tas.c

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/*
 * Apple Onboard Audio driver for tas codec
 *
 * Copyright 2006 Johannes Berg <[email protected]>
 *
 * GPL v2, can be found in COPYING.
 *
 * Open questions:
 *  - How to distinguish between 3004 and versions?
 *
 * FIXMEs:
 *  - This codec driver doesn't honour the 'connected'
 *    property of the aoa_codec struct, hence if
 *    it is used in machines where not everything is
 *    connected it will display wrong mixer elements.
 *  - Driver assumes that the microphone is always
 *    monaureal and connected to the right channel of
 *    the input. This should also be a codec-dependent
 *    flag, maybe the codec should have 3 different
 *    bits for the three different possibilities how
 *    it can be hooked up...
 *    But as long as I don't see any hardware hooked
 *    up that way...
 *  - As Apple notes in their code, the tas3004 seems
 *    to delay the right channel by one sample. You can
 *    see this when for example recording stereo in
 *    audacity, or recording the tas output via cable
 *    on another machine (use a sinus generator or so).
 *    I tried programming the BiQuads but couldn't
 *    make the delay work, maybe someone can read the
 *    datasheet and fix it. The relevant Apple comment
 *    is in AppleTAS3004Audio.cpp lines 1637 ff. Note
 *    that their comment describing how they program
 *    the filters sucks...
 *
 * Other things:
 *  - this should actually register *two* aoa_codec
 *    structs since it has two inputs. Then it must
 *    use the prepare callback to forbid running the
 *    secondary output on a different clock.
 *    Also, whatever bus knows how to do this must
 *    provide two soundbus_dev devices and the fabric
 *    must be able to link them correctly.
 *
 *    I don't even know if Apple ever uses the second
 *    port on the tas3004 though, I don't think their
 *    i2s controllers can even do it. OTOH, they all
 *    derive the clocks from common clocks, so it
 *    might just be possible. The framework allows the
 *    codec to refine the transfer_info items in the
 *    usable callback, so we can simply remove the
 *    rates the second instance is not using when it
 *    actually is in use.
 *    Maybe we'll need to make the sound busses have
 *    a 'clock group id' value so the codec can
 *    determine if the two outputs can be driven at
 *    the same time. But that is likely overkill, up
 *    to the fabric to not link them up incorrectly,
 *    and up to the hardware designer to not wire
 *    them up in some weird unusable way.
 */
#include <stddef.h>
#include <linux/i2c.h>
#include <asm/pmac_low_i2c.h>
#include <asm/prom.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>

MODULE_AUTHOR("Johannes Berg <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("tas codec driver for snd-aoa");

#include "tas.h"
#include "tas-gain-table.h"
#include "tas-basstreble.h"
#include "../aoa.h"
#include "../soundbus/soundbus.h"

#define PFX "snd-aoa-codec-tas: "


struct tas {
    struct aoa_codec    codec;
    struct i2c_client   *i2c;
    u32         mute_l:1, mute_r:1 ,
                controls_created:1 ,
                drc_enabled:1,
                hw_enabled:1;
    u8          cached_volume_l, cached_volume_r;
    u8          mixer_l[3], mixer_r[3];
    u8          bass, treble;
    u8          acr;
    int         drc_range;
    /* protects hardware access against concurrency from
     * userspace when hitting controls and during
     * codec init/suspend/resume */
    struct mutex        mtx;
};

static int tas_reset_init(struct tas *tas);

static struct tas *codec_to_tas(struct aoa_codec *codec)
{
    return container_of(codec, struct tas, codec);
}

static inline int tas_write_reg(struct tas *tas, u8 reg, u8 len, u8 *data)
{
    if (len == 1)
        return i2c_smbus_write_byte_data(tas->i2c, reg, *data);
    else
        return i2c_smbus_write_i2c_block_data(tas->i2c, reg, len, data);
}

static void tas3004_set_drc(struct tas *tas)
{
    unsigned char val[6];

