ASR_BASE

Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/usb/gadget/function/f_uac2.c b/marvell/linux/drivers/usb/gadget/function/f_uac2.c
new file mode 100644
index 0000000..11cc605
--- /dev/null
+++ b/marvell/linux/drivers/usb/gadget/function/f_uac2.c
@@ -0,0 +1,1213 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_uac2.c -- USB Audio Class 2.0 Function
+ *
+ * Copyright (C) 2011
+ *    Yadwinder Singh (yadi.brar01@gmail.com)
+ *    Jaswinder Singh (jaswinder.singh@linaro.org)
+ */
+
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/module.h>
+
+#include "u_audio.h"
+#include "u_uac2.h"
+
+/* UAC2 spec: 4.1 Audio Channel Cluster Descriptor */
+#define UAC2_CHANNEL_MASK 0x07FFFFFF
+
+/*
+ * The driver implements a simple UAC_2 topology.
+ * USB-OUT -> IT_1 -> OT_3 -> ALSA_Capture
+ * ALSA_Playback -> IT_2 -> OT_4 -> USB-IN
+ * Capture and Playback sampling rates are independently
+ *  controlled by two clock sources :
+ *    CLK_5 := c_srate, and CLK_6 := p_srate
+ */
+#define USB_OUT_CLK_ID	(out_clk_src_desc.bClockID)
+#define USB_IN_CLK_ID	(in_clk_src_desc.bClockID)
+
+#define CONTROL_ABSENT	0
+#define CONTROL_RDONLY	1
+#define CONTROL_RDWR	3
+
+#define CLK_FREQ_CTRL	0
+#define CLK_VLD_CTRL	2
+
+#define COPY_CTRL	0
+#define CONN_CTRL	2
+#define OVRLD_CTRL	4
+#define CLSTR_CTRL	6
+#define UNFLW_CTRL	8
+#define OVFLW_CTRL	10
+
+#define EPIN_EN(_opts) ((_opts)->p_chmask != 0)
+#define EPOUT_EN(_opts) ((_opts)->c_chmask != 0)
+
+struct f_uac2 {
+	struct g_audio g_audio;
+	u8 ac_intf, as_in_intf, as_out_intf;
+	u8 ac_alt, as_in_alt, as_out_alt;	/* needed for get_alt() */
+};
+
+static inline struct f_uac2 *func_to_uac2(struct usb_function *f)
+{
+	return container_of(f, struct f_uac2, g_audio.func);
+}
+
+static inline
+struct f_uac2_opts *g_audio_to_uac2_opts(struct g_audio *agdev)
+{
+	return container_of(agdev->func.fi, struct f_uac2_opts, func_inst);
+}
+
+/* --------- USB Function Interface ------------- */
+
+enum {
+	STR_ASSOC,
+	STR_IF_CTRL,
+	STR_CLKSRC_IN,
+	STR_CLKSRC_OUT,
+	STR_USB_IT,
+	STR_IO_IT,
+	STR_USB_OT,
+	STR_IO_OT,
+	STR_AS_OUT_ALT0,
+	STR_AS_OUT_ALT1,
+	STR_AS_IN_ALT0,
+	STR_AS_IN_ALT1,
+};
+
+static char clksrc_in[8];
+static char clksrc_out[8];
+
+static struct usb_string strings_fn[] = {
+	[STR_ASSOC].s = "Source/Sink",
+	[STR_IF_CTRL].s = "Topology Control",
+	[STR_CLKSRC_IN].s = clksrc_in,
+	[STR_CLKSRC_OUT].s = clksrc_out,
+	[STR_USB_IT].s = "USBH Out",
+	[STR_IO_IT].s = "USBD Out",
+	[STR_USB_OT].s = "USBH In",
+	[STR_IO_OT].s = "USBD In",
+	[STR_AS_OUT_ALT0].s = "Playback Inactive",
+	[STR_AS_OUT_ALT1].s = "Playback Active",
+	[STR_AS_IN_ALT0].s = "Capture Inactive",
+	[STR_AS_IN_ALT1].s = "Capture Active",
+	{ },
+};
+
+static struct usb_gadget_strings str_fn = {
+	.language = 0x0409,	/* en-us */
+	.strings = strings_fn,
+};
+
+static struct usb_gadget_strings *fn_strings[] = {
+	&str_fn,
+	NULL,
+};
+
+static struct usb_interface_assoc_descriptor iad_desc = {
+	.bLength = sizeof iad_desc,
+	.bDescriptorType = USB_DT_INTERFACE_ASSOCIATION,
+
+	.bFirstInterface = 0,
+	.bInterfaceCount = 3,
+	.bFunctionClass = USB_CLASS_AUDIO,
+	.bFunctionSubClass = UAC2_FUNCTION_SUBCLASS_UNDEFINED,
+	.bFunctionProtocol = UAC_VERSION_2,
+};
+
+/* Audio Control Interface */
+static struct usb_interface_descriptor std_ac_if_desc = {
+	.bLength = sizeof std_ac_if_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL,
+	.bInterfaceProtocol = UAC_VERSION_2,
+};
+
+/* Clock source for IN traffic */
+static struct uac_clock_source_descriptor in_clk_src_desc = {
+	.bLength = sizeof in_clk_src_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC2_CLOCK_SOURCE,
+	/* .bClockID = DYNAMIC */
+	.bmAttributes = UAC_CLOCK_SOURCE_TYPE_INT_FIXED,
+	.bmControls = (CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bAssocTerminal = 0,
+};
+
+/* Clock source for OUT traffic */
+static struct uac_clock_source_descriptor out_clk_src_desc = {
+	.bLength = sizeof out_clk_src_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC2_CLOCK_SOURCE,
+	/* .bClockID = DYNAMIC */
+	.bmAttributes = UAC_CLOCK_SOURCE_TYPE_INT_FIXED,
+	.bmControls = (CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bAssocTerminal = 0,
