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[PATCH v2 0/3] USB Audio Gadget refactoring

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  [PATCH v2 0/3] USB Audio Gadget refactoring Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2016-08-14 12:10 +0200
    [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new u_audio api Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2016-08-14 12:40 +0200
      Re: [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new  u_audio api Peter Chen <hzpeterchen@gmail.com> - 2016-08-16 05:10 +0200
        Re: [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new  u_audio api Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2016-08-16 22:40 +0200
    [PATCH v2 1/3] usb: gadget: f_uac2: remove platform driver/device creation Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2016-08-14 13:00 +0200
    Re: [PATCH v2 0/3] USB Audio Gadget refactoring Peter Chen <hzpeterchen@gmail.com> - 2016-08-16 11:30 +0200
      Re: [PATCH v2 0/3] USB Audio Gadget refactoring Clemens Ladisch <clemens@ladisch.de> - 2016-08-16 11:40 +0200
        Re: [PATCH v2 0/3] USB Audio Gadget refactoring Peter Chen <hzpeterchen@gmail.com> - 2016-08-16 12:00 +0200
          Re: [PATCH v2 0/3] USB Audio Gadget refactoring Clemens Ladisch <clemens@ladisch.de> - 2016-08-16 12:20 +0200
      Re: [PATCH v2 0/3] USB Audio Gadget refactoring Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2016-08-16 22:50 +0200

#1461763 — [PATCH v2 0/3] USB Audio Gadget refactoring

I came to this patch series when wanted to do two things:
 - use UAC1 as virtual ALSA sound card on gadget side,
   just like UAC2 is used so it's possible to do rate
   resampling
 - have both playback/capture support in UAC1

Since I wanted to have same behavior for both UAC1/UAC2,
obviously I've got an utility part (u_audio.c) for
virtual ALSA sound card handling like we have
for ethernet(u_ether) or serial(u_serial) functions.
Function-specific parts (f_uac1/f_uac2) became almost 
as storage for class-specific USB descriptors, some
boilerplate for configfs, binding and few USB
config request handling.

Originally in RFC [1] I've posted before, there was
major change to f_uac1 after that it couldn't do
direct play to existing ALSA sound card anymore,
representing audio on gadget side as virtual
ALSA sound card where audio streams are simply
sinked to and sourced from it, so it may break
current usecase for some people (and that's why
it was RFC).

During RFC discussion, it was agreed to not touch
existing f_uac1 implementation and create new one
instead. This patchset (v2) introduced new function
named f_uac1_newapi and doesn't touch current f_uac1
implementation, so people still can use old behavior

Now, it's possible to use existing user-space
applications for audio routing between Audio Gadget
and real sound card. I personally use alsaloop tool
from alsautils and have ability to create PCM
loopback between two different ALSA cards using
rate resampling, which was not possible with previous
"direct play to ALSA card" approach in f_uac1. 

While here, also dropped redundant platform
driver/device creation in f_uac2 driver (as well as
didn't add "never implemented" volume/mute functionality
in f_uac1 to f_uac1_newapi) that made this work even
easier to do.

This series is tested with both legacy g_audio.ko and
modern configfs approaches under Ubuntu 14.04 (UAC1 and
UAC2) and under Windows7 x64 (UAC1 only) having
perfect results in all cases.

Comments, testing are welcome.

v2 changes:
 - do not touch f_uac1, instead created f_uac1_newapi
 - added documentation for f_uac1_newapi
 - rebased on top of v4.8-rc1

[1] https://lkml.org/lkml/2016/5/23/649

Ruslan Bilovol (3):
  usb: gadget: f_uac2: remove platform driver/device creation
  usb: gadget: f_uac2: split out audio core
  usb: gadget: add f_uac1 variant based on new u_audio api

 .../ABI/testing/configfs-usb-gadget-uac1_newapi    |  12 +
 Documentation/usb/gadget-testing.txt               |  41 ++
 drivers/usb/gadget/Kconfig                         |  25 +
 drivers/usb/gadget/function/Makefile               |   3 +
 drivers/usb/gadget/function/f_uac1_newapi.c        | 795 +++++++++++++++++++++
 drivers/usb/gadget/function/f_uac2.c               | 778 +++-----------------
 drivers/usb/gadget/function/u_audio.c              | 632 ++++++++++++++++
 drivers/usb/gadget/function/u_audio.h              |  93 +++
 drivers/usb/gadget/function/u_uac1_newapi.h        |  39 +
 drivers/usb/gadget/legacy/Kconfig                  |  14 +-
 drivers/usb/gadget/legacy/audio.c                  |  56 +-
 11 files changed, 1803 insertions(+), 685 deletions(-)
 create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
 create mode 100644 drivers/usb/gadget/function/f_uac1_newapi.c
 create mode 100644 drivers/usb/gadget/function/u_audio.c
 create mode 100644 drivers/usb/gadget/function/u_audio.h
 create mode 100644 drivers/usb/gadget/function/u_uac1_newapi.h

-- 
1.9.1

[toc] | [next] | [standalone]

#1461778 — [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new u_audio api

This patch adds new function f_uac1_newapi that
uses recently created u_audio api. This makes
f_uac1_newapi implementation much simpler by
reusing existing u_audio core utilities.

This also drops previous f_uac1 approach (write
audio samples directly to existing ALSA sound
card) and moves to more generic/flexible
one - create an f_uac1 ALSA sound card that
represents USB Audio function and allows to
be used by userspace tools.

f_uac1_newapi also has capture support (gadget->host).
By default, capture interface has 48000kHz/2ch
configuration, same as playback channel has.

f_uac1_newapi descriptors naming conventios
uses f_uac2 driver naming convention that
makes it more common and meaningful.

Comparing to f_uac1, the f_uac1_newapi doesn't
have volume/mute functionality. This is because
the volume/mute feature unit was dummy
implementation since that driver creation (2009)
and never had real volume control or mute
functionality.

g_audio can be built using one of existing
uac functions (f_uac1, f_uac1_newapi or f_uac2)

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 .../ABI/testing/configfs-usb-gadget-uac1_newapi    |  12 +
 Documentation/usb/gadget-testing.txt               |  41 ++
 drivers/usb/gadget/Kconfig                         |  21 +
 drivers/usb/gadget/function/Makefile               |   2 +
 drivers/usb/gadget/function/f_uac1_newapi.c        | 795 +++++++++++++++++++++
 drivers/usb/gadget/function/u_uac1_newapi.h        |  39 +
 drivers/usb/gadget/legacy/Kconfig                  |  15 +-
 drivers/usb/gadget/legacy/audio.c                  |  52 ++
 8 files changed, 975 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
 create mode 100644 drivers/usb/gadget/function/f_uac1_newapi.c
 create mode 100644 drivers/usb/gadget/function/u_uac1_newapi.h

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
new file mode 100644
index 0000000..d355275
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
@@ -0,0 +1,12 @@
+What:		/config/usb-gadget/gadget/functions/uac1_newapi.name
+Date:		Aug 2016
+KernelVersion:	4.9
+Description:
+		The attributes:
+
+		c_chmask - capture channel mask
+		c_srate - capture sampling rate
+		c_ssize - capture sample size (bytes)
+		p_chmask - playback channel mask
+		p_srate - playback sampling rate
+		p_ssize - playback sample size (bytes)
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
index 5819605..4598d7f 100644
--- a/Documentation/usb/gadget-testing.txt
+++ b/Documentation/usb/gadget-testing.txt
@@ -20,6 +20,7 @@ provided by gadgets.
 17. UAC2 function
 18. UVC function
 19. PRINTER function
+20. UAC1 function (new API)
 
 
 1. ACM function
@@ -770,3 +771,43 @@ host:
 
 More advanced testing can be done with the prn_example
 described in Documentation/usb/gadget-printer.txt.
+
+
+20. UAC1 function (new API, using u_audio)
+=================
+
+The function is provided by usb_f_uac1_newapi.ko module.
+
+Function-specific configfs interface
+------------------------------------
+
+The function name to use when creating the function directory
+is "uac1_newapi". The uac1_newapi function provides these attributes
+in its function directory:
+
+	c_chmask - capture channel mask
+	c_srate - capture sampling rate
+	c_ssize - capture sample size (bytes)
+	p_chmask - playback channel mask
+	p_srate - playback sampling rate
+	p_ssize - playback sample size (bytes)
+
+The attributes have sane default values.
+
+Testing the UAC1 function
+-------------------------
+
+device: run the gadget
+host: aplay -l # should list our USB Audio Gadget
+
+This function does not require real hardware support, it just
+sends a stream of audio data to/from the host. In order to
+actually hear something at the device side, a command similar
+to this must be used at the device side:
+
+$ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 &
+
+e.g.:
+
+$ arecord -f dat -t wav -D hw:CARD=UAC1Gadget,DEV=0 | \
+aplay -D default:CARD=OdroidU3
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index a25afd8..abcb539 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -194,6 +194,9 @@ config USB_F_FS
 config USB_F_UAC1
 	tristate
 
+config USB_F_UAC1_NEWAPI
+	tristate
+
 config USB_F_UAC2
 	tristate
 
@@ -397,6 +400,24 @@ config USB_CONFIGFS_F_UAC1
 	  This driver requires a real Audio codec to be present
 	  on the device.
 