    if (tas->drc_enabled)
        val[0] = 0x50; /* 3:1 above threshold */
    else
        val[0] = 0x51; /* disabled */
    val[1] = 0x02; /* 1:1 below threshold */
    if (tas->drc_range > 0xef)
        val[2] = 0xef;
    else if (tas->drc_range < 0)
        val[2] = 0x00;
    else
        val[2] = tas->drc_range;
    val[3] = 0xb0;
    val[4] = 0x60;
    val[5] = 0xa0;

    tas_write_reg(tas, TAS_REG_DRC, 6, val);
}

static void tas_set_treble(struct tas *tas)
{
    u8 tmp;

    tmp = tas3004_treble(tas->treble);
    tas_write_reg(tas, TAS_REG_TREBLE, 1, &tmp);
}

static void tas_set_bass(struct tas *tas)
{
    u8 tmp;

    tmp = tas3004_bass(tas->bass);
    tas_write_reg(tas, TAS_REG_BASS, 1, &tmp);
}

static void tas_set_volume(struct tas *tas)
{
    u8 block[6];
    int tmp;
    u8 left, right;

    left = tas->cached_volume_l;
    right = tas->cached_volume_r;

    if (left > 177) left = 177;
    if (right > 177) right = 177;

    if (tas->mute_l) left = 0;
    if (tas->mute_r) right = 0;

    /* analysing the volume and mixer tables shows
     * that they are similar enough when we shift
     * the mixer table down by 4 bits. The error
     * is miniscule, in just one item the error
     * is 1, at a value of 0x07f17b (mixer table
     * value is 0x07f17a) */
    tmp = tas_gaintable[left];
    block[0] = tmp>>20;
    block[1] = tmp>>12;
    block[2] = tmp>>4;
    tmp = tas_gaintable[right];
    block[3] = tmp>>20;
    block[4] = tmp>>12;
    block[5] = tmp>>4;
    tas_write_reg(tas, TAS_REG_VOL, 6, block);
}

static void tas_set_mixer(struct tas *tas)
{
    u8 block[9];
    int tmp, i;
    u8 val;

    for (i=0;i<3;i++) {
        val = tas->mixer_l[i];
        if (val > 177) val = 177;
        tmp = tas_gaintable[val];
        block[3*i+0] = tmp>>16;
        block[3*i+1] = tmp>>8;
        block[3*i+2] = tmp;
    }
    tas_write_reg(tas, TAS_REG_LMIX, 9, block);

    for (i=0;i<3;i++) {
        val = tas->mixer_r[i];
        if (val > 177) val = 177;
        tmp = tas_gaintable[val];
        block[3*i+0] = tmp>>16;
        block[3*i+1] = tmp>>8;
        block[3*i+2] = tmp;
    }
    tas_write_reg(tas, TAS_REG_RMIX, 9, block);
}

/* alsa stuff */

static int tas_dev_register(struct snd_device *dev)
{
    return 0;
}

static struct snd_device_ops ops = {
    .dev_register = tas_dev_register,
};

static int tas_snd_vol_info(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_info *uinfo)
{
    uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
    uinfo->count = 2;
    uinfo->value.integer.min = 0;
    uinfo->value.integer.max = 177;
    return 0;
}

static int tas_snd_vol_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->cached_volume_l;
    ucontrol->value.integer.value[1] = tas->cached_volume_r;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_vol_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    if (ucontrol->value.integer.value[0] < 0 ||
        ucontrol->value.integer.value[0] > 177)
        return -EINVAL;
    if (ucontrol->value.integer.value[1] < 0 ||
        ucontrol->value.integer.value[1] > 177)
        return -EINVAL;

    mutex_lock(&tas->mtx);
    if (tas->cached_volume_l == ucontrol->value.integer.value[0]
     && tas->cached_volume_r == ucontrol->value.integer.value[1]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->cached_volume_l = ucontrol->value.integer.value[0];
    tas->cached_volume_r = ucontrol->value.integer.value[1];
    if (tas->hw_enabled)
        tas_set_volume(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new volume_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "Master Playback Volume",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_vol_info,
    .get = tas_snd_vol_get,
    .put = tas_snd_vol_put,
};

