ASoC: add support for Amstrad E3 (Delta) machine

This patch adds machine support for Amstrad E3 (Delta) videophone to ASoC.

Created and tested against linux-2.6.31-rc3.
Applies and works with linux-omap-2.6 commit
7c5cb7862d32cb344be7831d466535d5255e35ac as well.

Depends on:
1) latest version of the CX20442 codec driver that exposes v253_ops
   structure[1],
2) patch 2/3 form this series: TTY: Add definition of a new line
   discipline required by Amstrad E3 (Delta) ASoC driver[2].

CPU DAI parameters best matching the codec DAI has been selected out
empirically for best user experience.

Board specific audio function control (with related DAPM widgets) has been
modeled after empirically discovered codec capabilities.

Unlike other ASoC machine drivers, this one makes use of a codec provided line
discipline that is required for talking to a modem chip that can control the
codec behavoiur. As the line discipline operations must call board specific
bits as well, the machine driver registers its own line discipline ops, not
the codec provided, and then calls those codec provided from inside its own
callbacks.
If some kind of a glue, like a bus over a tty, exsited that could help in
runtime detection of a modem (bus adapter) over a more generic line discipline
(bus driver)[3], the line discipline code could be probably designed in a
more generic way.

In order to work at all, this driver requires a working McBSP1. On OMAP1510
based machines (not sure if other OMAP1 variants as well), where McBSP1 is a
DSP public peripheral, that means the kernel must provide basic DSP support,
ie. omap_dsp_init(), in order to power up the DSP. This used to be included in
linux-omap-2.6 tree up to commit 2512fd29db4eb09e82d182596304c7aaf76d2c5c.
Without that, the driver would not work, ie. not shift in/out any bits over
the CPU DAI[4]. This limitation is not board, but CPU specific, and may apply
to other code that makes use of McBSP1/McBSP3 on affected machines. I provide
an extra patch (4/3) as a temporary solution.

To work correctly in playback mode, this driver requires my prevoiusly
submitted patch that corrects pcm pointer calculation for OMAP1510 based
machines[5] (already included in linux-2.6.31-rc3).

To support codec controls, this driver requires my previously submitted patch
that adds support for modem found on Amstrad Delta[6].

[1] http://mailman.alsa-project.org/pipermail/alsa-devel/2009-July/019780.html
[2] http://www.spinics.net/lists/linux-serial/msg01862.html
[3] http://www.spinics.net/lists/linux-serial/msg01856.html
[4] http://www.spinics.net/lists/linux-omap/msg15114.html
[5] http://mailman.alsa-project.org/pipermail/alsa-devel/2009-June/018950.html
[6] http://www.spinics.net/lists/linux-omap/msg15432.html

Credits to:
Mark Underwood - for his initial, omap-alsa based sound driver for
this machine,
Mark Brown - for his help, patience and excellent subsytem maintainer support.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

3 files changed, 656 insertions, 0 deletions

diff --git a/sound/soc/omap/Kconfig b/sound/soc/omap/Kconfig
index a5a90e594535..2dee9839be86 100644
--- a/sound/soc/omap/Kconfig
+++ b/sound/soc/omap/Kconfig
@@ -15,6 +15,14 @@ config SND_OMAP_SOC_N810
         help
           Say Y if you want to add support for SoC audio on Nokia N810.
 
+config SND_OMAP_SOC_AMS_DELTA
+        tristate "SoC Audio support for Amstrad E3 (Delta) videophone"
+        depends on SND_OMAP_SOC && MACH_AMS_DELTA
+        select SND_OMAP_SOC_MCBSP
+        select SND_SOC_CX20442
+        help
+          Say Y if you want to add support for SoC audio on Amstrad Delta.
+
 config SND_OMAP_SOC_OSK5912
         tristate "SoC Audio support for omap osk5912"
         depends on SND_OMAP_SOC && MACH_OMAP_OSK && I2C
diff --git a/sound/soc/omap/Makefile b/sound/soc/omap/Makefile
index fefc48f02bd3..02d69471dcb5 100644
--- a/sound/soc/omap/Makefile
+++ b/sound/soc/omap/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_SND_OMAP_SOC_MCBSP) += snd-soc-omap-mcbsp.o
 