+config USB_CONFIGFS_F_UAC1_NEWAPI
+	bool "Audio Class 1.0 (new API)"
+	depends on USB_CONFIGFS
+	depends on SND
+	select USB_LIBCOMPOSITE
+	select SND_PCM
+	select USB_U_AUDIO
+	select USB_F_UAC1_NEWAPI
+	help
+	  This Audio function implements 1 AudioControl interface,
+	  1 AudioStreaming Interface each for USB-OUT and USB-IN.
+	  This driver doesn't expect any real Audio codec to be present
+	  on the device - the audio streams are simply sinked to and
+	  sourced from a virtual ALSA sound card created. The user-space
+	  application may choose to do whatever it wants with the data
+	  received from the USB Host and choose to provide whatever it
+	  wants as audio data to the USB Host.
+
 config USB_CONFIGFS_F_UAC2
 	bool "Audio Class 2.0"
 	depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
index b29f2ae..eeef5f8 100644
--- a/drivers/usb/gadget/function/Makefile
+++ b/drivers/usb/gadget/function/Makefile
@@ -35,6 +35,8 @@ obj-$(CONFIG_USB_F_FS)		+= usb_f_fs.o
 obj-$(CONFIG_USB_U_AUDIO)	+= u_audio.o
 usb_f_uac1-y			:= f_uac1.o u_uac1.o
 obj-$(CONFIG_USB_F_UAC1)	+= usb_f_uac1.o
+usb_f_uac1_newapi-y		:= f_uac1_newapi.o
+obj-$(CONFIG_USB_F_UAC1_NEWAPI)	+= usb_f_uac1_newapi.o
 usb_f_uac2-y			:= f_uac2.o
 obj-$(CONFIG_USB_F_UAC2)	+= usb_f_uac2.o
 usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o uvc_configfs.o
diff --git a/drivers/usb/gadget/function/f_uac1_newapi.c b/drivers/usb/gadget/function/f_uac1_newapi.c
new file mode 100644
index 0000000..e628fe5
--- /dev/null
+++ b/drivers/usb/gadget/function/f_uac1_newapi.c
@@ -0,0 +1,795 @@
+/*
+ * f_uac1_newapi.c -- USB Audio Class 1.0 Function (using new u_audio API)
+ *
+ * Copyright (C) 2016 Ruslan Bilovol <ruslan.bilovol@gmail.com>
+ *
+ * This file is based on f_uac1.c which is
+ *   Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
+ *   Copyright (C) 2008 Analog Devices, Inc
+ *
+ * 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/module.h>
+
+#include "u_audio.h"
+#include "u_uac1_newapi.h"
+
+struct f_uac1 {
+	struct gaudio gaudio;
+	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_uac1 *func_to_uac1(struct usb_function *f)
+{
+	return container_of(f, struct f_uac1, gaudio.func);
+}
+
+/*
+ * DESCRIPTORS ... most are static, but strings and full
+ * configuration descriptors are built on demand.
+ */
+
+/*
+ * We have three interfaces - one AudioControl and two AudioStreaming
+ *
+ * The driver implements a simple UAC_1 topology.
+ * USB-OUT -> IT_1 -> OT_2 -> ALSA_Capture
+ * ALSA_Playback -> IT_3 -> OT_4 -> USB-IN
+ */
+#define F_AUDIO_AC_INTERFACE		0
+#define F_AUDIO_AS_OUT_INTERFACE	1
+#define F_AUDIO_AS_IN_INTERFACE		2
+/* Number of streaming interfaces */
+#define F_AUDIO_NUM_INTERFACES		2
+
+/* B.3.1  Standard AC Interface Descriptor */
+static struct usb_interface_descriptor ac_interface_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bNumEndpoints =	0,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
+};
+
+/*
+ * The number of AudioStreaming and MIDIStreaming interfaces
+ * in the Audio Interface Collection
+ */
+DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);
+
+#define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
+/* 2 input terminals and 2 output terminals */
+#define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH \
+	+ 2*UAC_DT_INPUT_TERMINAL_SIZE + 2*UAC_DT_OUTPUT_TERMINAL_SIZE)
+/* B.3.2  Class-Specific AC Interface Descriptor */
+static struct uac1_ac_header_descriptor_2 ac_header_desc = {
+	.bLength =		UAC_DT_AC_HEADER_LENGTH,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_HEADER,
+	.bcdADC =		cpu_to_le16(0x0100),
+	.wTotalLength =		cpu_to_le16(UAC_DT_TOTAL_LENGTH),
+	.bInCollection =	F_AUDIO_NUM_INTERFACES,
+	.baInterfaceNr = {
+	/* Interface number of the AudioStream interfaces */
+		[0] =		1,
+		[1] =		2,
+	}
+};
+
+#define USB_OUT_IT_ID	1
+static struct uac_input_terminal_descriptor usb_out_it_desc = {
+	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
+	.bTerminalID =		USB_OUT_IT_ID,
+	.wTerminalType =	UAC_TERMINAL_STREAMING,
+	.bAssocTerminal =	0,
+	.wChannelConfig =	0x3,
+};
+
+#define IO_OUT_OT_ID	2
+static struct uac1_output_terminal_descriptor io_out_ot_desc = {
+	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
+	.bDescriptorType	= USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
+	.bTerminalID		= IO_OUT_OT_ID,
+	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
+	.bAssocTerminal		= 0,
+	.bSourceID		= USB_OUT_IT_ID,
+};
+
+#define IO_IN_IT_ID	3
+static struct uac_input_terminal_descriptor io_in_it_desc = {
+	.bLength		= UAC_DT_INPUT_TERMINAL_SIZE,
+	.bDescriptorType	= USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype	= UAC_INPUT_TERMINAL,
+	.bTerminalID		= IO_IN_IT_ID,
+	.wTerminalType		= UAC_INPUT_TERMINAL_MICROPHONE,
+	.bAssocTerminal		= 0,
+	.wChannelConfig		= 0x3,
+};
+
+#define USB_IN_OT_ID	4
+static struct uac1_output_terminal_descriptor usb_in_ot_desc = {
+	.bLength =		UAC_DT_OUTPUT_TERMINAL_SIZE,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_OUTPUT_TERMINAL,
+	.bTerminalID =		USB_IN_OT_ID,
+	.wTerminalType =	UAC_TERMINAL_STREAMING,
+	.bAssocTerminal =	0,
+	.bSourceID =		IO_IN_IT_ID,
+};
+
+/* B.4.1  Standard AS Interface Descriptor */
+static struct usb_interface_descriptor as_out_interface_alt_0_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bAlternateSetting =	0,
+	.bNumEndpoints =	0,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
+};
+
+static struct usb_interface_descriptor as_out_interface_alt_1_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bAlternateSetting =	1,
+	.bNumEndpoints =	1,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
+};
+
+static struct usb_interface_descriptor as_in_interface_alt_0_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bAlternateSetting =	0,
+	.bNumEndpoints =	0,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
+};
+
+static struct usb_interface_descriptor as_in_interface_alt_1_desc = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bAlternateSetting =	1,
+	.bNumEndpoints =	1,
+	.bInterfaceClass =	USB_CLASS_AUDIO,
+	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
+};
+
+/* B.4.2  Class-Specific AS Interface Descriptor */
+static struct uac1_as_header_descriptor as_out_header_desc = {
+	.bLength =		UAC_DT_AS_HEADER_SIZE,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_AS_GENERAL,
+	.bTerminalLink =	USB_OUT_IT_ID,
+	.bDelay =		1,
+	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
+};
+
+static struct uac1_as_header_descriptor as_in_header_desc = {
+	.bLength =		UAC_DT_AS_HEADER_SIZE,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_AS_GENERAL,
+	.bTerminalLink =	USB_IN_OT_ID,
+	.bDelay =		1,
+	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
+};
+
+DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
+
+static struct uac_format_type_i_discrete_descriptor_1 as_out_type_i_desc = {
+	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
+	.bFormatType =		UAC_FORMAT_TYPE_I,
+	.bSubframeSize =	2,
+	.bBitResolution =	16,
+	.bSamFreqType =		1,
+};
+
+/* Standard ISO OUT Endpoint Descriptor */
+static struct usb_endpoint_descriptor as_out_ep_desc  = {
+	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
+				| USB_ENDPOINT_XFER_ISOC,
+	.wMaxPacketSize	=	cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+	.bInterval =		4,
+};
+
+/* Class-specific AS ISO OUT Endpoint Descriptor */
+static struct uac_iso_endpoint_descriptor as_iso_out_desc = {
+	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
+	.bDescriptorType =	USB_DT_CS_ENDPOINT,
+	.bDescriptorSubtype =	UAC_EP_GENERAL,
+	.bmAttributes =		1,
+	.bLockDelayUnits =	1,
+	.wLockDelay =		cpu_to_le16(1),
+};
+
+static struct uac_format_type_i_discrete_descriptor_1 as_in_type_i_desc = {
+	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
+	.bFormatType =		UAC_FORMAT_TYPE_I,
+	.bSubframeSize =	2,
+	.bBitResolution =	16,
+	.bSamFreqType =		1,
+};
+
+/* Standard ISO OUT Endpoint Descriptor */
+static struct usb_endpoint_descriptor as_in_ep_desc  = {
+	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_SYNC_ASYNC
+				| USB_ENDPOINT_XFER_ISOC,
+	.wMaxPacketSize	=	cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+	.bInterval =		4,
+};
+
+/* Class-specific AS ISO OUT Endpoint Descriptor */
+static struct uac_iso_endpoint_descriptor as_iso_in_desc = {
+	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
+	.bDescriptorType =	USB_DT_CS_ENDPOINT,
+	.bDescriptorSubtype =	UAC_EP_GENERAL,
+	.bmAttributes =		1,
+	.bLockDelayUnits =	0,
+	.wLockDelay =		0,
+};
+
+static struct usb_descriptor_header *f_audio_desc[] = {
+	(struct usb_descriptor_header *)&ac_interface_desc,
+	(struct usb_descriptor_header *)&ac_header_desc,
+
+	(struct usb_descriptor_header *)&usb_out_it_desc,
+	(struct usb_descriptor_header *)&io_out_ot_desc,
+	(struct usb_descriptor_header *)&io_in_it_desc,
+	(struct usb_descriptor_header *)&usb_in_ot_desc,
+
+	(struct usb_descriptor_header *)&as_out_interface_alt_0_desc,
+	(struct usb_descriptor_header *)&as_out_interface_alt_1_desc,
+	(struct usb_descriptor_header *)&as_out_header_desc,
+
+	(struct usb_descriptor_header *)&as_out_type_i_desc,
+
+	(struct usb_descriptor_header *)&as_out_ep_desc,
+	(struct usb_descriptor_header *)&as_iso_out_desc,
+
+	(struct usb_descriptor_header *)&as_in_interface_alt_0_desc,
+	(struct usb_descriptor_header *)&as_in_interface_alt_1_desc,
+	(struct usb_descriptor_header *)&as_in_header_desc,
+
+	(struct usb_descriptor_header *)&as_in_type_i_desc,
+
+	(struct usb_descriptor_header *)&as_in_ep_desc,
+	(struct usb_descriptor_header *)&as_iso_in_desc,
+	NULL,
+};
+
+enum {
+	STR_AC_IF,
+	STR_USB_OUT_IT,
+	STR_USB_OUT_IT_CH_NAMES,
+	STR_IO_OUT_OT,
+	STR_IO_IN_IT,
+	STR_IO_IN_IT_CH_NAMES,
+	STR_USB_IN_OT,
+	STR_AS_OUT_IF_ALT0,
+	STR_AS_OUT_IF_ALT1,
+	STR_AS_IN_IF_ALT0,
+	STR_AS_IN_IF_ALT1,
+};
+
+static struct usb_string strings_uac1[] = {
+	[STR_AC_IF].s = "AC Interface",
+	[STR_USB_OUT_IT].s = "Playback Input terminal",
+	[STR_USB_OUT_IT_CH_NAMES].s = "Playback Channels",
+	[STR_IO_OUT_OT].s = "Playback Output terminal",
+	[STR_IO_IN_IT].s = "Capture Input terminal",
+	[STR_IO_IN_IT_CH_NAMES].s = "Capture Channels",
+	[STR_USB_IN_OT].s = "Capture Output terminal",
+	[STR_AS_OUT_IF_ALT0].s = "Playback Inactive",
+	[STR_AS_OUT_IF_ALT1].s = "Playback Active",
+	[STR_AS_IN_IF_ALT0].s = "Capture Inactive",
+	[STR_AS_IN_IF_ALT1].s = "Capture Active",
+	{ },
+};
+
+static struct usb_gadget_strings str_uac1 = {
+	.language = 0x0409,	/* en-us */
+	.strings = strings_uac1,
+};
+
+static struct usb_gadget_strings *uac1_strings[] = {
+	&str_uac1,
+	NULL,
+};
+
+/*
+ * This function is an ALSA sound card following USB Audio Class Spec 1.0.
+ */
+
+static int audio_set_endpoint_req(struct usb_function *f,
+		const struct usb_ctrlrequest *ctrl)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	int			value = -EOPNOTSUPP;
+	u16			ep = le16_to_cpu(ctrl->wIndex);
+	u16			len = le16_to_cpu(ctrl->wLength);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+
+	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
+			ctrl->bRequest, w_value, len, ep);
+
+	switch (ctrl->bRequest) {
+	case UAC_SET_CUR:
+		value = len;
+		break;
+
+	case UAC_SET_MIN:
+		break;
+
+	case UAC_SET_MAX:
+		break;
+
+	case UAC_SET_RES:
+		break;
+
+	case UAC_SET_MEM:
+		break;
+
+	default:
+		break;
+	}
+
+	return value;
+}
+
+static int audio_get_endpoint_req(struct usb_function *f,
+		const struct usb_ctrlrequest *ctrl)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	int value = -EOPNOTSUPP;
+	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
+	u16 len = le16_to_cpu(ctrl->wLength);
+	u16 w_value = le16_to_cpu(ctrl->wValue);
+
+	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
+			ctrl->bRequest, w_value, len, ep);
+
+	switch (ctrl->bRequest) {
+	case UAC_GET_CUR:
+	case UAC_GET_MIN:
+	case UAC_GET_MAX:
+	case UAC_GET_RES:
+		value = len;
+		break;
+	case UAC_GET_MEM:
+		break;
+	default:
+		break;
+	}
+
+	return value;
+}
+
+static int