#define tas_snd_mute_info   snd_ctl_boolean_stereo_info

static int tas_snd_mute_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = !tas->mute_l;
    ucontrol->value.integer.value[1] = !tas->mute_r;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_mute_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    if (tas->mute_l == !ucontrol->value.integer.value[0]
     && tas->mute_r == !ucontrol->value.integer.value[1]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->mute_l = !ucontrol->value.integer.value[0];
    tas->mute_r = !ucontrol->value.integer.value[1];
    if (tas->hw_enabled)
        tas_set_volume(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new mute_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "Master Playback Switch",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_mute_info,
    .get = tas_snd_mute_get,
    .put = tas_snd_mute_put,
};

static int tas_snd_mixer_info(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_info *uinfo)
{
    uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
    uinfo->count = 2;
    uinfo->value.integer.min = 0;
    uinfo->value.integer.max = 177;
    return 0;
}

static int tas_snd_mixer_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);
    int idx = kcontrol->private_value;

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->mixer_l[idx];
    ucontrol->value.integer.value[1] = tas->mixer_r[idx];
    mutex_unlock(&tas->mtx);

    return 0;
}

static int tas_snd_mixer_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);
    int idx = kcontrol->private_value;

    mutex_lock(&tas->mtx);
    if (tas->mixer_l[idx] == ucontrol->value.integer.value[0]
     && tas->mixer_r[idx] == ucontrol->value.integer.value[1]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->mixer_l[idx] = ucontrol->value.integer.value[0];
    tas->mixer_r[idx] = ucontrol->value.integer.value[1];

    if (tas->hw_enabled)
        tas_set_mixer(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

#define MIXER_CONTROL(n,descr,idx)          \
static struct snd_kcontrol_new n##_control = {      \
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,        \
    .name = descr " Playback Volume",       \
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,  \
    .info = tas_snd_mixer_info,         \
    .get = tas_snd_mixer_get,           \
    .put = tas_snd_mixer_put,           \
    .private_value = idx,               \
}

MIXER_CONTROL(pcm1, "PCM", 0);
MIXER_CONTROL(monitor, "Monitor", 2);

static int tas_snd_drc_range_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 = TAS3004_DRC_MAX;
    return 0;
}

static int tas_snd_drc_range_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->drc_range;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_drc_range_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    if (ucontrol->value.integer.value[0] < 0 ||
        ucontrol->value.integer.value[0] > TAS3004_DRC_MAX)
        return -EINVAL;

    mutex_lock(&tas->mtx);
    if (tas->drc_range == ucontrol->value.integer.value[0]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->drc_range = ucontrol->value.integer.value[0];
    if (tas->hw_enabled)
        tas3004_set_drc(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new drc_range_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "DRC Range",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_drc_range_info,
    .get = tas_snd_drc_range_get,
    .put = tas_snd_drc_range_put,
};

#define tas_snd_drc_switch_info     snd_ctl_boolean_mono_info

static int tas_snd_drc_switch_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->drc_enabled;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_drc_switch_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    if (tas->drc_enabled == ucontrol->value.integer.value[0]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->drc_enabled = !!ucontrol->value.integer.value[0];
    if (tas->hw_enabled)
        tas3004_set_drc(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new drc_switch_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "DRC Range Switch",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_drc_switch_info,
    .get = tas_snd_drc_switch_get,
    .put = tas_snd_drc_switch_put,
};

static int tas_snd_capture_source_info(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_info *uinfo)
{
    static char *texts[] = { "Line-In", "Microphone" };

    uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
    uinfo->count = 1;
    uinfo->value.enumerated.items = 2;
    if (uinfo->value.enumerated.item > 1)
        uinfo->value.enumerated.item = 1;
    strcpy(uinfo->value.enumerated.name, texts[uinfo->value.enumerated.item]);
    return 0;
}

static int tas_snd_capture_source_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.enumerated.item[0] = !!(tas->acr & TAS_ACR_INPUT_B);
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_capture_source_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);
    int oldacr;

    if (ucontrol->value.enumerated.item[0] > 1)
        return -EINVAL;
    mutex_lock(&tas->mtx);
    oldacr = tas->acr;

