ALSA: scarlett2: Add DSP controls
authorGeoffrey D. Bennett <g@b4.vu>
Tue, 12 Mar 2024 18:37:12 +0000 (05:07 +1030)
committerTakashi Iwai <tiwai@suse.de>
Thu, 18 Apr 2024 06:31:14 +0000 (08:31 +0200)
Add filter and compressor DSP controls for the Vocaster interfaces.
Mark scarlett2_notify_input_dsp() as __always_unused until it gets
used when the Vocaster callback function array is added.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Message-ID: <a45316f79600b862dae38da24f13def638b06476.1710264833.git.g@b4.vu>

sound/usb/mixer_scarlett2.c

index 17fadfddc2403a1215bc0c1f1d35d5c57baeb369..77bfaadb99b89d9b81de2c21d1c247ec7425f814 100644 (file)
@@ -87,6 +87,7 @@
  *  - disable/enable standalone mode
  *  - input mute, gain, autogain, safe mode
  *  - direct monitor mixes
+ *  - compressor and EQ
  *
  * <ditaa>
  *    /--------------\    18chn            20chn     /--------------\
@@ -214,6 +215,7 @@ static const u16 scarlett2_mixer_values[SCARLETT2_MIXER_VALUE_COUNT] = {
 #define SCARLETT2_LEVEL_SWITCH_MAX 2
 #define SCARLETT2_PAD_SWITCH_MAX 8
 #define SCARLETT2_AIR_SWITCH_MAX 8
+#define SCARLETT2_DSP_SWITCH_MAX 2
 #define SCARLETT2_INPUT_MUTE_SWITCH_MAX 2
 #define SCARLETT2_PHANTOM_SWITCH_MAX 2
 #define SCARLETT2_INPUT_GAIN_MAX 2
@@ -245,6 +247,59 @@ static const u16 scarlett2_mixer_values[SCARLETT2_MIXER_VALUE_COUNT] = {
 /* Maximum number of meters (sum of output port counts) */
 #define SCARLETT2_MAX_METERS 65
 
+/* Compressor parameter data
+ *
+ * The compressor parameters are 32-bit fixed point values with 24
+ * bits of fraction. Integer values are sufficient for the parameters
+ * except for ratio which we can set in 0.5:1 steps.
+ */
+struct compressor_param {
+       const char          *name;
+       snd_ctl_elem_type_t  type;
+       s32                  min;
+       s32                  max;
+       int                  scale_bits;
+};
+
+/* The available compressor parameters on the Vocaster:
+ * - Enable: Off, On
+ * - Threshold: -40dB to 0dB
+ * - Ratio: 1:1 to 50:1 in 0.5:1 steps
+ * - Knee Width: 0dB to 10dB
+ * - Attack: 30ms to 127ms
+ * - Release: 30ms to 127ms
+ * - Makeup Gain: 0dB to 24dB
+ */
+static const struct compressor_param compressor_params[] = {
+       { "Enable",      SNDRV_CTL_ELEM_TYPE_BOOLEAN,   0,   1,  0 },
+       { "Threshold",   SNDRV_CTL_ELEM_TYPE_INTEGER, -40,   0, 24 },
+       { "Ratio",       SNDRV_CTL_ELEM_TYPE_INTEGER,   2, 100, 23 },
+       { "Knee Width",  SNDRV_CTL_ELEM_TYPE_INTEGER,   0,  10, 24 },
+       { "Attack",      SNDRV_CTL_ELEM_TYPE_INTEGER,  30, 127, 24 },
+       { "Release",     SNDRV_CTL_ELEM_TYPE_INTEGER,  30, 127, 24 },
+       { "Makeup Gain", SNDRV_CTL_ELEM_TYPE_INTEGER,   0,  24, 24 },
+};
+
+#define SCARLETT2_COMPRESSOR_PARAM_COUNT ARRAY_SIZE(compressor_params)
+#define SCARLETT2_COMPRESSOR_CTLS_MAX \
+       (SCARLETT2_COMPRESSOR_PARAM_COUNT * SCARLETT2_DSP_SWITCH_MAX)
+
+/* Maximum number of filter controls */
+#define SCARLETT2_PRECOMP_FLT_CTLS_MAX (2 * SCARLETT2_DSP_SWITCH_MAX)
+#define SCARLETT2_PEQ_FLT_CTLS_MAX (3 * SCARLETT2_DSP_SWITCH_MAX)
+
+/* Number of biquad filter coefficients */
+#define SCARLETT2_BIQUAD_COEFFS 5
+
+/* Maximum number of filter coefficient values */
+#define SCARLETT2_PRECOMP_FLT_VALUES_MAX \
+       (SCARLETT2_PRECOMP_FLT_CTLS_MAX * SCARLETT2_BIQUAD_COEFFS)
+#define SCARLETT2_PEQ_FLT_VALUES_MAX \
+       (SCARLETT2_PEQ_FLT_CTLS_MAX * SCARLETT2_BIQUAD_COEFFS)
+
+/* Maximum number of PEQ filter slots */
+#define SCARLETT2_PEQ_FLT_SLOTS_MAX 4
+
 /* Hardware port types:
  * - None (no input to mux)
  * - Analogue I/O
@@ -330,6 +385,7 @@ static void scarlett2_notify_volume(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_level(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_pad(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_air(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_dsp(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_mute(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_phantom(struct usb_mixer_interface *mixer);
 static void scarlett2_notify_input_other(struct usb_mixer_interface *mixer);
@@ -417,6 +473,12 @@ enum {
        SCARLETT2_CONFIG_PAD_SWITCH,
        SCARLETT2_CONFIG_MSD_SWITCH,
        SCARLETT2_CONFIG_AIR_SWITCH,
+       SCARLETT2_CONFIG_DSP_SWITCH,
+       SCARLETT2_CONFIG_COMPRESSOR_PARAMS,
+       SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+       SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+       SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+       SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
        SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
        SCARLETT2_CONFIG_STANDALONE_SWITCH,
        SCARLETT2_CONFIG_PHANTOM_SWITCH,
@@ -918,6 +980,18 @@ struct scarlett2_device_info {
         */
        u8 air_option;
 
