]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
ALSA: usb-audio: add mixer support for Focusrite Forte
authorJegor van Opdorp <jegorvanopdorp@gmail.com>
Tue, 27 Jan 2026 08:15:41 +0000 (09:15 +0100)
committerTakashi Iwai <tiwai@suse.de>
Tue, 27 Jan 2026 08:58:50 +0000 (09:58 +0100)
Add mixer control support for the Focusrite Forte (USB ID 0x1235:0x8010),
an older USB audio interface that predates the Scarlett 2nd generation.

The Forte uses UAC2_CS_MEM (bRequest=0x03) for its input controls rather
than the standard UAC2_CS_CUR (0x01) used by Scarlett devices. This patch
adds Forte-specific control handlers that use the correct USB protocol.

Features implemented:
- Input source selection (Mic/Line/Inst) for both channels
- High pass filter switch
- 48V phantom power switch
- Phase invert switch
- Pad switch
- Preamp gain control (0-42 range, ~0-75dB)
- Matrix mixer controls (6 inputs x 4 outputs)
- Output volume and mute controls

The device is registered via mixer_quirks.c and uses the existing
mixer_scarlett.c infrastructure with Forte-specific additions.

Credit: This work builds on prior reverse-engineering by alastair-dm.

Link: https://github.com/alastair-dm/forte-mixer/wiki
Link: https://github.com/alastair-dm/forte-mixer
Link: https://github.com/jopdorp/forte-mixer
Signed-off-by: Jegor van Opdorp <jegorvanopdorp@gmail.com>
Link: https://patch.msgid.link/20260127081541.219669-1-jegorvanopdorp@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/usb/mixer_quirks.c
sound/usb/mixer_scarlett.c
sound/usb/mixer_scarlett.h

index f8eccb1c58da12e5a521cf4da6b4fb2094c6cccc..07d5cf0077d8aadff9053d690f0157e5eb6d69a2 100644 (file)
@@ -4417,6 +4417,9 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
                err = snd_create_std_mono_table(mixer, ebox44_table);
                break;
 
+       case USB_ID(0x1235, 0x8010): /* Focusrite Forte */
+               err = snd_forte_controls_create(mixer);
+               break;
        case USB_ID(0x1235, 0x8012): /* Focusrite Scarlett 6i6 */
        case USB_ID(0x1235, 0x8002): /* Focusrite Scarlett 8i6 */
        case USB_ID(0x1235, 0x8004): /* Focusrite Scarlett 18i6 */
index 8babfa3f7c458cc8695bb2cff42455e5dea65577..fa11f25288b79c0f38f139f1abd693e406c367a2 100644 (file)
 /* some gui mixers can't handle negative ctl values */
 #define SND_SCARLETT_LEVEL_BIAS 128
 #define SND_SCARLETT_MATRIX_IN_MAX 18
-#define SND_SCARLETT_CONTROLS_MAX 10
+#define SND_SCARLETT_CONTROLS_MAX 14
 #define SND_SCARLETT_OFFSETS_MAX 5
 
 enum {
@@ -143,6 +143,12 @@ enum {
        SCARLETT_SWITCH_IMPEDANCE,
        SCARLETT_SWITCH_PAD,
        SCARLETT_SWITCH_GAIN,
+       FORTE_INPUT_SOURCE,     /* mic/line/instrument selection */
+       FORTE_INPUT_HPF,        /* high pass filter */
+       FORTE_INPUT_PHANTOM,    /* 48V phantom power */
+       FORTE_INPUT_PHASE,      /* phase invert */
+       FORTE_INPUT_PAD,        /* pad */
+       FORTE_INPUT_GAIN,       /* preamp gain 0-42 (~0-75dB for mic) */
 };
 
 enum {
@@ -172,6 +178,8 @@ struct scarlett_device_info {
        int input_len;
        int output_len;
 
+       bool has_output_source_routing;
+
        struct scarlett_mixer_elem_enum_info opt_master;
        struct scarlett_mixer_elem_enum_info opt_matrix;
 
@@ -229,6 +237,239 @@ static const struct scarlett_mixer_elem_enum_info opt_sync = {
        }
 };
 