    /*
     * Despite what the data sheet says in one place, the
     * TAS_ACR_B_MONAUREAL bit forces mono output even when
     * input A (line in) is selected.
     */
    tas->acr &= ~(TAS_ACR_INPUT_B | TAS_ACR_B_MONAUREAL);
    if (ucontrol->value.enumerated.item[0])
        tas->acr |= TAS_ACR_INPUT_B | TAS_ACR_B_MONAUREAL |
              TAS_ACR_B_MON_SEL_RIGHT;
    if (oldacr == tas->acr) {
        mutex_unlock(&tas->mtx);
        return 0;
    }
    if (tas->hw_enabled)
        tas_write_reg(tas, TAS_REG_ACR, 1, &tas->acr);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new capture_source_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    /* If we name this 'Input Source', it properly shows up in
     * alsamixer as a selection, * but it's shown under the
     * 'Playback' category.
     * If I name it 'Capture Source', it shows up in strange
     * ways (two bools of which one can be selected at a
     * time) but at least it's shown in the 'Capture'
     * category.
     * I was told that this was due to backward compatibility,
     * but I don't understand then why the mangling is *not*
     * done when I name it "Input Source".....
     */
    .name = "Capture Source",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_capture_source_info,
    .get = tas_snd_capture_source_get,
    .put = tas_snd_capture_source_put,
};

static int tas_snd_treble_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 = TAS3004_TREBLE_MIN;
    uinfo->value.integer.max = TAS3004_TREBLE_MAX;
    return 0;
}

static int tas_snd_treble_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->treble;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_treble_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    if (ucontrol->value.integer.value[0] < TAS3004_TREBLE_MIN ||
        ucontrol->value.integer.value[0] > TAS3004_TREBLE_MAX)
        return -EINVAL;
    mutex_lock(&tas->mtx);
    if (tas->treble == ucontrol->value.integer.value[0]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->treble = ucontrol->value.integer.value[0];
    if (tas->hw_enabled)
        tas_set_treble(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new treble_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "Treble",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_treble_info,
    .get = tas_snd_treble_get,
    .put = tas_snd_treble_put,
};

static int tas_snd_bass_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 = TAS3004_BASS_MIN;
    uinfo->value.integer.max = TAS3004_BASS_MAX;
    return 0;
}

static int tas_snd_bass_get(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    mutex_lock(&tas->mtx);
    ucontrol->value.integer.value[0] = tas->bass;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_snd_bass_put(struct snd_kcontrol *kcontrol,
    struct snd_ctl_elem_value *ucontrol)
{
    struct tas *tas = snd_kcontrol_chip(kcontrol);

    if (ucontrol->value.integer.value[0] < TAS3004_BASS_MIN ||
        ucontrol->value.integer.value[0] > TAS3004_BASS_MAX)
        return -EINVAL;
    mutex_lock(&tas->mtx);
    if (tas->bass == ucontrol->value.integer.value[0]) {
        mutex_unlock(&tas->mtx);
        return 0;
    }

    tas->bass = ucontrol->value.integer.value[0];
    if (tas->hw_enabled)
        tas_set_bass(tas);
    mutex_unlock(&tas->mtx);
    return 1;
}

static struct snd_kcontrol_new bass_control = {
    .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
    .name = "Bass",
    .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
    .info = tas_snd_bass_info,
    .get = tas_snd_bass_get,
    .put = tas_snd_bass_put,
};

static struct transfer_info tas_transfers[] = {
    {
        /* input */
        .formats = SNDRV_PCM_FMTBIT_S16_BE | SNDRV_PCM_FMTBIT_S24_BE,
        .rates = SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
        .transfer_in = 1,
    },
    {
        /* output */
        .formats = SNDRV_PCM_FMTBIT_S16_BE | SNDRV_PCM_FMTBIT_S24_BE,
        .rates = SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
        .transfer_in = 0,
    },
    {}
};

static int tas_usable(struct codec_info_item *cii,
              struct transfer_info *ti,
              struct transfer_info *out)
{
    return 1;
}

static int tas_reset_init(struct tas *tas)
{
    u8 tmp;

