *buf = chip->buf;
    struct cx25821_dev *dev = chip->dev;
    struct sram_channel *audio_ch =
        &cx25821_sram_channels[AUDIO_SRAM_CHANNEL];
    u32 tmp = 0;

    /* enable output on the GPIO 0 for the MCLK ADC (Audio) */
    cx25821_set_gpiopin_direction(chip->dev, 0, 0);

    /* Make sure RISC/FIFO are off before changing FIFO/RISC settings */
    cx_clear(AUD_INT_DMA_CTL,
         FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);

    /* setup fifo + format - out channel */
    cx25821_sram_channel_setup_audio(chip->dev, audio_ch, buf->bpl,
                     buf->risc.dma);

    /* sets bpl size */
    cx_write(AUD_A_LNGTH, buf->bpl);

    /* reset counter */
    /* GP_COUNT_CONTROL_RESET = 0x3 */
    cx_write(AUD_A_GPCNT_CTL, GP_COUNT_CONTROL_RESET);
    atomic_set(&chip->count, 0);

    /* Set the input mode to 16-bit */
    tmp = cx_read(AUD_A_CFG);
    cx_write(AUD_A_CFG, tmp | FLD_AUD_DST_PK_MODE | FLD_AUD_DST_ENABLE |
         FLD_AUD_CLK_ENABLE);

    /*
    pr_info("DEBUG: Start audio DMA, %d B/line, cmds_start(0x%x)= %d lines/FIFO, %d periods, %d byte buffer\n",
        buf->bpl, audio_ch->cmds_start,
        cx_read(audio_ch->cmds_start + 12)>>1,
        chip->num_periods, buf->bpl * chip->num_periods);
    */

    /* Enables corresponding bits at AUD_INT_STAT */
    cx_write(AUD_A_INT_MSK, FLD_AUD_DST_RISCI1 | FLD_AUD_DST_OF |
         FLD_AUD_DST_SYNC | FLD_AUD_DST_OPC_ERR);

    /* Clean any pending interrupt bits already set */
    cx_write(AUD_A_INT_STAT, ~0);

    /* enable audio irqs */
    cx_set(PCI_INT_MSK, chip->dev->pci_irqmask | PCI_MSK_AUD_INT);

    /* Turn on audio downstream fifo and risc enable 0x101 */
    tmp = cx_read(AUD_INT_DMA_CTL);
    cx_set(AUD_INT_DMA_CTL, tmp |
           (FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN));

    mdelay(100);
    return 0;
}

/*
 * BOARD Specific: Resets audio DMA
 */
static int _cx25821_stop_audio_dma(struct cx25821_audio_dev *chip)
{
    struct cx25821_dev *dev = chip->dev;

    /* stop dma */
    cx_clear(AUD_INT_DMA_CTL,
         FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);

    /* disable irqs */
    cx_clear(PCI_INT_MSK, PCI_MSK_AUD_INT);
    cx_clear(AUD_A_INT_MSK, AUD_INT_OPC_ERR | AUD_INT_DN_SYNC |
         AUD_INT_DN_RISCI2 | AUD_INT_DN_RISCI1);

    return 0;
}

#define MAX_IRQ_LOOP 50

/*
 * BOARD Specific: IRQ dma bits
 */
static char *cx25821_aud_irqs[32] = {
    "dn_risci1", "up_risci1", "rds_dn_risc1",   /* 0-2 */
    NULL,                       /* reserved */
    "dn_risci2", "up_risci2", "rds_dn_risc2",   /* 4-6 */
    NULL,                       /* reserved */
    "dnf_of", "upf_uf", "rds_dnf_uf",       /* 8-10 */
    NULL,                       /* reserved */
    "dn_sync", "up_sync", "rds_dn_sync",        /* 12-14 */
    NULL,                       /* reserved */
    "opc_err", "par_err", "rip_err",        /* 16-18 */
    "pci_abort", "ber_irq", "mchg_irq"      /* 19-21 */
};

