usb: gadget: Gadget directory cleanup - group usb functions

The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the USB functions implementations into a separate directory.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 1354 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
new file mode 100644
index 000000000000..6261db4a9910
--- /dev/null
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -0,0 +1,1354 @@
+/*
+ * f_uac2.c -- USB Audio Class 2.0 Function
+ *
+ * Copyright (C) 2011
+ *    Yadwinder Singh (yadi.brar01@gmail.com)
+ *    Jaswinder Singh (jaswinder.singh@linaro.org)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+/* Playback(USB-IN) Default Stereo - Fl/Fr */
+static int p_chmask = 0x3;
+module_param(p_chmask, uint, S_IRUGO);
+MODULE_PARM_DESC(p_chmask, "Playback Channel Mask");
+
+/* Playback Default 48 KHz */
+static int p_srate = 48000;
+module_param(p_srate, uint, S_IRUGO);
+MODULE_PARM_DESC(p_srate, "Playback Sampling Rate");
+
+/* Playback Default 16bits/sample */
+static int p_ssize = 2;
+module_param(p_ssize, uint, S_IRUGO);
+MODULE_PARM_DESC(p_ssize, "Playback Sample Size(bytes)");
+
+/* Capture(USB-OUT) Default Stereo - Fl/Fr */
+static int c_chmask = 0x3;
+module_param(c_chmask, uint, S_IRUGO);
+MODULE_PARM_DESC(c_chmask, "Capture Channel Mask");
+
+/* Capture Default 64 KHz */
+static int c_srate = 64000;
+module_param(c_srate, uint, S_IRUGO);
+MODULE_PARM_DESC(c_srate, "Capture Sampling Rate");
+
+/* Capture Default 16bits/sample */
+static int c_ssize = 2;
+module_param(c_ssize, uint, S_IRUGO);
+MODULE_PARM_DESC(c_ssize, "Capture Sample Size(bytes)");
+
+/* Keep everyone on toes */
+#define USB_XFERS	2
+
+/*
+ * 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_IT_ID	1
+#define IO_IN_IT_ID	2
+#define IO_OUT_OT_ID	3
+#define USB_IN_OT_ID	4
+#define USB_OUT_CLK_ID	5
+#define USB_IN_CLK_ID	6
+
+#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
+
+const char *uac2_name = "snd_uac2";
+
+struct uac2_req {
+	struct uac2_rtd_params *pp; /* parent param */
+	struct usb_request *req;
+};
+
+struct uac2_rtd_params {
+	struct snd_uac2_chip *uac2; /* parent chip */
+	bool ep_enabled; /* if the ep is enabled */
+	/* Size of the ring buffer */
+	size_t dma_bytes;
+	unsigned char *dma_area;
+
+	struct snd_pcm_substream *ss;
+
+	/* Ring buffer */
+	ssize_t hw_ptr;
+
+	void *rbuf;
+
+	size_t period_size;
+
+	unsigned max_psize;
+	struct uac2_req ureq[USB_XFERS];
+
+	spinlock_t lock;
+};
+
+struct snd_uac2_chip {
+	struct platform_device pdev;
+	struct platform_driver pdrv;
+
+	struct uac2_rtd_params p_prm;
+	struct uac2_rtd_params c_prm;
+
+	struct snd_card *card;
+	struct snd_pcm *pcm;
+};
+
+#define BUFF_SIZE_MAX	(PAGE_SIZE * 16)
+#define PRD_SIZE_MAX	PAGE_SIZE
+#define MIN_PERIODS	4
+
+static struct snd_pcm_hardware uac2_pcm_hardware = {
+	.info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
+		 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
+		 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
+	.rates = SNDRV_PCM_RATE_CONTINUOUS,
+	.periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
+	.buffer_bytes_max = BUFF_SIZE_MAX,
+	.period_bytes_max = PRD_SIZE_MAX,
+	.periods_min = MIN_PERIODS,
+};
+
+struct audio_dev {
+	u8 ac_intf, ac_alt;
+	u8 as_out_intf, as_out_alt;
+	u8 as_in_intf, as_in_alt;
+
+	struct usb_ep *in_ep, *out_ep;
+	struct usb_function func;
+
+	/* The ALSA Sound Card it represents on the USB-Client side */
+	struct snd_uac2_chip uac2;