 # OMAP Machine Support
 snd-soc-n810-objs := n810.o
+snd-soc-ams-delta-objs := ams-delta.o
 snd-soc-osk5912-objs := osk5912.o
 snd-soc-overo-objs := overo.o
 snd-soc-omap2evm-objs := omap2evm.o
@@ -17,6 +18,7 @@ snd-soc-omap3beagle-objs := omap3beagle.o
 snd-soc-zoom2-objs := zoom2.o
 
 obj-$(CONFIG_SND_OMAP_SOC_N810) += snd-soc-n810.o
+obj-$(CONFIG_SND_OMAP_SOC_AMS_DELTA) += snd-soc-ams-delta.o
 obj-$(CONFIG_SND_OMAP_SOC_OSK5912) += snd-soc-osk5912.o
 obj-$(CONFIG_SND_OMAP_SOC_OVERO) += snd-soc-overo.o
 obj-$(CONFIG_MACH_OMAP2EVM) += snd-soc-omap2evm.o
diff --git a/sound/soc/omap/ams-delta.c b/sound/soc/omap/ams-delta.c
new file mode 100644
index 000000000000..4f35b1f18cb9
--- /dev/null
+++ b/sound/soc/omap/ams-delta.c
@@ -0,0 +1,646 @@
+/*
+ * ams-delta.c  --  SoC audio for Amstrad E3 (Delta) videophone
+ *
+ * Copyright (C) 2009 Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
+ *
+ * Initially based on sound/soc/omap/osk5912.x
+ * Copyright (C) 2008 Mistral Solutions
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/spinlock.h>
+#include <linux/tty.h>
+
+#include <sound/soc-dapm.h>
+#include <sound/jack.h>
+
+#include <asm/mach-types.h>
+
+#include <mach/board-ams-delta.h>
+#include <mach/mcbsp.h>
+
+#include "omap-mcbsp.h"
+#include "omap-pcm.h"
+#include "../codecs/cx20442.h"
+
+
+/* Board specific DAPM widgets */
+ const struct snd_soc_dapm_widget ams_delta_dapm_widgets[] = {
+        /* Handset */
+        SND_SOC_DAPM_MIC("Mouthpiece", NULL),
+        SND_SOC_DAPM_HP("Earpiece", NULL),
+        /* Handsfree/Speakerphone */
+        SND_SOC_DAPM_MIC("Microphone", NULL),
+        SND_SOC_DAPM_SPK("Speaker", NULL),
+};
+
+/* How they are connected to codec pins */
+static const struct snd_soc_dapm_route ams_delta_audio_map[] = {
+        {"TELIN", NULL, "Mouthpiece"},
+        {"Earpiece", NULL, "TELOUT"},
+
+        {"MIC", NULL, "Microphone"},
+        {"Speaker", NULL, "SPKOUT"},
+};
+
+/*
+ * Controls, functional after the modem line discipline is activated.
+ */
+
+/* Virtual switch: audio input/output constellations */
+static const char *ams_delta_audio_mode[] =
+        {"Mixed", "Handset", "Handsfree", "Speakerphone"};
+
+/* Selection <-> pin translation */
+#define AMS_DELTA_MOUTHPIECE    0
+#define AMS_DELTA_EARPIECE      1
+#define AMS_DELTA_MICROPHONE    2
+#define AMS_DELTA_SPEAKER       3
+#define AMS_DELTA_AGC           4
+
+#define AMS_DELTA_MIXED         ((1 << AMS_DELTA_EARPIECE) | \
+                                                (1 << AMS_DELTA_MICROPHONE))
+#define AMS_DELTA_HANDSET       ((1 << AMS_DELTA_MOUTHPIECE) | \
+                                                (1 << AMS_DELTA_EARPIECE))
+#define AMS_DELTA_HANDSFREE     ((1 << AMS_DELTA_MICROPHONE) | \
+                                                (1 << AMS_DELTA_SPEAKER))
+#define AMS_DELTA_SPEAKERPHONE  (AMS_DELTA_HANDSFREE | (1 << AMS_DELTA_AGC))
+
+unsigned short ams_delta_audio_mode_pins[] = {
+        AMS_DELTA_MIXED,
+        AMS_DELTA_HANDSET,
+        AMS_DELTA_HANDSFREE,
+        AMS_DELTA_SPEAKERPHONE,
+};
+
+static unsigned short ams_delta_audio_agc;
+
+static int ams_delta_set_audio_mode(struct snd_kcontrol *kcontrol,
+                                        struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec =  snd_kcontrol_chip(kcontrol);
+        struct soc_enum *control = (struct soc_enum *)kcontrol->private_value;
+        unsigned short pins;
+        int pin, changed = 0;
+
+        /* Refuse any mode changes if we are not able to control the codec. */
+        if (!codec->control_data)
+                return -EUNATCH;
+
+        if (ucontrol->value.enumerated.item[0] >= control->max)
+                return -EINVAL;
+
+        mutex_lock(&codec->mutex);
+
+        /* Translate selection to bitmap */
+        pins = ams_delta_audio_mode_pins[ucontrol->value.enumerated.item[0]];
+