+f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_request	*req = cdev->req;
+	int			value = -EOPNOTSUPP;
+	u16			w_index = le16_to_cpu(ctrl->wIndex);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+	u16			w_length = le16_to_cpu(ctrl->wLength);
+
+	/* composite driver infrastructure handles everything; interface
+	 * activation uses set_alt().
+	 */
+	switch (ctrl->bRequestType) {
+	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
+		value = audio_set_endpoint_req(f, ctrl);
+		break;
+
+	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
+		value = audio_get_endpoint_req(f, ctrl);
+		break;
+
+	default:
+		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			w_value, w_index, w_length);
+	}
+
+	/* respond with data transfer or status phase? */
+	if (value >= 0) {
+		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			w_value, w_index, w_length);
+		req->zero = 0;
+		req->length = value;
+		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0)
+			ERROR(cdev, "audio response on err %d\n", value);
+	}
+
+	/* device either stalls (value < 0) or reports success */
+	return value;
+}
+
+static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	struct f_uac1 *uac1 = func_to_uac1(f);
+	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 == uac1->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 == uac1->as_out_intf) {
+		uac1->as_out_alt = alt;
+
+		if (alt)
+			ret = gaudio_start_capture(&uac1->gaudio);
+		else
+			gaudio_stop_capture(&uac1->gaudio);
+	} else if (intf == uac1->as_in_intf) {
+		uac1->as_in_alt = alt;
+
+			if (alt)
+				ret = gaudio_start_playback(&uac1->gaudio);
+			else
+				gaudio_stop_playback(&uac1->gaudio);
+	} else {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int f_audio_get_alt(struct usb_function *f, unsigned intf)
+{
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_gadget *gadget = cdev->gadget;
+	struct device *dev = &gadget->dev;
+	struct f_uac1 *uac1 = func_to_uac1(f);
+
+	if (intf == uac1->ac_intf)
+		return uac1->ac_alt;
+	else if (intf == uac1->as_out_intf)
+		return uac1->as_out_alt;
+	else if (intf == uac1->as_in_intf)
+		return uac1->as_in_alt;
+	else
+		dev_err(dev, "%s:%d Invalid Interface %d!\n",
+			__func__, __LINE__, intf);
+
+	return -EINVAL;
+}
+
+
+static void f_audio_disable(struct usb_function *f)
+{
+	struct f_uac1 *uac1 = func_to_uac1(f);
+
+	uac1->as_out_alt = 0;
+	uac1->as_in_alt = 0;
+
+	gaudio_stop_capture(&uac1->gaudio);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* audio function driver setup/binding */
+static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev	*cdev = c->cdev;
+	struct usb_gadget		*gadget = cdev->gadget;
+	struct f_uac1			*uac1 = func_to_uac1(f);
+	struct gaudio			*audio = func_to_gaudio(f);
+	struct f_uac1_newapi_opts	*audio_opts;
+	struct usb_ep			*ep = NULL;
+	struct usb_string		*us;
+	u8				*sam_freq;
+	int				rate;
+	int				status;
+
+	audio_opts = container_of(f->fi, struct f_uac1_newapi_opts, func_inst);
+
+	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
+	if (IS_ERR(us))
+		return PTR_ERR(us);
+	ac_interface_desc.iInterface = us[STR_AC_IF].id;
+	usb_out_it_desc.iTerminal = us[STR_USB_OUT_IT].id;
+	usb_out_it_desc.iChannelNames = us[STR_USB_OUT_IT_CH_NAMES].id;
+	io_out_ot_desc.iTerminal = us[STR_IO_OUT_OT].id;
+	as_out_interface_alt_0_desc.iInterface = us[STR_AS_OUT_IF_ALT0].id;
+	as_out_interface_alt_1_desc.iInterface = us[STR_AS_OUT_IF_ALT1].id;
+	io_in_it_desc.iTerminal = us[STR_IO_IN_IT].id;
+	io_in_it_desc.iChannelNames = us[STR_IO_IN_IT_CH_NAMES].id;
+	usb_in_ot_desc.iTerminal = us[STR_USB_IN_OT].id;
+	as_in_interface_alt_0_desc.iInterface = us[STR_AS_IN_IF_ALT0].id;
+	as_in_interface_alt_1_desc.iInterface = us[STR_AS_IN_IF_ALT1].id;
+
+	/* Set channel numbers */
+	usb_out_it_desc.bNrChannels = num_channels(audio_opts->c_chmask);
+	usb_out_it_desc.wChannelConfig = cpu_to_le16(audio_opts->c_chmask);
+	as_out_type_i_desc.bNrChannels = num_channels(audio_opts->c_chmask);
+	as_out_type_i_desc.bSubframeSize = audio_opts->c_ssize;
+	as_out_type_i_desc.bBitResolution = audio_opts->c_ssize * 8;
+	io_in_it_desc.bNrChannels = num_channels(audio_opts->p_chmask);
+	io_in_it_desc.wChannelConfig = cpu_to_le16(audio_opts->p_chmask);
+	as_in_type_i_desc.bNrChannels = num_channels(audio_opts->p_chmask);
+	as_in_type_i_desc.bSubframeSize = audio_opts->p_ssize;
+	as_in_type_i_desc.bBitResolution = audio_opts->p_ssize * 8;
+
+	/* Set sample rates */
+	rate = audio_opts->c_srate;
+	sam_freq = as_out_type_i_desc.tSamFreq[0];
+	memcpy(sam_freq, &rate, 3);
+	rate = audio_opts->p_srate;
+	sam_freq = as_in_type_i_desc.tSamFreq[0];
+	memcpy(sam_freq, &rate, 3);
+
+	/* allocate instance-specific interface IDs, and patch descriptors */
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	ac_interface_desc.bInterfaceNumber = status;
+	uac1->ac_intf = status;
+	uac1->ac_alt = 0;
+
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	as_out_interface_alt_0_desc.bInterfaceNumber = status;
+	as_out_interface_alt_1_desc.bInterfaceNumber = status;
+	uac1->as_out_intf = status;
+	uac1->as_out_alt = 0;
+
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	as_in_interface_alt_0_desc.bInterfaceNumber = status;
+	as_in_interface_alt_1_desc.bInterfaceNumber = status;
+	uac1->as_in_intf = status;
+	uac1->as_in_alt = 0;
+
+	audio->gadget = gadget;
+
+	status = -ENODEV;
+
+	/* allocate instance-specific endpoints */
+	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
+	if (!ep)
+		goto fail;
+	audio->out_ep = ep;
+	audio->out_ep->desc = &as_out_ep_desc;
+
+	ep = usb_ep_autoconfig(cdev->gadget, &as_in_ep_desc);
+	if (!ep)
+		goto fail;
+	audio->in_ep = ep;
+	audio->in_ep->desc = &as_in_ep_desc;
+
+	/* copy descriptors, and track endpoint copies */
+	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
+					NULL);
+	if (status)
+		goto fail;
+
+	audio->out_ep_maxpsize = as_out_ep_desc.wMaxPacketSize;
+	audio->in_ep_maxpsize = as_in_ep_desc.wMaxPacketSize;
+	audio->params.c_chmask = audio_opts->c_chmask;
+	audio->params.c_srate = audio_opts->c_srate;
+	audio->params.c_ssize = audio_opts->c_ssize;
+	audio->params.p_chmask = audio_opts->p_chmask;
+	audio->params.p_srate = audio_opts->p_srate;
+	audio->params.p_ssize = audio_opts->p_ssize;
+
+	status = gaudio_setup(audio, "UAC1_PCM", "UAC1_Gadget");
+	if (status)
+		goto err_card_register;
+
+	return 0;
+
+err_card_register:
+	usb_free_all_descriptors(f);
+fail:
+	return status;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static inline struct
+f_uac1_newapi_opts *to_f_uac1_newapi_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_uac1_newapi_opts,
+			    func_inst.group);
+}
+
+static void f_uac1_attr_release(struct config_item *item)
+{
+	struct f_uac1_newapi_opts *opts = to_f_uac1_newapi_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations f_uac1_item_ops = {
+	.release	= f_uac1_attr_release,
+};
+
+#define UAC1_ATTRIBUTE(name)						\
+static ssize_t f_uac1_newapi_opts_##name##_show(			\
+					  struct config_item *item,	\
+					  char *page)			\
+{									\
+	struct f_uac1_newapi_opts *opts = to_f_uac1_newapi_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_uac1_newapi_opts_##name##_store(			\
+					  struct config_item *item,	\
+					  const char *page, size_t len)	\
+{									\
+	struct f_uac1_newapi_opts *opts = to_f_uac1_newapi_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_uac1_newapi_opts_, name)
+
+UAC1_ATTRIBUTE(c_chmask);
+UAC1_ATTRIBUTE(c_srate);
+UAC1_ATTRIBUTE(c_ssize);
+UAC1_ATTRIBUTE(p_chmask);
+UAC1_ATTRIBUTE(p_srate);
+UAC1_ATTRIBUTE(p_ssize);
+
+static struct configfs_attribute *f_uac1_attrs[] = {
+	&f_uac1_newapi_opts_attr_c_chmask,
+	&f_uac1_newapi_opts_attr_c_srate,
+	&f_uac1_newapi_opts_attr_c_ssize,
+	&f_uac1_newapi_opts_attr_p_chmask,
+	&f_uac1_newapi_opts_attr_p_srate,
+	&f_uac1_newapi_opts_attr_p_ssize,
+	NULL,
+};
+
+static struct config_item_type f_uac1_func_type = {
+	.ct_item_ops	= &f_uac1_item_ops,
+	.ct_attrs	= f_uac1_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void f_audio_free_inst(struct usb_function_instance *f)
+{
+	struct f_uac1_newapi_opts *opts;
+
+	opts = container_of(f, struct f_uac1_newapi_opts, func_inst);
+	kfree(opts);
+}
+
+static struct usb_function_instance *f_audio_alloc_inst(void)
+{
+	struct f_uac1_newapi_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&opts->lock);
+	opts->func_inst.free_func_inst = f_audio_free_inst;
+
+	config_group_init_type_name(&opts->func_inst.group, "",
+				    &f_uac1_func_type);
+
+	opts->c_chmask = UAC1_DEF_CCHMASK;
+	opts->c_srate = UAC1_DEF_CSRATE;
+	opts->c_ssize = UAC1_DEF_CSSIZE;
+	opts->p_chmask = UAC1_DEF_PCHMASK;
+	opts->p_srate = UAC1_DEF_PSRATE;
+	opts->p_ssize = UAC1_DEF_PSSIZE;
+	return &opts->func_inst;
+}
+
+static void f_audio_free(struct usb_function *f)
+{
+	struct gaudio *audio;
+	struct f_uac1_newapi_opts *opts;
+
+	audio = func_to_gaudio(f);
+	opts = container_of(f->fi, struct f_uac1_newapi_opts, func_inst);
+	kfree(audio);
+	mutex_lock(&opts->lock);
+	--opts->refcnt;
+	mutex_unlock(&opts->lock);
+}
+
+static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct gaudio *audio = func_to_gaudio(f);
+
+	gaudio_cleanup(audio);
+	usb_free_all_descriptors(f);
+
+	audio->gadget = NULL;
+}
+
+static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
+{
+	struct f_uac1 *uac1;
+	struct f_uac1_newapi_opts *opts;
+
+	/* allocate and initialize one new instance */
+	uac1 = kzalloc(sizeof(*uac1), GFP_KERNEL);
+	if (!uac1)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_uac1_newapi_opts, func_inst);
+	mutex_lock(&opts->lock);
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
+
+	uac1->gaudio.func.name = "uac1_newapi_func";
+	uac1->gaudio.func.bind = f_audio_bind;
+	uac1->gaudio.func.unbind = f_audio_unbind;
+	uac1->gaudio.func.set_alt = f_audio_set_alt;
+	uac1->gaudio.func.get_alt = f_audio_get_alt;
+	uac1->gaudio.func.setup = f_audio_setup;
+	uac1->gaudio.func.disable = f_audio_disable;
+	uac1->gaudio.func.free_func = f_audio_free;
+
+	return &uac1->gaudio.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(uac1_newapi, f_audio_alloc_inst, f_audio_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ruslan Bilovol");
diff --git a/drivers/usb/gadget/function/u_uac1_newapi.h b/drivers/usb/gadget/function/u_uac1_newapi.h
new file mode 100644
index 0000000..2fcc3cf2
--- /dev/null
+++ b/drivers/usb/gadget/function/u_uac1_newapi.h
@@ -0,0 +1,39 @@
+/*
+ * u_uac1_newapi.h - Utility definitions for UAC1 function
+ *
+ * Copyright (C) 2016 Ruslan Bilovol <ruslan.bilovol@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __U_UAC1_NEWAPI_H
+#define __U_UAC1_NEWAPI_H
+
+#include <linux/usb/composite.h>
+
+#define UAC1_OUT_EP_MAX_PACKET_SIZE	200
+#define UAC1_DEF_CCHMASK	0x3
+#define UAC1_DEF_CSRATE		48000
+#define UAC1_DEF_CSSIZE		2
+#define UAC1_DEF_PCHMASK	0x3
+#define UAC1_DEF_PSRATE		48000
+#define UAC1_DEF_PSSIZE		2
+
+
+struct f_uac1_newapi_opts {
+	struct usb_function_instance	func_inst;
+	int				c_chmask;
+	int				c_srate;
+	int				c_ssize;
+	int				p_chmask;
+	int				p_srate;
+	int				p_ssize;
+	unsigned			bound:1;
+
+	struct mutex			lock;
+	int				refcnt;
+};
+
+#endif /* __U_UAC1_NEWAPI_H */
diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
index 5344064..9757a3a 100644
--- a/drivers/usb/gadget/legacy/Kconfig
+++ b/drivers/usb/gadget/legacy/Kconfig
@@ -54,9 +54,10 @@ config USB_AUDIO
 	depends on SND
 	select USB_LIBCOMPOSITE
 	select SND_PCM
-	select USB_F_UAC1 if GADGET_UAC1
+	select USB_F_UAC1 if (GADGET_UAC1 && !GADGET_UAC1_NEWAPI)
+	select USB_F_UAC1_NEWAPI if (GADGET_UAC1 && GADGET_UAC1_NEWAPI)
 	select USB_F_UAC2 if !GADGET_UAC1
-	select USB_U_AUDIO if USB_F_UAC2
+	select USB_U_AUDIO if (USB_F_UAC2 || USB_F_UAC1_NEWAPI)
 	help
 	  This Gadget Audio driver is compatible with USB Audio Class
 	  specification 2.0. It implements 1 AudioControl interface,
@@ -81,6 +82,16 @@ config GADGET_UAC1
 	  paths hardwired to the Audio codec chip on-board and doesn't work
 	  without one.
 