+};
+
+static struct audio_dev *agdev_g;
+
+static inline
+struct audio_dev *func_to_agdev(struct usb_function *f)
+{
+	return container_of(f, struct audio_dev, func);
+}
+
+static inline
+struct audio_dev *uac2_to_agdev(struct snd_uac2_chip *u)
+{
+	return container_of(u, struct audio_dev, uac2);
+}
+
+static inline
+struct snd_uac2_chip *pdev_to_uac2(struct platform_device *p)
+{
+	return container_of(p, struct snd_uac2_chip, pdev);
+}
+
+static inline
+uint num_channels(uint chanmask)
+{
+	uint num = 0;
+
+	while (chanmask) {
+		num += (chanmask & 1);
+		chanmask >>= 1;
+	}
+
+	return num;
+}
+
+static void
+agdev_iso_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	unsigned pending;
+	unsigned long flags;
+	bool update_alsa = false;
+	unsigned char *src, *dst;
+	int status = req->status;
+	struct uac2_req *ur = req->context;
+	struct snd_pcm_substream *substream;
+	struct uac2_rtd_params *prm = ur->pp;
+	struct snd_uac2_chip *uac2 = prm->uac2;
+
+	/* i/f shutting down */
+	if (!prm->ep_enabled || req->status == -ESHUTDOWN)
+		return;
+
+	/*
+	 * We can't really do much about bad xfers.
+	 * Afterall, the ISOCH xfers could fail legitimately.
+	 */
+	if (status)
+		pr_debug("%s: iso_complete status(%d) %d/%d\n",
+			__func__, status, req->actual, req->length);
+
+	substream = prm->ss;
+
+	/* Do nothing if ALSA isn't active */
+	if (!substream)
+		goto exit;
+
+	spin_lock_irqsave(&prm->lock, flags);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		src = prm->dma_area + prm->hw_ptr;
+		req->actual = req->length;
+		dst = req->buf;
+	} else {
+		dst = prm->dma_area + prm->hw_ptr;
+		src = req->buf;
+	}
+
+	pending = prm->hw_ptr % prm->period_size;
+	pending += req->actual;
+	if (pending >= prm->period_size)
+		update_alsa = true;
+
+	prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;
+
+	spin_unlock_irqrestore(&prm->lock, flags);
+
+	/* Pack USB load in ALSA ring buffer */
+	memcpy(dst, src, req->actual);
+exit:
+	if (usb_ep_queue(ep, req, GFP_ATOMIC))
+		dev_err(&uac2->pdev.dev, "%d Error!\n", __LINE__);
+
+	if (update_alsa)
+		snd_pcm_period_elapsed(substream);
+
+	return;
+}
+
+static int
+uac2_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
+	struct uac2_rtd_params *prm;
+	unsigned long flags;
+	int err = 0;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		prm = &uac2->p_prm;
+	else
+		prm = &uac2->c_prm;
+
+	spin_lock_irqsave(&prm->lock, flags);
+
+	/* Reset */
+	prm->hw_ptr = 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		prm->ss = substream;
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		prm->ss = NULL;
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	spin_unlock_irqrestore(&prm->lock, flags);
+
+	/* Clear buffer after Play stops */
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
+		memset(prm->rbuf, 0, prm->max_psize * USB_XFERS);
+
+	return err;
+}
+
+static snd_pcm_uframes_t uac2_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
+	struct uac2_rtd_params *prm;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		prm = &uac2->p_prm;
+	else
+		prm = &uac2->c_prm;
+
+	return bytes_to_frames(substream->runtime, prm->hw_ptr);
+}
+
+static int uac2_pcm_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *hw_params)
+{
+	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
+	struct uac2_rtd_params *prm;
+	int err;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		prm = &uac2->p_prm;
+	else
+		prm = &uac2->c_prm;
+
+	err = snd_pcm_lib_malloc_pages(substream,