+       /* the number of analogue inputs with DSP control */
+       u8 dsp_input_count;
+
+       /* number of pre-compressor filters */
+       u8 precomp_flt_count;
+
+       /* number of parametric EQ filters */
+       u8 peq_flt_count;
+
+       /* number of PEQ filters plus unused slots */
+       u8 peq_flt_total_count;
+
        /* the number of analogue inputs with a software switchable
         * mute control
         */
@@ -1004,6 +1078,7 @@ struct scarlett2_data {
        u8 input_level_updated;
        u8 input_pad_updated;
        u8 input_air_updated;
+       u8 input_dsp_updated;
        u8 input_mute_updated;
        u8 input_phantom_updated;
        u8 input_select_updated;
@@ -1027,6 +1102,12 @@ struct scarlett2_data {
        u8 pad_switch[SCARLETT2_PAD_SWITCH_MAX];
        u8 dim_mute[SCARLETT2_DIM_MUTE_COUNT];
        u8 air_switch[SCARLETT2_AIR_SWITCH_MAX];
+       u8 dsp_switch[SCARLETT2_DSP_SWITCH_MAX];
+       s32 compressor_values[SCARLETT2_COMPRESSOR_CTLS_MAX];
+       s32 precomp_flt_values[SCARLETT2_PRECOMP_FLT_VALUES_MAX];
+       s32 peq_flt_values[SCARLETT2_PEQ_FLT_VALUES_MAX];
+       u8 precomp_flt_switch[SCARLETT2_DSP_SWITCH_MAX];
+       u8 peq_flt_switch[SCARLETT2_DSP_SWITCH_MAX];
        u8 input_mute_switch[SCARLETT2_INPUT_MUTE_SWITCH_MAX];
        u8 phantom_switch[SCARLETT2_PHANTOM_SWITCH_MAX];
        u8 phantom_persistence;
@@ -1055,6 +1136,7 @@ struct scarlett2_data {
        struct snd_kcontrol *level_ctls[SCARLETT2_LEVEL_SWITCH_MAX];
        struct snd_kcontrol *pad_ctls[SCARLETT2_PAD_SWITCH_MAX];
        struct snd_kcontrol *air_ctls[SCARLETT2_AIR_SWITCH_MAX];
+       struct snd_kcontrol *dsp_ctls[SCARLETT2_DSP_SWITCH_MAX];
        struct snd_kcontrol *input_mute_ctls[SCARLETT2_INPUT_MUTE_SWITCH_MAX];
        struct snd_kcontrol *phantom_ctls[SCARLETT2_PHANTOM_SWITCH_MAX];
        struct snd_kcontrol *input_select_ctl;
@@ -1066,6 +1148,11 @@ struct scarlett2_data {
        struct snd_kcontrol *pcm_input_switch_ctl;
        struct snd_kcontrol *mux_ctls[SCARLETT2_MUX_MAX];
        struct snd_kcontrol *mix_ctls[SCARLETT2_MIX_MAX];
+       struct snd_kcontrol *compressor_ctls[SCARLETT2_COMPRESSOR_CTLS_MAX];
+       struct snd_kcontrol *precomp_flt_ctls[SCARLETT2_PRECOMP_FLT_CTLS_MAX];
+       struct snd_kcontrol *peq_flt_ctls[SCARLETT2_PEQ_FLT_CTLS_MAX];
+       struct snd_kcontrol *precomp_flt_switch_ctls[SCARLETT2_DSP_SWITCH_MAX];
+       struct snd_kcontrol *peq_flt_switch_ctls[SCARLETT2_DSP_SWITCH_MAX];
        struct snd_kcontrol *direct_monitor_ctl;
        struct snd_kcontrol *speaker_switching_ctl;
        struct snd_kcontrol *talkback_ctl;
@@ -2174,6 +2261,54 @@ static int scarlett2_usb_set_data(
                             &req, sizeof(u32) * 2 + size, NULL, 0);
 }
 