+};
+
+/* Input Terminal for USB_OUT */
+static struct uac2_input_terminal_descriptor usb_out_it_desc = {
+	.bLength = sizeof usb_out_it_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
+	/* .bTerminalID = DYNAMIC */
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	/* .bCSourceID = DYNAMIC */
+	.iChannelNames = 0,
+	.bmControls = cpu_to_le16(CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Input Terminal for I/O-In */
+static struct uac2_input_terminal_descriptor io_in_it_desc = {
+	.bLength = sizeof io_in_it_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
+	/* .bTerminalID = DYNAMIC */
+	.wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_MICROPHONE),
+	.bAssocTerminal = 0,
+	/* .bCSourceID = DYNAMIC */
+	.iChannelNames = 0,
+	.bmControls = cpu_to_le16(CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Ouput Terminal for USB_IN */
+static struct uac2_output_terminal_descriptor usb_in_ot_desc = {
+	.bLength = sizeof usb_in_ot_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
+	/* .bTerminalID = DYNAMIC */
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	/* .bSourceID = DYNAMIC */
+	/* .bCSourceID = DYNAMIC */
+	.bmControls = cpu_to_le16(CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Ouput Terminal for I/O-Out */
+static struct uac2_output_terminal_descriptor io_out_ot_desc = {
+	.bLength = sizeof io_out_ot_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
+	/* .bTerminalID = DYNAMIC */
+	.wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_SPEAKER),
+	.bAssocTerminal = 0,
+	/* .bSourceID = DYNAMIC */
+	/* .bCSourceID = DYNAMIC */
+	.bmControls = cpu_to_le16(CONTROL_RDWR << COPY_CTRL),
+};
+
+static struct uac2_ac_header_descriptor ac_hdr_desc = {
+	.bLength = sizeof ac_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_MS_HEADER,
+	.bcdADC = cpu_to_le16(0x200),
+	.bCategory = UAC2_FUNCTION_IO_BOX,
+	/* .wTotalLength = DYNAMIC */
+	.bmControls = 0,
+};
+
+/* Audio Streaming OUT Interface - Alt0 */
+static struct usb_interface_descriptor std_as_out_if0_desc = {
+	.bLength = sizeof std_as_out_if0_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_2,
+};
+
+/* Audio Streaming OUT Interface - Alt1 */
+static struct usb_interface_descriptor std_as_out_if1_desc = {
+	.bLength = sizeof std_as_out_if1_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 1,
+	.bNumEndpoints = 1,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_2,
+};
+
+/* Audio Stream OUT Intface Desc */
+static struct uac2_as_header_descriptor as_out_hdr_desc = {
+	.bLength = sizeof as_out_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_AS_GENERAL,
+	/* .bTerminalLink = DYNAMIC */
+	.bmControls = 0,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+	.bmFormats = cpu_to_le32(UAC_FORMAT_TYPE_I_PCM),
+	.iChannelNames = 0,
+};
+
+/* Audio USB_OUT Format */
+static struct uac2_format_type_i_descriptor as_out_fmt1_desc = {
+	.bLength = sizeof as_out_fmt1_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype = UAC_FORMAT_TYPE,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+};
+
+/* STD AS ISO OUT Endpoint */
+static struct usb_endpoint_descriptor fs_epout_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bEndpointAddress = USB_DIR_OUT,
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	/* .wMaxPacketSize = DYNAMIC */
+	.bInterval = 1,
+};
+
+static struct usb_endpoint_descriptor hs_epout_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	/* .wMaxPacketSize = DYNAMIC */
+	.bInterval = 4,
+};
+
+/* CS AS ISO OUT Endpoint */
+static struct uac2_iso_endpoint_descriptor as_iso_out_desc = {
+	.bLength = sizeof as_iso_out_desc,
+	.bDescriptorType = USB_DT_CS_ENDPOINT,
+
+	.bDescriptorSubtype = UAC_EP_GENERAL,
+	.bmAttributes = 0,
+	.bmControls = 0,
+	.bLockDelayUnits = 0,
+	.wLockDelay = 0,
+};
+
+/* Audio Streaming IN Interface - Alt0 */
+static struct usb_interface_descriptor std_as_in_if0_desc = {
+	.bLength = sizeof std_as_in_if0_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 0,
+	.bNumEndpoints = 0,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_2,
+};
+
+/* Audio Streaming IN Interface - Alt1 */