+config GADGET_UAC1_NEWAPI
+	bool "Use new API (u_audio) for UAC 1.0 driver"
+	depends on GADGET_UAC1
+	help
+	  This is an alternative UAC Spec-1.0 driver implementation
+	  that uses new API (u_audio), and doesn't expect any real
+	  audio codec to be present on the device (the audio streams
+	  are simply sinked to and sourced from a virtual ALSA sound
+	  card created)
+
 config USB_ETH
 	tristate "Ethernet Gadget (with CDC Ethernet support)"
 	depends on NET
diff --git a/drivers/usb/gadget/legacy/audio.c b/drivers/usb/gadget/legacy/audio.c
index 5d7b3c6..1debabc 100644
--- a/drivers/usb/gadget/legacy/audio.c
+++ b/drivers/usb/gadget/legacy/audio.c
@@ -53,6 +53,39 @@ static int c_ssize = UAC2_DEF_CSSIZE;
 module_param(c_ssize, uint, S_IRUGO);
 MODULE_PARM_DESC(c_ssize, "Capture Sample Size(bytes)");
 #else
+#ifdef CONFIG_GADGET_UAC1_NEWAPI
+#include "u_uac1_newapi.h"
+
+/* Playback(USB-IN) Default Stereo - Fl/Fr */
+static int p_chmask = UAC1_DEF_PCHMASK;
+module_param(p_chmask, uint, S_IRUGO);
+MODULE_PARM_DESC(p_chmask, "Playback Channel Mask");
+
+/* Playback Default 48 KHz */
+static int p_srate = UAC1_DEF_PSRATE;
+module_param(p_srate, uint, S_IRUGO);
+MODULE_PARM_DESC(p_srate, "Playback Sampling Rate");
+
+/* Playback Default 16bits/sample */
+static int p_ssize = UAC1_DEF_PSSIZE;
+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 = UAC1_DEF_CCHMASK;
+module_param(c_chmask, uint, S_IRUGO);
+MODULE_PARM_DESC(c_chmask, "Capture Channel Mask");
+
+/* Capture Default 48 KHz */
+static int c_srate = UAC1_DEF_CSRATE;
+module_param(c_srate, uint, S_IRUGO);
+MODULE_PARM_DESC(c_srate, "Capture Sampling Rate");
+
+/* Capture Default 16bits/sample */
+static int c_ssize = UAC1_DEF_CSSIZE;
+module_param(c_ssize, uint, S_IRUGO);
+MODULE_PARM_DESC(c_ssize, "Capture Sample Size(bytes)");
+#else /* CONFIG_GADGET_UAC1_NEWAPI */
 #include "u_uac1.h"
 
