ASoC: rt5640: Add button press support

Enable button press detection for headsets by using the ovcd IRQ to get
notified of button presses.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5640.c

@@ -2119,6 +2119,24 @@ static void rt5640_disable_micbias1_for_ovcd(struct snd_soc_component *component
 	snd_soc_dapm_mutex_unlock(dapm);
 }
 
+static void rt5640_enable_micbias1_ovcd_irq(struct snd_soc_component *component)
+{
+	struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component);
+
+	snd_soc_component_update_bits(component, RT5640_IRQ_CTRL2,
+		RT5640_IRQ_MB1_OC_MASK, RT5640_IRQ_MB1_OC_NOR);
+	rt5640->ovcd_irq_enabled = true;
+}
+
+static void rt5640_disable_micbias1_ovcd_irq(struct snd_soc_component *component)
+{
+	struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component);
+
+	snd_soc_component_update_bits(component, RT5640_IRQ_CTRL2,
+		RT5640_IRQ_MB1_OC_MASK, RT5640_IRQ_MB1_OC_BP);
+	rt5640->ovcd_irq_enabled = false;
+}
+
 static void rt5640_clear_micbias1_ovcd(struct snd_soc_component *component)
 {
 	snd_soc_component_update_bits(component, RT5640_IRQ_CTRL2,
@@ -2149,10 +2167,80 @@ static bool rt5640_jack_inserted(struct snd_soc_component *component)
 		return (val & RT5640_JD_STATUS);
 }
 
-/* Jack detect timings */
+/* Jack detect and button-press timings */
 #define JACK_SETTLE_TIME	100 /* milli seconds */
 #define JACK_DETECT_COUNT	5
 #define JACK_DETECT_MAXCOUNT	20  /* Aprox. 2 seconds worth of tries */
+#define JACK_UNPLUG_TIME	80  /* milli seconds */
+#define BP_POLL_TIME		10  /* milli seconds */
+#define BP_POLL_MAXCOUNT	200 /* assume something is wrong after this */
+#define BP_THRESHOLD		3
+
+static void rt5640_start_button_press_work(struct snd_soc_component *component)
+{
+	struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component);
+
+	rt5640->poll_count = 0;
+	rt5640->press_count = 0;
+	rt5640->release_count = 0;
+	rt5640->pressed = false;
+	rt5640->press_reported = false;
+	rt5640_clear_micbias1_ovcd(component);
+	schedule_delayed_work(&rt5640->bp_work, msecs_to_jiffies(BP_POLL_TIME));
+}
+
+static void rt5640_button_press_work(struct work_struct *work)
+{
+	struct rt5640_priv *rt5640 =
+		container_of(work, struct rt5640_priv, bp_work.work);
+	struct snd_soc_component *component = rt5640->component;
+
+	/* Check the jack was not removed underneath us */
+	if (!rt5640_jack_inserted(component))
+		return;
+
+	if (rt5640_micbias1_ovcd(component)) {
+		rt5640->release_count = 0;
+		rt5640->press_count++;
+		/* Remember till after JACK_UNPLUG_TIME wait */
+		if (rt5640->press_count >= BP_THRESHOLD)
+			rt5640->pressed = true;
+		rt5640_clear_micbias1_ovcd(component);
+	} else {
+		rt5640->press_count = 0;
+		rt5640->release_count++;
+	}
+
+	/*
+	 * The pins get temporarily shorted on jack unplug, so we poll for
+	 * at least JACK_UNPLUG_TIME milli-seconds before reporting a press.
+	 */
+	rt5640->poll_count++;
+	if (rt5640->poll_count < (JACK_UNPLUG_TIME / BP_POLL_TIME)) {
+		schedule_delayed_work(&rt5640->bp_work,
+				      msecs_to_jiffies(BP_POLL_TIME));
+		return;
+	}
+
+	if (rt5640->pressed && !rt5640->press_reported) {
+		dev_dbg(component->dev, "headset button press\n");
+		snd_soc_jack_report(rt5640->jack, SND_JACK_BTN_0,
+				    SND_JACK_BTN_0);
+		rt5640->press_reported = true;
+	}
+
+	if (rt5640->release_count >= BP_THRESHOLD) {
+		if (rt5640->press_reported) {
+			dev_dbg(component->dev, "headset button release\n");
+			snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0);
+		}
+		/* Re-enable OVCD IRQ to detect next press */
+		rt5640_enable_micbias1_ovcd_irq(component);
+		return; /* Stop polling */
+	}
+
+	schedule_delayed_work(&rt5640->bp_work, msecs_to_jiffies(BP_POLL_TIME));
+}
 