+static struct usb_interface_descriptor std_as_in_if1_desc = {
+	.bLength = sizeof std_as_in_if1_desc,
+	.bDescriptorType = USB_DT_INTERFACE,
+
+	.bAlternateSetting = 1,
+	.bNumEndpoints = 1,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
+	.bInterfaceProtocol = UAC_VERSION_2,
+};
+
+/* Audio Stream IN Intface Desc */
+static struct uac2_as_header_descriptor as_in_hdr_desc = {
+	.bLength = sizeof as_in_hdr_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+
+	.bDescriptorSubtype = UAC_AS_GENERAL,
+	/* .bTerminalLink = DYNAMIC */
+	.bmControls = 0,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+	.bmFormats = cpu_to_le32(UAC_FORMAT_TYPE_I_PCM),
+	.iChannelNames = 0,
+};
+
+/* Audio USB_IN Format */
+static struct uac2_format_type_i_descriptor as_in_fmt1_desc = {
+	.bLength = sizeof as_in_fmt1_desc,
+	.bDescriptorType = USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype = UAC_FORMAT_TYPE,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+};
+
+/* STD AS ISO IN Endpoint */
+static struct usb_endpoint_descriptor fs_epin_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bEndpointAddress = USB_DIR_IN,
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	/* .wMaxPacketSize = DYNAMIC */
+	.bInterval = 1,
+};
+
+static struct usb_endpoint_descriptor hs_epin_desc = {
+	.bLength = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType = USB_DT_ENDPOINT,
+
+	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
+	/* .wMaxPacketSize = DYNAMIC */
+	.bInterval = 4,
+};
+
+/* CS AS ISO IN Endpoint */
+static struct uac2_iso_endpoint_descriptor as_iso_in_desc = {
+	.bLength = sizeof as_iso_in_desc,
+	.bDescriptorType = USB_DT_CS_ENDPOINT,
+
+	.bDescriptorSubtype = UAC_EP_GENERAL,
+	.bmAttributes = 0,
+	.bmControls = 0,
+	.bLockDelayUnits = 0,
+	.wLockDelay = 0,
+};
+
+static struct usb_descriptor_header *fs_audio_desc[] = {
+	(struct usb_descriptor_header *)&iad_desc,
+	(struct usb_descriptor_header *)&std_ac_if_desc,
+
+	(struct usb_descriptor_header *)&ac_hdr_desc,
+	(struct usb_descriptor_header *)&in_clk_src_desc,
+	(struct usb_descriptor_header *)&out_clk_src_desc,
+	(struct usb_descriptor_header *)&usb_out_it_desc,
+	(struct usb_descriptor_header *)&io_in_it_desc,
+	(struct usb_descriptor_header *)&usb_in_ot_desc,
+	(struct usb_descriptor_header *)&io_out_ot_desc,
+
+	(struct usb_descriptor_header *)&std_as_out_if0_desc,
+	(struct usb_descriptor_header *)&std_as_out_if1_desc,
+
+	(struct usb_descriptor_header *)&as_out_hdr_desc,
+	(struct usb_descriptor_header *)&as_out_fmt1_desc,
+	(struct usb_descriptor_header *)&fs_epout_desc,
+	(struct usb_descriptor_header *)&as_iso_out_desc,
+
+	(struct usb_descriptor_header *)&std_as_in_if0_desc,
+	(struct usb_descriptor_header *)&std_as_in_if1_desc,
+
+	(struct usb_descriptor_header *)&as_in_hdr_desc,
+	(struct usb_descriptor_header *)&as_in_fmt1_desc,
+	(struct usb_descriptor_header *)&fs_epin_desc,
+	(struct usb_descriptor_header *)&as_iso_in_desc,
+	NULL,
+};
+
+static struct usb_descriptor_header *hs_audio_desc[] = {
+	(struct usb_descriptor_header *)&iad_desc,
+	(struct usb_descriptor_header *)&std_ac_if_desc,
+
+	(struct usb_descriptor_header *)&ac_hdr_desc,
+	(struct usb_descriptor_header *)&in_clk_src_desc,
+	(struct usb_descriptor_header *)&out_clk_src_desc,
+	(struct usb_descriptor_header *)&usb_out_it_desc,
+	(struct usb_descriptor_header *)&io_in_it_desc,
+	(struct usb_descriptor_header *)&usb_in_ot_desc,
+	(struct usb_descriptor_header *)&io_out_ot_desc,
+
+	(struct usb_descriptor_header *)&std_as_out_if0_desc,
+	(struct usb_descriptor_header *)&std_as_out_if1_desc,
+
+	(struct usb_descriptor_header *)&as_out_hdr_desc,
+	(struct usb_descriptor_header *)&as_out_fmt1_desc,
+	(struct usb_descriptor_header *)&hs_epout_desc,
+	(struct usb_descriptor_header *)&as_iso_out_desc,
+
+	(struct usb_descriptor_header *)&std_as_in_if0_desc,
+	(struct usb_descriptor_header *)&std_as_in_if1_desc,
+
+	(struct usb_descriptor_header *)&as_in_hdr_desc,
+	(struct usb_descriptor_header *)&as_in_fmt1_desc,
+	(struct usb_descriptor_header *)&hs_epin_desc,
+	(struct usb_descriptor_header *)&as_iso_in_desc,
+	NULL,
+};
+
+struct cntrl_cur_lay3 {
+	__le32	dCUR;
+};
+