 static char *fn_play = FILE_PCM_PLAYBACK;
@@ -78,6 +111,7 @@ MODULE_PARM_DESC(req_count, "ISO OUT endpoint request count");
 static int audio_buf_size = UAC1_AUDIO_BUF_SIZE;
 module_param(audio_buf_size, int, S_IRUGO);
 MODULE_PARM_DESC(audio_buf_size, "Audio buffer size");
+#endif /* CONFIG_GADGET_UAC1_NEWAPI */
 #endif
 
 /* string IDs are assigned dynamically */
@@ -207,8 +241,12 @@ static int audio_bind(struct usb_composite_dev *cdev)
 #ifndef CONFIG_GADGET_UAC1
 	struct f_uac2_opts	*uac2_opts;
 #else
+#ifdef CONFIG_GADGET_UAC1_NEWAPI
+	struct f_uac1_newapi_opts	*uac1_opts;
+#else
 	struct f_uac1_opts	*uac1_opts;
 #endif
+#endif
 	int			status;
 
 #ifndef CONFIG_GADGET_UAC1
@@ -216,7 +254,11 @@ static int audio_bind(struct usb_composite_dev *cdev)
 	if (IS_ERR(fi_uac2))
 		return PTR_ERR(fi_uac2);
 #else
+#ifdef CONFIG_GADGET_UAC1_NEWAPI
+	fi_uac1 = usb_get_function_instance("uac1_newapi");
+#else
 	fi_uac1 = usb_get_function_instance("uac1");
+#endif
 	if (IS_ERR(fi_uac1))
 		return PTR_ERR(fi_uac1);
 #endif
@@ -230,6 +272,15 @@ static int audio_bind(struct usb_composite_dev *cdev)
 	uac2_opts->c_srate = c_srate;
 	uac2_opts->c_ssize = c_ssize;
 #else
+#ifdef CONFIG_GADGET_UAC1_NEWAPI
+	uac1_opts = container_of(fi_uac1, struct f_uac1_newapi_opts, func_inst);
+	uac1_opts->p_chmask = p_chmask;
+	uac1_opts->p_srate = p_srate;
+	uac1_opts->p_ssize = p_ssize;
+	uac1_opts->c_chmask = c_chmask;
+	uac1_opts->c_srate = c_srate;
+	uac1_opts->c_ssize = c_ssize;
+#else /* CONFIG_GADGET_UAC1_NEWAPI */
 	uac1_opts = container_of(fi_uac1, struct f_uac1_opts, func_inst);
 	uac1_opts->fn_play = fn_play;
 	uac1_opts->fn_cap = fn_cap;
@@ -237,6 +288,7 @@ static int audio_bind(struct usb_composite_dev *cdev)
 	uac1_opts->req_buf_size = req_buf_size;
 	uac1_opts->req_count = req_count;
 	uac1_opts->audio_buf_size = audio_buf_size;
+#endif /* CONFIG_GADGET_UAC1_NEWAPI */
 #endif
 
 	status = usb_string_ids_tab(cdev, strings_dev);
-- 
1.9.1

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#1463373 — Re: [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new u_audio api

