root/sound/i2c/other/ak4113.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Routines for control of the AK4113 via I2C/4-wire serial interface
 *  IEC958 (S/PDIF) receiver by Asahi Kasei
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Copyright (c) by Pavel Hofman <pavel.hofman@ivitera.com>
 */

#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/pcm.h>
#include <sound/ak4113.h>
#include <sound/asoundef.h>
#include <sound/info.h>

MODULE_AUTHOR("Pavel Hofman <pavel.hofman@ivitera.com>");
MODULE_DESCRIPTION("AK4113 IEC958 (S/PDIF) receiver by Asahi Kasei");
MODULE_LICENSE("GPL");

#define AK4113_ADDR                     0x00 /* fixed address */

static void ak4113_stats(struct work_struct *work);
static void ak4113_init_regs(struct ak4113 *chip);


static void reg_write(struct ak4113 *ak4113, unsigned char reg,
                unsigned char val)
{
        ak4113->write(ak4113->private_data, reg, val);
        if (reg < sizeof(ak4113->regmap))
                ak4113->regmap[reg] = val;
}

static inline unsigned char reg_read(struct ak4113 *ak4113, unsigned char reg)
{
        return ak4113->read(ak4113->private_data, reg);
}

static void snd_ak4113_free(struct ak4113 *chip)
{
        atomic_inc(&chip->wq_processing);       /* don't schedule new work */
        cancel_delayed_work_sync(&chip->work);
        kfree(chip);
}

static int snd_ak4113_dev_free(struct snd_device *device)
{
        struct ak4113 *chip = device->device_data;
        snd_ak4113_free(chip);
        return 0;
}

int snd_ak4113_create(struct snd_card *card, ak4113_read_t *read,
                ak4113_write_t *write, const unsigned char *pgm,
                void *private_data, struct ak4113 **r_ak4113)
{
        struct ak4113 *chip;
        int err;
        unsigned char reg;
        static const struct snd_device_ops ops = {
                .dev_free =     snd_ak4113_dev_free,
        };

        chip = kzalloc_obj(*chip);
        if (chip == NULL)
                return -ENOMEM;
        spin_lock_init(&chip->lock);
        chip->card = card;
        chip->read = read;
        chip->write = write;
        chip->private_data = private_data;
        INIT_DELAYED_WORK(&chip->work, ak4113_stats);
        atomic_set(&chip->wq_processing, 0);
        mutex_init(&chip->reinit_mutex);

        for (reg = 0; reg < AK4113_WRITABLE_REGS ; reg++)
                chip->regmap[reg] = pgm[reg];
        ak4113_init_regs(chip);

        chip->rcs0 = reg_read(chip, AK4113_REG_RCS0) & ~(AK4113_QINT |
                        AK4113_CINT | AK4113_STC);
        chip->rcs1 = reg_read(chip, AK4113_REG_RCS1);
        chip->rcs2 = reg_read(chip, AK4113_REG_RCS2);
        err = snd_device_new(card, SNDRV_DEV_CODEC, chip, &ops);
        if (err < 0)
                goto __fail;

        if (r_ak4113)
                *r_ak4113 = chip;
        return 0;

__fail:
        snd_ak4113_free(chip);
        return err;
}
EXPORT_SYMBOL_GPL(snd_ak4113_create);

void snd_ak4113_reg_write(struct ak4113 *chip, unsigned char reg,
                unsigned char mask, unsigned char val)
{
        if (reg >= AK4113_WRITABLE_REGS)
                return;
        reg_write(chip, reg, (chip->regmap[reg] & ~mask) | val);
}
EXPORT_SYMBOL_GPL(snd_ak4113_reg_write);

static void ak4113_init_regs(struct ak4113 *chip)
{
        unsigned char old = chip->regmap[AK4113_REG_PWRDN], reg;

