ALSA: usb-audio: Support jack detection on Dell dock

The Dell WD15 dock has a headset and a line out port. Add support for
detecting if a jack is inserted into one of these ports.
For the headset jack, additionally determine if a mic is present.

The WD15 contains an ALC4020 USB audio controller and ALC3263 audio codec
from Realtek. It is a UAC 1 device, and UAC 1 does not support jack
detection. Instead, jack detection works by sending HD Audio commands over
vendor-type USB messages.

I found out how it works by looking at USB captures on Windows.
The audio codec is very similar to the one supported by
sound/soc/codecs/rt298.c / rt298.h, some constant names and the mic
detection are adapted from there. The realtek_add_jack function is adapted
from build_connector_control in sound/usb/mixer.c.

I tested this on a WD15 dock with the latest firmware.
Signed-off-by: Jan Schär <jan@jschaer.ch>
Link: https://lore.kernel.org/r/20220627171855.42338-1-jan@jschaer.chSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_quirks.c

@@ -24,6 +24,7 @@
 #include <sound/asoundef.h>
 #include <sound/core.h>
 #include <sound/control.h>
+#include <sound/hda_verbs.h>
 #include <sound/hwdep.h>
 #include <sound/info.h>
 #include <sound/tlv.h>
@@ -1934,6 +1935,169 @@ static int snd_soundblaster_e1_switch_create(struct usb_mixer_interface *mixer)
 					  NULL);
 }
 
+/*
+ * Dell WD15 dock jack detection
+ *
+ * The WD15 contains an ALC4020 USB audio controller and ALC3263 audio codec
+ * from Realtek. It is a UAC 1 device, and UAC 1 does not support jack
+ * detection. Instead, jack detection works by sending HD Audio commands over
+ * vendor-type USB messages.
+ */
+
+#define HDA_VERB_CMD(V, N, D) (((N) << 20) | ((V) << 8) | (D))
+
+#define REALTEK_HDA_VALUE 0x0038
+
+#define REALTEK_HDA_SET		62
+#define REALTEK_HDA_GET_OUT	88
+#define REALTEK_HDA_GET_IN	89
+
+#define REALTEK_LINE1			0x1a
+#define REALTEK_VENDOR_REGISTERS	0x20
+#define REALTEK_HP_OUT			0x21
+
+#define REALTEK_CBJ_CTRL2 0x50
+
+#define REALTEK_JACK_INTERRUPT_NODE 5
+
+#define REALTEK_MIC_FLAG 0x100
+
+static int realtek_hda_set(struct snd_usb_audio *chip, u32 cmd)
+{
+	struct usb_device *dev = chip->dev;
+	u32 buf = cpu_to_be32(cmd);
+
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), REALTEK_HDA_SET,
+			       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_OUT,
+			       REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+}
+
+static int realtek_hda_get(struct snd_usb_audio *chip, u32 cmd, u32 *value)
+{
+	struct usb_device *dev = chip->dev;
+	int err;
+	u32 buf = cpu_to_be32(cmd);
+
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), REALTEK_HDA_GET_OUT,
+			      USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_OUT,
+			      REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), REALTEK_HDA_GET_IN,
+			      USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+			      REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+
+	*value = be32_to_cpu(buf);
+	return 0;
+}
+
+static int realtek_ctl_connector_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = kcontrol->private_data;
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	u32 pv = kcontrol->private_value;
+	u32 node_id = pv & 0xff;
+	u32 sense;
+	u32 cbj_ctrl2;
+	bool presence;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+	err = realtek_hda_get(chip,
+			      HDA_VERB_CMD(AC_VERB_GET_PIN_SENSE, node_id, 0),
+			      &sense);
+	if (err < 0)
+		goto err;
+	if (pv & REALTEK_MIC_FLAG) {
+		err = realtek_hda_set(chip,
+				      HDA_VERB_CMD(AC_VERB_SET_COEF_INDEX,
+						   REALTEK_VENDOR_REGISTERS,
+						   REALTEK_CBJ_CTRL2));
+		if (err < 0)
+			goto err;
+		err = realtek_hda_get(chip,
+				      HDA_VERB_CMD(AC_VERB_GET_PROC_COEF,
+						   REALTEK_VENDOR_REGISTERS, 0),
+				      &cbj_ctrl2);
+		if (err < 0)
+			goto err;
+	}
+err:
+	snd_usb_unlock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	presence = sense & AC_PINSENSE_PRESENCE;
+	if (pv & REALTEK_MIC_FLAG)
+		presence = presence && (cbj_ctrl2 & 0x0070) == 0x0070;
+	ucontrol->value.integer.value[0] = presence;
+	return 0;
+}
+
+static const struct snd_kcontrol_new realtek_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 = realtek_ctl_connector_get,
+};
+
+static int realtek_resume_jack(struct usb_mixer_elem_list *list)
+{
+	snd_ctl_notify(list->mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &list->kctl->id);
+	return 0;
+}
+
+static int realtek_add_jack(struct usb_mixer_interface *mixer,
+			    char *name, u32 val)
+{
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+
+	cval = kzalloc(sizeof(*cval), GFP_KERNEL);
+	if (!cval)
+		return -ENOMEM;
+	snd_usb_mixer_elem_init_std(&cval->head, mixer,
+				    REALTEK_JACK_INTERRUPT_NODE);
+	cval->head.resume = realtek_resume_jack;
+	cval->val_type = USB_MIXER_BOOLEAN;
+	cval->channels = 1;
+	cval->min = 0;
+	cval->max = 1;
+	kctl = snd_ctl_new1(&realtek_connector_ctl_ro, cval);
+	if (!kctl) {
+		kfree(cval);
+		return -ENOMEM;
+	}
+	kctl->private_value = val;
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+	kctl->private_free = snd_usb_mixer_elem_free;
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int dell_dock_mixer_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = realtek_add_jack(mixer, "Line Out Jack", REALTEK_LINE1);
+	if (err < 0)
+		return err;
+	err = realtek_add_jack(mixer, "Headphone Jack", REALTEK_HP_OUT);
+	if (err < 0)
+		return err;
+	err = realtek_add_jack(mixer, "Headset Mic Jack",
+			       REALTEK_HP_OUT | REALTEK_MIC_FLAG);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
 static void dell_dock_init_vol(struct snd_usb_audio *chip, int ch, int id)
 {
 	u16 buf = 0;
@@ -3245,6 +3409,9 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		err = snd_soundblaster_e1_switch_create(mixer);
 		break;
 	case USB_ID(0x0bda, 0x4014): /* Dell WD15 dock */
+		err = dell_dock_mixer_create(mixer);
+		if (err < 0)
+			break;
 		err = dell_dock_mixer_init(mixer);
 		break;