+/* Send a SCARLETT2_USB_SET_DATA command with multiple values.
+ * offset: location in the device's data space
+ * size: size in bytes of each value (1, 2, 4)
+ * count: number of values
+ */
+static int scarlett2_usb_set_data_buf(
+       struct usb_mixer_interface *mixer,
+       int offset, int size, int count, void *buf)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       int bytes = size * count;
+       struct {
+               __le32 offset;
+               __le32 size;
+               u8 data[];
+       } __packed *req;
+       int err;
+       int buf_size = struct_size(req, data, bytes);
+
+       req = kmalloc(buf_size, GFP_KERNEL);
+       if (!req)
+               return -ENOMEM;
+
+       req->offset = cpu_to_le32(offset);
+       req->size = cpu_to_le32(bytes);
+       if (size == 1) {
+               memcpy(req->data, buf, count);
+       } else if (size == 2) {
+               u16 *buf_16 = buf;
+               int i;
+
+               for (i = 0; i < count; i++)
+                       ((__le16 *)req->data)[i] = cpu_to_le16(buf_16[i]);
+       } else {
+               u32 *buf_32 = buf;
+               int i;
+
+               for (i = 0; i < count; i++)
+                       ((__le32 *)req->data)[i] = cpu_to_le32(buf_32[i]);
+       }
+
+       err = scarlett2_usb(private->mixer, SCARLETT2_USB_SET_DATA,
+                           req, buf_size, NULL, 0);
+
+       kfree(req);
+       return err;
+}
+
 /* Send a SCARLETT2_USB_DATA_CMD command.
  * Configuration changes require activation with this after they have
  * been uploaded by a previous SCARLETT2_USB_SET_DATA.
@@ -2288,6 +2423,47 @@ static int scarlett2_usb_set_config(
        return 0;
 }
 
+/* Send USB messages to set a SCARLETT2_CONFIG_* parameter with
+ * multiple values
+ */
+static int scarlett2_usb_set_config_buf(
+       struct usb_mixer_interface *mixer,
+       int config_item_num, int index, int count, void *buf)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_config_set *config_set = private->config_set;
+       const struct scarlett2_config *config_item =
+               &config_set->items[config_item_num];
+       int offset, size;
+       int err;
+
+       /* Check that the configuration item is present in the
+        * configuration set used by this device
+        */
+       if (!config_item->offset)
+               return -EFAULT;
+
+       /* Convert config_item->size in bits to size in bytes and
+        * calculate offset
+        */
+       if (config_item->size >= 8) {
+               size = config_item->size / 8;
+               offset = config_item->offset + index * size;
+
+       /* Bit updates not supported */
+       } else {
+               return -EFAULT;
+       }
+
+       /* Write the new values */
+       err = scarlett2_usb_set_data_buf(mixer, offset, size, count, buf);
+       if (err < 0)
+               return err;
+
+       /* Activate the change */
+       return scarlett2_usb_activate_config(mixer, config_item->activate);
+}
+
 /* Send SCARLETT2_USB_DATA_CMD SCARLETT2_USB_CONFIG_SAVE */
 static void scarlett2_config_save(struct usb_mixer_interface *mixer)
 {
@@ -2985,6 +3161,8 @@ static void scarlett2_autogain_update_access(struct usb_mixer_interface *mixer)
                scarlett2_set_ctl_access(private->input_mute_ctls[i], val);
        for (i = 0; i < info->phantom_count; i++)
                scarlett2_set_ctl_access(private->phantom_ctls[i], val);
+       for (i = 0; i < info->dsp_input_count; i++)
+               scarlett2_set_ctl_access(private->dsp_ctls[i], val);
 }
 
 /* Notify of access mode change for all controls read-only while
@@ -3018,6 +3196,9 @@ static void scarlett2_autogain_notify_access(struct usb_mixer_interface *mixer)
        for (i = 0; i < info->air_input_count; i++)
                snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
                               &private->air_ctls[i]->id);
+       for (i = 0; i < info->dsp_input_count; i++)
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+                              &private->dsp_ctls[i]->id);
        for (i = 0; i < info->mute_input_count; i++)
                snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
                               &private->input_mute_ctls[i]->id);
@@ -4635,25 +4816,25 @@ static const struct snd_kcontrol_new scarlett2_air_ctl[2] = {
        }
 };
 
-/*** Input Mute Switch Controls ***/
+/*** DSP Switch Control ***/
 
-static int scarlett2_update_input_mute(struct usb_mixer_interface *mixer)
+static int scarlett2_update_input_dsp(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
 
-       private->input_mute_updated = 0;
+       private->input_dsp_updated = 0;
 
-       if (!info->mute_input_count)
+       if (!info->dsp_input_count)
                return 0;
 
        return scarlett2_usb_get_config(
-               mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
-               info->mute_input_count, private->input_mute_switch);
+               mixer, SCARLETT2_CONFIG_DSP_SWITCH,
+               info->dsp_input_count, private->dsp_switch);
 }
 
-static int scarlett2_input_mute_ctl_get(struct snd_kcontrol *kctl,
-                                       struct snd_ctl_elem_value *ucontrol)
+static int scarlett2_dsp_ctl_get(struct snd_kcontrol *kctl,
+                                struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct usb_mixer_interface *mixer = elem->head.mixer;
@@ -4667,21 +4848,20 @@ static int scarlett2_input_mute_ctl_get(struct snd_kcontrol *kctl,
                goto unlock;
        }
 
-       if (private->input_mute_updated) {
-               err = scarlett2_update_input_mute(mixer);
+       if (private->input_dsp_updated) {
+               err = scarlett2_update_input_dsp(mixer);
                if (err < 0)
                        goto unlock;
        }
-       ucontrol->value.integer.value[0] =
-               private->input_mute_switch[elem->control];
+       ucontrol->value.integer.value[0] = private->dsp_switch[elem->control];
 
 unlock:
        mutex_unlock(&private->data_mutex);
        return err;
 }
 
-static int scarlett2_input_mute_ctl_put(struct snd_kcontrol *kctl,
-                                       struct snd_ctl_elem_value *ucontrol)
+static int scarlett2_dsp_ctl_put(struct snd_kcontrol *kctl,
+                                struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct usb_mixer_interface *mixer = elem->head.mixer;
@@ -4701,18 +4881,17 @@ static int scarlett2_input_mute_ctl_put(struct snd_kcontrol *kctl,
        if (err < 0)
                goto unlock;
 
