2 files changed, 111 insertions, 6 deletions

diff --git a/sound/soc/codecs/cx20442.c b/sound/soc/codecs/cx20442.c
index 7bbb77baa231..f33245510c3b 100644
--- a/sound/soc/codecs/cx20442.c
+++ b/sound/soc/codecs/cx20442.c
@@ -13,6 +13,8 @@
  *  option) any later version.
  */
 
+#include <linux/tty.h>
+
 #include <sound/core.h>
 #include <sound/initval.h>
 #include <sound/soc-dapm.h>
@@ -172,8 +174,7 @@ static int cx20442_write(struct snd_soc_codec *codec, unsigned int reg,
                 return -EINVAL;
 
         /* hw_write and control_data pointers required for talking to the modem
-         * are expected to be set by the machine driver's line discipline
-         * initialization code */
+         * are expected to be set by the line discipline initialization code */
         if (!codec->hw_write || !codec->control_data)
                 return -EIO;
 
@@ -208,6 +209,111 @@ static int cx20442_write(struct snd_soc_codec *codec, unsigned int reg,
         return 0;
 }
 
+
+/* Moved up here as line discipline referres it during initialization */
+static struct snd_soc_codec *cx20442_codec;
+
+
+/*
+ * Line discpline related code
+ *
+ * Any of the callback functions below can be used in two ways:
+ * 1) registerd by a machine driver as one of line discipline operations,
+ * 2) called from a machine's provided line discipline callback function
+ *    in case when extra machine specific code must be run as well.
+ */
+
+/* Modem init: echo off, digital speaker off, quiet off, voice mode */
+static const char *v253_init = "ate0m0q0+fclass=8\r";
+
+/* Line discipline .open() */
+static int v253_open(struct tty_struct *tty)
+{
+        struct snd_soc_codec *codec = cx20442_codec;
+        int ret, len = strlen(v253_init);
+
+        /* Doesn't make sense without write callback */
+        if (!tty->ops->write)
+                return -EINVAL;
+
+        /* Pass the codec structure address for use by other ldisc callbacks */
+        tty->disc_data = codec;
+
+        if (tty->ops->write(tty, v253_init, len) != len) {
+                ret = -EIO;
+                goto err;
+        }
+        /* Actual setup will be performed after the modem responds. */
+        return 0;
+err:
+        tty->disc_data = NULL;
+        return ret;
+}
+
+/* Line discipline .close() */
+static void v253_close(struct tty_struct *tty)
+{
+        struct snd_soc_codec *codec = tty->disc_data;
+
+        tty->disc_data = NULL;
+
+        if (!codec)
+                return;
+
+        /* Prevent the codec driver from further accessing the modem */
+        codec->hw_write = NULL;
+        codec->control_data = NULL;
+        codec->pop_time = 0;
+}
+
+/* Line discipline .hangup() */
+static int v253_hangup(struct tty_struct *tty)
+{
+        v253_close(tty);
+        return 0;
+}
+
+/* Line discipline .receive_buf() */
+static void v253_receive(struct tty_struct *tty,
+                                const unsigned char *cp, char *fp, int count)
+{
+        struct snd_soc_codec *codec = tty->disc_data;
+
+        if (!codec)
+                return;
+
+        if (!codec->control_data) {
+                /* First modem response, complete setup procedure */
+
+                /* Set up codec driver access to modem controls */
+                codec->control_data = tty;
+                codec->hw_write = (hw_write_t)tty->ops->write;
+                codec->pop_time = 1;
+        }
+}
+
+/* Line discipline .write_wakeup() */
+static void v253_wakeup(struct tty_struct *tty)
+{
+}
+
+struct tty_ldisc_ops v253_ops = {
+        .magic = TTY_LDISC_MAGIC,
+        .name = "cx20442",
+        .owner = THIS_MODULE,
+        .open = v253_open,
+        .close = v253_close,
+        .hangup = v253_hangup,
+        .receive_buf = v253_receive,
+        .write_wakeup = v253_wakeup,
+};
+EXPORT_SYMBOL_GPL(v253_ops);
+
+
+/*
+ * Codec DAI
+ */
+
 struct snd_soc_dai cx20442_dai = {
         .name = "CX20442",
         .playback = {
@@ -227,8 +333,6 @@ struct snd_soc_dai cx20442_dai = {
 };
 EXPORT_SYMBOL_GPL(cx20442_dai);
 
-static struct snd_soc_codec *cx20442_codec;
-
 static int cx20442_codec_probe(struct platform_device *pdev)
 {
         struct snd_soc_device *socdev = platform_get_drvdata(pdev);
@@ -313,13 +417,13 @@ static int cx20442_register(struct cx20442_priv *cx20442)
 
         ret = snd_soc_register_codec(codec);
         if (ret != 0) {
-                dev_err(&codec->dev, "Failed to register codec: %d\n", ret);
+                dev_err(codec->dev, "Failed to register codec: %d\n", ret);
                 goto err;
         }
 
         ret = snd_soc_register_dai(&cx20442_dai);
         if (ret != 0) {
-                dev_err(&codec->dev, "Failed to register DAI: %d\n", ret);
+                dev_err(codec->dev, "Failed to register DAI: %d\n", ret);
                 goto err_codec;
         }
 
diff --git a/sound/soc/codecs/cx20442.h b/sound/soc/codecs/cx20442.h
index d0a4f297aef4..688a5eb62e17 100644
--- a/sound/soc/codecs/cx20442.h
+++ b/sound/soc/codecs/cx20442.h
@@ -15,5 +15,6 @@
 
 extern struct snd_soc_dai cx20442_dai;
 extern struct snd_soc_codec_device cx20442_codec_dev;
+extern struct tty_ldisc_ops v253_ops;
 
 #endif