        /* bring the chip to reset state and powerdown state */
        reg_write(chip, AK4113_REG_PWRDN, old & ~(AK4113_RST|AK4113_PWN));
        udelay(200);
        /* release reset, but leave powerdown */
        reg_write(chip, AK4113_REG_PWRDN, (old | AK4113_RST) & ~AK4113_PWN);
        udelay(200);
        for (reg = 1; reg < AK4113_WRITABLE_REGS; reg++)
                reg_write(chip, reg, chip->regmap[reg]);
        /* release powerdown, everything is initialized now */
        reg_write(chip, AK4113_REG_PWRDN, old | AK4113_RST | AK4113_PWN);
}

void snd_ak4113_reinit(struct ak4113 *chip)
{
        if (atomic_inc_return(&chip->wq_processing) == 1)
                cancel_delayed_work_sync(&chip->work);
        scoped_guard(mutex, &chip->reinit_mutex) {
                ak4113_init_regs(chip);
        }
        /* bring up statistics / event queing */
        if (atomic_dec_and_test(&chip->wq_processing))
                schedule_delayed_work(&chip->work, HZ / 10);
}
EXPORT_SYMBOL_GPL(snd_ak4113_reinit);

static unsigned int external_rate(unsigned char rcs1)
{
        switch (rcs1 & (AK4113_FS0|AK4113_FS1|AK4113_FS2|AK4113_FS3)) {
        case AK4113_FS_8000HZ:
                return 8000;
        case AK4113_FS_11025HZ:
                return 11025;
        case AK4113_FS_16000HZ:
                return 16000;
        case AK4113_FS_22050HZ:
                return 22050;
        case AK4113_FS_24000HZ:
                return 24000;
        case AK4113_FS_32000HZ:
                return 32000;
        case AK4113_FS_44100HZ:
                return 44100;
        case AK4113_FS_48000HZ:
                return 48000;
        case AK4113_FS_64000HZ:
                return 64000;
        case AK4113_FS_88200HZ:
                return 88200;
        case AK4113_FS_96000HZ:
                return 96000;
        case AK4113_FS_176400HZ:
                return 176400;
        case AK4113_FS_192000HZ:
                return 192000;
        default:
                return 0;
        }
}

static int snd_ak4113_in_error_info(struct snd_kcontrol *kcontrol,
                                    struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = LONG_MAX;
        return 0;
}

static int snd_ak4113_in_error_get(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);

        guard(spinlock_irq)(&chip->lock);
        ucontrol->value.integer.value[0] =
                chip->errors[kcontrol->private_value];
        chip->errors[kcontrol->private_value] = 0;
        return 0;
}

#define snd_ak4113_in_bit_info          snd_ctl_boolean_mono_info

static int snd_ak4113_in_bit_get(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);
        unsigned char reg = kcontrol->private_value & 0xff;
        unsigned char bit = (kcontrol->private_value >> 8) & 0xff;
        unsigned char inv = (kcontrol->private_value >> 31) & 1;

        ucontrol->value.integer.value[0] =
                ((reg_read(chip, reg) & (1 << bit)) ? 1 : 0) ^ inv;
        return 0;
}

static int snd_ak4113_rx_info(struct snd_kcontrol *kcontrol,
                              struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = 5;
        return 0;
}

static int snd_ak4113_rx_get(struct snd_kcontrol *kcontrol,
                             struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);

        ucontrol->value.integer.value[0] =
                (AK4113_IPS(chip->regmap[AK4113_REG_IO1]));
        return 0;
}

static int snd_ak4113_rx_put(struct snd_kcontrol *kcontrol,
                             struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);
        int change;
        u8 old_val;

        guard(spinlock_irq)(&chip->lock);
        old_val = chip->regmap[AK4113_REG_IO1];
        change = ucontrol->value.integer.value[0] != AK4113_IPS(old_val);
        if (change)
                reg_write(chip, AK4113_REG_IO1,
                                (old_val & (~AK4113_IPS(0xff))) |
                                (AK4113_IPS(ucontrol->value.integer.value[0])));
        return change;
}