+/* Forte-specific input control options */
+static const struct scarlett_mixer_elem_enum_info opt_forte_source = {
+       .start = 0,
+       .len = 3,
+       .offsets = {},
+       .names = (char const * const []){
+               "Mic", "Line", "Inst"
+       }
+};
+
+/*
+ * Forte-specific USB control functions
+ * Forte input controls use bRequest=0x03 (UAC2_CS_MEM) instead of 0x01
+ * wValue = (control_code << 8) | channel
+ * wIndex = interface | (0x3c << 8) like Scarlett meter/matrix controls
+ */
+static int forte_set_ctl_value(struct usb_mixer_elem_info *elem, int value)
+{
+       struct snd_usb_audio *chip = elem->head.mixer->chip;
+       unsigned char buf[2];
+       int wValue = elem->control;  /* Just control code, NO shift, NO channel */
+       int idx = snd_usb_ctrl_intf(elem->head.mixer->hostif) | (elem->head.id << 8);
+       int err;
+
+       /* Wiki format: "2 bytes, chan 0,1 and value"
+        * Data order: [channel, value] - channel FIRST per wiki
+        */
+       buf[0] = elem->idx_off;  /* Channel: 0 or 1 */
+       buf[1] = value & 0xff;   /* Value: 0-2 for source, 0-1 for switches */
+
+       err = snd_usb_lock_shutdown(chip);
+       if (err < 0)
+               return -EIO;
+
+       err = snd_usb_ctl_msg(chip->dev,
+                             usb_sndctrlpipe(chip->dev, 0),
+                             UAC2_CS_MEM,  /* bRequest = 0x03 */
+                             USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+                             wValue, idx, buf, 2);
+
+       snd_usb_unlock_shutdown(chip);
+
+       if (err < 0) {
+               usb_audio_err(chip, "forte_set FAILED: req=0x03 wVal=0x%04x wIdx=0x%04x buf=[%02x,%02x] err=%d\n",
+                             wValue, idx, buf[0], buf[1], err);
+               return err;
+       }
+       return 0;
+}
+
+static int forte_get_ctl_value(struct usb_mixer_elem_info *elem, int *value)
+{
+       /* Device may not support reading input controls.
+        * Return cached value or default to avoid blocking module load.
+        */
+       if (elem->cached)
+               *value = elem->cache_val[0];
+       else
+               *value = 0;  /* Default: first option */
+
+       return 0;
+}
+
+/*
+ * Forte Input Gain control functions
+ * Gain range is 0-42 (0x00-0x2a) which maps to approximately:
+ * - Mic: 0 to +75dB (~1.8dB per step)
+ * - Instrument: +14 to +68dB
+ * - Line: -12 to +42dB
+ * We use a TLV scale of 0 to 7500 centidB (0 to 75dB) in ~179 cB steps
+ */
+#define FORTE_INPUT_GAIN_MAX 42
+
+static int forte_input_gain_info(struct snd_kcontrol *kctl,
+                                struct snd_ctl_elem_info *uinfo)
+{
+       uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+       uinfo->count = 1;
+       uinfo->value.integer.min = 0;
+       uinfo->value.integer.max = FORTE_INPUT_GAIN_MAX;
+       uinfo->value.integer.step = 1;
+       return 0;
+}
+
+static int forte_input_gain_get(struct snd_kcontrol *kctl,
+                               struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       int err, val;
+
+       /* Use Forte-specific USB command with UAC2_CS_MEM */
+       err = forte_get_ctl_value(elem, &val);
+       if (err < 0)
+               return err;
+
+       ucontrol->value.integer.value[0] = clamp(val, 0, FORTE_INPUT_GAIN_MAX);
+       return 0;
+}
+
+static int forte_input_gain_put(struct snd_kcontrol *kctl,
+                               struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       int err, oval, val;
+
+       /* Read current value */
+       err = forte_get_ctl_value(elem, &oval);
+       if (err < 0)
+               return err;
+
+       val = clamp((int)ucontrol->value.integer.value[0], 0, FORTE_INPUT_GAIN_MAX);
+       if (oval != val) {
+               /* Use Forte-specific USB command */
+               err = forte_set_ctl_value(elem, val);
+               if (err < 0)
+                       return err;
+               elem->cached |= 1;
+               elem->cache_val[0] = val;
+               return 1;
+       }
+       return 0;
+}
+
+static int forte_input_gain_resume(struct usb_mixer_elem_list *list)
+{
+       struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+       if (elem->cached)
+               forte_set_ctl_value(elem, *elem->cache_val);
+       return 0;
+}
+
+/*
+ * Forte-specific enum control functions (for Source selection)
+ * Uses bRequest=0x03 (UAC2_CS_MEM) instead of standard 0x01
+ */
+static int forte_ctl_enum_get(struct snd_kcontrol *kctl,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+       int err, val;
+
+       err = forte_get_ctl_value(elem, &val);
+       if (err < 0)
+               return err;
+
+       val = clamp(val - opt->start, 0, opt->len - 1);
+       ucontrol->value.enumerated.item[0] = val;
+       return 0;
+}
+
+static int forte_ctl_enum_put(struct snd_kcontrol *kctl,
+                             struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+       int err, oval, val;
+
+       err = forte_get_ctl_value(elem, &oval);
+       if (err < 0)
+               return err;
+
+       val = ucontrol->value.integer.value[0] + opt->start;
+       if (val != oval) {
+               err = forte_set_ctl_value(elem, val);
+               if (err < 0)
+                       return err;
+               elem->cached |= 1;
+               elem->cache_val[0] = val;
+               return 1;
+       }
+       return 0;
+}
+
+static int forte_ctl_enum_resume(struct usb_mixer_elem_list *list)
+{
+       struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+       if (elem->cached)
+               forte_set_ctl_value(elem, *elem->cache_val);
+       return 0;
+}
+
+/*
+ * Forte-specific switch control functions (for HPF, 48V, Phase, Pad)
+ * Uses bRequest=0x03 (UAC2_CS_MEM) instead of standard 0x01
+ */
+static int forte_ctl_switch_get(struct snd_kcontrol *kctl,
+                               struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       int err, val;
+
+       err = forte_get_ctl_value(elem, &val);
+       if (err < 0)
+               return err;
+
+       ucontrol->value.integer.value[0] = val ? 1 : 0;
+       return 0;
+}
+
+static int forte_ctl_switch_put(struct snd_kcontrol *kctl,
+                               struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       int err, oval, val;
+
+       err = forte_get_ctl_value(elem, &oval);
+       if (err < 0)
+               return err;
+
+       val = ucontrol->value.integer.value[0] ? 1 : 0;
+       if (val != oval) {
+               err = forte_set_ctl_value(elem, val);
+               if (err < 0)
+                       return err;
+               elem->cached |= 1;
+               elem->cache_val[0] = val;
+               return 1;
+       }
+       return 0;
+}
+
+static int forte_ctl_switch_resume(struct usb_mixer_elem_list *list)
+{
+       struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+       if (elem->cached)
+               forte_set_ctl_value(elem, *elem->cache_val);
+       return 0;
+}
+
 static int scarlett_ctl_switch_info(struct snd_kcontrol *kctl,
                struct snd_ctl_elem_info *uinfo)
 {
@@ -534,6 +775,37 @@ static const struct snd_kcontrol_new usb_scarlett_ctl_sync = {
        .get =  scarlett_ctl_meter_get,
 };
 