-       oval = private->input_mute_switch[index];
+       oval = private->dsp_switch[index];
        val = ucontrol->value.integer.value[0];
 
        if (oval == val)
                goto unlock;
 
-       private->input_mute_switch[index] = val;
+       private->dsp_switch[index] = val;
 
        /* Send switch change to the device */
-       err = scarlett2_usb_set_config(
-               mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
-                       index, val);
+       err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_DSP_SWITCH,
+                                      index, val);
        if (err == 0)
                err = 1;
 
@@ -4721,113 +4900,173 @@ unlock:
        return err;
 }
 
-static const struct snd_kcontrol_new scarlett2_input_mute_ctl = {
+static const struct snd_kcontrol_new scarlett2_dsp_ctl = {
        .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
        .name = "",
        .info = scarlett2_autogain_disables_ctl_info,
-       .get  = scarlett2_input_mute_ctl_get,
-       .put  = scarlett2_input_mute_ctl_put,
+       .get  = scarlett2_dsp_ctl_get,
+       .put  = scarlett2_dsp_ctl_put,
 };
 
-/*** Phantom Switch Controls ***/
+/*** DSP Compressor Parameter Controls ***/
 
-static int scarlett2_update_input_phantom(struct usb_mixer_interface *mixer)
+static int scarlett2_update_compressor_values(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       int err;
-
-       private->input_phantom_updated = 0;
+       int err, i, j;
 
-       if (!info->phantom_count)
+       if (!info->dsp_input_count)
                return 0;
 
        err = scarlett2_usb_get_config(
-               mixer, SCARLETT2_CONFIG_PHANTOM_SWITCH,
-               info->phantom_count, private->phantom_switch);
+               mixer, SCARLETT2_CONFIG_COMPRESSOR_PARAMS,
+               SCARLETT2_COMPRESSOR_PARAM_COUNT * info->dsp_input_count,
+               private->compressor_values);
+
        if (err < 0)
                return err;
 
-       if (scarlett2_has_config_item(private,
-                                     SCARLETT2_CONFIG_PHANTOM_PERSISTENCE)) {
-               err = scarlett2_usb_get_config(
-                       mixer, SCARLETT2_CONFIG_PHANTOM_PERSISTENCE,
-                       1, &private->phantom_persistence);
-               if (err < 0)
-                       return err;
+       for (i = 0; i < SCARLETT2_COMPRESSOR_PARAM_COUNT; i++) {
+               const struct compressor_param *param = &compressor_params[i];
+
+               for (j = 0; j < info->dsp_input_count; j++) {
+                       int idx = i + j * SCARLETT2_COMPRESSOR_PARAM_COUNT;
+                       int val = private->compressor_values[idx];
+
+                       val >>= param->scale_bits;
+                       val = clamp(val, param->min, param->max);
+                       private->compressor_values[idx] = val;
+               }
        }
 
        return 0;
 }
 
-/* Check if phantom power on the given input is currently changing state */
-static int scarlett2_phantom_is_switching(
-       struct scarlett2_data *private, int line_num)
+static int scarlett2_compressor_ctl_get(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
 {
-       const struct scarlett2_device_info *info = private->info;
-       int index = line_num / info->inputs_per_phantom;
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
 
-       return !!(private->phantom_switch[index] & 0x02);
+       ucontrol->value.integer.value[0] =
+               private->compressor_values[elem->control];
+       return 0;
 }
 
-/* Update autogain controls' access mode when phantom power changes state */
-static void scarlett2_phantom_update_access(struct usb_mixer_interface *mixer)
+static int scarlett2_compressor_ctl_put(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
 {
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
        struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_device_info *info = private->info;
-       int i;
 
-       /* Disable autogain controls if phantom power is changing state */
-       for (i = 0; i < info->gain_input_count; i++) {
-               int val = !scarlett2_phantom_is_switching(private, i);
+       int index = elem->control;
+       int channel = index / SCARLETT2_COMPRESSOR_PARAM_COUNT;
+       int param_index = index % SCARLETT2_COMPRESSOR_PARAM_COUNT;
+       int oval, val, err;
+       s32 scaled_val;
 
-               scarlett2_set_ctl_access(private->autogain_ctls[i], val);
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
        }
+
+       err = scarlett2_check_put_during_autogain(mixer);
+       if (err < 0)
+               goto unlock;
+
+       oval = private->compressor_values[index];
+       val = ucontrol->value.integer.value[0];
+       if (oval == val)
+               goto unlock;
+
+       private->compressor_values[index] = val;
+
+       const struct compressor_param *param = &compressor_params[param_index];
+
+       scaled_val = val << param->scale_bits;
+
+       /* Send change to the device */
+
+       /* The channel needs to be put in the parameter buffer index
+        * field (param_buf_addr + 1); the value field isn't used in
+        * this case.
+        */
+       err = scarlett2_usb_set_data(
+               mixer, private->config_set->param_buf_addr + 1, 1, channel);
+       if (err < 0)
+               goto unlock;
+
+       err = scarlett2_usb_set_config(
+               mixer, SCARLETT2_CONFIG_COMPRESSOR_PARAMS, index, scaled_val);
+       if (err < 0)
+               goto unlock;
+
+       if (err == 0)
+               err = 1;
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
 }
 