+        /* Setup pins after corresponding bits if changed */
+        pin = !!(pins & (1 << AMS_DELTA_MOUTHPIECE));
+        if (pin != snd_soc_dapm_get_pin_status(codec, "Mouthpiece")) {
+                changed = 1;
+                if (pin)
+                        snd_soc_dapm_enable_pin(codec, "Mouthpiece");
+                else
+                        snd_soc_dapm_disable_pin(codec, "Mouthpiece");
+        }
+        pin = !!(pins & (1 << AMS_DELTA_EARPIECE));
+        if (pin != snd_soc_dapm_get_pin_status(codec, "Earpiece")) {
+                changed = 1;
+                if (pin)
+                        snd_soc_dapm_enable_pin(codec, "Earpiece");
+                else
+                        snd_soc_dapm_disable_pin(codec, "Earpiece");
+        }
+        pin = !!(pins & (1 << AMS_DELTA_MICROPHONE));
+        if (pin != snd_soc_dapm_get_pin_status(codec, "Microphone")) {
+                changed = 1;
+                if (pin)
+                        snd_soc_dapm_enable_pin(codec, "Microphone");
+                else
+                        snd_soc_dapm_disable_pin(codec, "Microphone");
+        }
+        pin = !!(pins & (1 << AMS_DELTA_SPEAKER));
+        if (pin != snd_soc_dapm_get_pin_status(codec, "Speaker")) {
+                changed = 1;
+                if (pin)
+                        snd_soc_dapm_enable_pin(codec, "Speaker");
+                else
+                        snd_soc_dapm_disable_pin(codec, "Speaker");
+        }
+        pin = !!(pins & (1 << AMS_DELTA_AGC));
+        if (pin != ams_delta_audio_agc) {
+                ams_delta_audio_agc = pin;
+                changed = 1;
+                if (pin)
+                        snd_soc_dapm_enable_pin(codec, "AGCIN");
+                else
+                        snd_soc_dapm_disable_pin(codec, "AGCIN");
+        }
+        if (changed)
+                snd_soc_dapm_sync(codec);
+
+        mutex_unlock(&codec->mutex);
+
+        return changed;
+}
+
+static int ams_delta_get_audio_mode(struct snd_kcontrol *kcontrol,
+                                        struct snd_ctl_elem_value *ucontrol)
+{
+        struct snd_soc_codec *codec =  snd_kcontrol_chip(kcontrol);
+        unsigned short pins, mode;
+
+        pins = ((snd_soc_dapm_get_pin_status(codec, "Mouthpiece") <<
+                                                        AMS_DELTA_MOUTHPIECE) |
+                        (snd_soc_dapm_get_pin_status(codec, "Earpiece") <<
+                                                        AMS_DELTA_EARPIECE));
+        if (pins)
+                pins |= (snd_soc_dapm_get_pin_status(codec, "Microphone") <<
+                                                        AMS_DELTA_MICROPHONE);
+        else
+                pins = ((snd_soc_dapm_get_pin_status(codec, "Microphone") <<
+                                                        AMS_DELTA_MICROPHONE) |
+                        (snd_soc_dapm_get_pin_status(codec, "Speaker") <<
+                                                        AMS_DELTA_SPEAKER) |
+                        (ams_delta_audio_agc << AMS_DELTA_AGC));
+
+        for (mode = 0; mode < ARRAY_SIZE(ams_delta_audio_mode); mode++)
+                if (pins == ams_delta_audio_mode_pins[mode])
+                        break;
+
+        if (mode >= ARRAY_SIZE(ams_delta_audio_mode))
+                return -EINVAL;
+
+        ucontrol->value.enumerated.item[0] = mode;
+
+        return 0;
+}
+
+static const struct soc_enum ams_delta_audio_enum[] = {
+        SOC_ENUM_SINGLE_EXT(ARRAY_SIZE(ams_delta_audio_mode),
+                                                ams_delta_audio_mode),
+};
+
+static const struct snd_kcontrol_new ams_delta_audio_controls[] = {
+        SOC_ENUM_EXT("Audio Mode", ams_delta_audio_enum[0],
+                        ams_delta_get_audio_mode, ams_delta_set_audio_mode),
+};
+
+/* Hook switch */