+/* Forte-specific control structures - use bRequest=0x03 instead of 0x01 */
+static const struct snd_kcontrol_new usb_forte_ctl_enum = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .name = "",
+       .info = scarlett_ctl_enum_info,
+       .get =  forte_ctl_enum_get,
+       .put =  forte_ctl_enum_put,
+};
+
+static const struct snd_kcontrol_new usb_forte_ctl_switch = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .name = "",
+       .info = snd_ctl_boolean_mono_info,
+       .get =  forte_ctl_switch_get,
+       .put =  forte_ctl_switch_put,
+};
+
+/* Forte input gain: 0-42 maps to approximately 0-75dB (~179 cB per step) */
+static const DECLARE_TLV_DB_SCALE(db_scale_forte_input_gain, 0, 179, 0);
+
+static const struct snd_kcontrol_new usb_forte_ctl_input_gain = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                 SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+       .name = "",
+       .info = forte_input_gain_info,
+       .get =  forte_input_gain_get,
+       .put =  forte_input_gain_put,
+       .tlv = { .p = db_scale_forte_input_gain }
+};
+
 static int add_new_ctl(struct usb_mixer_interface *mixer,
                       const struct snd_kcontrol_new *ncontrol,
                       usb_mixer_elem_resume_func_t resume,
@@ -608,37 +880,83 @@ static int add_output_ctls(struct usb_mixer_interface *mixer,
        if (err < 0)
                return err;
 
-       /* Add L channel source playback enumeration */
-       snprintf(mx, sizeof(mx), "Master %dL (%s) Source Playback Enum",
-               index + 1, name);
-       err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
-                         scarlett_ctl_enum_resume, 0x33, 0x00,
-                         2*index, USB_MIXER_S16, 1, mx, &info->opt_master,
-                         &elem);
-       if (err < 0)
-               return err;
+       /* Add L/R source routing if device supports it */
+       if (info->has_output_source_routing) {
+               /* Add L channel source playback enumeration */
+               snprintf(mx, sizeof(mx), "Master %dL (%s) Source Playback Enum",
+                       index + 1, name);
+               err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+                                 scarlett_ctl_enum_resume, 0x33, 0x00,
+                                 2*index, USB_MIXER_S16, 1, mx, &info->opt_master,
+                                 &elem);
+               if (err < 0)
+                       return err;
 