-/* Notify of access mode change for autogain which can't be enabled
- * while phantom power is changing.
- */
-static void scarlett2_phantom_notify_access(struct usb_mixer_interface *mixer)
+static int scarlett2_compressor_ctl_info(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
 {
-       struct snd_card *card = mixer->chip->card;
-       struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_device_info *info = private->info;
-       int i;
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       int control = elem->control % SCARLETT2_COMPRESSOR_PARAM_COUNT;
 
-       for (i = 0; i < info->gain_input_count; i++)
-               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
-                              &private->autogain_ctls[i]->id);
+       uinfo->type = compressor_params[control].type;
+       uinfo->count = 1;
+       uinfo->value.integer.min = compressor_params[control].min;
+       uinfo->value.integer.max = compressor_params[control].max;
+       uinfo->value.integer.step = 1;
+       return 0;
 }
 
-/* Call scarlett2_update_input_phantom() and
- * scarlett2_phantom_update_access() if input_phantom_updated is set.
- */
-static int scarlett2_check_input_phantom_updated(
-       struct usb_mixer_interface *mixer)
+static const struct snd_kcontrol_new scarlett2_compressor_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .name = "",
+       .info = scarlett2_compressor_ctl_info,
+       .get  = scarlett2_compressor_ctl_get,
+       .put  = scarlett2_compressor_ctl_put,
+};
+
+/*** DSP Pre-Compressor and PEQ Filter Controls ***/
+
+static int scarlett2_precomp_flt_switch_ctl_get(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
 {
-       struct scarlett2_data *private = mixer->private_data;
-       int err;
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
 
-       if (!private->input_phantom_updated)
-               return 0;
+       ucontrol->value.integer.value[0] = private->precomp_flt_switch[elem->control];
 
-       err = scarlett2_update_input_phantom(mixer);
-       if (err < 0)
-               return err;
+       return 0;
+}
 
-       scarlett2_phantom_update_access(mixer);
+static int scarlett2_peq_flt_switch_ctl_get(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+
+       ucontrol->value.integer.value[0] =
+               private->peq_flt_switch[elem->control];
 
        return 0;
 }
 
-static int scarlett2_phantom_ctl_get(struct snd_kcontrol *kctl,
-                                    struct snd_ctl_elem_value *ucontrol)
+static int scarlett2_precomp_flt_switch_ctl_put(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct usb_mixer_interface *mixer = elem->head.mixer;
        struct scarlett2_data *private = mixer->private_data;
-       int err;
+       int oval, val, err = 0;
 
        mutex_lock(&private->data_mutex);
 
@@ -4836,28 +5075,33 @@ static int scarlett2_phantom_ctl_get(struct snd_kcontrol *kctl,
                goto unlock;
        }
 
-       err = scarlett2_check_input_phantom_updated(mixer);
-       if (err < 0)
+       oval = private->precomp_flt_switch[elem->control];
+       val = ucontrol->value.integer.value[0];
+
+       if (oval == val)
                goto unlock;
 
-       ucontrol->value.integer.value[0] = scarlett2_decode_muteable(
-               private->phantom_switch[elem->control]);
+       private->precomp_flt_switch[elem->control] = val;
+
+       /* Send change to the device */
+       err = scarlett2_usb_set_config(
+               mixer, SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+               elem->control, val);
+       if (err == 0)
+               err = 1;
 
 unlock:
        mutex_unlock(&private->data_mutex);
        return err;
 }
 
-static int scarlett2_phantom_ctl_put(struct snd_kcontrol *kctl,
-                                    struct snd_ctl_elem_value *ucontrol)
+static int scarlett2_peq_flt_switch_ctl_put(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct usb_mixer_interface *mixer = elem->head.mixer;
        struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_device_info *info = private->info;
-
-       int index = elem->control;
-       int oval, val, err;
+       int oval, val, err = 0;
 
        mutex_lock(&private->data_mutex);
 
@@ -4866,19 +5110,526 @@ static int scarlett2_phantom_ctl_put(struct snd_kcontrol *kctl,
                goto unlock;
        }
 
-       err = scarlett2_check_put_during_autogain(mixer);
-       if (err < 0)
-               goto unlock;
-
-       oval = private->phantom_switch[index];
-       val = !!ucontrol->value.integer.value[0];
+       oval = private->peq_flt_switch[elem->control];
+       val = ucontrol->value.integer.value[0];
 
        if (oval == val)
                goto unlock;
 
-       private->phantom_switch[index] = val;
+       private->peq_flt_switch[elem->control] = val;
 