/*
 * BOARD Specific: Threats IRQ audio specific calls
 */
static void cx25821_aud_irq(struct cx25821_audio_dev *chip, u32 status,
                u32 mask)
{
    struct cx25821_dev *dev = chip->dev;

    if (0 == (status & mask))
        return;

    cx_write(AUD_A_INT_STAT, status);
    if (debug > 1 || (status & mask & ~0xff))
        cx25821_print_irqbits(dev->name, "irq aud", cx25821_aud_irqs,
                ARRAY_SIZE(cx25821_aud_irqs), status, mask);

    /* risc op code error */
    if (status & AUD_INT_OPC_ERR) {
        pr_warn("WARNING %s/1: Audio risc op code error\n", dev->name);

        cx_clear(AUD_INT_DMA_CTL,
             FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);
        cx25821_sram_channel_dump_audio(dev,
                &cx25821_sram_channels[AUDIO_SRAM_CHANNEL]);
    }
    if (status & AUD_INT_DN_SYNC) {
        pr_warn("WARNING %s: Downstream sync error!\n", dev->name);
        cx_write(AUD_A_GPCNT_CTL, GP_COUNT_CONTROL_RESET);
        return;
    }

    /* risc1 downstream */
    if (status & AUD_INT_DN_RISCI1) {
        atomic_set(&chip->count, cx_read(AUD_A_GPCNT));
        snd_pcm_period_elapsed(chip->substream);
    }
}

/*
 * BOARD Specific: Handles IRQ calls
 */
static irqreturn_t cx25821_irq(int irq, void *dev_id)
{
    struct cx25821_audio_dev *chip = dev_id;
    struct cx25821_dev *dev = chip->dev;
    u32 status, pci_status;
    u32 audint_status, audint_mask;
    int loop, handled = 0;

    audint_status = cx_read(AUD_A_INT_STAT);
    audint_mask = cx_read(AUD_A_INT_MSK);
    status = cx_read(PCI_INT_STAT);

    for (loop = 0; loop < 1; loop++) {
        status = cx_read(PCI_INT_STAT);
        if (0 == status) {
            status = cx_read(PCI_INT_STAT);
            audint_status = cx_read(AUD_A_INT_STAT);
            audint_mask = cx_read(AUD_A_INT_MSK);

            if (status) {
                handled = 1;
                cx_write(PCI_INT_STAT, status);

                cx25821_aud_irq(chip, audint_status,
                        audint_mask);
                break;
            } else {
                goto out;
            }
        }

        handled = 1;
        cx_write(PCI_INT_STAT, status);

        cx25821_aud_irq(chip, audint_status, audint_mask);
    }

    pci_status = cx_read(PCI_INT_STAT);

    if (handled)
        cx_write(PCI_INT_STAT, pci_status);

out:
    return IRQ_RETVAL(handled);
}

static int dsp_buffer_free(struct cx25821_audio_dev *chip)
{
    BUG_ON(!chip->dma_size);

    dprintk(2, "Freeing buffer\n");
    videobuf_dma_unmap(&chip->pci->dev, chip->dma_risc);
    videobuf_dma_free(chip->dma_risc);
    btcx_riscmem_free(chip->pci, &chip->buf->risc);
    kfree(chip->buf);

    chip->dma_risc = NULL;
    chip->dma_size = 0;

    return 0;
}

/****************************************************************************
                ALSA PCM Interface
 ****************************************************************************/

/*
 * Digital hardware definition
 */
#define DEFAULT_FIFO_SIZE   384
static struct snd_pcm_hardware snd_cx25821_digital_hw = {
    .info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
        SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP_VALID,
    .formats = SNDRV_PCM_FMTBIT_S16_LE,

