ALSA: usb-audio: Implement jack detection for HP Thunderbolt Dock G2

The HP Thunderbolt Dock G2 includes a headset jack with support for
jack detection. However, this being a UAC1 device, detection is
implemented via vendor-defined URB Controls.

Implement it in a similar way to the Dell WD15/19 docks, but with
different commands.

Signed-off-by: Tasos Sahanidis <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/usb/mixer_quirks.c

···
 	return 0;
 }
 
+/*
+ * HP Thunderbolt Dock G2 jack detection
+ *
+ * Similar to the Dell WD15/WD19, but with different commands.
+ */
+
+#define HP_DOCK_JACK_INTERRUPT_NODE	7
+
+#define HP_DOCK_GET			37
+
+#define HP_DOCK_JACK_PRESENCE		0xffb8
+#define HP_DOCK_JACK_PRESENCE_BIT	BIT(2)
+
+#define HP_DOCK_MIC_SENSE		0xf753
+#define HP_DOCK_MIC_SENSE_COMPLETE_BIT	BIT(4)
+
+#define HP_DOCK_MIC_SENSE_MASK		(BIT(2) | BIT(1) | BIT(0))
+/* #define HP_DOCK_MIC_SENSE_PRESENT	0x2 */
+#define HP_DOCK_MIC_SENSE_NOT_PRESENT	0x4
+
+static int hp_dock_ctl_connector_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	u32 pv = kcontrol->private_value;
+	bool presence;
+	int err;
+	u8 buf;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+		       HP_DOCK_GET,
+		       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+		       0, HP_DOCK_JACK_PRESENCE, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+
+	presence = !(buf & HP_DOCK_JACK_PRESENCE_BIT);
+
+	if (pv && presence) {
+		for (int i = 0; i < 20; i++) {
+			err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+			       HP_DOCK_GET,
+			       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+			       0, HP_DOCK_MIC_SENSE, &buf, sizeof(buf));
+			if (err < 0)
+				return err;
+
+			/* Mic sense is complete, we have a result. */
+			if (buf & HP_DOCK_MIC_SENSE_COMPLETE_BIT)
+				break;
+
+			msleep(100);
+		}
+
+		/*
+		 * If we reach the retry limit without mic sense having
+		 * completed, buf will contain HP_DOCK_MIC_SENSE_PRESENT,
+		 * thus presence remains true even when detection fails.
+		 */
+		if ((buf & HP_DOCK_MIC_SENSE_MASK) == HP_DOCK_MIC_SENSE_NOT_PRESENT)
+			presence = false;
+	}
+	ucontrol->value.integer.value[0] = presence;
+	return 0;
+}
+
+static const struct snd_kcontrol_new hp_dock_connector_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "", /* will be filled later manually */
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = hp_dock_ctl_connector_get,
+};
+
+static int hp_dock_mixer_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = realtek_add_jack(mixer, "Headsets Playback Jack", 0,
+			       HP_DOCK_JACK_INTERRUPT_NODE,
+			       &hp_dock_connector_ctl_ro);
+	if (err < 0)
+		return err;
+
+	err = realtek_add_jack(mixer, "Headset Capture Jack", 1,
+			       HP_DOCK_JACK_INTERRUPT_NODE,
+			       &hp_dock_connector_ctl_ro);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+
 /* RME Class Compliant device quirks */
 
 #define SND_RME_GET_STATUS1			23
···
 		break;
 	case USB_ID(0x2b73, 0x0034): /* Pioneer DJ DJM-V10 */
 		err = snd_djm_controls_create(mixer, SND_DJM_V10_IDX);
+		break;
+	case USB_ID(0x03f0, 0x0269): /* HP TB Dock G2 */
+		err = hp_dock_mixer_create(mixer);
 		break;
 	}