+					params_buffer_bytes(hw_params));
+	if (err >= 0) {
+		prm->dma_bytes = substream->runtime->dma_bytes;
+		prm->dma_area = substream->runtime->dma_area;
+		prm->period_size = params_period_bytes(hw_params);
+	}
+
+	return err;
+}
+
+static int uac2_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
+	struct uac2_rtd_params *prm;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		prm = &uac2->p_prm;
+	else
+		prm = &uac2->c_prm;
+
+	prm->dma_area = NULL;
+	prm->dma_bytes = 0;
+	prm->period_size = 0;
+
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int uac2_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	runtime->hw = uac2_pcm_hardware;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		spin_lock_init(&uac2->p_prm.lock);
+		runtime->hw.rate_min = p_srate;
+		runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE; /* ! p_ssize ! */
+		runtime->hw.channels_min = num_channels(p_chmask);
+		runtime->hw.period_bytes_min = 2 * uac2->p_prm.max_psize
+						/ runtime->hw.periods_min;
+	} else {
+		spin_lock_init(&uac2->c_prm.lock);
+		runtime->hw.rate_min = c_srate;
+		runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE; /* ! c_ssize ! */
+		runtime->hw.channels_min = num_channels(c_chmask);
+		runtime->hw.period_bytes_min = 2 * uac2->c_prm.max_psize
+						/ runtime->hw.periods_min;
+	}
+
+	runtime->hw.rate_max = runtime->hw.rate_min;
+	runtime->hw.channels_max = runtime->hw.channels_min;
+
+	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+
+	return 0;
+}
+
+/* ALSA cries without these function pointers */
+static int uac2_pcm_null(struct snd_pcm_substream *substream)
+{
+	return 0;
+}
+
+static struct snd_pcm_ops uac2_pcm_ops = {
+	.open = uac2_pcm_open,
+	.close = uac2_pcm_null,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = uac2_pcm_hw_params,
+	.hw_free = uac2_pcm_hw_free,
+	.trigger = uac2_pcm_trigger,
+	.pointer = uac2_pcm_pointer,
+	.prepare = uac2_pcm_null,
+};
+
+static int snd_uac2_probe(struct platform_device *pdev)
+{
+	struct snd_uac2_chip *uac2 = pdev_to_uac2(pdev);
+	struct snd_card *card;
+	struct snd_pcm *pcm;
+	int err;
+
+	/* Choose any slot, with no id */
+	err = snd_card_new(&pdev->dev, -1, NULL, THIS_MODULE, 0, &card);
+	if (err < 0)
+		return err;
+
+	uac2->card = card;
+
+	/*
+	 * Create first PCM device
+	 * Create a substream only for non-zero channel streams
+	 */
+	err = snd_pcm_new(uac2->card, "UAC2 PCM", 0,
+			       p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
+	if (err < 0)
+		goto snd_fail;
+
+	strcpy(pcm->name, "UAC2 PCM");
+	pcm->private_data = uac2;
+
+	uac2->pcm = pcm;
+
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac2_pcm_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac2_pcm_ops);
+
+	strcpy(card->driver, "UAC2_Gadget");
+	strcpy(card->shortname, "UAC2_Gadget");
+	sprintf(card->longname, "UAC2_Gadget %i", pdev->id);
+
+	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+		snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
+
+	err = snd_card_register(card);
+	if (!err) {
+		platform_set_drvdata(pdev, card);
+		return 0;
+	}
+
+snd_fail:
+	snd_card_free(card);
+
+	uac2->pcm = NULL;
+	uac2->card = NULL;
+
+	return err;
+}
+
+static int snd_uac2_remove(struct platform_device *pdev)
+{
+	struct snd_card *card = platform_get_drvdata(pdev);
+
+	if (card)
+		return snd_card_free(card);
+
+	return 0;
+}
+
+static int alsa_uac2_init(struct audio_dev *agdev)
+{
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	int err;