-       /* Add R channel source playback enumeration */
-       snprintf(mx, sizeof(mx), "Master %dR (%s) Source Playback Enum",
-               index + 1, name);
-       err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
-                         scarlett_ctl_enum_resume, 0x33, 0x00,
-                         2*index+1, USB_MIXER_S16, 1, mx, &info->opt_master,
-                         &elem);
-       if (err < 0)
-               return err;
+               /* Add R channel source playback enumeration */
+               snprintf(mx, sizeof(mx), "Master %dR (%s) Source Playback Enum",
+                       index + 1, name);
+               err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+                                 scarlett_ctl_enum_resume, 0x33, 0x00,
+                                 2*index+1, USB_MIXER_S16, 1, mx, &info->opt_master,
+                                 &elem);
+               if (err < 0)
+                       return err;
+       }
 
        return 0;
 }
 
 /********************** device-specific config *************************/
 
+static const struct scarlett_device_info forte_info = {
+       .matrix_in = 6,
+       .matrix_out = 4,
+       .input_len = 2,
+       .output_len = 4,
+       .has_output_source_routing = false,
+
+       .opt_master = {
+               .start = -1,
+               .len = 13,
+               .offsets = {0, 4, 6, 6, 6},
+               .names = NULL
+       },
+
+       .opt_matrix = {
+               .start = -1,
+               .len = 7,
+               .offsets = {0, 4, 6, 6, 6},
+               .names = NULL
+       },
+
+       .num_controls = 14,
+       .controls = {
+               { .num = 0, .type = SCARLETT_OUTPUTS, .name = "Line Out" },
+               { .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+               /* Input 1 controls */
+               { .num = 1, .type = FORTE_INPUT_GAIN, .name = NULL},
+               { .num = 1, .type = FORTE_INPUT_SOURCE, .name = NULL},
+               { .num = 1, .type = FORTE_INPUT_HPF, .name = NULL},
+               { .num = 1, .type = FORTE_INPUT_PHANTOM, .name = NULL},
+               { .num = 1, .type = FORTE_INPUT_PHASE, .name = NULL},
+               { .num = 1, .type = FORTE_INPUT_PAD, .name = NULL},
+               /* Input 2 controls */
+               { .num = 2, .type = FORTE_INPUT_GAIN, .name = NULL},
+               { .num = 2, .type = FORTE_INPUT_SOURCE, .name = NULL},
+               { .num = 2, .type = FORTE_INPUT_HPF, .name = NULL},
+               { .num = 2, .type = FORTE_INPUT_PHANTOM, .name = NULL},
+               { .num = 2, .type = FORTE_INPUT_PHASE, .name = NULL},
+               { .num = 2, .type = FORTE_INPUT_PAD, .name = NULL},
+       },
+};
+
 /*  untested...  */
 static const struct scarlett_device_info s6i6_info = {
        .matrix_in = 18,
        .matrix_out = 8,
        .input_len = 6,
        .output_len = 6,
+       .has_output_source_routing = true,
 
        .opt_master = {
                .start = -1,
@@ -681,6 +999,7 @@ static const struct scarlett_device_info s8i6_info = {
        .matrix_out = 6,
        .input_len = 8,
        .output_len = 6,
+       .has_output_source_routing = true,
 
        .opt_master = {
                .start = -1,
@@ -720,6 +1039,7 @@ static const struct scarlett_device_info s18i6_info = {
        .matrix_out = 6,
        .input_len = 18,
        .output_len = 6,
+       .has_output_source_routing = true,
 
        .opt_master = {
                .start = -1,
@@ -757,6 +1077,7 @@ static const struct scarlett_device_info s18i8_info = {
        .matrix_out = 8,
        .input_len = 18,
        .output_len = 8,
+       .has_output_source_routing = true,
 
        .opt_master = {
                .start = -1,
@@ -799,6 +1120,7 @@ static const struct scarlett_device_info s18i20_info = {
        .matrix_out = 8,
        .input_len = 18,
        .output_len = 20,
+       .has_output_source_routing = true,
 