On Sun, Aug 14, 2016 at 01:21:24AM +0300, Ruslan Bilovol wrote:
> This patch adds new function f_uac1_newapi that
> uses recently created u_audio api. This makes
> f_uac1_newapi implementation much simpler by
> reusing existing u_audio core utilities.
> 
> This also drops previous f_uac1 approach (write
> audio samples directly to existing ALSA sound
> card) and moves to more generic/flexible
> one - create an f_uac1 ALSA sound card that
> represents USB Audio function and allows to
> be used by userspace tools.
> 
> f_uac1_newapi also has capture support (gadget->host).
> By default, capture interface has 48000kHz/2ch
> configuration, same as playback channel has.
> 
> f_uac1_newapi descriptors naming conventios
> uses f_uac2 driver naming convention that
> makes it more common and meaningful.
> 
> Comparing to f_uac1, the f_uac1_newapi doesn't
> have volume/mute functionality. This is because
> the volume/mute feature unit was dummy
> implementation since that driver creation (2009)
> and never had real volume control or mute
> functionality.
> 
> g_audio can be built using one of existing
> uac functions (f_uac1, f_uac1_newapi or f_uac2)
> 
> Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
> ---
>  .../ABI/testing/configfs-usb-gadget-uac1_newapi    |  12 +
>  Documentation/usb/gadget-testing.txt               |  41 ++
>  drivers/usb/gadget/Kconfig                         |  21 +
>  drivers/usb/gadget/function/Makefile               |   2 +
>  drivers/usb/gadget/function/f_uac1_newapi.c        | 795 +++++++++++++++++++++
>  drivers/usb/gadget/function/u_uac1_newapi.h        |  39 +
>  drivers/usb/gadget/legacy/Kconfig                  |  15 +-
>  drivers/usb/gadget/legacy/audio.c                  |  52 ++
>  8 files changed, 975 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
>  create mode 100644 drivers/usb/gadget/function/f_uac1_newapi.c
>  create mode 100644 drivers/usb/gadget/function/u_uac1_newapi.h
> 
> diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
> new file mode 100644
> index 0000000..d355275
> --- /dev/null
> +++ b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
> @@ -0,0 +1,12 @@
> +What:		/config/usb-gadget/gadget/functions/uac1_newapi.name
> +Date:		Aug 2016
> +KernelVersion:	4.9
> +Description:
> +		The attributes:
> +
> +		c_chmask - capture channel mask
> +		c_srate - capture sampling rate
> +		c_ssize - capture sample size (bytes)
> +		p_chmask - playback channel mask
> +		p_srate - playback sampling rate
> +		p_ssize - playback sample size (bytes)
> diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
> index 5819605..4598d7f 100644
> --- a/Documentation/usb/gadget-testing.txt
> +++ b/Documentation/usb/gadget-testing.txt
> @@ -20,6 +20,7 @@ provided by gadgets.
>  17. UAC2 function
>  18. UVC function
>  19. PRINTER function
> +20. UAC1 function (new API)
>  
>  
>  1. ACM function
> @@ -770,3 +771,43 @@ host:
>  
>  More advanced testing can be done with the prn_example
>  described in Documentation/usb/gadget-printer.txt.
> +
> +
> +20. UAC1 function (new API, using u_audio)
> +=================
> +
> +The function is provided by usb_f_uac1_newapi.ko module.
> +
> +Function-specific configfs interface
> +------------------------------------
> +
> +The function name to use when creating the function directory
> +is "uac1_newapi". The uac1_newapi function provides these attributes
> +in its function directory:
> +
> +	c_chmask - capture channel mask
> +	c_srate - capture sampling rate
> +	c_ssize - capture sample size (bytes)
> +	p_chmask - playback channel mask
> +	p_srate - playback sampling rate
> +	p_ssize - playback sample size (bytes)
> +
> +The attributes have sane default values.
> +
> +Testing the UAC1 function
> +-------------------------
> +
> +device: run the gadget
> +host: aplay -l # should list our USB Audio Gadget
> +
> +This function does not require real hardware support, it just
> +sends a stream of audio data to/from the host. In order to
> +actually hear something at the device side, a command similar
> +to this must be used at the device side:
> +
> +$ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 &
> +
> +e.g.:
> +
> +$ arecord -f dat -t wav -D hw:CARD=UAC1Gadget,DEV=0 | \
> +aplay -D default:CARD=OdroidU3
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index a25afd8..abcb539 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -194,6 +194,9 @@ config USB_F_FS
>  config USB_F_UAC1
>  	tristate
>  
> +config USB_F_UAC1_NEWAPI
> +	tristate
> +
>  config USB_F_UAC2
>  	tristate
>  
> @@ -397,6 +400,24 @@ config USB_CONFIGFS_F_UAC1
>  	  This driver requires a real Audio codec to be present
>  	  on the device.
>  
> +config USB_CONFIGFS_F_UAC1_NEWAPI
> +	bool "Audio Class 1.0 (new API)"
> +	depends on USB_CONFIGFS
> +	depends on SND
> +	select USB_LIBCOMPOSITE
> +	select SND_PCM
> +	select USB_U_AUDIO
> +	select USB_F_UAC1_NEWAPI
> +	help
> +	  This Audio function implements 1 AudioControl interface,
> +	  1 AudioStreaming Interface each for USB-OUT and USB-IN.

%s/1/one

-- 

Best Regards,
Peter Chen

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#1464134 — Re: [PATCH v2 3/3] usb: gadget: add f_uac1 variant based on new u_audio api

On Tue, Aug 16, 2016 at 5:52 AM, Peter Chen <hzpeterchen@gmail.com> wrote:
> On Sun, Aug 14, 2016 at 01:21:24AM +0300, Ruslan Bilovol wrote:
>> This patch adds new function f_uac1_newapi that
>> uses recently created u_audio api. This makes
>> f_uac1_newapi implementation much simpler by
>> reusing existing u_audio core utilities.
>>
>> This also drops previous f_uac1 approach (write
>> audio samples directly to existing ALSA sound
>> card) and moves to more generic/flexible
>> one - create an f_uac1 ALSA sound card that
>> represents USB Audio function and allows to
>> be used by userspace tools.
>>
>> f_uac1_newapi also has capture support (gadget->host).
>> By default, capture interface has 48000kHz/2ch
>> configuration, same as playback channel has.
>>
>> f_uac1_newapi descriptors naming conventios
>> uses f_uac2 driver naming convention that
>> makes it more common and meaningful.
>>
>> Comparing to f_uac1, the f_uac1_newapi doesn't
>> have volume/mute functionality. This is because
>> the volume/mute feature unit was dummy
>> implementation since that driver creation (2009)
>> and never had real volume control or mute
>> functionality.
>>
>> g_audio can be built using one of existing
>> uac functions (f_uac1, f_uac1_newapi or f_uac2)
>>
>> Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
>> ---
>>  .../ABI/testing/configfs-usb-gadget-uac1_newapi    |  12 +
>>  Documentation/usb/gadget-testing.txt               |  41 ++
>>  drivers/usb/gadget/Kconfig                         |  21 +
>>  drivers/usb/gadget/function/Makefile               |   2 +
>>  drivers/usb/gadget/function/f_uac1_newapi.c        | 795 +++++++++++++++++++++
>>  drivers/usb/gadget/function/u_uac1_newapi.h        |  39 +
>>  drivers/usb/gadget/legacy/Kconfig                  |  15 +-
>>  drivers/usb/gadget/legacy/audio.c                  |  52 ++
>>  8 files changed, 975 insertions(+), 2 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
>>  create mode 100644 drivers/usb/gadget/function/f_uac1_newapi.c
>>  create mode 100644 drivers/usb/gadget/function/u_uac1_newapi.h
>>
>> diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
>> new file mode 100644
>> index 0000000..d355275
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/configfs-usb-gadget-uac1_newapi
>> @@ -0,0 +1,12 @@
>> +What:                /config/usb-gadget/gadget/functions/uac1_newapi.name
>> +Date:                Aug 2016
>> +KernelVersion:       4.9
>> +Description:
>> +             The attributes:
>> +
>> +             c_chmask - capture channel mask
>> +             c_srate - capture sampling rate
>> +             c_ssize - capture sample size (bytes)
>> +             p_chmask - playback channel mask
>> +             p_srate - playback sampling rate
>> +             p_ssize - playback sample size (bytes)
>> diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
>> index 5819605..4598d7f 100644
>> --- a/Documentation/usb/gadget-testing.txt
>> +++ b/Documentation/usb/gadget-testing.txt
>> @@ -20,6 +20,7 @@ provided by gadgets.
>>  17. UAC2 function
>>  18. UVC function
>>  19. PRINTER function
>> +20. UAC1 function (new API)
>>
>>
>>  1. ACM function
>> @@ -770,3 +771,43 @@ host:
>>
>>  More advanced testing can be done with the prn_example
>>  described in Documentation/usb/gadget-printer.txt.
>> +
>> +
>> +20. UAC1 function (new API, using u_audio)
>> +=================
>> +
>> +The function is provided by usb_f_uac1_newapi.ko module.
>> +
>> +Function-specific configfs interface
>> +------------------------------------
>> +
>> +The function name to use when creating the function directory
>> +is "uac1_newapi". The uac1_newapi function provides these attributes
>> +in its function directory:
>> +
>> +     c_chmask - capture channel mask
>> +     c_srate - capture sampling rate
>> +     c_ssize - capture sample size (bytes)
>> +     p_chmask - playback channel mask
>> +     p_srate - playback sampling rate
>> +     p_ssize - playback sample size (bytes)
>> +
>> +The attributes have sane default values.
>> +
>> +Testing the UAC1 function
>> +-------------------------
>> +
>> +device: run the gadget
>> +host: aplay -l # should list our USB Audio Gadget
>> +
>> +This function does not require real hardware support, it just
>> +sends a stream of audio data to/from the host. In order to
>> +actually hear something at the device side, a command similar
>> +to this must be used at the device side:
>> +
>> +$ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 &
>> +
>> +e.g.:
>> +
>> +$ arecord -f dat -t wav -D hw:CARD=UAC1Gadget,DEV=0 | \
>> +aplay -D default:CARD=OdroidU3
>> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
>> index a25afd8..abcb539 100644
>> --- a/drivers/usb/gadget/Kconfig
>> +++ b/drivers/usb/gadget/Kconfig
>> @@ -194,6 +194,9 @@ config USB_F_FS
>>  config USB_F_UAC1
>>       tristate
>>
>> +config USB_F_UAC1_NEWAPI
>> +     tristate
>> +
>>  config USB_F_UAC2
>>       tristate
>>
>> @@ -397,6 +400,24 @@ config USB_CONFIGFS_F_UAC1
>>         This driver requires a real Audio codec to be present
>>         on the device.
>>
>> +config USB_CONFIGFS_F_UAC1_NEWAPI
>> +     bool "Audio Class 1.0 (new API)"
>> +     depends on USB_CONFIGFS
>> +     depends on SND
>> +     select USB_LIBCOMPOSITE
>> +     select SND_PCM
>> +     select USB_U_AUDIO
>> +     select USB_F_UAC1_NEWAPI
>> +     help
>> +       This Audio function implements 1 AudioControl interface,
>> +       1 AudioStreaming Interface each for USB-OUT and USB-IN.
>
> %s/1/one
>

That's same naming as already used for UAC1 and UAC2 description
in this Kconfig file. Let's keep it "1" for consistency

Best regards,
Ruslan

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#1461794 — [PATCH v2 1/3] usb: gadget: f_uac2: remove platform driver/device creation

Simplify f_uac2 by removing platform driver/device
creation; use composite's usb_gadget device as
parent for sound card and for debug prints.
This removes extra layer of code without any functional
change.