+struct cntrl_range_lay3 {
+	__le16	wNumSubRanges;
+	__le32	dMIN;
+	__le32	dMAX;
+	__le32	dRES;
+} __packed;
+
+static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
+	struct usb_endpoint_descriptor *ep_desc,
+	enum usb_device_speed speed, bool is_playback)
+{
+	int chmask, srate, ssize;
+	u16 max_size_bw, max_size_ep;
+	unsigned int factor;
+
+	switch (speed) {
+	case USB_SPEED_FULL:
+		max_size_ep = 1023;
+		factor = 1000;
+		break;
+
+	case USB_SPEED_HIGH:
+		max_size_ep = 1024;
+		factor = 8000;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (is_playback) {
+		chmask = uac2_opts->p_chmask;
+		srate = uac2_opts->p_srate;
+		ssize = uac2_opts->p_ssize;
+	} else {
+		chmask = uac2_opts->c_chmask;
+		srate = uac2_opts->c_srate;
+		ssize = uac2_opts->c_ssize;
+	}
+
+	max_size_bw = num_channels(chmask) * ssize *
+		((srate / (factor / (1 << (ep_desc->bInterval - 1)))) + 1);
+	ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw,
+						    max_size_ep));
+
+	return 0;
+}
+
+/* Use macro to overcome line length limitation */
+#define USBDHDR(p) (struct usb_descriptor_header *)(p)
+
+static void setup_descriptor(struct f_uac2_opts *opts)
+{
+	/* patch descriptors */
+	int i = 1; /* ID's start with 1 */
+
+	if (EPOUT_EN(opts))
+		usb_out_it_desc.bTerminalID = i++;
+	if (EPIN_EN(opts))
+		io_in_it_desc.bTerminalID = i++;
+	if (EPOUT_EN(opts))
+		io_out_ot_desc.bTerminalID = i++;
+	if (EPIN_EN(opts))
+		usb_in_ot_desc.bTerminalID = i++;
+	if (EPOUT_EN(opts))
+		out_clk_src_desc.bClockID = i++;
+	if (EPIN_EN(opts))
+		in_clk_src_desc.bClockID = i++;
+
+	usb_out_it_desc.bCSourceID = out_clk_src_desc.bClockID;
+	usb_in_ot_desc.bSourceID = io_in_it_desc.bTerminalID;
+	usb_in_ot_desc.bCSourceID = in_clk_src_desc.bClockID;
+	io_in_it_desc.bCSourceID = in_clk_src_desc.bClockID;
+	io_out_ot_desc.bCSourceID = out_clk_src_desc.bClockID;
+	io_out_ot_desc.bSourceID = usb_out_it_desc.bTerminalID;
+	as_out_hdr_desc.bTerminalLink = usb_out_it_desc.bTerminalID;
+	as_in_hdr_desc.bTerminalLink = usb_in_ot_desc.bTerminalID;
+
+	iad_desc.bInterfaceCount = 1;
+	ac_hdr_desc.wTotalLength = cpu_to_le16(sizeof(ac_hdr_desc));
+
+	if (EPIN_EN(opts)) {
+		u16 len = le16_to_cpu(ac_hdr_desc.wTotalLength);
+
+		len += sizeof(in_clk_src_desc);
+		len += sizeof(usb_in_ot_desc);
+		len += sizeof(io_in_it_desc);
+		ac_hdr_desc.wTotalLength = cpu_to_le16(len);
+		iad_desc.bInterfaceCount++;
+	}
+	if (EPOUT_EN(opts)) {
+		u16 len = le16_to_cpu(ac_hdr_desc.wTotalLength);
+
+		len += sizeof(out_clk_src_desc);
+		len += sizeof(usb_out_it_desc);
+		len += sizeof(io_out_ot_desc);
+		ac_hdr_desc.wTotalLength = cpu_to_le16(len);
+		iad_desc.bInterfaceCount++;
+	}
+
+	i = 0;
+	fs_audio_desc[i++] = USBDHDR(&iad_desc);
+	fs_audio_desc[i++] = USBDHDR(&std_ac_if_desc);
+	fs_audio_desc[i++] = USBDHDR(&ac_hdr_desc);
+	if (EPIN_EN(opts))
+		fs_audio_desc[i++] = USBDHDR(&in_clk_src_desc);
+	if (EPOUT_EN(opts)) {
+		fs_audio_desc[i++] = USBDHDR(&out_clk_src_desc);
+		fs_audio_desc[i++] = USBDHDR(&usb_out_it_desc);
+	}
+	if (EPIN_EN(opts)) {
+		fs_audio_desc[i++] = USBDHDR(&io_in_it_desc);
+		fs_audio_desc[i++] = USBDHDR(&usb_in_ot_desc);
+	}
+	if (EPOUT_EN(opts)) {
+		fs_audio_desc[i++] = USBDHDR(&io_out_ot_desc);
+		fs_audio_desc[i++] = USBDHDR(&std_as_out_if0_desc);
+		fs_audio_desc[i++] = USBDHDR(&std_as_out_if1_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_out_hdr_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_out_fmt1_desc);
+		fs_audio_desc[i++] = USBDHDR(&fs_epout_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_iso_out_desc);
+	}
+	if (EPIN_EN(opts)) {
+		fs_audio_desc[i++] = USBDHDR(&std_as_in_if0_desc);
+		fs_audio_desc[i++] = USBDHDR(&std_as_in_if1_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_in_hdr_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_in_fmt1_desc);
+		fs_audio_desc[i++] = USBDHDR(&fs_epin_desc);
+		fs_audio_desc[i++] = USBDHDR(&as_iso_in_desc);
+	}
+	fs_audio_desc[i] = NULL;
+
+	i = 0;
+	hs_audio_desc[i++] = USBDHDR(&iad_desc);
+	hs_audio_desc[i++] = USBDHDR(&std_ac_if_desc);
+	hs_audio_desc[i++] = USBDHDR(&ac_hdr_desc);
+	if (EPIN_EN(opts))
+		hs_audio_desc[i++] = USBDHDR(&in_clk_src_desc);