static int snd_ak4113_rate_info(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 1;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = 192000;
        return 0;
}

static int snd_ak4113_rate_get(struct snd_kcontrol *kcontrol,
                               struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);

        ucontrol->value.integer.value[0] = external_rate(reg_read(chip,
                                AK4113_REG_RCS1));
        return 0;
}

static int snd_ak4113_spdif_info(struct snd_kcontrol *kcontrol,
                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
        uinfo->count = 1;
        return 0;
}

static int snd_ak4113_spdif_get(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);
        unsigned i;

        for (i = 0; i < AK4113_REG_RXCSB_SIZE; i++)
                ucontrol->value.iec958.status[i] = reg_read(chip,
                                AK4113_REG_RXCSB0 + i);
        return 0;
}

static int snd_ak4113_spdif_mask_info(struct snd_kcontrol *kcontrol,
                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
        uinfo->count = 1;
        return 0;
}

static int snd_ak4113_spdif_mask_get(struct snd_kcontrol *kcontrol,
                                      struct snd_ctl_elem_value *ucontrol)
{
        memset(ucontrol->value.iec958.status, 0xff, AK4113_REG_RXCSB_SIZE);
        return 0;
}

static int snd_ak4113_spdif_pinfo(struct snd_kcontrol *kcontrol,
                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = 0xffff;
        uinfo->count = 4;
        return 0;
}

static int snd_ak4113_spdif_pget(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);
        unsigned short tmp;

        ucontrol->value.integer.value[0] = 0xf8f2;
        ucontrol->value.integer.value[1] = 0x4e1f;
        tmp = reg_read(chip, AK4113_REG_Pc0) |
                (reg_read(chip, AK4113_REG_Pc1) << 8);
        ucontrol->value.integer.value[2] = tmp;
        tmp = reg_read(chip, AK4113_REG_Pd0) |
                (reg_read(chip, AK4113_REG_Pd1) << 8);
        ucontrol->value.integer.value[3] = tmp;
        return 0;
}

static int snd_ak4113_spdif_qinfo(struct snd_kcontrol *kcontrol,
                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
        uinfo->count = AK4113_REG_QSUB_SIZE;
        return 0;
}

static int snd_ak4113_spdif_qget(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
{
        struct ak4113 *chip = snd_kcontrol_chip(kcontrol);
        unsigned i;

        for (i = 0; i < AK4113_REG_QSUB_SIZE; i++)
                ucontrol->value.bytes.data[i] = reg_read(chip,
                                AK4113_REG_QSUB_ADDR + i);
        return 0;
}

/* Don't forget to change AK4113_CONTROLS define!!! */
static const struct snd_kcontrol_new snd_ak4113_iec958_controls[] = {
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Parity Errors",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_error_info,
        .get =          snd_ak4113_in_error_get,
        .private_value = AK4113_PARITY_ERRORS,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 V-Bit Errors",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_error_info,
        .get =          snd_ak4113_in_error_get,
        .private_value = AK4113_V_BIT_ERRORS,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 C-CRC Errors",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_error_info,
        .get =          snd_ak4113_in_error_get,
        .private_value = AK4113_CCRC_ERRORS,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Q-CRC Errors",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_error_info,
        .get =          snd_ak4113_in_error_get,
        .private_value = AK4113_QCRC_ERRORS,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 External Rate",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_rate_info,
        .get =          snd_ak4113_rate_get,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         SNDRV_CTL_NAME_IEC958("", CAPTURE, MASK),
        .access =       SNDRV_CTL_ELEM_ACCESS_READ,
        .info =         snd_ak4113_spdif_mask_info,
        .get =          snd_ak4113_spdif_mask_get,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         SNDRV_CTL_NAME_IEC958("", CAPTURE, DEFAULT),
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_spdif_info,
        .get =          snd_ak4113_spdif_get,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Preamble Capture Default",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_spdif_pinfo,
        .get =          snd_ak4113_spdif_pget,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Q-subcode Capture Default",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_spdif_qinfo,
        .get =          snd_ak4113_spdif_qget,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Audio",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_bit_info,
        .get =          snd_ak4113_in_bit_get,
        .private_value = (1<<31) | (1<<8) | AK4113_REG_RCS0,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 Non-PCM Bitstream",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_bit_info,
        .get =          snd_ak4113_in_bit_get,
        .private_value = (0<<8) | AK4113_REG_RCS1,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "IEC958 DTS Bitstream",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_VOLATILE,
        .info =         snd_ak4113_in_bit_info,
        .get =          snd_ak4113_in_bit_get,
        .private_value = (1<<8) | AK4113_REG_RCS1,
},
{
        .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
        .name =         "AK4113 Input Select",
        .access =       SNDRV_CTL_ELEM_ACCESS_READ |
                SNDRV_CTL_ELEM_ACCESS_WRITE,
        .info =         snd_ak4113_rx_info,
        .get =          snd_ak4113_rx_get,
        .put =          snd_ak4113_rx_put,
}
};