-       /* To set the Gen 4 muteable controls, bit 1 gets set */
+       /* Send change to the device */
+       err = scarlett2_usb_set_config(
+               mixer, SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+               elem->control, val);
+       if (err == 0)
+               err = 1;
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static const struct snd_kcontrol_new scarlett2_precomp_flt_switch_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .name = "",
+       .info = snd_ctl_boolean_mono_info,
+       .get  = scarlett2_precomp_flt_switch_ctl_get,
+       .put  = scarlett2_precomp_flt_switch_ctl_put,
+};
+
+static const struct snd_kcontrol_new scarlett2_peq_flt_switch_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .name = "",
+       .info = snd_ctl_boolean_mono_info,
+       .get  = scarlett2_peq_flt_switch_ctl_get,
+       .put  = scarlett2_peq_flt_switch_ctl_put,
+};
+
+static int scarlett2_update_filter_values(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int err, i, j, k, src_idx, dst_idx;
+       s32 peq_flt_values[SCARLETT2_DSP_SWITCH_MAX *
+                          SCARLETT2_PEQ_FLT_SLOTS_MAX *
+                          SCARLETT2_BIQUAD_COEFFS];
+
+       if (!info->dsp_input_count)
+               return 0;
+
+       /* Get filter switch values */
+       err = scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+               info->dsp_input_count, private->precomp_flt_switch);
+       if (err < 0)
+               return err;
+
+       err = scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+               info->dsp_input_count * info->peq_flt_count,
+               private->peq_flt_switch);
+       if (err < 0)
+               return err;
+
+       /* Get pre-compressor filter values directly */
+       err = scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+               info->dsp_input_count *
+                       info->precomp_flt_count *
+                       SCARLETT2_BIQUAD_COEFFS,
+               private->precomp_flt_values);
+
+       if (err < 0)
+               return err;
+
+       /* PEQ filter values need to be copied via buffer because of
+        * padding after peq_flt_count up to peq_flt_total_count
+        */
+       err = scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
+               info->dsp_input_count *
+                       info->peq_flt_total_count *
+                       SCARLETT2_BIQUAD_COEFFS,
+               peq_flt_values);
+
+       for (i = 0, dst_idx = 0; i < info->dsp_input_count; i++) {
+               src_idx = i *
+                         info->peq_flt_total_count *
+                         SCARLETT2_BIQUAD_COEFFS;
+               for (j = 0; j < info->peq_flt_count; j++)
+                       for (k = 0;
+                            k < SCARLETT2_BIQUAD_COEFFS;
+                            k++, src_idx++, dst_idx++)
+                               private->peq_flt_values[dst_idx] =
+                                       peq_flt_values[src_idx];
+       }
+
+       return 0;
+}
+
+static int scarlett2_precomp_flt_ctl_get(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+       int i, idx;
+
+       for (i = 0, idx = elem->control * SCARLETT2_BIQUAD_COEFFS;
+            i < SCARLETT2_BIQUAD_COEFFS;
+            i++, idx++)
+               ucontrol->value.integer.value[i] =
+                       private->precomp_flt_values[idx];
+
+       return 0;
+}
+
+static int scarlett2_peq_flt_ctl_get(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+       int i, idx;
+
+       for (i = 0, idx = elem->control * SCARLETT2_BIQUAD_COEFFS;
+            i < SCARLETT2_BIQUAD_COEFFS;
+            i++, idx++)
+               ucontrol->value.integer.value[i] =
+                       private->peq_flt_values[idx];
+
+       return 0;
+}
+
+static int scarlett2_precomp_flt_ctl_put(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+
+       int index = elem->control * SCARLETT2_BIQUAD_COEFFS;
+       int i, oval, val, err;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       err = scarlett2_check_put_during_autogain(mixer);
+       if (err < 0)
+               goto unlock;
+
+       /* Check if any of the values have changed; if not, return */
+       for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++) {
+               oval = private->precomp_flt_values[index + i];
+               val = ucontrol->value.integer.value[i];
+               if (oval != val)
+                       break;
+       }
+
+       if (i == SCARLETT2_BIQUAD_COEFFS)
+               goto unlock;
+
+       /* Update the values */
+       for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++)
+               private->precomp_flt_values[index + i] =
+                       ucontrol->value.integer.value[i];
+
+       /* Send change to the device */
+       err = scarlett2_usb_set_data(
+               mixer, private->config_set->param_buf_addr, 1, index);
+       if (err < 0)
+               goto unlock;
+
+       err = scarlett2_usb_set_config_buf(
+               mixer, SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+               index, SCARLETT2_BIQUAD_COEFFS,
+               &private->precomp_flt_values[index]);
+
+       if (err == 0)
+               err = 1;
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static int scarlett2_peq_flt_ctl_put(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+
+       int src_index = elem->control * SCARLETT2_BIQUAD_COEFFS;
+       int dst_index = (
+               elem->control /
+               info->peq_flt_count *
+               info->peq_flt_total_count +
+               elem->control % info->peq_flt_count
+       ) * SCARLETT2_BIQUAD_COEFFS;
+       int i, oval, val, err;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       err = scarlett2_check_put_during_autogain(mixer);
+       if (err < 0)
+               goto unlock;
+
+       /* Check if any of the values have changed; if not, return */
+       for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++) {
+               oval = private->peq_flt_values[src_index + i];
+               val = ucontrol->value.integer.value[i];
+               if (oval != val)
+                       break;
+       }
+
+       if (i == SCARLETT2_BIQUAD_COEFFS)
+               goto unlock;
+
+       /* Update the values */
+       for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++)
+               private->peq_flt_values[src_index + i] =
+                       ucontrol->value.integer.value[i];
+
+       /* Send change to the device */
+       err = scarlett2_usb_set_data(
+               mixer, private->config_set->param_buf_addr, 1, dst_index);
+       if (err < 0)
+               goto unlock;
+
+       err = scarlett2_usb_set_config_buf(
+               mixer, SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
+               dst_index, SCARLETT2_BIQUAD_COEFFS,
+               &private->peq_flt_values[src_index]);
+
+       if (err == 0)
+               err = 1;
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static int scarlett2_flt_ctl_info(