+
+	uac2->pdrv.probe = snd_uac2_probe;
+	uac2->pdrv.remove = snd_uac2_remove;
+	uac2->pdrv.driver.name = uac2_name;
+
+	uac2->pdev.id = 0;
+	uac2->pdev.name = uac2_name;
+
+	/* Register snd_uac2 driver */
+	err = platform_driver_register(&uac2->pdrv);
+	if (err)
+		return err;
+
+	/* Register snd_uac2 device */
+	err = platform_device_register(&uac2->pdev);
+	if (err)
+		platform_driver_unregister(&uac2->pdrv);
+
+	return err;
+}
+
+static void alsa_uac2_exit(struct audio_dev *agdev)
+{
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+
+	platform_driver_unregister(&uac2->pdrv);
+	platform_device_unregister(&uac2->pdev);
+}
+
+
+/* --------- 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_qualifier_descriptor devqual_desc = {
+	.bLength = sizeof devqual_desc,
+	.bDescriptorType = USB_DT_DEVICE_QUALIFIER,
+
+	.bcdUSB = cpu_to_le16(0x200),
+	.bDeviceClass = USB_CLASS_MISC,
+	.bDeviceSubClass = 0x02,
+	.bDeviceProtocol = 0x01,
+	.bNumConfigurations = 1,
+	.bRESERVED = 0,
+};
+
+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 */
+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 = USB_IN_CLK_ID,
+	.bmAttributes = UAC_CLOCK_SOURCE_TYPE_INT_FIXED,
+	.bmControls = (CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bAssocTerminal = 0,
+};
+
+/* Clock source for OUT traffic */
+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 = USB_OUT_CLK_ID,
+	.bmAttributes = UAC_CLOCK_SOURCE_TYPE_INT_FIXED,
+	.bmControls = (CONTROL_RDONLY << CLK_FREQ_CTRL),
+	.bAssocTerminal = 0,
+};
+
+/* Input Terminal for USB_OUT */
+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 = USB_OUT_IT_ID,
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	.bCSourceID = USB_OUT_CLK_ID,
+	.iChannelNames = 0,
+	.bmControls = (CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Input Terminal for I/O-In */
+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 = IO_IN_IT_ID,
+	.wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_UNDEFINED),
+	.bAssocTerminal = 0,
+	.bCSourceID = USB_IN_CLK_ID,
+	.iChannelNames = 0,
+	.bmControls = (CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Ouput Terminal for USB_IN */
+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 = USB_IN_OT_ID,
+	.wTerminalType = cpu_to_le16(UAC_TERMINAL_STREAMING),
+	.bAssocTerminal = 0,
+	.bSourceID = IO_IN_IT_ID,
+	.bCSourceID = USB_IN_CLK_ID,
+	.bmControls = (CONTROL_RDWR << COPY_CTRL),
+};
+
+/* Ouput Terminal for I/O-Out */
+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 = IO_OUT_OT_ID,
+	.wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_UNDEFINED),
+	.bAssocTerminal = 0,
+	.bSourceID = USB_OUT_IT_ID,
+	.bCSourceID = USB_OUT_CLK_ID,
+	.bmControls = (CONTROL_RDWR << COPY_CTRL),
+};
+
+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 = sizeof in_clk_src_desc + sizeof out_clk_src_desc
+			 + sizeof usb_out_it_desc + sizeof io_in_it_desc
+			+ sizeof usb_in_ot_desc + sizeof io_out_ot_desc,
+	.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 */
+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 = USB_OUT_IT_ID,
+	.bmControls = 0,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+	.bmFormats = cpu_to_le32(UAC_FORMAT_TYPE_I_PCM),
+	.iChannelNames = 0,
+};
+
+/* Audio USB_OUT Format */
+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 */
+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,
+	.bInterval = 1,
+};
+
+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,