        .opt_master = {
                .start = -1,
@@ -906,6 +1228,61 @@ static int scarlett_controls_create_generic(struct usb_mixer_interface *mixer,
                        if (err < 0)
                                return err;
                        break;
+               /* Forte input controls - use wIndex 0x3c per wiki docs */
+               case FORTE_INPUT_GAIN:
+                       sprintf(mx, "Line In %d Gain Capture Volume", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_input_gain,
+                                         forte_input_gain_resume, 0x3c,
+                                         0x06, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         NULL, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
+               case FORTE_INPUT_SOURCE:
+                       sprintf(mx, "Input %d Source", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_enum,
+                                         forte_ctl_enum_resume, 0x3c,
+                                         0x07, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         &opt_forte_source, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
+               case FORTE_INPUT_HPF:
+                       sprintf(mx, "Input %d High Pass Filter Switch", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+                                         forte_ctl_switch_resume, 0x3c,
+                                         0x08, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         NULL, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
+               case FORTE_INPUT_PHANTOM:
+                       sprintf(mx, "Input %d 48V Phantom Power Switch", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+                                         forte_ctl_switch_resume, 0x3c,
+                                         0x09, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         NULL, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
+               case FORTE_INPUT_PHASE:
+                       sprintf(mx, "Input %d Phase Invert Switch", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+                                         forte_ctl_switch_resume, 0x3c,
+                                         0x0a, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         NULL, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
+               case FORTE_INPUT_PAD:
+                       sprintf(mx, "Input %d Pad Switch", ctl->num);
+                       err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+                                         forte_ctl_switch_resume, 0x3c,
+                                         0x0b, ctl->num - 1, USB_MIXER_S16, 1, mx,
+                                         NULL, &elem);
+                       if (err < 0)
+                               return err;
+                       break;
                }
        }
 
@@ -1014,3 +1391,64 @@ int snd_scarlett_controls_create(struct usb_mixer_interface *mixer)
 
        return err;
 }
+
+/*
+ * Create and initialize a mixer for the Focusrite(R) Forte
+ */
+int snd_forte_controls_create(struct usb_mixer_interface *mixer)
+{
+       int err, i, o;
+       char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+       const struct scarlett_device_info *info;
+       struct usb_mixer_elem_info *elem;
+
+       /* only use UAC_VERSION_2 */
+       if (!mixer->protocol)
+               return 0;
+
+       switch (mixer->chip->usb_id) {
+       case USB_ID(0x1235, 0x8010):
+               info = &forte_info;
+               break;
+       default: /* device not (yet) supported */
+               return -EINVAL;
+       }
+
+       /* generic function to create controls */
+       err = scarlett_controls_create_generic(mixer, info);
+       if (err < 0)
+               return err;
+
+       /* setup matrix controls */
+       for (i = 0; i < info->matrix_in; i++) {
+               snprintf(mx, sizeof(mx), "Matrix %02d Input Playback Route",
+                        i+1);
+               err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+                                 scarlett_ctl_enum_resume, 0x32,
+                                 0x06, i, USB_MIXER_S16, 1, mx,
+                                 &info->opt_matrix, &elem);
+               if (err < 0)
+                       return err;
+
+               for (o = 0; o < info->matrix_out; o++) {
+                       sprintf(mx, "Matrix %02d Mix %c Playback Volume", i+1,
+                               o+'A');
+                       err = add_new_ctl(mixer, &usb_scarlett_ctl,
+                                         scarlett_ctl_resume, 0x3c, 0x01,
+                                         (i << 2) + (o & 0x03), USB_MIXER_S16,
+                                         1, mx, NULL, &elem);
+                       if (err < 0)
+                               return err;
+
+               }
+       }
+
+       /* val_len == 1 and UAC2_CS_MEM */
+       err = add_new_ctl(mixer, &usb_scarlett_ctl_sync, NULL, 0x3c, 0x00, 2,
+                         USB_MIXER_U8, 1, "Sample Clock Sync Status",
+                         &opt_sync, &elem);
+       if (err < 0)
+               return err;
+
+       return err;
+}
index bbf063b793705ae553e58a1a83590b05ab325452..c44fe7d72ee34b28783ba218ce8e205a1e78ea7b 100644 (file)
@@ -3,5 +3,6 @@
 #define __USB_MIXER_SCARLETT_H
 
 int snd_scarlett_controls_create(struct usb_mixer_interface *mixer);
+int snd_forte_controls_create(struct usb_mixer_interface *mixer);
 
 #endif /* __USB_MIXER_SCARLETT_H */