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac2.c | 107 +++++++++--------------------------
 1 file changed, 28 insertions(+), 79 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index cd214ec8..e14628c 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -13,7 +13,6 @@
 
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
-#include <linux/platform_device.h>
 #include <linux/module.h>
 
 #include <sound/core.h>
@@ -54,8 +53,6 @@
 #define UNFLW_CTRL	8
 #define OVFLW_CTRL	10
 
-static const char *uac2_name = "snd_uac2";
-
 struct uac2_req {
 	struct uac2_rtd_params *pp; /* parent param */
 	struct usb_request *req;
@@ -84,9 +81,6 @@ struct uac2_rtd_params {
 };
 
 struct snd_uac2_chip {
-	struct platform_device pdev;
-	struct platform_driver pdrv;
-
 	struct uac2_rtd_params p_prm;
 	struct uac2_rtd_params c_prm;
 
@@ -125,6 +119,7 @@ struct audio_dev {
 
 	struct usb_ep *in_ep, *out_ep;
 	struct usb_function func;
+	struct usb_gadget *gadget;
 
 	/* The ALSA Sound Card it represents on the USB-Client side */
 	struct snd_uac2_chip uac2;
@@ -143,12 +138,6 @@ struct audio_dev *uac2_to_agdev(struct snd_uac2_chip *u)
 }
 
 static inline
-struct snd_uac2_chip *pdev_to_uac2(struct platform_device *p)
-{
-	return container_of(p, struct snd_uac2_chip, pdev);
-}
-
-static inline
 struct f_uac2_opts *agdev_to_uac2_opts(struct audio_dev *agdev)
 {
 	return container_of(agdev->func.fi, struct f_uac2_opts, func_inst);
@@ -257,7 +246,7 @@ agdev_iso_complete(struct usb_ep *ep, struct usb_request *req)
 
 exit:
 	if (usb_ep_queue(ep, req, GFP_ATOMIC))
-		dev_err(&uac2->pdev.dev, "%d Error!\n", __LINE__);
+		dev_err(uac2->card->dev, "%d Error!\n", __LINE__);
 
 	if (update_alsa)
 		snd_pcm_period_elapsed(substream);
@@ -441,23 +430,22 @@ static struct snd_pcm_ops uac2_pcm_ops = {
 	.prepare = uac2_pcm_null,
 };
 
-static int snd_uac2_probe(struct platform_device *pdev)
+static int snd_uac2_probe(struct audio_dev *audio_dev)
 {
-	struct snd_uac2_chip *uac2 = pdev_to_uac2(pdev);
+	struct snd_uac2_chip *uac2 = &audio_dev->uac2;
 	struct snd_card *card;
 	struct snd_pcm *pcm;
-	struct audio_dev *audio_dev;
 	struct f_uac2_opts *opts;
 	int err;
 	int p_chmask, c_chmask;
 
-	audio_dev = uac2_to_agdev(uac2);
 	opts = container_of(audio_dev->func.fi, struct f_uac2_opts, func_inst);
 	p_chmask = opts->p_chmask;
 	c_chmask = opts->c_chmask;
 
 	/* Choose any slot, with no id */
-	err = snd_card_new(&pdev->dev, -1, NULL, THIS_MODULE, 0, &card);
+	err = snd_card_new(&audio_dev->gadget->dev,
+			-1, NULL, THIS_MODULE, 0, &card);
 	if (err < 0)
 		return err;
 
@@ -482,16 +470,15 @@ static int snd_uac2_probe(struct platform_device *pdev)
 
 	strcpy(card->driver, "UAC2_Gadget");
 	strcpy(card->shortname, "UAC2_Gadget");
-	sprintf(card->longname, "UAC2_Gadget %i", pdev->id);
+	sprintf(card->longname, "UAC2_Gadget %i", card->dev->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);
+
+	if (!err)
 		return 0;
-	}
 
 snd_fail:
 	snd_card_free(card);
@@ -502,9 +489,9 @@ snd_fail:
 	return err;
 }
 
-static int snd_uac2_remove(struct platform_device *pdev)
+static int snd_uac2_remove(struct audio_dev *audio_dev)
 {
-	struct snd_card *card = platform_get_drvdata(pdev);
+	struct snd_card *card = audio_dev->uac2.card;
 
 	if (card)
 		return snd_card_free(card);
@@ -512,45 +499,6 @@ static int snd_uac2_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static void snd_uac2_release(struct device *dev)
-{
-	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
-}
-
-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;
-	uac2->pdev.dev.release = snd_uac2_release;
-
-	/* 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 ------------- */
 
@@ -959,7 +907,7 @@ free_ep(struct uac2_rtd_params *prm, struct usb_ep *ep)
 	}
 
 	if (usb_ep_disable(ep))
-		dev_err(&uac2->pdev.dev,
+		dev_err(uac2->card->dev,
 			"%s:%d Error!\n", __func__, __LINE__);
 }
 
@@ -993,7 +941,7 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 	struct snd_uac2_chip *uac2 = &agdev->uac2;
 	struct usb_composite_dev *cdev = cfg->cdev;
 	struct usb_gadget *gadget = cdev->gadget;
-	struct device *dev = &uac2->pdev.dev;
+	struct device *dev = &gadget->dev;
 	struct uac2_rtd_params *prm;
 	struct f_uac2_opts *uac2_opts;
 	struct usb_string *us;
@@ -1064,6 +1012,8 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 	agdev->as_in_intf = ret;
 	agdev->as_in_alt = 0;
 
+	agdev->gadget = gadget;
+
 	agdev->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);
 	if (!agdev->out_ep) {
 		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
@@ -1109,7 +1059,7 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 		goto err_free_descs;
 	}
 
-	ret = alsa_uac2_init(agdev);
+	ret = snd_uac2_probe(agdev);
 	if (ret)
 		goto err_free_descs;
 	return 0;
@@ -1119,6 +1069,7 @@ err_free_descs:
 err:
 	kfree(agdev->uac2.p_prm.rbuf);
 	kfree(agdev->uac2.c_prm.rbuf);
+	agdev->gadget = NULL;
 	return -EINVAL;
 }
 
@@ -1129,7 +1080,7 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
 	struct audio_dev *agdev = func_to_agdev(fn);
 	struct snd_uac2_chip *uac2 = &agdev->uac2;
 	struct usb_gadget *gadget = cdev->gadget;
-	struct device *dev = &uac2->pdev.dev;
+	struct device *dev = &gadget->dev;
 	struct usb_request *req;
 	struct usb_ep *ep;
 	struct uac2_rtd_params *prm;
@@ -1230,7 +1181,6 @@ 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;
@@ -1239,7 +1189,7 @@ afunc_get_alt(struct usb_function *fn, unsigned intf)
 	else if (intf == agdev->as_in_intf)
 		return agdev->as_in_alt;
 	else
-		dev_err(&uac2->pdev.dev,
+		dev_err(&agdev->gadget->dev,
 			"%s:%d Invalid Interface %d!\n",
 			__func__, __LINE__, intf);
 
@@ -1264,7 +1214,6 @@ 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;
 	struct f_uac2_opts *opts;
 	u16 w_length = le16_to_cpu(cr->wLength);
 	u16 w_index = le16_to_cpu(cr->wIndex);
@@ -1293,7 +1242,7 @@ in_rq_cur(struct usb_function *fn, const struct usb_ctrlrequest *cr)
 		*(u8 *)req->buf = 1;
 		value = min_t(unsigned, w_length, 1);
 	} else {
-		dev_err(&uac2->pdev.dev,
+		dev_err(&agdev->gadget->dev,
 			"%s:%d control_selector=%d TODO!\n",
 			__func__, __LINE__, control_selector);
 	}
@@ -1306,7 +1255,6 @@ 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;
 	struct f_uac2_opts *opts;
 	u16 w_length = le16_to_cpu(cr->wLength);
 	u16 w_index = le16_to_cpu(cr->wIndex);
@@ -1336,7 +1284,7 @@ in_rq_range(struct usb_function *fn, const struct usb_ctrlrequest *cr)
 		value = min_t(unsigned, w_length, sizeof r);
 		memcpy(req->buf, &r, value);
 	} else {
-		dev_err(&uac2->pdev.dev,
+		dev_err(&agdev->gadget->dev,
 			"%s:%d control_selector=%d TODO!\n",
 			__func__, __LINE__, control_selector);
 	}
@@ -1372,12 +1320,11 @@ 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,
+		dev_err(&agdev->gadget->dev,
 			"%s:%d Error!\n", __func__, __LINE__);
 		return -EOPNOTSUPP;
 	}
@@ -1395,7 +1342,6 @@ 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;
@@ -1407,14 +1353,15 @@ afunc_setup(struct usb_function *fn, const struct usb_ctrlrequest *cr)
 	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__);
+		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(&uac2->pdev.dev,
+			dev_err(&agdev->gadget->dev,
 				"%s:%d Error!\n", __func__, __LINE__);
 			req->status = 0;
 		}
@@ -1553,7 +1500,7 @@ static void afunc_unbind(struct usb_configuration *c, struct usb_function *f)
 	struct audio_dev *agdev = func_to_agdev(f);
 	struct uac2_rtd_params *prm;
 
