GTA04 audio jack support.

Separate "driver" linked in to the twl4030 audio driver.
Auto and manual calibration.

Signed-off-by: NeilBrown <neilb@suse.de>

3 files changed, 238 insertions, 1 deletions

diff --git a/sound/soc/omap/Makefile b/sound/soc/omap/Makefile
index 128b509..09cd9e2 100644
--- a/sound/soc/omap/Makefile
+++ b/sound/soc/omap/Makefile
@@ -20,7 +20,7 @@ snd-soc-am3517evm-objs := am3517evm.o
 snd-soc-omap-abe-twl6040-objs := omap-abe-twl6040.o
 snd-soc-omap-twl4030-objs := omap-twl4030.o
 snd-soc-omap3pandora-objs := omap3pandora.o
-snd-soc-gta04-objs := gta04-voice.o gta04-headset.o
+snd-soc-gta04-objs := gta04-voice.o gta04-headset.o gta04-jack.o
 # gta04-fm.o gta04-audio.o
 snd-soc-omap-hdmi-card-objs := omap-hdmi-card.o
 
diff --git a/sound/soc/omap/gta04-jack.c b/sound/soc/omap/gta04-jack.c
new file mode 100644
index 0000000..0d96582
--- /dev/null
+++ b/sound/soc/omap/gta04-jack.c
@@ -0,0 +1,230 @@
+
+/*
+ * Jack driver for GTA04.
+ * Copyright Neil Brown <neilb@suse.de> 2013
+ *
+ * The DC current through the headset microphone pins is
+ * converted to a voltage which is presented on TWL4030 madc 7.
+ * To be able to read a current, the Headset Mic Bias must
+ * be enabled.
+ *
+ * When the jack device is open, enable the Headset Mic Bias
+ * and poll mdac 7 every 500msec.  Once we see an insertion,
+ * we increase the rate to ever 50msec until we see a removal.
+ *
+ * There are 4 possible states:
+ * - Nothing plugged in, open circuit - voltage is low
+ * - short circuit due to headphone with no mic (3-contact TRS)
+ *   inserted.  Voltage is high.
+ * - short circuit due to button on headset being pushed.
+ *   Voltage is also high.
+ * - Microphone is in circuit.  Voltage is even higher.  I don't
+ *   understand how it can be higher than than with a short
+ *   circuit, but that is what I measure.
+ *
+ * To differentiate between the two short circuits we look at how
+ * we got there.  A transition from open to short means a 3-contact
+ * TRS with no mic.  A transition from mic to short means the button
+ * on the mic was pressed.
+ *
+ * As different devices report different actual voltages we need
+ * some calibration.  As we cannot do this automatically we complete
+ * precision, we allow user-space to tell us the calibration.
+ * We assume that open-circuit is always below 100, and other
+ * readings are above that.
+ * The highest level we see for 3 consecutive readings is assumed
+ * to be the 'microphone' level, and short-circuit is 5% below that.
+ * If headphones with no mic are inserted this will be wrong, but not
+ * terribly wrong.  As soon as a headset with a mic is inserted it
+ * will get corrected and stay corrected.
+ * In order to keep this correct across a reboot, user-space can
+ * read the current setting from
+ *      /sys/modules/snd_soc_gta04/parameters/jack_level.
+ * and then write back the value after reboot.  Once a value is
+ * written, auto-calibration is disabled.
+ * Writing the value '0' can re-enable auto-calibration.
+ */
+
+#include <linux/input.h>
+#include <sound/jack.h>
+#include <sound/soc.h>
+#include <linux/suspend.h>
+#include <linux/i2c/twl4030-madc.h>
+#include <linux/module.h>
+
+static struct {
+	struct snd_soc_jack hs_jack;
+	struct delayed_work jack_work;
+	struct snd_soc_codec *codec;
+	int open;
+	/* When any jack is present, we:
+	 * - poll more quickly to catch button presses
+	 * - assume a 'short' is 'button press', not 'headset has
+	 *   no mic
+	 * 'present' stores SND_JACK_HEADPHONE or SND_JACK_HEADSET
+	 * indicating what we think is present.
+	 */
+	int present;
+	/* Calibration reports a single number which roughly
+	 * points to 'short'.
+	 * Less than half this is 'open circuit'.
+	 * More than this is 'microphone
+	 */
+	long level;
+	int level_fixed;
+	long level_new;
+	int level_count;
+} jack;
+
+static void gta04_jack_work(struct work_struct *work)
+{
+	long val;
+	long delay = msecs_to_jiffies(500);
+	int jackbits;
+
+	/* choose delay *before* checking presence so we still get
+	 * one long delay on first insertion to help with debounce.
+	 */
+	if (jack.present)
+		delay = msecs_to_jiffies(50);
+
+	val = twl4030_get_madc_conversion(7);
+	if (val < 0)
+		goto out;
+	/* On my device:
+	 * open circuit = around 20
+	 * short circuit = around 800, or 325 on another device
+	 * microphone   = around 830-840 !!! 345 on other device.
+	 */
+	if (!jack.level_fixed) {
+		if (jack.level * 21/20 + 2 < val) {