+	.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 */
+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 = USB_IN_OT_ID,
+	.bmControls = 0,
+	.bFormatType = UAC_FORMAT_TYPE_I,
+	.bmFormats = cpu_to_le32(UAC_FORMAT_TYPE_I_PCM),
+	.iChannelNames = 0,
+};
+
+/* Audio USB_IN Format */
+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 */
+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,
+	.bInterval = 1,
+};
+
+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,
+	.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 {
+	__u32	dCUR;
+};
+
+struct cntrl_range_lay3 {
+	__u16	wNumSubRanges;
+	__u32	dMIN;
+	__u32	dMAX;
+	__u32	dRES;
+} __packed;
+
+static inline void
+free_ep(struct uac2_rtd_params *prm, struct usb_ep *ep)
+{
+	struct snd_uac2_chip *uac2 = prm->uac2;
+	int i;
+
+	prm->ep_enabled = false;
+
+	for (i = 0; i < USB_XFERS; i++) {
+		if (prm->ureq[i].req) {
+			usb_ep_dequeue(ep, prm->ureq[i].req);
+			usb_ep_free_request(ep, prm->ureq[i].req);
+			prm->ureq[i].req = NULL;
+		}
+	}
+
+	if (usb_ep_disable(ep))
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+}
+
+static int __init
+afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
+{
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	struct usb_composite_dev *cdev = cfg->cdev;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct uac2_rtd_params *prm;
+	int ret;
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+	std_ac_if_desc.bInterfaceNumber = ret;
+	agdev->ac_intf = ret;
+	agdev->ac_alt = 0;
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+	std_as_out_if0_desc.bInterfaceNumber = ret;
+	std_as_out_if1_desc.bInterfaceNumber = ret;
+	agdev->as_out_intf = ret;
+	agdev->as_out_alt = 0;
+
+	ret = usb_interface_id(cfg, fn);
+	if (ret < 0) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+	std_as_in_if0_desc.bInterfaceNumber = ret;
+	std_as_in_if1_desc.bInterfaceNumber = ret;
+	agdev->as_in_intf = ret;
+	agdev->as_in_alt = 0;
+
+	agdev->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);
+	if (!agdev->out_ep) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		goto err;
+	}
+	agdev->out_ep->driver_data = agdev;
+
+	agdev->in_ep = usb_ep_autoconfig(gadget, &fs_epin_desc);
+	if (!agdev->in_ep) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		goto err;
+	}
+	agdev->in_ep->driver_data = agdev;
+
+	uac2->p_prm.uac2 = uac2;
+	uac2->c_prm.uac2 = uac2;
+
+	hs_epout_desc.bEndpointAddress = fs_epout_desc.bEndpointAddress;
+	hs_epout_desc.wMaxPacketSize = fs_epout_desc.wMaxPacketSize;
+	hs_epin_desc.bEndpointAddress = fs_epin_desc.bEndpointAddress;
+	hs_epin_desc.wMaxPacketSize = fs_epin_desc.wMaxPacketSize;
+
+	ret = usb_assign_descriptors(fn, fs_audio_desc, hs_audio_desc, NULL);
+	if (ret)
+		goto err;
+
+	prm = &agdev->uac2.c_prm;
+	prm->max_psize = hs_epout_desc.wMaxPacketSize;
+	prm->rbuf = kzalloc(prm->max_psize * USB_XFERS, GFP_KERNEL);
+	if (!prm->rbuf) {
+		prm->max_psize = 0;
+		goto err;
+	}
+
+	prm = &agdev->uac2.p_prm;
+	prm->max_psize = hs_epin_desc.wMaxPacketSize;
+	prm->rbuf = kzalloc(prm->max_psize * USB_XFERS, GFP_KERNEL);
+	if (!prm->rbuf) {
+		prm->max_psize = 0;
+		goto err;
+	}
+
+	ret = alsa_uac2_init(agdev);
+	if (ret)
+		goto err;
+	return 0;
+err:
+	kfree(agdev->uac2.p_prm.rbuf);
+	kfree(agdev->uac2.c_prm.rbuf);
+	usb_free_all_descriptors(fn);
+	if (agdev->in_ep)
+		agdev->in_ep->driver_data = NULL;
+	if (agdev->out_ep)
+		agdev->out_ep->driver_data = NULL;
+	return -EINVAL;
+}
+
+static void
