[PATCH 2/3] Add Audient EVO4 mixer quirks

[Christian Ruppert <arc@gmx.li>]

The controls enumerated by the Audient EVO4 are incomplete. Add missing
controls for
  * channel muting
  * the cross-fader
  * the recording mixer
  * phantom power

The driver is structured so that it should be trivial to extend it to the
EVO8 (and potentially other Audient devices) but we need a kind soul who
has access to that hardware to correctly map the control names and test
everything.

Signed-off-by: Christian Ruppert <arc@gmx.li>
---
 MAINTAINERS              |   7 +
 sound/usb/Makefile       |   1 +
 sound/usb/mixer_evo.c    | 505 +++++++++++++++++++++++++++++++++++++++
 sound/usb/mixer_evo.h    |  12 +
 sound/usb/mixer_quirks.c |   5 +
 5 files changed, 530 insertions(+)
 create mode 100644 sound/usb/mixer_evo.c
 create mode 100644 sound/usb/mixer_evo.h

diff --git a/MAINTAINERS b/MAINTAINERS
index c2414447892c..5f8df442b1a5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4346,6 +4346,13 @@ F:	drivers/net/ieee802154/at86rf230.h
 F:	drivers/net/ieee802154/atusb.c
 F:	drivers/net/ieee802154/atusb.h
 
