v4.19.13 snapshot.
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
new file mode 100644
index 0000000..3d12af8
--- /dev/null
+++ b/sound/usb/mixer.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBMIXER_H
+#define __USBMIXER_H
+
+#include <sound/info.h>
+
+struct usb_mixer_interface {
+ struct snd_usb_audio *chip;
+ struct usb_host_interface *hostif;
+ struct list_head list;
+ unsigned int ignore_ctl_error;
+ struct urb *urb;
+ /* array[MAX_ID_ELEMS], indexed by unit id */
+ struct usb_mixer_elem_list **id_elems;
+
+ /* the usb audio specification version this interface complies to */
+ int protocol;
+
+ /* Sound Blaster remote control stuff */
+ const struct rc_config *rc_cfg;
+ u32 rc_code;
+ wait_queue_head_t rc_waitq;
+ struct urb *rc_urb;
+ struct usb_ctrlrequest *rc_setup_packet;
+ u8 rc_buffer[6];
+
+ bool disconnected;
+};
+
+#define MAX_CHANNELS 16 /* max logical channels */
+
+enum {
+ USB_MIXER_BOOLEAN,
+ USB_MIXER_INV_BOOLEAN,
+ USB_MIXER_S8,
+ USB_MIXER_U8,
+ USB_MIXER_S16,
+ USB_MIXER_U16,
+ USB_MIXER_S32,
+ USB_MIXER_U32,
+};
+
+typedef void (*usb_mixer_elem_dump_func_t)(struct snd_info_buffer *buffer,
+ struct usb_mixer_elem_list *list);
+typedef int (*usb_mixer_elem_resume_func_t)(struct usb_mixer_elem_list *elem);
+
+struct usb_mixer_elem_list {
+ struct usb_mixer_interface *mixer;
+ struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */
+ struct snd_kcontrol *kctl;
+ unsigned int id;
+ usb_mixer_elem_dump_func_t dump;
+ usb_mixer_elem_resume_func_t resume;
+};
+
+/* iterate over mixer element list of the given unit id */
+#define for_each_mixer_elem(list, mixer, id) \
+ for ((list) = (mixer)->id_elems[id]; (list); (list) = (list)->next_id_elem)
+#define mixer_elem_list_to_info(list) \
+ container_of(list, struct usb_mixer_elem_info, head)
+
+struct usb_mixer_elem_info {
+ struct usb_mixer_elem_list head;
+ unsigned int control; /* CS or ICN (high byte) */
+ unsigned int cmask; /* channel mask bitmap: 0 = master */
+ unsigned int idx_off; /* Control index offset */
+ unsigned int ch_readonly;
+ unsigned int master_readonly;
+ int channels;
+ int val_type;
+ int min, max, res;
+ int dBmin, dBmax;
+ int cached;
+ int cache_val[MAX_CHANNELS];
+ u8 initialized;
+ u8 min_mute;
+ void *private_data;
+};
+
+int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
+ int ignore_error);
+void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer);
+
+void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid);
+
+int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
+ int request, int validx, int value_set);
+
+int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
+ struct snd_kcontrol *kctl);
+
+void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
+ struct usb_mixer_interface *mixer,
+ int unitid);
+
+int snd_usb_mixer_vol_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+ unsigned int size, unsigned int __user *_tlv);
+
+#ifdef CONFIG_PM
+int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer);
+int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume);
+#endif
+
+int snd_usb_set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
+ int index, int value);
+
+int snd_usb_get_cur_mix_value(struct usb_mixer_elem_info *cval,
+ int channel, int index, int *value);
+
+extern void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl);
+
+extern struct snd_kcontrol_new *snd_usb_feature_unit_ctl;
+
+#endif /* __USBMIXER_H */