    .rates = SNDRV_PCM_RATE_48000,
    .rate_min = 48000,
    .rate_max = 48000,
    .channels_min = 2,
    .channels_max = 2,
    /* Analog audio output will be full of clicks and pops if there
       are not exactly four lines in the SRAM FIFO buffer.  */
    .period_bytes_min = DEFAULT_FIFO_SIZE / 3,
    .period_bytes_max = DEFAULT_FIFO_SIZE / 3,
    .periods_min = 1,
    .periods_max = AUDIO_LINE_SIZE,
    /* 128 * 128 = 16384 = 1024 * 16 */
    .buffer_bytes_max = (AUDIO_LINE_SIZE * AUDIO_LINE_SIZE),
};

/*
 * audio pcm capture open callback
 */
static int snd_cx25821_pcm_open(struct snd_pcm_substream *substream)
{
    struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;
    int err;
    unsigned int bpl = 0;

    if (!chip) {
        pr_err("DEBUG: cx25821 can't find device struct. Can't proceed with open\n");
        return -ENODEV;
    }

    err = snd_pcm_hw_constraint_pow2(runtime, 0,
                     SNDRV_PCM_HW_PARAM_PERIODS);
    if (err < 0)
        goto _error;

    chip->substream = substream;

    runtime->hw = snd_cx25821_digital_hw;

    if (cx25821_sram_channels[AUDIO_SRAM_CHANNEL].fifo_size !=
        DEFAULT_FIFO_SIZE) {
        /* since there are 3 audio Clusters */
        bpl = cx25821_sram_channels[AUDIO_SRAM_CHANNEL].fifo_size / 3;
        bpl &= ~7;  /* must be multiple of 8 */

        if (bpl > AUDIO_LINE_SIZE)
            bpl = AUDIO_LINE_SIZE;

        runtime->hw.period_bytes_min = bpl;
        runtime->hw.period_bytes_max = bpl;
    }

    return 0;
_error:
    dprintk(1, "Error opening PCM!\n");
    return err;
}

/*
 * audio close callback
 */
static int snd_cx25821_close(struct snd_pcm_substream *substream)
{
    return 0;
}

/*
 * hw_params callback
 */
static int snd_cx25821_hw_params(struct snd_pcm_substream *substream,
                 struct snd_pcm_hw_params *hw_params)
{
    struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
    struct videobuf_dmabuf *dma;

    struct cx25821_audio_buffer *buf;
    int ret;

    if (substream->runtime->dma_area) {
        dsp_buffer_free(chip);
        substream->runtime->dma_area = NULL;
    }

    chip->period_size = params_period_bytes(hw_params);
    chip->num_periods = params_periods(hw_params);
    chip->dma_size = chip->period_size * params_periods(hw_params);

    BUG_ON(!chip->dma_size);
    BUG_ON(chip->num_periods & (chip->num_periods - 1));

    buf = kzalloc(sizeof(*buf), GFP_KERNEL);
    if (NULL == buf)
        return -ENOMEM;

    if (chip->period_size > AUDIO_LINE_SIZE)
        chip->period_size = AUDIO_LINE_SIZE;

    buf->bpl = chip->period_size;

    dma = &buf->dma;
    videobuf_dma_init(dma);
    ret = videobuf_dma_init_kernel(dma, PCI_DMA_FROMDEVICE,
            (PAGE_ALIGN(chip->dma_size) >> PAGE_SHIFT));
    if (ret < 0)
        goto error;

    ret = videobuf_dma_map(&chip->pci->dev, dma);
    if (ret < 0)
        goto error;

    ret = cx25821_risc_databuffer_audio(chip->pci, &buf->risc, dma->sglist,
            chip->period_size, chip->num_periods, 1);
    if (ret < 0) {
        pr_info("DEBUG: ERROR after cx25821_risc_databuffer_audio()\n");
        goto error;
    }