+       struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+       uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+       uinfo->count = SCARLETT2_BIQUAD_COEFFS;
+       uinfo->value.integer.min = INT_MIN;
+       uinfo->value.integer.max = INT_MAX;
+       uinfo->value.integer.step = 1;
+       return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_precomp_flt_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .name = "",
+       .info = scarlett2_flt_ctl_info,
+       .get  = scarlett2_precomp_flt_ctl_get,
+       .put  = scarlett2_precomp_flt_ctl_put,
+};
+
+static const struct snd_kcontrol_new scarlett2_peq_flt_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .name = "",
+       .info = scarlett2_flt_ctl_info,
+       .get  = scarlett2_peq_flt_ctl_get,
+       .put  = scarlett2_peq_flt_ctl_put,
+};
+
+/*** Input Mute Switch Controls ***/
+
+static int scarlett2_update_input_mute(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+
+       private->input_mute_updated = 0;
+
+       if (!info->mute_input_count)
+               return 0;
+
+       return scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
+               info->mute_input_count, private->input_mute_switch);
+}
+
+static int scarlett2_input_mute_ctl_get(struct snd_kcontrol *kctl,
+                                       struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+       int err = 0;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       if (private->input_mute_updated) {
+               err = scarlett2_update_input_mute(mixer);
+               if (err < 0)
+                       goto unlock;
+       }
+       ucontrol->value.integer.value[0] =
+               private->input_mute_switch[elem->control];
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static int scarlett2_input_mute_ctl_put(struct snd_kcontrol *kctl,
+                                       struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+
+       int index = elem->control;
+       int oval, val, err;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       err = scarlett2_check_put_during_autogain(mixer);
+       if (err < 0)
+               goto unlock;
+
+       oval = private->input_mute_switch[index];
+       val = ucontrol->value.integer.value[0];
+
+       if (oval == val)
+               goto unlock;
+
+       private->input_mute_switch[index] = val;
+
+       /* Send switch change to the device */
+       err = scarlett2_usb_set_config(
+               mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
+                       index, val);
+       if (err == 0)
+               err = 1;
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static const struct snd_kcontrol_new scarlett2_input_mute_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .name = "",
+       .info = scarlett2_autogain_disables_ctl_info,
+       .get  = scarlett2_input_mute_ctl_get,
+       .put  = scarlett2_input_mute_ctl_put,
+};
+
+/*** Phantom Switch Controls ***/
+
+static int scarlett2_update_input_phantom(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int err;
+
+       private->input_phantom_updated = 0;
+
+       if (!info->phantom_count)
+               return 0;
+
+       err = scarlett2_usb_get_config(
+               mixer, SCARLETT2_CONFIG_PHANTOM_SWITCH,
+               info->phantom_count, private->phantom_switch);
+       if (err < 0)
+               return err;
+
+       if (scarlett2_has_config_item(private,
+                                     SCARLETT2_CONFIG_PHANTOM_PERSISTENCE)) {
+               err = scarlett2_usb_get_config(
+                       mixer, SCARLETT2_CONFIG_PHANTOM_PERSISTENCE,
+                       1, &private->phantom_persistence);
+               if (err < 0)
+                       return err;
+       }
+
+       return 0;
+}
+
+/* Check if phantom power on the given input is currently changing state */
+static int scarlett2_phantom_is_switching(
+       struct scarlett2_data *private, int line_num)
+{
+       const struct scarlett2_device_info *info = private->info;
+       int index = line_num / info->inputs_per_phantom;
+
+       return !!(private->phantom_switch[index] & 0x02);
+}
+
+/* Update autogain controls' access mode when phantom power changes state */
+static void scarlett2_phantom_update_access(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int i;
+
+       /* Disable autogain controls if phantom power is changing state */
+       for (i = 0; i < info->gain_input_count; i++) {
+               int val = !scarlett2_phantom_is_switching(private, i);
+
+               scarlett2_set_ctl_access(private->autogain_ctls[i], val);
+       }
+}
+
+/* Notify of access mode change for autogain which can't be enabled
+ * while phantom power is changing.
+ */
+static void scarlett2_phantom_notify_access(struct usb_mixer_interface *mixer)
+{
+       struct snd_card *card = mixer->chip->card;
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int i;
+
+       for (i = 0; i < info->gain_input_count; i++)
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+                              &private->autogain_ctls[i]->id);
+}
+
+/* Call scarlett2_update_input_phantom() and
+ * scarlett2_phantom_update_access() if input_phantom_updated is set.
+ */
+static int scarlett2_check_input_phantom_updated(
+       struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       int err;
+
+       if (!private->input_phantom_updated)
+               return 0;
+
+       err = scarlett2_update_input_phantom(mixer);
+       if (err < 0)
+               return err;
+
+       scarlett2_phantom_update_access(mixer);
+
+       return 0;
+}
+
+static int scarlett2_phantom_ctl_get(struct snd_kcontrol *kctl,
+                                    struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+       int err;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       err = scarlett2_check_input_phantom_updated(mixer);
+       if (err < 0)
+               goto unlock;
+
+       ucontrol->value.integer.value[0] = scarlett2_decode_muteable(
+               private->phantom_switch[elem->control]);
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static int scarlett2_phantom_ctl_put(struct snd_kcontrol *kctl,
+                                    struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+
+       int index = elem->control;
+       int oval, val, err;
+
+       mutex_lock(&private->data_mutex);
+
+       if (private->hwdep_in_use) {
+               err = -EBUSY;
+               goto unlock;
+       }
+
+       err = scarlett2_check_put_during_autogain(mixer);
+       if (err < 0)
+               goto unlock;
+
+       oval = private->phantom_switch[index];
+       val = !!ucontrol->value.integer.value[0];
+
+       if (oval == val)
+               goto unlock;
+
+       private->phantom_switch[index] = val;
+
+       /* To set the Gen 4 muteable controls, bit 1 gets set */
        if (private->config_set->items[SCARLETT2_CONFIG_PHANTOM_SWITCH].mute)
                val = (!val) | 0x02;
 