+AUDIENT EVO MIXER DRIVER
+M:	Christian Ruppert <arc@gmx.li>
+L:	linux-sound@vger.kernel.org
+S:	Maintained
+F:	sound/usb/mixer_evo.c
+F:	sound/usb/mixer_evo.h
+
 AUDIT SUBSYSTEM
 M:	Paul Moore <paul@paul-moore.com>
 M:	Eric Paris <eparis@redhat.com>
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index e62794a87e73..2e842dcc73de 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -11,6 +11,7 @@ snd-usb-audio-y := 	card.o \
 			helper.o \
 			implicit.o \
 			mixer.o \
+			mixer_evo.o \
 			mixer_quirks.o \
 			mixer_scarlett.o \
 			mixer_scarlett2.o \
diff --git a/sound/usb/mixer_evo.c b/sound/usb/mixer_evo.c
new file mode 100644
index 000000000000..c327b82c8d2d
--- /dev/null
+++ b/sound/usb/mixer_evo.c
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Audient EVO driver for ALSA
+ * Copyright (C) 2026 Christian Ruppert <arc@gmx.li>
+ *
+ * Based on the work of Ivan Hazucha for audient-evo-py.
+ * https://github.com/vanzaho/audient-evo-py/
+ */
+
+
+#include <asm/byteorder.h>
+#include <linux/usb.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "helper.h"
+#include "mixer_evo.h"
+
+
+enum snd_evo_type {
+	SND_EVO_TYPE_MONITOR = 0,
+	SND_EVO_TYPE_PHANTOM,
+	SND_EVO_TYPE_MUTE,
+	SND_EVO_TYPE_MUTE_OUT,
+	SND_EVO_TYPE_MIXER,
+	SND_EVO_TYPE_NCTYPES
+};
+
+static const struct snd_evo_ctrl_type {
+	snd_ctl_elem_type_t type;
+	bool invert;
+	union {
+		int integer;
+	} min;
+	union {
+		int integer;
+	} max;
+	u16 wValue;
+	u16 wIndex;
+} snd_evo_ctypes[SND_EVO_TYPE_NCTYPES] = {
+	[SND_EVO_TYPE_MONITOR] = {
+		.type = SNDRV_CTL_ELEM_TYPE_INTEGER,
+		.min.integer = 0,
+		.max.integer = 127,
+		.wValue = 0x0000,
+		.wIndex = 0x3800,
+	},
+	[SND_EVO_TYPE_PHANTOM] = {
+		.type = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
+		.invert = false,
+		.min.integer = 0,
+		.max.integer = 1,
+		.wValue = 0x0000,
+		.wIndex = 0x3A00,
+	},
+	[SND_EVO_TYPE_MUTE] = {
+		.type = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
+		.invert = true,
+		.min.integer = 0,
+		.max.integer = 1,
+		.wValue = 0x0200,
+		.wIndex = 0x3A00,
+	},
+	[SND_EVO_TYPE_MUTE_OUT] = {
+		.type = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
+		.invert = true,
+		.min.integer = 0,
+		.max.integer = 1,
+		.wValue = 0x0100,
+		.wIndex = 0x3B00,
+	},
+	[SND_EVO_TYPE_MIXER] = {
+		.type = SNDRV_CTL_ELEM_TYPE_INTEGER,
+		.min.integer = -128 * 256,
+		.max.integer = 6 * 256,
+		.wValue = 0x0100,
+		.wIndex = 0x3C00,
+	},
+};
+
+#define SND_EVO_FLAGS_DIRECTION (1L<<0)
+#define SND_EVO_FLAGS_CAPTURE (1L<<0)
+#define SND_EVO_FLAGS_PLAYBACK (0L<<0)
+
+struct snd_evo_ctrl {
+	char *basename;
+	enum snd_evo_type type;
+	unsigned int channels;
+	unsigned int hwchannels;
+	unsigned int val_offs;
+	unsigned long flags;
+};
+
+static const struct snd_evo_ctrl evo4_controls[] = {
+	{
+		.basename = "Master",
+		.type = SND_EVO_TYPE_MUTE_OUT,
+		.channels = 1,
+		.hwchannels = 1,
+		.val_offs = 0,
+		.flags = SND_EVO_FLAGS_PLAYBACK,
+	},
+	{
+		.basename = "Mic",
+		.type = SND_EVO_TYPE_MUTE,
+		.channels = 4,
+		.hwchannels = 2,
+		.val_offs = 0,
+		.flags = SND_EVO_FLAGS_PLAYBACK,
+	},
+	{
+		.basename = "Monitor",
+		.type = SND_EVO_TYPE_MONITOR,
+		.channels = 1,
+		.hwchannels = 1,
+		.val_offs = 0,
+		.flags = SND_EVO_FLAGS_PLAYBACK,
+	},
+	{
+		.basename = "Mic 1",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 0,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Mic 2",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 2,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Master Left",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 4,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Master Right",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 6,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Loopback Left",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 8,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Loopback Right",
+		.type = SND_EVO_TYPE_MIXER,
+		.channels = 2,
+		.hwchannels = 2,
+		.val_offs = 10,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Mic 1 Phantom",
+		.type = SND_EVO_TYPE_PHANTOM,
+		.channels = 1,
+		.hwchannels = 1,
+		.val_offs = 0,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{
+		.basename = "Mic 2 Phantom",
+		.type = SND_EVO_TYPE_PHANTOM,
+		.channels = 1,
+		.hwchannels = 1,
+		.val_offs = 1,
+		.flags = SND_EVO_FLAGS_CAPTURE,
+	},
+	{ 0 }, /* sentinel */
+};
+
+static const struct evo_devinfo {
+	u32 usb_id;
+	const struct snd_evo_ctrl *controls;
+} evo_devinfo[] = {