+			if (jack.level_count == 0 ||
+			    val < jack.level_new*21/20)
+				jack.level_new = val*20/21;
+			if (jack.level_count >= 3) {
+				jack.level = jack.level_new;
+				jack.level_count = 0;
+			} else
+				jack.level_count += 1;
+		} else
+			jack.level_count = 0;
+	}
+	if (val < jack.level / 2) {
+		/* open circuit */
+		jackbits = 0;
+		jack.present = 0;
+		/* debounce */
+		delay = msecs_to_jiffies(500);
+	} else if (val < jack.level) {
+		/* short */
+		if (jack.present == 0) {
+			/* Inserted headset with no mic */
+			jack.present = SND_JACK_HEADPHONE;
+			jackbits = jack.present;
+		} else if (jack.present & SND_JACK_MICROPHONE) {
+			/* mic shorted -> button press */
+			jackbits = SND_JACK_BTN_0 | jack.present;
+		} else {
+			/* headphones still present */
+			jackbits = jack.present;
+		}
+	} else {
+		/* There is a microphone there */
+		jack.present = SND_JACK_HEADSET;
+		jackbits = jack.present;
+	}
+	snd_soc_jack_report(&jack.hs_jack, jackbits,
+			    SND_JACK_HEADSET | SND_JACK_BTN_0);
+
+out:
+	if (jack.open)
+		schedule_delayed_work(&jack.jack_work, delay);
+}
+
+static int gta04_jack_pm_notify(struct notifier_block *b, unsigned long v, void *d)
+{
+	if (!jack.codec || !jack.open)
+		return 0;
+	switch(v) {
+	case PM_SUSPEND_PREPARE:
+		/* Disable Headset Mic Bias while asleep */
+		snd_soc_dapm_disable_pin(&jack.codec->dapm, "Headset Mic Bias");
+		snd_soc_dapm_sync(&jack.codec->dapm);
+		break;
+
+	case PM_POST_SUSPEND:
+		snd_soc_dapm_force_enable_pin(&jack.codec->dapm, "Headset Mic Bias");
+		snd_soc_dapm_sync(&jack.codec->dapm);
+		break;
+	default: break;
+	}
+	return 0;
+}
+
+static struct notifier_block gta04_jack_pm_notify_block = {
+	.notifier_call = gta04_jack_pm_notify,
+};
+
+static int gta04_jack_open(struct input_dev *dev)
+{
+	snd_soc_dapm_force_enable_pin(&jack.codec->dapm, "Headset Mic Bias");
+	snd_soc_dapm_sync(&jack.codec->dapm);
+	jack.open = 1;
+	schedule_delayed_work(&jack.jack_work, msecs_to_jiffies(100));
+	return 0;
+}
+
+static void gta04_jack_close(struct input_dev *dev)
+{
+	jack.open = 0;
+	cancel_delayed_work_sync(&jack.jack_work);
+	snd_soc_dapm_disable_pin(&jack.codec->dapm, "Headset Mic Bias");
+	snd_soc_dapm_sync(&jack.codec->dapm);
+}
+
+int gta04_jack_probe(struct snd_soc_codec *codec)
+{
+	struct snd_soc_dapm_context *dapm = &codec->dapm;
+	int ret;
+	ret = snd_soc_jack_new(codec, "Headset Jack",
+			       SND_JACK_HEADSET | SND_JACK_BTN_0,
+			       &jack.hs_jack);
+	if (ret)
+		return ret;
+	register_pm_notifier(&gta04_jack_pm_notify_block);
+
+	INIT_DELAYED_WORK(&jack.jack_work, gta04_jack_work);
+	jack.codec = codec;
+	if (jack.level < 100)
+		jack.level = 100;
+	jack.hs_jack.jack->input_dev->open = gta04_jack_open;
+	jack.hs_jack.jack->input_dev->close = gta04_jack_close;
+
+	return snd_soc_dapm_sync(dapm);
+}
+
+void gta04_jack_remove(struct snd_soc_codec *codec)
+{
+	unregister_pm_notifier(&gta04_jack_pm_notify_block);
+	cancel_delayed_work(&jack.jack_work);
+}
+
+static int get_level(char *buffer, struct kernel_param *kp)
+{
+	return sprintf(buffer, "%ld", jack.level);
+}
+static int set_level(const char *val, struct kernel_param *kp)
+{
+	long num;
+	if (kstrtol(val, 10, &num) < 0)
+		return -EINVAL;
+	if (num == 0) {
+		jack.level = 100;
+		jack.level_fixed = 0;
+	} else {
+		jack.level = num;
+		jack.level_fixed = 1;
+	}
+	return 0;
+}
+module_param_call(jack_level, set_level, get_level, NULL, S_IRUSR|S_IWUSR);
diff --git a/sound/soc/omap/omap-twl4030.c b/sound/soc/omap/omap-twl4030.c
index 2a9324f..3824f15 100644
--- a/sound/soc/omap/omap-twl4030.c
+++ b/sound/soc/omap/omap-twl4030.c
@@ -47,6 +47,7 @@
 struct omap_twl4030 {
 	int jack_detect;	/* board can detect jack events */
 	struct snd_soc_jack hs_jack;
+	void (*jack_remove)(struct snd_soc_codec *codec);
 };
 
 static int omap_twl4030_hw_params(struct snd_pcm_substream *substream,
@@ -229,6 +230,10 @@ static int omap_twl4030_init(struct snd_soc_pcm_runtime *rtd)
 	twl4030_disconnect_pin(dapm, pdata->has_digimic1, "Digital1 Mic");
 	twl4030_disconnect_pin(dapm, pdata->has_linein, "Line In");
 
+	if (pdata->jack_init &&
+	    pdata->jack_init(codec))
+		priv->jack_remove = pdata->jack_remove;
+
 	return ret;
 }
 
@@ -357,6 +362,8 @@ static int omap_twl4030_remove(struct platform_device *pdev)
 		snd_soc_jack_free_gpios(&priv->hs_jack,
 					ARRAY_SIZE(hs_jack_gpios),
 					hs_jack_gpios);
+	if (priv->jack_remove)
+		priv->jack_remove(NULL);
 	snd_soc_unregister_card(card);
 
 	return 0;