+static struct snd_soc_jack ams_delta_hook_switch;
+static struct snd_soc_jack_gpio ams_delta_hook_switch_gpios[] = {
+        {
+                .gpio = 4,
+                .name = "hook_switch",
+                .report = SND_JACK_HEADSET,
+                .invert = 1,
+                .debounce_time = 150,
+        }
+};
+
+/* After we are able to control the codec over the modem,
+ * the hook switch can be used for dynamic DAPM reconfiguration. */
+static struct snd_soc_jack_pin ams_delta_hook_switch_pins[] = {
+        /* Handset */
+        {
+                .pin = "Mouthpiece",
+                .mask = SND_JACK_MICROPHONE,
+        },
+        {
+                .pin = "Earpiece",
+                .mask = SND_JACK_HEADPHONE,
+        },
+        /* Handsfree */
+        {
+                .pin = "Microphone",
+                .mask = SND_JACK_MICROPHONE,
+                .invert = 1,
+        },
+        {
+                .pin = "Speaker",
+                .mask = SND_JACK_HEADPHONE,
+                .invert = 1,
+        },
+};
+
+
+/*
+ * Modem line discipline, required for making above controls functional.
+ * Activated from userspace with ldattach, possibly invoked from udev rule.
+ */
+
+/* To actually apply any modem controlled configuration changes to the codec,
+ * we must connect codec DAI pins to the modem for a moment.  Be carefull not
+ * to interfere with our digital mute function that shares the same hardware. */
+static struct timer_list cx81801_timer;
+static bool cx81801_cmd_pending;
+static bool ams_delta_muted;
+static DEFINE_SPINLOCK(ams_delta_lock);
+
+static void cx81801_timeout(unsigned long data)
+{
+        int muted;
+
+        spin_lock(&ams_delta_lock);
+        cx81801_cmd_pending = 0;
+        muted = ams_delta_muted;
+        spin_unlock(&ams_delta_lock);
+
+        /* Reconnect the codec DAI back from the modem to the CPU DAI
+         * only if digital mute still off */
+        if (!muted)
+                ams_delta_latch2_write(AMS_DELTA_LATCH2_MODEM_CODEC, 0);
+}
+
+/* Line discipline .open() */
+static int cx81801_open(struct tty_struct *tty)
+{
+        return v253_ops.open(tty);
+}
+
+/* Line discipline .close() */
+static void cx81801_close(struct tty_struct *tty)
+{
+        struct snd_soc_codec *codec = tty->disc_data;
+
+        del_timer_sync(&cx81801_timer);
+
+        v253_ops.close(tty);
+
+        /* Prevent the hook switch from further changing the DAPM pins */
+        INIT_LIST_HEAD(&ams_delta_hook_switch.pins);
+
+        /* Revert back to default audio input/output constellation */
+        snd_soc_dapm_disable_pin(codec, "Mouthpiece");
+        snd_soc_dapm_enable_pin(codec, "Earpiece");
+        snd_soc_dapm_enable_pin(codec, "Microphone");
+        snd_soc_dapm_disable_pin(codec, "Speaker");
+        snd_soc_dapm_disable_pin(codec, "AGCIN");
+        snd_soc_dapm_sync(codec);
+}
+
+/* Line discipline .hangup() */
+static int cx81801_hangup(struct tty_struct *tty)
+{
+        cx81801_close(tty);
+        return 0;
+}
+
+/* Line discipline .recieve_buf() */
+static void cx81801_receive(struct tty_struct *tty,
+                                const unsigned char *cp, char *fp, int count)
+{
+        struct snd_soc_codec *codec = tty->disc_data;
+        const unsigned char *c;
+        int apply, ret;
+
+        if (!codec->control_data) {
+                /* First modem response, complete setup procedure */
+
+                /* Initialize timer used for config pulse generation */
+                setup_timer(&cx81801_timer, cx81801_timeout, 0);
+
+                v253_ops.receive_buf(tty, cp, fp, count);
+
+                /* Link hook switch to DAPM pins */
+                ret = snd_soc_jack_add_pins(&ams_delta_hook_switch,
+                                        ARRAY_SIZE(ams_delta_hook_switch_pins),
+                                        ams_delta_hook_switch_pins);