+afunc_unbind(struct usb_configuration *cfg, struct usb_function *fn)
+{
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct uac2_rtd_params *prm;
+
+	alsa_uac2_exit(agdev);
+
+	prm = &agdev->uac2.p_prm;
+	kfree(prm->rbuf);
+
+	prm = &agdev->uac2.c_prm;
+	kfree(prm->rbuf);
+	usb_free_all_descriptors(fn);
+
+	if (agdev->in_ep)
+		agdev->in_ep->driver_data = NULL;
+	if (agdev->out_ep)
+		agdev->out_ep->driver_data = NULL;
+}
+
+static int
+afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
+{
+	struct usb_composite_dev *cdev = fn->config->cdev;
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct usb_request *req;
+	struct usb_ep *ep;
+	struct uac2_rtd_params *prm;
+	int i;
+
+	/* No i/f has more than 2 alt settings */
+	if (alt > 1) {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+
+	if (intf == agdev->ac_intf) {
+		/* Control I/f has only 1 AltSetting - 0 */
+		if (alt) {
+			dev_err(&uac2->pdev.dev,
+				"%s:%d Error!\n", __func__, __LINE__);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	if (intf == agdev->as_out_intf) {
+		ep = agdev->out_ep;
+		prm = &uac2->c_prm;
+		config_ep_by_speed(gadget, fn, ep);
+		agdev->as_out_alt = alt;
+	} else if (intf == agdev->as_in_intf) {
+		ep = agdev->in_ep;
+		prm = &uac2->p_prm;
+		config_ep_by_speed(gadget, fn, ep);
+		agdev->as_in_alt = alt;
+	} else {
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Error!\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+
+	if (alt == 0) {
+		free_ep(prm, ep);
+		return 0;
+	}
+
+	prm->ep_enabled = true;
+	usb_ep_enable(ep);
+
+	for (i = 0; i < USB_XFERS; i++) {
+		if (prm->ureq[i].req) {
+			if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
+				dev_err(&uac2->pdev.dev, "%d Error!\n",
+					__LINE__);
+			continue;
+		}
+
+		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
+		if (req == NULL) {
+			dev_err(&uac2->pdev.dev,
+				"%s:%d Error!\n", __func__, __LINE__);
+			return -EINVAL;
+		}
+
+		prm->ureq[i].req = req;
+		prm->ureq[i].pp = prm;
+
+		req->zero = 0;
+		req->context = &prm->ureq[i];
+		req->length = prm->max_psize;
+		req->complete =	agdev_iso_complete;
+		req->buf = prm->rbuf + i * req->length;
+
+		if (usb_ep_queue(ep, req, GFP_ATOMIC))
+			dev_err(&uac2->pdev.dev, "%d Error!\n", __LINE__);
+	}
+
+	return 0;
+}
+
+static int
+afunc_get_alt(struct usb_function *fn, unsigned intf)
+{
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+
+	if (intf == agdev->ac_intf)
+		return agdev->ac_alt;
+	else if (intf == agdev->as_out_intf)
+		return agdev->as_out_alt;
+	else if (intf == agdev->as_in_intf)
+		return agdev->as_in_alt;
+	else
+		dev_err(&uac2->pdev.dev,
+			"%s:%d Invalid Interface %d!\n",
+			__func__, __LINE__, intf);
+
+	return -EINVAL;
+}
+
+static void
+afunc_disable(struct usb_function *fn)
+{
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+
+	free_ep(&uac2->p_prm, agdev->in_ep);
+	agdev->as_in_alt = 0;
+
+	free_ep(&uac2->c_prm, agdev->out_ep);
+	agdev->as_out_alt = 0;
+}
+
+static int
+in_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
+{
+	struct usb_request *req = fn->config->cdev->req;
+	struct audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	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;
+
+	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+		struct cntrl_cur_lay3 c;
+
+		if (entity_id == USB_IN_CLK_ID)
+			c.dCUR = p_srate;
+		else if (entity_id == USB_OUT_CLK_ID)