@@ -5568,6 +6319,69 @@ static int scarlett2_add_line_out_ctls(struct usb_mixer_interface *mixer)
 
 /*** Create the analogue input controls ***/
 
+static int scarlett2_add_dsp_ctls(struct usb_mixer_interface *mixer, int i)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int j, err;
+       char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+       const char *compr_fmt = "Line In %d Compressor %s";
+       const char *flt_switch_fmt = "Line In %d %s Filter Enable";
+       const char *flt_fmt = "Line In %d %s Coefficients %d";
+
+       /* Add compressor controls */
+       for (j = 0; j < SCARLETT2_COMPRESSOR_PARAM_COUNT; j++) {
+               const struct compressor_param *param = &compressor_params[j];
+               int idx = i * SCARLETT2_COMPRESSOR_PARAM_COUNT + j;
+
+               scnprintf(s, sizeof(s), compr_fmt, i + 1, param->name);
+               err = scarlett2_add_new_ctl(
+                       mixer, &scarlett2_compressor_ctl,
+                       i * SCARLETT2_COMPRESSOR_PARAM_COUNT + j,
+                       1, s, &private->compressor_ctls[idx]);
+               if (err < 0)
+                       return err;
+       }
+
+       /* Add filter enable controls */
+       scnprintf(s, sizeof(s), flt_switch_fmt, i + 1, "Pre-Comp");
+       err = scarlett2_add_new_ctl(
+               mixer, &scarlett2_precomp_flt_switch_ctl,
+               i, 1, s, &private->precomp_flt_switch_ctls[i]);
+       if (err < 0)
+               return err;
+
+       scnprintf(s, sizeof(s), flt_switch_fmt, i + 1, "PEQ");
+       err = scarlett2_add_new_ctl(
+               mixer, &scarlett2_peq_flt_switch_ctl,
+               i, 1, s, &private->peq_flt_switch_ctls[i]);
+       if (err < 0)
+               return err;
+
+       /* Add filter coefficient controls */
+       for (j = 0; j < info->precomp_flt_count; j++) {
+               scnprintf(s, sizeof(s), flt_fmt, i + 1, "Pre-Comp", j + 1);
+               err = scarlett2_add_new_ctl(
+                       mixer, &scarlett2_precomp_flt_ctl,
+                       i * info->precomp_flt_count + j,
+                       1, s, &private->precomp_flt_switch_ctls[j]);
+               if (err < 0)
+                       return err;
+       }
+
+       for (j = 0; j < info->peq_flt_count; j++) {
+               scnprintf(s, sizeof(s), flt_fmt, i + 1, "PEQ", j + 1);
+               err = scarlett2_add_new_ctl(
+                       mixer, &scarlett2_peq_flt_ctl,
+                       i * info->peq_flt_count + j,
+                       1, s, &private->peq_flt_switch_ctls[j]);
+               if (err < 0)
+                       return err;
+       }
+
+       return 0;
+}
+
 static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
@@ -5607,6 +6421,19 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
                        return err;
        }
 
+       /* Add input DSP controls */
+       for (i = 0; i < info->dsp_input_count; i++) {
+               scnprintf(s, sizeof(s), fmt, i + 1, "DSP", "Switch");
+               err = scarlett2_add_new_ctl(mixer, &scarlett2_dsp_ctl,
+                                           i, 1, s, &private->dsp_ctls[i]);
+               if (err < 0)
+                       return err;
+
+               err = scarlett2_add_dsp_ctls(mixer, i);
+               if (err < 0)
+                       return err;
+       }
+
        /* Add input mute controls */
        for (i = 0; i < info->mute_input_count; i++) {
                scnprintf(s, sizeof(s), fmt, i + 1, "Mute", "Switch");
@@ -6678,6 +7505,22 @@ static void scarlett2_notify_input_air(struct usb_mixer_interface *mixer)
                               &private->air_ctls[i]->id);
 }
 
+/* Notify on input DSP switch change */
+static __always_unused void scarlett2_notify_input_dsp(
+       struct usb_mixer_interface *mixer)
+{
+       struct snd_card *card = mixer->chip->card;
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int i;
+
+       private->input_dsp_updated = 1;
+
+       for (i = 0; i < info->dsp_input_count; i++)
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+                              &private->dsp_ctls[i]->id);
+}
+
 /* Notify on input mute switch change */
 static __always_unused void scarlett2_notify_input_mute(
        struct usb_mixer_interface *mixer)
@@ -7307,6 +8150,18 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
        if (err < 0)
                return err;
 
+       err = scarlett2_update_input_dsp(mixer);
+       if (err < 0)
+               return err;
+
+       err = scarlett2_update_compressor_values(mixer);
+       if (err < 0)
+               return err;
+
+       err = scarlett2_update_filter_values(mixer);
+       if (err < 0)
+               return err;
+
        err = scarlett2_update_input_mute(mixer);
        if (err < 0)
                return err;