+	if (EPOUT_EN(opts)) {
+		hs_audio_desc[i++] = USBDHDR(&out_clk_src_desc);
+		hs_audio_desc[i++] = USBDHDR(&usb_out_it_desc);
+	}
+	if (EPIN_EN(opts)) {
+		hs_audio_desc[i++] = USBDHDR(&io_in_it_desc);
+		hs_audio_desc[i++] = USBDHDR(&usb_in_ot_desc);
+	}
+	if (EPOUT_EN(opts)) {
+		hs_audio_desc[i++] = USBDHDR(&io_out_ot_desc);
+		hs_audio_desc[i++] = USBDHDR(&std_as_out_if0_desc);
+		hs_audio_desc[i++] = USBDHDR(&std_as_out_if1_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_out_hdr_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_out_fmt1_desc);
+		hs_audio_desc[i++] = USBDHDR(&hs_epout_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_iso_out_desc);
+	}
+	if (EPIN_EN(opts)) {
+		hs_audio_desc[i++] = USBDHDR(&std_as_in_if0_desc);
+		hs_audio_desc[i++] = USBDHDR(&std_as_in_if1_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_in_hdr_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_in_fmt1_desc);
+		hs_audio_desc[i++] = USBDHDR(&hs_epin_desc);
+		hs_audio_desc[i++] = USBDHDR(&as_iso_in_desc);
+	}
+	hs_audio_desc[i] = NULL;
+}
+
+static int afunc_validate_opts(struct g_audio *agdev, struct device *dev)
+{
+	struct f_uac2_opts *opts = g_audio_to_uac2_opts(agdev);
+
+	if (!opts->p_chmask && !opts->c_chmask) {
+		dev_err(dev, "Error: no playback and capture channels\n");
+		return -EINVAL;
+	} else if (opts->p_chmask & ~UAC2_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported playback channels mask\n");
+		return -EINVAL;
+	} else if (opts->c_chmask & ~UAC2_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported capture channels mask\n");
+		return -EINVAL;
+	} else if ((opts->p_ssize < 1) || (opts->p_ssize > 4)) {
+		dev_err(dev, "Error: incorrect playback sample size\n");
+		return -EINVAL;
+	} else if ((opts->c_ssize < 1) || (opts->c_ssize > 4)) {
+		dev_err(dev, "Error: incorrect capture sample size\n");
+		return -EINVAL;
+	} else if (!opts->p_srate) {
+		dev_err(dev, "Error: incorrect playback sampling rate\n");
+		return -EINVAL;
+	} else if (!opts->c_srate) {
+		dev_err(dev, "Error: incorrect capture sampling rate\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int
+afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
+{
+	struct f_uac2 *uac2 = func_to_uac2(fn);
+	struct g_audio *agdev = func_to_g_audio(fn);
+	struct usb_composite_dev *cdev = cfg->cdev;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	struct f_uac2_opts *uac2_opts = g_audio_to_uac2_opts(agdev);
+	struct usb_string *us;
+	int ret;
+
+	ret = afunc_validate_opts(agdev, dev);
+	if (ret)
+		return ret;
+
+	us = usb_gstrings_attach(cdev, fn_strings, ARRAY_SIZE(strings_fn));
+	if (IS_ERR(us))
+		return PTR_ERR(us);
+	iad_desc.iFunction = us[STR_ASSOC].id;
+	std_ac_if_desc.iInterface = us[STR_IF_CTRL].id;
+	in_clk_src_desc.iClockSource = us[STR_CLKSRC_IN].id;
+	out_clk_src_desc.iClockSource = us[STR_CLKSRC_OUT].id;
+	usb_out_it_desc.iTerminal = us[STR_USB_IT].id;
+	io_in_it_desc.iTerminal = us[STR_IO_IT].id;
+	usb_in_ot_desc.iTerminal = us[STR_USB_OT].id;
+	io_out_ot_desc.iTerminal = us[STR_IO_OT].id;
+	std_as_out_if0_desc.iInterface = us[STR_AS_OUT_ALT0].id;
+	std_as_out_if1_desc.iInterface = us[STR_AS_OUT_ALT1].id;
+	std_as_in_if0_desc.iInterface = us[STR_AS_IN_ALT0].id;
+	std_as_in_if1_desc.iInterface = us[STR_AS_IN_ALT1].id;
+
+
+	/* Initialize the configurable parameters */
+	usb_out_it_desc.bNrChannels = num_channels(uac2_opts->c_chmask);
+	usb_out_it_desc.bmChannelConfig = cpu_to_le32(uac2_opts->c_chmask);
+	io_in_it_desc.bNrChannels = num_channels(uac2_opts->p_chmask);
+	io_in_it_desc.bmChannelConfig = cpu_to_le32(uac2_opts->p_chmask);
+	as_out_hdr_desc.bNrChannels = num_channels(uac2_opts->c_chmask);
+	as_out_hdr_desc.bmChannelConfig = cpu_to_le32(uac2_opts->c_chmask);
+	as_in_hdr_desc.bNrChannels = num_channels(uac2_opts->p_chmask);
+	as_in_hdr_desc.bmChannelConfig = cpu_to_le32(uac2_opts->p_chmask);
+	as_out_fmt1_desc.bSubslotSize = uac2_opts->c_ssize;
+	as_out_fmt1_desc.bBitResolution = uac2_opts->c_ssize * 8;
+	as_in_fmt1_desc.bSubslotSize = uac2_opts->p_ssize;
+	as_in_fmt1_desc.bBitResolution = uac2_opts->p_ssize * 8;
+
+	snprintf(clksrc_in, sizeof(clksrc_in), "%uHz", uac2_opts->p_srate);
