This patch adds machine independent line discipline code, prevoiusly exsiting
inside my Amstrad Delta ASoC machine dirver, to the Conexant CX20442 codec
driver. The code can be used as a standalone line discipline, or as a set of
codec specific functions called from machine's line discipline callbacks.
Anyway, the line discipline itself must be registered by a machine driver.
Suggested by ASoC manintainer Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
(Hardly understood, imperfectly implemented and)
Signed-off-by: Janusz Krzysztofik <jkrzyszt@xxxxxxxxxxxx>
---
Mark, does it follow your idea closely enough?
--- linux-2.6.31-rc3/sound/soc/codecs/cx20442.h.orig 2009-07-22
04:56:45.000000000 +0200
+++ linux-2.6.31-rc3/sound/soc/codecs/cx20442.h 2009-07-28 21:23:17.000000000
+0200
@@ -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
--- linux-2.6.31-rc3/sound/soc/codecs/cx20442.c.orig 2009-07-28
20:26:18.000000000 +0200
+++ linux-2.6.31-rc3/sound/soc/codecs/cx20442.c 2009-07-28 21:19:43.000000000
+0200
@@ -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_
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 a line discipline initialization code */
if (!codec->hw_write || !codec->control_data)
return -EIO;
@@ -208,6 +209,111 @@ static int cx20442_write(struct snd_soc_
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 inside a machine specific 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)
+{
+}
+
+static 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);
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