    /* Loop back to start of program */
    buf->risc.jmp[0] = cpu_to_le32(RISC_JUMP | RISC_IRQ1 | RISC_CNT_INC);
    buf->risc.jmp[1] = cpu_to_le32(buf->risc.dma);
    buf->risc.jmp[2] = cpu_to_le32(0);  /* bits 63-32 */

    chip->buf = buf;
    chip->dma_risc = dma;

    substream->runtime->dma_area = chip->dma_risc->vaddr;
    substream->runtime->dma_bytes = chip->dma_size;
    substream->runtime->dma_addr = 0;

    return 0;

error:
    kfree(buf);
    return ret;
}

/*
 * hw free callback
 */
static int snd_cx25821_hw_free(struct snd_pcm_substream *substream)
{
    struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);

    if (substream->runtime->dma_area) {
        dsp_buffer_free(chip);
        substream->runtime->dma_area = NULL;
    }

    return 0;
}

/*
 * prepare callback
 */
static int snd_cx25821_prepare(struct snd_pcm_substream *substream)
{
    return 0;
}

/*
 * trigger callback
 */
static int snd_cx25821_card_trigger(struct snd_pcm_substream *substream,
                    int cmd)
{
    struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
    int err = 0;

    /* Local interrupts are already disabled by ALSA */
    spin_lock(&chip->reg_lock);

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        err = _cx25821_start_audio_dma(chip);
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        err = _cx25821_stop_audio_dma(chip);
        break;
    default:
        err = -EINVAL;
        break;
    }

    spin_unlock(&chip->reg_lock);

    return err;
}

/*
 * pointer callback
 */
static snd_pcm_uframes_t snd_cx25821_pointer(struct snd_pcm_substream
                         *substream)
{
    struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;
    u16 count;

    count = atomic_read(&chip->count);

    return runtime->period_size * (count & (runtime->periods - 1));
}

/*
 * page callback (needed for mmap)
 */
static struct page *snd_cx25821_page(struct snd_pcm_substream *substream,
                     unsigned long offset)
{
    void *pageptr = substream->runtime->dma_area + offset;

    return vmalloc_to_page(pageptr);
}

/*
 * operators
 */
static struct snd_pcm_ops snd_cx25821_pcm_ops = {
    .open = snd_cx25821_pcm_open,
    .close = snd_cx25821_close,
    .ioctl = snd_pcm_lib_ioctl,
    .hw_params = snd_cx25821_hw_params,
    .hw_free = snd_cx25821_hw_free,
    .prepare = snd_cx25821_prepare,
    .trigger = snd_cx25821_card_trigger,
    .pointer = snd_cx25821_pointer,
    .page = snd_cx25821_page,
};

/*
 * ALSA create a PCM device:  Called when initializing the board.
 * Sets up the name and hooks up the callbacks
 */
static int snd_cx25821_pcm(struct cx25821_audio_dev *chip, int device,
               char *name)
{
    struct snd_pcm *pcm;
    int err;

    err = snd_pcm_new(chip->card, name, device, 0, 1, &pcm);
    if (err < 0) {
        pr_info("ERROR: FAILED snd_pcm_new() in %s\n", __func__);
        return err;
    }
    pcm->private_data = chip;
    pcm->info_flags = 0;
    strcpy(pcm->name, name);
    snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_cx25821_pcm_ops);

    return 0;
}

/****************************************************************************
            Basic Flow for Sound Devices
 ****************************************************************************/

/*
 * PCI ID Table - 14f1:8801 and 14f1:8811 means function 1: Audio
 * Only boards with eeprom and byte 1 at eeprom=1 have it
 */

static DEFINE_PCI_DEVICE_TABLE(cx25821_audio_pci_tbl) = {
    {0x14f1, 0x0920, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
    {0,}
};

MODULE_DEVICE_TABLE(pci, cx25821_audio_pci_tbl);