+	snprintf(clksrc_out, sizeof(clksrc_out), "%uHz", uac2_opts->c_srate);
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+	iad_desc.bFirstInterface = ret;
+
+	std_ac_if_desc.bInterfaceNumber = ret;
+	uac2->ac_intf = ret;
+	uac2->ac_alt = 0;
+
+	if (EPOUT_EN(uac2_opts)) {
+		ret = usb_interface_id(cfg, fn);
+		if (ret < 0) {
+			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+			return ret;
+		}
+		std_as_out_if0_desc.bInterfaceNumber = ret;
+		std_as_out_if1_desc.bInterfaceNumber = ret;
+		uac2->as_out_intf = ret;
+		uac2->as_out_alt = 0;
+	}
+
+	if (EPIN_EN(uac2_opts)) {
+		ret = usb_interface_id(cfg, fn);
+		if (ret < 0) {
+			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+			return ret;
+		}
+		std_as_in_if0_desc.bInterfaceNumber = ret;
+		std_as_in_if1_desc.bInterfaceNumber = ret;
+		uac2->as_in_intf = ret;
+		uac2->as_in_alt = 0;
+	}
+
+	/* Calculate wMaxPacketSize according to audio bandwidth */
+	ret = set_ep_max_packet_size(uac2_opts, &fs_epin_desc, USB_SPEED_FULL,
+				     true);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &fs_epout_desc, USB_SPEED_FULL,
+				     false);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &hs_epin_desc, USB_SPEED_HIGH,
+				     true);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &hs_epout_desc, USB_SPEED_HIGH,
+				     false);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	if (EPOUT_EN(uac2_opts)) {
+		agdev->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);
+		if (!agdev->out_ep) {
+			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+			return -ENODEV;
+		}
+	}
+
+	if (EPIN_EN(uac2_opts)) {
+		agdev->in_ep = usb_ep_autoconfig(gadget, &fs_epin_desc);
+		if (!agdev->in_ep) {
+			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+			return -ENODEV;
+		}
+	}
+
+	agdev->in_ep_maxpsize = max_t(u16,
+				le16_to_cpu(fs_epin_desc.wMaxPacketSize),
+				le16_to_cpu(hs_epin_desc.wMaxPacketSize));
+	agdev->out_ep_maxpsize = max_t(u16,
+				le16_to_cpu(fs_epout_desc.wMaxPacketSize),
+				le16_to_cpu(hs_epout_desc.wMaxPacketSize));
+
+	hs_epout_desc.bEndpointAddress = fs_epout_desc.bEndpointAddress;
+	hs_epin_desc.bEndpointAddress = fs_epin_desc.bEndpointAddress;
+
+	setup_descriptor(uac2_opts);
+
+	ret = usb_assign_descriptors(fn, fs_audio_desc, hs_audio_desc, NULL,
+				     NULL);
+	if (ret)
+		return ret;
+
+	agdev->gadget = gadget;
+
+	agdev->params.p_chmask = uac2_opts->p_chmask;
+	agdev->params.p_srate = uac2_opts->p_srate;
+	agdev->params.p_ssize = uac2_opts->p_ssize;
+	agdev->params.c_chmask = uac2_opts->c_chmask;
+	agdev->params.c_srate = uac2_opts->c_srate;
+	agdev->params.c_ssize = uac2_opts->c_ssize;
+	agdev->params.req_number = uac2_opts->req_number;
+	ret = g_audio_setup(agdev, "UAC2 PCM", "UAC2_Gadget");
+	if (ret)
+		goto err_free_descs;
+	return 0;
+
+err_free_descs:
+	usb_free_all_descriptors(fn);
+	agdev->gadget = NULL;
+	return ret;
+}
+
+static int
+afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
+{
+	struct usb_composite_dev *cdev = fn->config->cdev;
+	struct f_uac2 *uac2 = func_to_uac2(fn);
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	int ret = 0;
+
+	/* No i/f has more than 2 alt settings */
+	if (alt > 1) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+
+	if (intf == uac2->ac_intf) {
+		/* Control I/f has only 1 AltSetting - 0 */
+		if (alt) {
+			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	if (intf == uac2->as_out_intf) {
+		uac2->as_out_alt = alt;
+
+		if (alt)
+			ret = u_audio_start_capture(&uac2->g_audio);
+		else
+			u_audio_stop_capture(&uac2->g_audio);
+	} else if (intf == uac2->as_in_intf) {
+		uac2->as_in_alt = alt;
+
+		if (alt)
+			ret = u_audio_start_playback(&uac2->g_audio);
+		else
+			u_audio_stop_playback(&uac2->g_audio);
+	} else {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int
+afunc_get_alt(struct usb_function *fn, unsigned intf)
+{
+	struct f_uac2 *uac2 = func_to_uac2(fn);
+	struct g_audio *agdev = func_to_g_audio(fn);
+
+	if (intf == uac2->ac_intf)
+		return uac2->ac_alt;
+	else if (intf == uac2->as_out_intf)
+		return uac2->as_out_alt;
+	else if (intf == uac2->as_in_intf)
+		return uac2->as_in_alt;