+	{
+		.usb_id = USB_ID(USB_AUDIENT_VID, USB_EVO4_PID),
+		.controls = evo4_controls,
+	},
+	{
+		.usb_id = USB_ID(USB_AUDIENT_VID, USB_EVO4_PID),
+		.controls = NULL,
+	},
+	{ 0 } /* sentinel */
+};
+
+
+static inline unsigned long snd_evo_kctl_priv(enum snd_evo_type type,
+					      u8 valoffs, u8 hwchannels)
+{
+	unsigned long type_l = type & 0xFF;
+	unsigned long valoffs_l = valoffs & 0xFF;
+	unsigned long hwchannels_l = hwchannels & 0xFF;
+
+	return (hwchannels_l << 16) | (valoffs_l << 8) | type_l;
+}
+
+static __always_inline
+const struct snd_evo_ctrl_type *snd_evo_kctl_type(struct snd_kcontrol *kctl)
+{
+	return &snd_evo_ctypes[kctl->private_value & 0xFF];
+}
+
+static __always_inline u16 snd_evo_kctl_valoffs(struct snd_kcontrol *kctl)
+{
+	return (kctl->private_value >> 8) & 0xFF;
+}
+
+static __always_inline u16 snd_evo_kctl_hwchannels(struct snd_kcontrol *kctl)
+{
+	return (kctl->private_value >> 16) & 0xFF;
+}
+
+static inline u16 snd_evo_kctl_channels(struct snd_kcontrol *kctl)
+{
+	struct usb_mixer_elem_info *info = kctl->private_data;
+
+	return info->channels;
+}
+
+
+#define EVO_REQ_CUR (0x01)
+#define EVO_REQTYPE_SET (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE)
+#define EVO_REQTYPE_GET (USB_DIR_IN  | USB_TYPE_CLASS | USB_RECIP_INTERFACE)
+
+static inline int snd_evo_get_cur(struct usb_mixer_interface *mixer,
+				  u16 value, u16 index,
+				  void *buf, size_t len)
+{
+	struct usb_device *const dev = mixer->chip->dev;
+
+	return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			       EVO_REQ_CUR, EVO_REQTYPE_GET,
+			       value, index, buf, len);
+}
+
+static inline int snd_evo_set_cur(struct usb_mixer_interface *mixer,
+				  u16 value, u16 index,
+				  void *buf, size_t len)
+{
+	struct usb_device *const dev = mixer->chip->dev;
+
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			       EVO_REQ_CUR, EVO_REQTYPE_SET,
+			       value, index, buf, len);
+}
+
+
+static int snd_ctl_evo_boolean_get(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ctl_val)
+{
+	struct usb_mixer_elem_list *const list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *const mixer = list->mixer;
+
+	const unsigned int nchan = snd_evo_kctl_channels(kctl);
+	const unsigned int hwchan = snd_evo_kctl_hwchannels(kctl);
+	const struct snd_evo_ctrl_type *const ctype = snd_evo_kctl_type(kctl);
+	const u16 value = ctype->wValue + snd_evo_kctl_valoffs(kctl);
+	const u16 index = ctype->wIndex;
+
+	int i;
+
+	for (i = 0; i < hwchan; i++) {
+		u32 buf;
+		int ret;
+
+		ret = snd_evo_get_cur(mixer, value + i, index,
+				      &buf, sizeof(buf));
+		if (ret < 0)
+			return ret;
+
+		ctl_val->value.integer.value[i] = le32_to_cpu(buf) ? 1 : 0;
+
+		if (ctype->invert)
+			ctl_val->value.integer.value[i] ^= 0x1;
+	}
+
+	for (; i < nchan; i++)
+		ctl_val->value.integer.value[i] = ctype->invert
+							? ctype->max.integer
+							: ctype->min.integer;
+
+	return 0;
+}
+
+static int snd_ctl_evo_boolean_set(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ctl_val)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+
+	const unsigned int hwchan = snd_evo_kctl_hwchannels(kctl);
+	const struct snd_evo_ctrl_type *const ctype = snd_evo_kctl_type(kctl);
+	const u16 value = ctype->wValue + snd_evo_kctl_valoffs(kctl);
+	const u16 index = ctype->wIndex;
+
+	int changed = 0;
+	int i;
+
+	for (i = 0; i < hwchan; i++) {
+		u32 rbuf;
+		u32 buf = cpu_to_le32(ctl_val->value.integer.value[i] ? 1 : 0);
+		int ret;
+
+		if (ctype->invert)
+			buf ^= 0x1;
+
+		ret = snd_evo_get_cur(mixer, value + i, index,
+				      &rbuf, sizeof(rbuf));
+		if (ret < 0)
+			return ret;
+
+		if (rbuf != buf) {
+			changed = 1;
+
+			ret = snd_evo_set_cur(mixer, value + i, index,
+					      &buf, sizeof(buf));
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return changed;
+}
+
+static int snd_ctl_evo_integer_get(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ctl_val)
+{
+	struct usb_mixer_elem_list *const list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *const mixer = list->mixer;
+
+	const unsigned int nchan = snd_evo_kctl_channels(kctl);
+	const unsigned int hwchan = snd_evo_kctl_hwchannels(kctl);
+	const struct snd_evo_ctrl_type *const ctype = snd_evo_kctl_type(kctl);
+	const u16 value = ctype->wValue + snd_evo_kctl_valoffs(kctl);
+	const u16 index = ctype->wIndex;
+
+	int i;
+
+	for (i = 0; i < hwchan; i++) {
+		u16 buf;
+		s16 val;
+		int ret;
+
+		ret = snd_evo_get_cur(mixer, value + i, index,
+				      &buf, sizeof(buf));