+                if (ret)
+                        dev_warn(codec->socdev->card->dev,
+                                "Failed to link hook switch to DAPM pins, "
+                                "will continue with hook switch unlinked.\n");
+
+                return;
+        }
+
+        v253_ops.receive_buf(tty, cp, fp, count);
+
+        for (c = &cp[count - 1]; c >= cp; c--) {
+                if (*c != '\r')
+                        continue;
+                /* Complete modem response received, apply config to codec */
+
+                spin_lock_bh(&ams_delta_lock);
+                mod_timer(&cx81801_timer, jiffies + msecs_to_jiffies(150));
+                apply = !ams_delta_muted && !cx81801_cmd_pending;
+                cx81801_cmd_pending = 1;
+                spin_unlock_bh(&ams_delta_lock);
+
+                /* Apply config pulse by connecting the codec to the modem
+                 * if not already done */
+                if (apply)
+                        ams_delta_latch2_write(AMS_DELTA_LATCH2_MODEM_CODEC,
+                                                AMS_DELTA_LATCH2_MODEM_CODEC);
+                break;
+        }
+}
+
+/* Line discipline .write_wakeup() */
+static void cx81801_wakeup(struct tty_struct *tty)
+{
+        v253_ops.write_wakeup(tty);
+}
+
+static struct tty_ldisc_ops cx81801_ops = {
+        .magic = TTY_LDISC_MAGIC,
+        .name = "cx81801",
+        .owner = THIS_MODULE,
+        .open = cx81801_open,
+        .close = cx81801_close,
+        .hangup = cx81801_hangup,
+        .receive_buf = cx81801_receive,
+        .write_wakeup = cx81801_wakeup,
+};
+
+
+/*
+ * Even if not very usefull, the sound card can still work without any of the
+ * above functonality activated.  You can still control its audio input/output
+ * constellation and speakerphone gain from userspace by issueing AT commands
+ * over the modem port.
+ */
+
+static int ams_delta_hw_params(struct snd_pcm_substream *substream,
+                         struct snd_pcm_hw_params *params)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+
+        /* Set cpu DAI configuration */
+        return snd_soc_dai_set_fmt(rtd->dai->cpu_dai,
+                                   SND_SOC_DAIFMT_DSP_A |
+                                   SND_SOC_DAIFMT_NB_NF |
+                                   SND_SOC_DAIFMT_CBM_CFM);
+}
+
+static struct snd_soc_ops ams_delta_ops = {
+        .hw_params = ams_delta_hw_params,
+};
+
+
+/* Board specific codec bias level control */
+static int ams_delta_set_bias_level(struct snd_soc_card *card,
+                                        enum snd_soc_bias_level level)
+{
+        struct snd_soc_codec *codec = card->codec;
+
+        switch (level) {
+        case SND_SOC_BIAS_ON:
+        case SND_SOC_BIAS_PREPARE:
+        case SND_SOC_BIAS_STANDBY:
+                if (codec->bias_level == SND_SOC_BIAS_OFF)
+                        ams_delta_latch2_write(AMS_DELTA_LATCH2_MODEM_NRESET,
+                                                AMS_DELTA_LATCH2_MODEM_NRESET);
+                break;
+        case SND_SOC_BIAS_OFF:
+                if (codec->bias_level != SND_SOC_BIAS_OFF)
+                        ams_delta_latch2_write(AMS_DELTA_LATCH2_MODEM_NRESET,
+                                                0);
+        }
+        codec->bias_level = level;
+
+        return 0;
+}
+
+/* Digital mute implemented using modem/CPU multiplexer.
+ * Shares hardware with codec config pulse generation */
+static bool ams_delta_muted = 1;
+
+static int ams_delta_digital_mute(struct snd_soc_dai *dai, int mute)
+{
+        int apply;
+
+        if (ams_delta_muted == mute)
+                return 0;
+
+        spin_lock_bh(&ams_delta_lock);
+        ams_delta_muted = mute;
+        apply = !cx81801_cmd_pending;
+        spin_unlock_bh(&ams_delta_lock);
+
+        if (apply)