+	else
+		dev_err(&agdev->gadget->dev,
+			"%s:%d Invalid Interface %d!\n",
+			__func__, __LINE__, intf);
+
+	return -EINVAL;
+}
+
+static void
+afunc_disable(struct usb_function *fn)
+{
+	struct f_uac2 *uac2 = func_to_uac2(fn);
+
+	uac2->as_in_alt = 0;
+	uac2->as_out_alt = 0;
+	u_audio_stop_capture(&uac2->g_audio);
+	u_audio_stop_playback(&uac2->g_audio);
+}
+
+static int
+in_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_request *req = fn->config->cdev->req;
+	struct g_audio *agdev = func_to_g_audio(fn);
+	struct f_uac2_opts *opts;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u8 entity_id = (w_index >> 8) & 0xff;
+	u8 control_selector = w_value >> 8;
+	int value = -EOPNOTSUPP;
+	int p_srate, c_srate;
+
+	opts = g_audio_to_uac2_opts(agdev);
+	p_srate = opts->p_srate;
+	c_srate = opts->c_srate;
+
+	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+		struct cntrl_cur_lay3 c;
+		memset(&c, 0, sizeof(struct cntrl_cur_lay3));
+
+		if (entity_id == USB_IN_CLK_ID)
+			c.dCUR = cpu_to_le32(p_srate);
+		else if (entity_id == USB_OUT_CLK_ID)
+			c.dCUR = cpu_to_le32(c_srate);
+
+		value = min_t(unsigned, w_length, sizeof c);
+		memcpy(req->buf, &c, value);
+	} else if (control_selector == UAC2_CS_CONTROL_CLOCK_VALID) {
+		*(u8 *)req->buf = 1;
+		value = min_t(unsigned, w_length, 1);
+	} else {
+		dev_err(&agdev->gadget->dev,
+			"%s:%d control_selector=%d TODO!\n",
+			__func__, __LINE__, control_selector);
+	}
+
+	return value;
+}
+
+static int
+in_rq_range(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_request *req = fn->config->cdev->req;
+	struct g_audio *agdev = func_to_g_audio(fn);
+	struct f_uac2_opts *opts;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u8 entity_id = (w_index >> 8) & 0xff;
+	u8 control_selector = w_value >> 8;
+	struct cntrl_range_lay3 r;
+	int value = -EOPNOTSUPP;
+	int p_srate, c_srate;
+
+	opts = g_audio_to_uac2_opts(agdev);
+	p_srate = opts->p_srate;
+	c_srate = opts->c_srate;
+
+	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+		if (entity_id == USB_IN_CLK_ID)
+			r.dMIN = cpu_to_le32(p_srate);
+		else if (entity_id == USB_OUT_CLK_ID)
+			r.dMIN = cpu_to_le32(c_srate);
+		else
+			return -EOPNOTSUPP;
+
+		r.dMAX = r.dMIN;
+		r.dRES = 0;
+		r.wNumSubRanges = cpu_to_le16(1);
+
+		value = min_t(unsigned, w_length, sizeof r);
+		memcpy(req->buf, &r, value);
+	} else {
+		dev_err(&agdev->gadget->dev,
+			"%s:%d control_selector=%d TODO!\n",
+			__func__, __LINE__, control_selector);
+	}
+
+	return value;
+}
+
+static int
+ac_rq_in(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	if (cr->bRequest == UAC2_CS_CUR)
+		return in_rq_cur(fn, cr);
+	else if (cr->bRequest == UAC2_CS_RANGE)
+		return in_rq_range(fn, cr);
+	else
+		return -EOPNOTSUPP;
+}
+
+static int
+out_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	u16 w_length = le16_to_cpu(cr->wLength);
+	u16 w_value = le16_to_cpu(cr->wValue);
+	u8 control_selector = w_value >> 8;
+
+	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ)
+		return w_length;
+
+	return -EOPNOTSUPP;
+}
+
+static int
+setup_rq_inf(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct f_uac2 *uac2 = func_to_uac2(fn);
+	struct g_audio *agdev = func_to_g_audio(fn);
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u8 intf = w_index & 0xff;
+
+	if (intf != uac2->ac_intf) {
+		dev_err(&agdev->gadget->dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return -EOPNOTSUPP;
+	}
+
+	if (cr->bRequestType & USB_DIR_IN)
+		return ac_rq_in(fn, cr);
+	else if (cr->bRequest == UAC2_CS_CUR)
+		return out_rq_cur(fn, cr);
+
+	return -EOPNOTSUPP;
+}
+
+static int
+afunc_setup(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_composite_dev *cdev = fn->config->cdev;
+	struct g_audio *agdev = func_to_g_audio(fn);
+	struct usb_request *req = cdev->req;
+	u16 w_length = le16_to_cpu(cr->wLength);
+	int value = -EOPNOTSUPP;
+
+	/* Only Class specific requests are supposed to reach here */
+	if ((cr->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
+		return -EOPNOTSUPP;
+
+	if ((cr->bRequestType & USB_RECIP_MASK) == USB_RECIP_INTERFACE)
+		value = setup_rq_inf(fn, cr);
+	else
+		dev_err(&agdev->gadget->dev, "%s:%d Error!\n",