+			c.dCUR = 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(&uac2->pdev.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 audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	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;
+
+	if (control_selector == UAC2_CS_CONTROL_SAM_FREQ) {
+		if (entity_id == USB_IN_CLK_ID)
+			r.dMIN = p_srate;
+		else if (entity_id == USB_OUT_CLK_ID)
+			r.dMIN = c_srate;
+		else
+			return -EOPNOTSUPP;
+
+		r.dMAX = r.dMIN;
+		r.dRES = 0;
+		r.wNumSubRanges = 1;
+
+		value = min_t(unsigned, w_length, sizeof r);
+		memcpy(req->buf, &r, value);
+	} else {
+		dev_err(&uac2->pdev.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 audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	u16 w_index = le16_to_cpu(cr->wIndex);
+	u8 intf = w_index & 0xff;
+
+	if (intf != agdev->ac_intf) {
+		dev_err(&uac2->pdev.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 audio_dev *agdev = func_to_agdev(fn);
+	struct snd_uac2_chip *uac2 = &agdev->uac2;
+	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(&uac2->pdev.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(&uac2->pdev.dev,
+				"%s:%d Error!\n", __func__, __LINE__);
+			req->status = 0;
+		}
+	}
+
+	return value;
+}
+
+static int audio_bind_config(struct usb_configuration *cfg)
+{
+	int res;
+
+	agdev_g = kzalloc(sizeof *agdev_g, GFP_KERNEL);
+	if (agdev_g == NULL)
+		return -ENOMEM;
+
+	res = usb_string_ids_tab(cfg->cdev, strings_fn);
+	if (res)
+		return res;
+	iad_desc.iFunction = strings_fn[STR_ASSOC].id;
+	std_ac_if_desc.iInterface = strings_fn[STR_IF_CTRL].id;
+	in_clk_src_desc.iClockSource = strings_fn[STR_CLKSRC_IN].id;
+	out_clk_src_desc.iClockSource = strings_fn[STR_CLKSRC_OUT].id;
+	usb_out_it_desc.iTerminal = strings_fn[STR_USB_IT].id;
+	io_in_it_desc.iTerminal = strings_fn[STR_IO_IT].id;
+	usb_in_ot_desc.iTerminal = strings_fn[STR_USB_OT].id;
+	io_out_ot_desc.iTerminal = strings_fn[STR_IO_OT].id;
+	std_as_out_if0_desc.iInterface = strings_fn[STR_AS_OUT_ALT0].id;
+	std_as_out_if1_desc.iInterface = strings_fn[STR_AS_OUT_ALT1].id;
+	std_as_in_if0_desc.iInterface = strings_fn[STR_AS_IN_ALT0].id;
+	std_as_in_if1_desc.iInterface = strings_fn[STR_AS_IN_ALT1].id;
+
+	agdev_g->func.name = "uac2_func";
+	agdev_g->func.strings = fn_strings;
+	agdev_g->func.bind = afunc_bind;
+	agdev_g->func.unbind = afunc_unbind;
+	agdev_g->func.set_alt = afunc_set_alt;
+	agdev_g->func.get_alt = afunc_get_alt;
+	agdev_g->func.disable = afunc_disable;
+	agdev_g->func.setup = afunc_setup;
+
+	/* Initialize the configurable parameters */
+	usb_out_it_desc.bNrChannels = num_channels(c_chmask);
+	usb_out_it_desc.bmChannelConfig = cpu_to_le32(c_chmask);
+	io_in_it_desc.bNrChannels = num_channels(p_chmask);
+	io_in_it_desc.bmChannelConfig = cpu_to_le32(p_chmask);
+	as_out_hdr_desc.bNrChannels = num_channels(c_chmask);
+	as_out_hdr_desc.bmChannelConfig = cpu_to_le32(c_chmask);
+	as_in_hdr_desc.bNrChannels = num_channels(p_chmask);
+	as_in_hdr_desc.bmChannelConfig = cpu_to_le32(p_chmask);
+	as_out_fmt1_desc.bSubslotSize = c_ssize;
+	as_out_fmt1_desc.bBitResolution = c_ssize * 8;
+	as_in_fmt1_desc.bSubslotSize = p_ssize;
+	as_in_fmt1_desc.bBitResolution = p_ssize * 8;
+
+	snprintf(clksrc_in, sizeof(clksrc_in), "%uHz", p_srate);
+	snprintf(clksrc_out, sizeof(clksrc_out), "%uHz", c_srate);
+
+	res = usb_add_function(cfg, &agdev_g->func);
+	if (res < 0)
+		kfree(agdev_g);
+
+	return res;
+}
+
+static void
+uac2_unbind_config(struct usb_configuration *cfg)
+{
+	kfree(agdev_g);
+	agdev_g = NULL;
+}