    tas->codec.gpio->methods->all_amps_off(tas->codec.gpio);
    msleep(5);
    tas->codec.gpio->methods->set_hw_reset(tas->codec.gpio, 0);
    msleep(5);
    tas->codec.gpio->methods->set_hw_reset(tas->codec.gpio, 1);
    msleep(20);
    tas->codec.gpio->methods->set_hw_reset(tas->codec.gpio, 0);
    msleep(10);
    tas->codec.gpio->methods->all_amps_restore(tas->codec.gpio);

    tmp = TAS_MCS_SCLK64 | TAS_MCS_SPORT_MODE_I2S | TAS_MCS_SPORT_WL_24BIT;
    if (tas_write_reg(tas, TAS_REG_MCS, 1, &tmp))
        goto outerr;

    tas->acr |= TAS_ACR_ANALOG_PDOWN;
    if (tas_write_reg(tas, TAS_REG_ACR, 1, &tas->acr))
        goto outerr;

    tmp = 0;
    if (tas_write_reg(tas, TAS_REG_MCS2, 1, &tmp))
        goto outerr;

    tas3004_set_drc(tas);

    /* Set treble & bass to 0dB */
    tas->treble = TAS3004_TREBLE_ZERO;
    tas->bass = TAS3004_BASS_ZERO;
    tas_set_treble(tas);
    tas_set_bass(tas);

    tas->acr &= ~TAS_ACR_ANALOG_PDOWN;
    if (tas_write_reg(tas, TAS_REG_ACR, 1, &tas->acr))
        goto outerr;

    return 0;
 outerr:
    return -ENODEV;
}

static int tas_switch_clock(struct codec_info_item *cii, enum clock_switch clock)
{
    struct tas *tas = cii->codec_data;

    switch(clock) {
    case CLOCK_SWITCH_PREPARE_SLAVE:
        /* Clocks are going away, mute mute mute */
        tas->codec.gpio->methods->all_amps_off(tas->codec.gpio);
        tas->hw_enabled = 0;
        break;
    case CLOCK_SWITCH_SLAVE:
        /* Clocks are back, re-init the codec */
        mutex_lock(&tas->mtx);
        tas_reset_init(tas);
        tas_set_volume(tas);
        tas_set_mixer(tas);
        tas->hw_enabled = 1;
        tas->codec.gpio->methods->all_amps_restore(tas->codec.gpio);
        mutex_unlock(&tas->mtx);
        break;
    default:
        /* doesn't happen as of now */
        return -EINVAL;
    }
    return 0;
}

#ifdef CONFIG_PM
/* we are controlled via i2c and assume that is always up
 * If that wasn't the case, we'd have to suspend once
 * our i2c device is suspended, and then take note of that! */
static int tas_suspend(struct tas *tas)
{
    mutex_lock(&tas->mtx);
    tas->hw_enabled = 0;
    tas->acr |= TAS_ACR_ANALOG_PDOWN;
    tas_write_reg(tas, TAS_REG_ACR, 1, &tas->acr);
    mutex_unlock(&tas->mtx);
    return 0;
}

static int tas_resume(struct tas *tas)
{
    /* reset codec */
    mutex_lock(&tas->mtx);
    tas_reset_init(tas);
    tas_set_volume(tas);
    tas_set_mixer(tas);
    tas->hw_enabled = 1;
    mutex_unlock(&tas->mtx);
    return 0;
}

static int _tas_suspend(struct codec_info_item *cii, pm_message_t state)
{
    return tas_suspend(cii->codec_data);
}

static int _tas_resume(struct codec_info_item *cii)
{
    return tas_resume(cii->codec_data);
}
#else /* CONFIG_PM */
#define _tas_suspend    NULL
#define _tas_resume NULL
#endif /* CONFIG_PM */

static struct codec_info tas_codec_info = {
    .transfers = tas_transfers,
    /* in theory, we can drive it at 512 too...
     * but so far the framework doesn't allow
     * for that and I don't see much point in it. */
    .sysclock_factor = 256,
    /* same here, could be 32 for just one 16 bit format */
    .bus_factor = 64,
    .owner = THIS_MODULE,
    .usable = tas_usable,
    .switch_clock = tas_switch_clock,
    .suspend = _tas_suspend,
    .resume = _tas_resume,
};