+				__func__, __LINE__);
+
+	if (value >= 0) {
+		req->length = value;
+		req->zero = value < w_length;
+		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0) {
+			dev_err(&agdev->gadget->dev,
+				"%s:%d Error!\n", __func__, __LINE__);
+			req->status = 0;
+		}
+	}
+
+	return value;
+}
+
+static inline struct f_uac2_opts *to_f_uac2_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_uac2_opts,
+			    func_inst.group);
+}
+
+static void f_uac2_attr_release(struct config_item *item)
+{
+	struct f_uac2_opts *opts = to_f_uac2_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations f_uac2_item_ops = {
+	.release	= f_uac2_attr_release,
+};
+
+#define UAC2_ATTRIBUTE(name)						\
+static ssize_t f_uac2_opts_##name##_show(struct config_item *item,	\
+					 char *page)			\
+{									\
+	struct f_uac2_opts *opts = to_f_uac2_opts(item);		\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%u\n", opts->name);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t f_uac2_opts_##name##_store(struct config_item *item,	\
+					  const char *page, size_t len)	\
+{									\
+	struct f_uac2_opts *opts = to_f_uac2_opts(item);		\
+	int ret;							\
+	u32 num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou32(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	opts->name = num;						\
+	ret = len;							\
+									\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+CONFIGFS_ATTR(f_uac2_opts_, name)
+
+UAC2_ATTRIBUTE(p_chmask);
+UAC2_ATTRIBUTE(p_srate);
+UAC2_ATTRIBUTE(p_ssize);
+UAC2_ATTRIBUTE(c_chmask);
+UAC2_ATTRIBUTE(c_srate);
+UAC2_ATTRIBUTE(c_ssize);
+UAC2_ATTRIBUTE(req_number);
+
+static struct configfs_attribute *f_uac2_attrs[] = {
+	&f_uac2_opts_attr_p_chmask,
+	&f_uac2_opts_attr_p_srate,
+	&f_uac2_opts_attr_p_ssize,
+	&f_uac2_opts_attr_c_chmask,
+	&f_uac2_opts_attr_c_srate,
+	&f_uac2_opts_attr_c_ssize,
+	&f_uac2_opts_attr_req_number,
+	NULL,
+};
+
+static const struct config_item_type f_uac2_func_type = {
+	.ct_item_ops	= &f_uac2_item_ops,
+	.ct_attrs	= f_uac2_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void afunc_free_inst(struct usb_function_instance *f)
+{
+	struct f_uac2_opts *opts;
+
+	opts = container_of(f, struct f_uac2_opts, func_inst);
+	kfree(opts);
+}
+
+static struct usb_function_instance *afunc_alloc_inst(void)
+{
+	struct f_uac2_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = afunc_free_inst;
+
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &f_uac2_func_type);
+
+	opts->p_chmask = UAC2_DEF_PCHMASK;
+	opts->p_srate = UAC2_DEF_PSRATE;
+	opts->p_ssize = UAC2_DEF_PSSIZE;
+	opts->c_chmask = UAC2_DEF_CCHMASK;
+	opts->c_srate = UAC2_DEF_CSRATE;
+	opts->c_ssize = UAC2_DEF_CSSIZE;
+	opts->req_number = UAC2_DEF_REQ_NUM;
+	return &opts->func_inst;
+}
+
+static void afunc_free(struct usb_function *f)
+{
+	struct g_audio *agdev;
+	struct f_uac2_opts *opts;
+
+	agdev = func_to_g_audio(f);
+	opts = container_of(f->fi, struct f_uac2_opts, func_inst);
+	kfree(agdev);
+	mutex_lock(&opts->lock);
+	--opts->refcnt;
+	mutex_unlock(&opts->lock);
+}
+
+static void afunc_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct g_audio *agdev = func_to_g_audio(f);
+
+	g_audio_cleanup(agdev);
+	usb_free_all_descriptors(f);
+
+	agdev->gadget = NULL;
+}
+
+static struct usb_function *afunc_alloc(struct usb_function_instance *fi)
+{
+	struct f_uac2	*uac2;
+	struct f_uac2_opts *opts;
+
+	uac2 = kzalloc(sizeof(*uac2), GFP_KERNEL);
+	if (uac2 == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_uac2_opts, func_inst);
+	mutex_lock(&opts->lock);
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
+
+	uac2->g_audio.func.name = "uac2_func";
+	uac2->g_audio.func.bind = afunc_bind;
+	uac2->g_audio.func.unbind = afunc_unbind;
+	uac2->g_audio.func.set_alt = afunc_set_alt;
+	uac2->g_audio.func.get_alt = afunc_get_alt;
+	uac2->g_audio.func.disable = afunc_disable;
+	uac2->g_audio.func.setup = afunc_setup;
+	uac2->g_audio.func.free_func = afunc_free;
+
+	return &uac2->g_audio.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(uac2, afunc_alloc_inst, afunc_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Yadwinder Singh");
+MODULE_AUTHOR("Jaswinder Singh");