static void snd_ak4113_proc_regs_read(struct snd_info_entry *entry,
                struct snd_info_buffer *buffer)
{
        struct ak4113 *ak4113 = entry->private_data;
        int reg, val;
        /* all ak4113 registers 0x00 - 0x1c */
        for (reg = 0; reg < 0x1d; reg++) {
                val = reg_read(ak4113, reg);
                snd_iprintf(buffer, "0x%02x = 0x%02x\n", reg, val);
        }
}

static void snd_ak4113_proc_init(struct ak4113 *ak4113)
{
        snd_card_ro_proc_new(ak4113->card, "ak4113", ak4113,
                             snd_ak4113_proc_regs_read);
}

int snd_ak4113_build(struct ak4113 *ak4113,
                struct snd_pcm_substream *cap_substream)
{
        struct snd_kcontrol *kctl;
        unsigned int idx;
        int err;

        if (snd_BUG_ON(!cap_substream))
                return -EINVAL;
        ak4113->substream = cap_substream;
        for (idx = 0; idx < AK4113_CONTROLS; idx++) {
                kctl = snd_ctl_new1(&snd_ak4113_iec958_controls[idx], ak4113);
                if (kctl == NULL)
                        return -ENOMEM;
                kctl->id.device = cap_substream->pcm->device;
                kctl->id.subdevice = cap_substream->number;
                err = snd_ctl_add(ak4113->card, kctl);
                if (err < 0)
                        return err;
                ak4113->kctls[idx] = kctl;
        }
        snd_ak4113_proc_init(ak4113);
        /* trigger workq */
        schedule_delayed_work(&ak4113->work, HZ / 10);
        return 0;
}
EXPORT_SYMBOL_GPL(snd_ak4113_build);

int snd_ak4113_external_rate(struct ak4113 *ak4113)
{
        unsigned char rcs1;

        rcs1 = reg_read(ak4113, AK4113_REG_RCS1);
        return external_rate(rcs1);
}
EXPORT_SYMBOL_GPL(snd_ak4113_external_rate);

int snd_ak4113_check_rate_and_errors(struct ak4113 *ak4113, unsigned int flags)
{
        struct snd_pcm_runtime *runtime =
                ak4113->substream ? ak4113->substream->runtime : NULL;
        unsigned long _flags;
        int res = 0;
        unsigned char rcs0, rcs1, rcs2;
        unsigned char c0, c1;