/*
 * Not used in the function snd_cx25821_dev_free so removing
 * from the file.
 */
/*
static int snd_cx25821_free(struct cx25821_audio_dev *chip)
{
    if (chip->irq >= 0)
        free_irq(chip->irq, chip);

    cx25821_dev_unregister(chip->dev);
    pci_disable_device(chip->pci);

    return 0;
}
*/

/*
 * Component Destructor
 */
static void snd_cx25821_dev_free(struct snd_card *card)
{
    struct cx25821_audio_dev *chip = card->private_data;

    /* snd_cx25821_free(chip); */
    snd_card_free(chip->card);
}

/*
 * Alsa Constructor - Component probe
 */
static int cx25821_audio_initdev(struct cx25821_dev *dev)
{
    struct snd_card *card;
    struct cx25821_audio_dev *chip;
    int err;

    if (devno >= SNDRV_CARDS) {
        pr_info("DEBUG ERROR: devno >= SNDRV_CARDS %s\n", __func__);
        return -ENODEV;
    }

    if (!enable[devno]) {
        ++devno;
        pr_info("DEBUG ERROR: !enable[devno] %s\n", __func__);
        return -ENOENT;
    }

    err = snd_card_create(index[devno], id[devno], THIS_MODULE,
            sizeof(struct cx25821_audio_dev), &card);
    if (err < 0) {
        pr_info("DEBUG ERROR: cannot create snd_card_new in %s\n",
            __func__);
        return err;
    }

    strcpy(card->driver, "cx25821");

    /* Card "creation" */
    card->private_free = snd_cx25821_dev_free;
    chip = card->private_data;
    spin_lock_init(&chip->reg_lock);

    chip->dev = dev;
    chip->card = card;
    chip->pci = dev->pci;
    chip->iobase = pci_resource_start(dev->pci, 0);

    chip->irq = dev->pci->irq;

    err = request_irq(dev->pci->irq, cx25821_irq,
              IRQF_SHARED, chip->dev->name, chip);

    if (err < 0) {
        pr_err("ERROR %s: can't get IRQ %d for ALSA\n", chip->dev->name,
            dev->pci->irq);
        goto error;
    }

    err = snd_cx25821_pcm(chip, 0, "cx25821 Digital");
    if (err < 0) {
        pr_info("DEBUG ERROR: cannot create snd_cx25821_pcm %s\n",
            __func__);
        goto error;
    }

    snd_card_set_dev(card, &chip->pci->dev);

    strcpy(card->shortname, "cx25821");
    sprintf(card->longname, "%s at 0x%lx irq %d", chip->dev->name,
        chip->iobase, chip->irq);
    strcpy(card->mixername, "CX25821");

    pr_info("%s/%i: ALSA support for cx25821 boards\n", card->driver,
        devno);

    err = snd_card_register(card);
    if (err < 0) {
        pr_info("DEBUG ERROR: cannot register sound card %s\n",
            __func__);
        goto error;
    }

    snd_cx25821_cards[devno] = card;

    devno++;
    return 0;

error:
    snd_card_free(card);
    return err;
}

/****************************************************************************
                LINUX MODULE INIT
 ****************************************************************************/
static void cx25821_audio_fini(void)
{
    snd_card_free(snd_cx25821_cards[0]);
}

/*
 * Module initializer
 *
 * Loops through present saa7134 cards, and assigns an ALSA device
 * to each one
 *
 */
static int cx25821_alsa_init(void)
{
    struct cx25821_dev *dev = NULL;
    struct list_head *list;

    mutex_lock(&cx25821_devlist_mutex);
    list_for_each(list, &cx25821_devlist) {
        dev = list_entry(list, struct cx25821_dev, devlist);
        cx25821_audio_initdev(dev);
    }
    mutex_unlock(&cx25821_devlist_mutex);

    if (dev == NULL)
        pr_info("ERROR ALSA: no cx25821 cards found\n");

    return 0;

}

late_initcall(cx25821_alsa_init);
module_exit(cx25821_audio_fini);

/* ----------------------------------------------------------- */
/*
 * Local variables:
 * c-basic-offset: 8
 * End:
 */