+                ams_delta_latch2_write(AMS_DELTA_LATCH2_MODEM_CODEC,
+                                mute ? AMS_DELTA_LATCH2_MODEM_CODEC : 0);
+        return 0;
+}
+
+/* Our codec DAI probably doesn't have its own .ops structure */
+static struct snd_soc_dai_ops ams_delta_dai_ops = {
+        .digital_mute = ams_delta_digital_mute,
+};
+
+/* Will be used if the codec ever has its own digital_mute function */
+static int ams_delta_startup(struct snd_pcm_substream *substream)
+{
+        return ams_delta_digital_mute(NULL, 0);
+}
+
+static void ams_delta_shutdown(struct snd_pcm_substream *substream)
+{
+        ams_delta_digital_mute(NULL, 1);
+}
+
+
+/*
+ * Card initialization
+ */
+
+static int ams_delta_cx20442_init(struct snd_soc_codec *codec)
+{
+        struct snd_soc_dai *codec_dai = codec->dai;
+        struct snd_soc_card *card = codec->socdev->card;
+        int ret;
+        /* Codec is ready, now add/activate board specific controls */
+
+        /* Set up digital mute if not provided by the codec */
+        if (!codec_dai->ops) {
+                codec_dai->ops = &ams_delta_dai_ops;
+        } else if (!codec_dai->ops->digital_mute) {
+                codec_dai->ops->digital_mute = ams_delta_digital_mute;
+        } else {
+                ams_delta_ops.startup = ams_delta_startup;
+                ams_delta_ops.shutdown = ams_delta_shutdown;
+        }
+
+        /* Set codec bias level */
+        ams_delta_set_bias_level(card, SND_SOC_BIAS_STANDBY);
+
+        /* Add hook switch - can be used to control the codec from userspace
+         * even if line discipline fails */
+        ret = snd_soc_jack_new(card, "hook_switch",
+                                SND_JACK_HEADSET, &ams_delta_hook_switch);
+        if (ret)
+                dev_warn(card->dev,
+                                "Failed to allocate resources for hook switch, "
+                                "will continue without one.\n");
+        else {
+                ret = snd_soc_jack_add_gpios(&ams_delta_hook_switch,
+                                        ARRAY_SIZE(ams_delta_hook_switch_gpios),
+                                        ams_delta_hook_switch_gpios);
+                if (ret)
+                        dev_warn(card->dev,
+                                "Failed to set up hook switch GPIO line, "
+                                "will continue with hook switch inactive.\n");
+        }
+
+        /* Register optional line discipline for over the modem control */
+        ret = tty_register_ldisc(N_AMSDELTA, &cx81801_ops);
+        if (ret) {
+                dev_warn(card->dev,
+                                "Failed to register line discipline, "
+                                "will continue without any controls.\n");
+                return 0;
+        }
+
+        /* Add board specific DAPM widgets and routes */
+        ret = snd_soc_dapm_new_controls(codec, ams_delta_dapm_widgets,
+                                        ARRAY_SIZE(ams_delta_dapm_widgets));
+        if (ret) {
+                dev_warn(card->dev,
+                                "Failed to register DAPM controls, "
+                                "will continue without any.\n");
+                return 0;
+        }
+
+        ret = snd_soc_dapm_add_routes(codec, ams_delta_audio_map,
+                                        ARRAY_SIZE(ams_delta_audio_map));
+        if (ret) {
+                dev_warn(card->dev,
+                                "Failed to set up DAPM routes, "
+                                "will continue with codec default map.\n");
+                return 0;
+        }
+
+        /* Set up initial pin constellation */
+        snd_soc_dapm_disable_pin(codec, "Mouthpiece");
+        snd_soc_dapm_enable_pin(codec, "Earpiece");
+        snd_soc_dapm_enable_pin(codec, "Microphone");
+        snd_soc_dapm_disable_pin(codec, "Speaker");