+		if (ret < 0)
+			return ret;
+
+		val = le16_to_cpu(buf);
+		ctl_val->value.integer.value[i] = val;
+	}
+
+	for (; i < nchan; i++)
+		ctl_val->value.integer.value[i] = ctype->min.integer;
+
+	return 0;
+}
+
+static int snd_ctl_evo_integer_set(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ctl_val)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+
+	const unsigned int hwchan = snd_evo_kctl_hwchannels(kctl);
+	const struct snd_evo_ctrl_type *const ctype = snd_evo_kctl_type(kctl);
+	const u16 value = ctype->wValue + snd_evo_kctl_valoffs(kctl);
+	const u16 index = ctype->wIndex;
+
+	int changed = 0;
+	int i;
+
+	for (i = 0; i < hwchan; i++) {
+		s16 rbuf;
+		s16 buf = cpu_to_le16(ctl_val->value.integer.value[i]);
+		int ret;
+
+		ret = snd_evo_get_cur(mixer, value + i, index,
+				      &rbuf, sizeof(rbuf));
+		if (ret < 0)
+			return ret;
+
+		if (rbuf != buf) {
+			changed = 1;
+
+			ret = snd_evo_set_cur(mixer, value + i, index,
+					      &buf, sizeof(buf));
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return changed;
+}
+
+static int snd_ctl_evo_info(struct snd_kcontrol *kctl,
+			    struct snd_ctl_elem_info *uinfo)
+{
+	const struct snd_evo_ctrl_type *const ctype = snd_evo_kctl_type(kctl);
+
+	uinfo->type = ctype->type;
+	uinfo->access = SNDRV_CTL_ELEM_ACCESS_READWRITE
+			| SNDRV_CTL_ELEM_ACCESS_VOLATILE;
+	uinfo->count = snd_evo_kctl_channels(kctl);
+	uinfo->value.integer.min = ctype->min.integer;
+	uinfo->value.integer.max = ctype->max.integer;
+	return 0;
+}
+
+
+static int snd_evo_add_ctrl(struct usb_mixer_interface *mixer,
+			    const struct snd_evo_ctrl *ctrl)
+{
+	const struct snd_evo_ctrl_type *ctype = &snd_evo_ctypes[ctrl->type];
+	char name[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	struct snd_kcontrol_new knew = { 0 };
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+
+	knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
+	knew.name = name;
+	knew.info = snd_ctl_evo_info;
+	knew.private_value = snd_evo_kctl_priv(ctrl->type, ctrl->val_offs,
+					       ctrl->hwchannels);
+
+	switch (ctype->type) {
+	case SNDRV_CTL_ELEM_TYPE_INTEGER:
+		knew.get = snd_ctl_evo_integer_get;
+		knew.put = snd_ctl_evo_integer_set;
+		break;
+	case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
+		knew.get = snd_ctl_evo_boolean_get;
+		knew.put = snd_ctl_evo_boolean_set;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	snprintf(name, sizeof(name), "%s %s %s", ctrl->basename,
+		 ((ctrl->flags & SND_EVO_FLAGS_DIRECTION)
+			== SND_EVO_FLAGS_CAPTURE) ? "Capture" : "Playback",
+		 (ctype->type == SNDRV_CTL_ELEM_TYPE_BOOLEAN)
+			? "Switch" : "Volume");
+
+	elem = kzalloc_obj(*elem);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->channels = ctrl->channels;
+
+	kctl = snd_ctl_new1(&knew, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	return snd_usb_mixer_add_control(&elem->head, kctl);
+}
+
+
+/* called from mixer_quirks.c */
+int snd_evo_controls_create(struct usb_mixer_interface *mixer)
+{
+	const struct evo_devinfo *info;
+	const struct snd_evo_ctrl *ctrl;
+
+	for (info = evo_devinfo; info->controls; info++)
+		if (info->usb_id == mixer->chip->usb_id)
+			break;
+
+	if (!info->controls)
+		return -ENODEV;
+
+	for (ctrl = info->controls; ctrl->basename; ctrl++) {
+		const int ret = snd_evo_add_ctrl(mixer, ctrl);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
diff --git a/sound/usb/mixer_evo.h b/sound/usb/mixer_evo.h
new file mode 100644
index 000000000000..7fe7e197185c
--- /dev/null
+++ b/sound/usb/mixer_evo.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USB_MIXER_EVO_H
+#define __USB_MIXER_EVO_H
+
+#include "mixer.h"
+
+#define USB_AUDIENT_VID (0x2708)
+#define USB_EVO4_PID (0x0006)
+
+int snd_evo_controls_create(struct usb_mixer_interface *mixer);
+
+#endif /* __USB_MIXER_EVO_H */
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index fc622eb95dc5..1e266fdbbb8e 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -38,6 +38,7 @@
 #include "mixer_scarlett2.h"
 #include "mixer_us16x08.h"
 #include "mixer_s1810c.h"
+#include "mixer_evo.h"
 #include "helper.h"
 #include "fcp.h"
 
@@ -4539,6 +4540,10 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		err = snd_fcp_init(mixer);
 		break;
 
+	case USB_ID(USB_AUDIENT_VID, USB_EVO4_PID): /* Audient EVO 4 */
+		err = snd_evo_controls_create(mixer);
+		break;
+
 	case USB_ID(0x041e, 0x323b): /* Creative Sound Blaster E1 */
 		err = snd_soundblaster_e1_switch_create(mixer);
 		break;
-- 
2.55.0