static int tas_init_codec(struct aoa_codec *codec)
{
    struct tas *tas = codec_to_tas(codec);
    int err;

    if (!tas->codec.gpio || !tas->codec.gpio->methods) {
        printk(KERN_ERR PFX "gpios not assigned!!\n");
        return -EINVAL;
    }

    mutex_lock(&tas->mtx);
    if (tas_reset_init(tas)) {
        printk(KERN_ERR PFX "tas failed to initialise\n");
        mutex_unlock(&tas->mtx);
        return -ENXIO;
    }
    tas->hw_enabled = 1;
    mutex_unlock(&tas->mtx);

    if (tas->codec.soundbus_dev->attach_codec(tas->codec.soundbus_dev,
                           aoa_get_card(),
                           &tas_codec_info, tas)) {
        printk(KERN_ERR PFX "error attaching tas to soundbus\n");
        return -ENODEV;
    }

    if (aoa_snd_device_new(SNDRV_DEV_LOWLEVEL, tas, &ops)) {
        printk(KERN_ERR PFX "failed to create tas snd device!\n");
        return -ENODEV;
    }
    err = aoa_snd_ctl_add(snd_ctl_new1(&volume_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&mute_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&pcm1_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&monitor_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&capture_source_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&drc_range_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&drc_switch_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&treble_control, tas));
    if (err)
        goto error;

    err = aoa_snd_ctl_add(snd_ctl_new1(&bass_control, tas));
    if (err)
        goto error;

    return 0;
 error:
    tas->codec.soundbus_dev->detach_codec(tas->codec.soundbus_dev, tas);
    snd_device_free(aoa_get_card(), tas);
    return err;
}

static void tas_exit_codec(struct aoa_codec *codec)
{
    struct tas *tas = codec_to_tas(codec);

    if (!tas->codec.soundbus_dev)
        return;
    tas->codec.soundbus_dev->detach_codec(tas->codec.soundbus_dev, tas);
}


static int tas_i2c_probe(struct i2c_client *client,
             const struct i2c_device_id *id)
{
    struct device_node *node = client->dev.of_node;
    struct tas *tas;

    tas = kzalloc(sizeof(struct tas), GFP_KERNEL);

    if (!tas)
        return -ENOMEM;

    mutex_init(&tas->mtx);
    tas->i2c = client;
    i2c_set_clientdata(client, tas);

    /* seems that half is a saner default */
    tas->drc_range = TAS3004_DRC_MAX / 2;

    strlcpy(tas->codec.name, "tas", MAX_CODEC_NAME_LEN);
    tas->codec.owner = THIS_MODULE;
    tas->codec.init = tas_init_codec;
    tas->codec.exit = tas_exit_codec;
    tas->codec.node = of_node_get(node);

    if (aoa_codec_register(&tas->codec)) {
        goto fail;
    }
    printk(KERN_DEBUG
           "snd-aoa-codec-tas: tas found, addr 0x%02x on %s\n",
           (unsigned int)client->addr, node->full_name);
    return 0;
 fail:
    mutex_destroy(&tas->mtx);
    kfree(tas);
    return -EINVAL;
}

static int tas_i2c_remove(struct i2c_client *client)
{
    struct tas *tas = i2c_get_clientdata(client);
    u8 tmp = TAS_ACR_ANALOG_PDOWN;

    aoa_codec_unregister(&tas->codec);
    of_node_put(tas->codec.node);

    /* power down codec chip */
    tas_write_reg(tas, TAS_REG_ACR, 1, &tmp);

    mutex_destroy(&tas->mtx);
    kfree(tas);
    return 0;
}

static const struct i2c_device_id tas_i2c_id[] = {
    { "MAC,tas3004", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c,tas_i2c_id);

static struct i2c_driver tas_driver = {
    .driver = {
        .name = "aoa_codec_tas",
        .owner = THIS_MODULE,
    },
    .probe = tas_i2c_probe,
    .remove = tas_i2c_remove,
    .id_table = tas_i2c_id,
};

module_i2c_driver(tas_driver);