+        snd_soc_dapm_disable_pin(codec, "AGCIN");
+        snd_soc_dapm_disable_pin(codec, "AGCOUT");
+        snd_soc_dapm_sync(codec);
+
+        /* Add virtual switch */
+        ret = snd_soc_add_controls(codec, ams_delta_audio_controls,
+                                        ARRAY_SIZE(ams_delta_audio_controls));
+        if (ret)
+                dev_warn(card->dev,
+                                "Failed to register audio mode control, "
+                                "will continue without it.\n");
+
+        return 0;
+}
+
+/* DAI glue - connects codec <--> CPU */
+static struct snd_soc_dai_link ams_delta_dai_link = {
+        .name = "CX20442",
+        .stream_name = "CX20442",
+        .cpu_dai = &omap_mcbsp_dai[0],
+        .codec_dai = &cx20442_dai,
+        .init = ams_delta_cx20442_init,
+        .ops = &ams_delta_ops,
+};
+
+/* Audio card driver */
+static struct snd_soc_card ams_delta_audio_card = {
+        .name = "AMS_DELTA",
+        .platform = &omap_soc_platform,
+        .dai_link = &ams_delta_dai_link,
+        .num_links = 1,
+        .set_bias_level = ams_delta_set_bias_level,
+};
+
+/* Audio subsystem */
+static struct snd_soc_device ams_delta_snd_soc_device = {
+        .card = &ams_delta_audio_card,
+        .codec_dev = &cx20442_codec_dev,
+};
+
+/* Module init/exit */
+static struct platform_device *ams_delta_audio_platform_device;
+static struct platform_device *cx20442_platform_device;
+
+static int __init ams_delta_module_init(void)
+{
+        int ret;
+
+        if (!(machine_is_ams_delta()))
+                return -ENODEV;
+
+        ams_delta_audio_platform_device =
+                        platform_device_alloc("soc-audio", -1);
+        if (!ams_delta_audio_platform_device)
+                return -ENOMEM;
+
+        platform_set_drvdata(ams_delta_audio_platform_device,
+                                &ams_delta_snd_soc_device);
+        ams_delta_snd_soc_device.dev = &ams_delta_audio_platform_device->dev;
+        *(unsigned int *)ams_delta_dai_link.cpu_dai->private_data = OMAP_MCBSP1;
+
+        ret = platform_device_add(ams_delta_audio_platform_device);
+        if (ret)
+                goto err;
+
+        /*
+         * Codec platform device could be registered from elsewhere (board?),
+         * but I do it here as it makes sense only if used with the card.
+         */
+        cx20442_platform_device = platform_device_register_simple("cx20442",
+                                                                -1, NULL, 0);
+        return 0;
+err:
+        platform_device_put(ams_delta_audio_platform_device);
+        return ret;
+}
+module_init(ams_delta_module_init);
+
+static void __exit ams_delta_module_exit(void)
+{
+        struct snd_soc_codec *codec;
+        struct tty_struct *tty;
+
+        if (ams_delta_audio_card.codec) {
+                codec = ams_delta_audio_card.codec;
+
+                if (codec->control_data) {
+                        tty = codec->control_data;
+
+                        tty_hangup(tty);
+                }
+        }
+
+        if (tty_unregister_ldisc(N_AMSDELTA) != 0)
+                dev_warn(&ams_delta_audio_platform_device->dev,
+                        "failed to unregister AMSDELTA line discipline\n");
+
+        snd_soc_jack_free_gpios(&ams_delta_hook_switch,
+                        ARRAY_SIZE(ams_delta_hook_switch_gpios),
+                        ams_delta_hook_switch_gpios);
+
+        /* Keep modem power on */
+        ams_delta_set_bias_level(&ams_delta_audio_card, SND_SOC_BIAS_STANDBY);
+
+        platform_device_unregister(cx20442_platform_device);
+        platform_device_unregister(ams_delta_audio_platform_device);
+}
+module_exit(ams_delta_module_exit);
+
+MODULE_AUTHOR("Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>");
+MODULE_DESCRIPTION("ALSA SoC driver for Amstrad E3 (Delta) videophone");
+MODULE_LICENSE("GPL");