 static int rt5640_detect_headset(struct snd_soc_component *component)
 {
@@ -2209,17 +2297,51 @@ static void rt5640_jack_work(struct work_struct *work)
 	if (!rt5640_jack_inserted(component)) {
 		/* Jack removed, or spurious IRQ? */
 		if (rt5640->jack->status & SND_JACK_HEADPHONE) {
-			snd_soc_jack_report(rt5640->jack, 0, SND_JACK_HEADSET);
+			if (rt5640->jack->status & SND_JACK_MICROPHONE) {
+				cancel_delayed_work_sync(&rt5640->bp_work);
+				rt5640_disable_micbias1_ovcd_irq(component);
+				rt5640_disable_micbias1_for_ovcd(component);
+			}
+			snd_soc_jack_report(rt5640->jack, 0,
+					    SND_JACK_HEADSET | SND_JACK_BTN_0);
 			dev_dbg(component->dev, "jack unplugged\n");
 		}
 	} else if (!(rt5640->jack->status & SND_JACK_HEADPHONE)) {
 		/* Jack inserted */
+		WARN_ON(rt5640->ovcd_irq_enabled);
 		rt5640_enable_micbias1_for_ovcd(component);
 		status = rt5640_detect_headset(component);
+		if (status == SND_JACK_HEADSET) {
+			/* Enable ovcd IRQ for button press detect. */
+			rt5640_enable_micbias1_ovcd_irq(component);
+		} else {
+			/* No more need for overcurrent detect. */
 			rt5640_disable_micbias1_for_ovcd(component);
-
+		}
 		dev_dbg(component->dev, "detect status %#02x\n", status);
 		snd_soc_jack_report(rt5640->jack, status, SND_JACK_HEADSET);
+	} else if (rt5640->ovcd_irq_enabled && rt5640_micbias1_ovcd(component)) {
+		dev_dbg(component->dev, "OVCD IRQ\n");
+
+		/*
+		 * The ovcd IRQ keeps firing while the button is pressed, so
+		 * we disable it and start polling the button until released.
+		 *
+		 * The disable will make the IRQ pin 0 again and since we get
+		 * IRQs on both edges (so as to detect both jack plugin and
+		 * unplug) this means we will immediately get another IRQ.
+		 * The ovcd_irq_enabled check above makes the 2ND IRQ a NOP.
+		 */
+		rt5640_disable_micbias1_ovcd_irq(component);
+		rt5640_start_button_press_work(component);
+
+		/*
+		 * If the jack-detect IRQ flag goes high (unplug) after our
+		 * above rt5640_jack_inserted() check and before we have
+		 * disabled the OVCD IRQ, the IRQ pin will stay high and as
+		 * we react to edges, we miss the unplug event -> recheck.
+		 */
+		queue_work(system_long_wq, &rt5640->jack_work);
 	}
 }
 
@@ -2238,6 +2360,7 @@ static void rt5640_cancel_work(void *data)
 	struct rt5640_priv *rt5640 = data;
 
 	cancel_work_sync(&rt5640->jack_work);
+	cancel_delayed_work_sync(&rt5640->bp_work);
 }
 
 static void rt5640_enable_jack_detect(struct snd_soc_component *component,
@@ -2282,10 +2405,25 @@ static void rt5640_enable_jack_detect(struct snd_soc_component *component,
 	snd_soc_component_update_bits(component, RT5640_IRQ_CTRL2,
 		RT5640_MB1_OC_STKY_MASK, RT5640_MB1_OC_STKY_EN);
 
+	/*
+	 * All IRQs get or-ed together, so we need the jack IRQ to report 0
+	 * when a jack is inserted so that the OVCD IRQ then toggles the IRQ
+	 * pin 0/1 instead of it being stuck to 1. So we invert the JD polarity
+	 * on systems where the hardware does not already do this.
+	 */
+	if (rt5640->jd_inverted)
 		snd_soc_component_write(component, RT5640_IRQ_CTRL1,
 					RT5640_IRQ_JD_NOR);
+	else
+		snd_soc_component_write(component, RT5640_IRQ_CTRL1,
+					RT5640_IRQ_JD_NOR | RT5640_JD_P_INV);
 
 	rt5640->jack = jack;
+	if (rt5640->jack->status & SND_JACK_MICROPHONE) {
+		rt5640_enable_micbias1_for_ovcd(component);
+		rt5640_enable_micbias1_ovcd_irq(component);
+	}
+
 	enable_irq(rt5640->irq);
 	/* sync initial jack state */
 	queue_work(system_long_wq, &rt5640->jack_work);
@@ -2298,6 +2436,12 @@ static void rt5640_disable_jack_detect(struct snd_soc_component *component)
 	disable_irq(rt5640->irq);
 	rt5640_cancel_work(rt5640);
 
+	if (rt5640->jack->status & SND_JACK_MICROPHONE) {
+		rt5640_disable_micbias1_ovcd_irq(component);
+		rt5640_disable_micbias1_for_ovcd(component);
+		snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0);
+	}
+
 	rt5640->jack = NULL;
 }
 
@@ -2677,6 +2821,7 @@ static int rt5640_i2c_probe(struct i2c_client *i2c,
 
 	rt5640->hp_mute = 1;
 	rt5640->irq = i2c->irq;
+	INIT_DELAYED_WORK(&rt5640->bp_work, rt5640_button_press_work);
 	INIT_WORK(&rt5640->jack_work, rt5640_jack_work);
 
 	/* Make sure work is stopped on probe-error / remove */

sound/soc/codecs/rt5640.h

@@ -2139,7 +2139,14 @@ struct rt5640_priv {
 	bool hp_mute;
 	bool asrc_en;
 
-	/* Jack detect data */
+	/* Jack and button detect data */
+	bool ovcd_irq_enabled;
+	bool pressed;
+	bool press_reported;
+	int press_count;
+	int release_count;
+	int poll_count;
+	struct delayed_work bp_work;
 	struct work_struct jack_work;
 	struct snd_soc_jack *jack;
 	unsigned int jd_src;