        rcs1 = reg_read(ak4113, AK4113_REG_RCS1);
        if (flags & AK4113_CHECK_NO_STAT)
                goto __rate;
        rcs0 = reg_read(ak4113, AK4113_REG_RCS0);
        rcs2 = reg_read(ak4113, AK4113_REG_RCS2);
        scoped_guard(spinlock_irqsave, &ak4113->lock) {
                if (rcs0 & AK4113_PAR)
                        ak4113->errors[AK4113_PARITY_ERRORS]++;
                if (rcs0 & AK4113_V)
                        ak4113->errors[AK4113_V_BIT_ERRORS]++;
                if (rcs2 & AK4113_CCRC)
                        ak4113->errors[AK4113_CCRC_ERRORS]++;
                if (rcs2 & AK4113_QCRC)
                        ak4113->errors[AK4113_QCRC_ERRORS]++;
                c0 = (ak4113->rcs0 & (AK4113_QINT | AK4113_CINT | AK4113_STC |
                                      AK4113_AUDION | AK4113_AUTO | AK4113_UNLCK)) ^
                        (rcs0 & (AK4113_QINT | AK4113_CINT | AK4113_STC |
                                 AK4113_AUDION | AK4113_AUTO | AK4113_UNLCK));
                c1 = (ak4113->rcs1 & (AK4113_DTSCD | AK4113_NPCM | AK4113_PEM |
                                      AK4113_DAT | 0xf0)) ^
                        (rcs1 & (AK4113_DTSCD | AK4113_NPCM | AK4113_PEM |
                                 AK4113_DAT | 0xf0));
                ak4113->rcs0 = rcs0 & ~(AK4113_QINT | AK4113_CINT | AK4113_STC);
                ak4113->rcs1 = rcs1;
                ak4113->rcs2 = rcs2;
        }

        if (rcs0 & AK4113_PAR)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[0]->id);
        if (rcs0 & AK4113_V)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[1]->id);
        if (rcs2 & AK4113_CCRC)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[2]->id);
        if (rcs2 & AK4113_QCRC)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[3]->id);

        /* rate change */
        if (c1 & 0xf0)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[4]->id);

        if ((c1 & AK4113_PEM) | (c0 & AK4113_CINT))
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[6]->id);
        if (c0 & AK4113_QINT)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[8]->id);

        if (c0 & AK4113_AUDION)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[9]->id);
        if (c1 & AK4113_NPCM)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[10]->id);
        if (c1 & AK4113_DTSCD)
                snd_ctl_notify(ak4113->card, SNDRV_CTL_EVENT_MASK_VALUE,
                                &ak4113->kctls[11]->id);

        if (ak4113->change_callback && (c0 | c1) != 0)
                ak4113->change_callback(ak4113, c0, c1);

__rate:
        /* compare rate */
        res = external_rate(rcs1);
        if (!(flags & AK4113_CHECK_NO_RATE) && runtime &&
                        (runtime->rate != res)) {
                snd_pcm_stream_lock_irqsave(ak4113->substream, _flags);
                if (snd_pcm_running(ak4113->substream)) {
                        snd_pcm_stop(ak4113->substream,
                                        SNDRV_PCM_STATE_DRAINING);
                        wake_up(&runtime->sleep);
                        res = 1;
                }
                snd_pcm_stream_unlock_irqrestore(ak4113->substream, _flags);
        }
        return res;
}
EXPORT_SYMBOL_GPL(snd_ak4113_check_rate_and_errors);

static void ak4113_stats(struct work_struct *work)
{
        struct ak4113 *chip = container_of(work, struct ak4113, work.work);

        if (atomic_inc_return(&chip->wq_processing) == 1)
                snd_ak4113_check_rate_and_errors(chip, chip->check_flags);

        if (atomic_dec_and_test(&chip->wq_processing))
                schedule_delayed_work(&chip->work, HZ / 10);
}

#ifdef CONFIG_PM
void snd_ak4113_suspend(struct ak4113 *chip)
{
        atomic_inc(&chip->wq_processing); /* don't schedule new work */
        cancel_delayed_work_sync(&chip->work);
}
EXPORT_SYMBOL(snd_ak4113_suspend);

void snd_ak4113_resume(struct ak4113 *chip)
{
        atomic_dec(&chip->wq_processing);
        snd_ak4113_reinit(chip);
}
EXPORT_SYMBOL(snd_ak4113_resume);
#endif