-	alsa_uac2_exit(agdev);
+	snd_uac2_remove(agdev);
 
 	prm = &agdev->uac2.p_prm;
 	kfree(prm->rbuf);
@@ -1561,6 +1508,8 @@ static void afunc_unbind(struct usb_configuration *c, struct usb_function *f)
 	prm = &agdev->uac2.c_prm;
 	kfree(prm->rbuf);
 	usb_free_all_descriptors(f);
+
+	agdev->gadget = NULL;
 }
 
 static struct usb_function *afunc_alloc(struct usb_function_instance *fi)
-- 
1.9.1

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#1463595

On Sun, Aug 14, 2016 at 01:21:21AM +0300, Ruslan Bilovol wrote:
> I came to this patch series when wanted to do two things:
>  - use UAC1 as virtual ALSA sound card on gadget side,
>    just like UAC2 is used so it's possible to do rate
>    resampling
>  - have both playback/capture support in UAC1
> 
> Since I wanted to have same behavior for both UAC1/UAC2,
> obviously I've got an utility part (u_audio.c) for
> virtual ALSA sound card handling like we have
> for ethernet(u_ether) or serial(u_serial) functions.
> Function-specific parts (f_uac1/f_uac2) became almost 
> as storage for class-specific USB descriptors, some
> boilerplate for configfs, binding and few USB
> config request handling.
> 
> Originally in RFC [1] I've posted before, there was
> major change to f_uac1 after that it couldn't do
> direct play to existing ALSA sound card anymore,
> representing audio on gadget side as virtual
> ALSA sound card where audio streams are simply
> sinked to and sourced from it, so it may break
> current usecase for some people (and that's why
> it was RFC).
> 
> During RFC discussion, it was agreed to not touch
> existing f_uac1 implementation and create new one
> instead. This patchset (v2) introduced new function
> named f_uac1_newapi and doesn't touch current f_uac1
> implementation, so people still can use old behavior
> 
> Now, it's possible to use existing user-space
> applications for audio routing between Audio Gadget
> and real sound card. I personally use alsaloop tool
> from alsautils and have ability to create PCM
> loopback between two different ALSA cards using
> rate resampling, which was not possible with previous
> "direct play to ALSA card" approach in f_uac1. 
> 
> While here, also dropped redundant platform
> driver/device creation in f_uac2 driver (as well as
> didn't add "never implemented" volume/mute functionality
> in f_uac1 to f_uac1_newapi) that made this work even
> easier to do.
> 
> This series is tested with both legacy g_audio.ko and
> modern configfs approaches under Ubuntu 14.04 (UAC1 and
> UAC2) and under Windows7 x64 (UAC1 only) having
> perfect results in all cases.
> 

I find UAC2 (UAC1 is ok)  support is not well with the latest mainline
kernel w/o your patch set. The windows7 can't install the driver
successfully and the playback shows underrun (using local codec)
using Linux host.

Do you use the unchanged mainline kernel?

My configfs parameters like below:
echo 2 > functions/uac2.1/c_ssize
echo 48000 > functions/uac2.1/c_srate
echo 3 > functions/uac2.1/c_chmask
echo 2 > functions/uac2.1/p_ssize
echo 48000 > functions/uac2.1/p_srate
echo 3 > functions/uac2.1/p_chmask


Console output:
root@imx6qdlsolo:~# arecord -f dat -t wav -D hw:1,0 | aplay -D hw:0,0 &
[1] 859
root@imx6qdlsolo:~# 
root@imx6qdlsolo:~# Recording WAVE 'stdin' : Signed 16 bit Little
Endian, Rate 48000 Hz, Stereo
Playing WAVE 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz,
Stereo
underrun!!! (at least 36.634 ms long)
underrun!!! (at least 36.117 ms long)
underrun!!! (at least 42.132 ms long)
underrun!!! (at least 40.157 ms long)
underrun!!! (at least 36.207 ms long)
underrun!!! (at least 39.173 ms long)
underrun!!! (at least 36.119 ms long)
underrun!!! (at least 36.164 ms long)


-- 

Best Regards,
Peter Chen

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#1463613

Peter Chen wrote:
> I find UAC2 (UAC1 is ok)  support is not well with the latest mainline
> kernel w/o your patch set. The windows7 can't install the driver
> successfully

Windows does not have UAC2 support.

> and the playback shows underrun (using local codec)
> using Linux host.

> # arecord -f dat -t wav -D hw:1,0 | aplay -D hw:0,0 &

The clocks of the two devices are not synchronized.

In the ALSA API, a PCM device is assumed to have its own clock, so it is
not possible to synchronize the USB gadget to the actual sound device
without some separate mechanism (like the old uac1 gadget probably has).


Regards,
Clemens

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#1463637

On Tue, Aug 16, 2016 at 11:32:55AM +0200, Clemens Ladisch wrote:
> Peter Chen wrote:
> > I find UAC2 (UAC1 is ok)  support is not well with the latest mainline
> > kernel w/o your patch set. The windows7 can't install the driver
> > successfully
> 
> Windows does not have UAC2 support.
> 

Thanks, before windows7 or all windows versions have no UAC2 support?

> > and the playback shows underrun (using local codec)
> > using Linux host.
> 
> > # arecord -f dat -t wav -D hw:1,0 | aplay -D hw:0,0 &
> 
> The clocks of the two devices are not synchronized.
> 
> In the ALSA API, a PCM device is assumed to have its own clock, so it is
> not possible to synchronize the USB gadget to the actual sound device
> without some separate mechanism (like the old uac1 gadget probably has).
> 

The reason for immediate underrun is the small USB request number.
The default request number of USB is 2 for UAC2, but 256 for
UAC1. I have a internal 4.1.y version which works fine for UAC2 with
only two requests, maybe ALSA has changed some recently.

Yes, we need feedback endpoint to adjust sample rate for mismatch
clocks between USB and codec.

-- 

Best Regards,
Peter Chen

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#1463644

Peter Chen wrote:
> On Tue, Aug 16, 2016 at 11:32:55AM +0200, Clemens Ladisch wrote:
>> Windows does not have UAC2 support.
>
> Thanks, before windows7 or all windows versions have no UAC2 support?

So far, no version has it.


Regards,
Clemens

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#1464149

On Tue, Aug 16, 2016 at 12:16 PM, Peter Chen <hzpeterchen@gmail.com> wrote:
> On Sun, Aug 14, 2016 at 01:21:21AM +0300, Ruslan Bilovol wrote:
>> I came to this patch series when wanted to do two things:
>>  - use UAC1 as virtual ALSA sound card on gadget side,
>>    just like UAC2 is used so it's possible to do rate
>>    resampling
>>  - have both playback/capture support in UAC1
>>
>> Since I wanted to have same behavior for both UAC1/UAC2,
>> obviously I've got an utility part (u_audio.c) for
>> virtual ALSA sound card handling like we have
>> for ethernet(u_ether) or serial(u_serial) functions.
>> Function-specific parts (f_uac1/f_uac2) became almost
>> as storage for class-specific USB descriptors, some
>> boilerplate for configfs, binding and few USB
>> config request handling.
>>
>> Originally in RFC [1] I've posted before, there was
>> major change to f_uac1 after that it couldn't do
>> direct play to existing ALSA sound card anymore,
>> representing audio on gadget side as virtual
>> ALSA sound card where audio streams are simply
>> sinked to and sourced from it, so it may break
>> current usecase for some people (and that's why
>> it was RFC).
>>
>> During RFC discussion, it was agreed to not touch
>> existing f_uac1 implementation and create new one
>> instead. This patchset (v2) introduced new function
>> named f_uac1_newapi and doesn't touch current f_uac1
>> implementation, so people still can use old behavior
>>
>> Now, it's possible to use existing user-space
>> applications for audio routing between Audio Gadget
>> and real sound card. I personally use alsaloop tool
>> from alsautils and have ability to create PCM
>> loopback between two different ALSA cards using
>> rate resampling, which was not possible with previous
>> "direct play to ALSA card" approach in f_uac1.
>>
>> While here, also dropped redundant platform
>> driver/device creation in f_uac2 driver (as well as
>> didn't add "never implemented" volume/mute functionality
>> in f_uac1 to f_uac1_newapi) that made this work even
>> easier to do.
>>
>> This series is tested with both legacy g_audio.ko and
>> modern configfs approaches under Ubuntu 14.04 (UAC1 and
>> UAC2) and under Windows7 x64 (UAC1 only) having
>> perfect results in all cases.
>>
>
> I find UAC2 (UAC1 is ok)  support is not well with the latest mainline
> kernel w/o your patch set. The windows7 can't install the driver
> successfully and the playback shows underrun (using local codec)
> using Linux host.

As Clemens already pointed, Windows 7 doesn't have
UAC2 support "out of the box". That's why I tested only UAC1 on it.

>
> Do you use the unchanged mainline kernel?

Yes, this patchset is based on v4.8-rc1 tag.

>
> My configfs parameters like below:
> echo 2 > functions/uac2.1/c_ssize
> echo 48000 > functions/uac2.1/c_srate
> echo 3 > functions/uac2.1/c_chmask
> echo 2 > functions/uac2.1/p_ssize
> echo 48000 > functions/uac2.1/p_srate
> echo 3 > functions/uac2.1/p_chmask

I usually don't change these (use default values here)

I use BeagleBone Black for this patchset verification.
Here is how I configure it through configfs:

uac_2
------------
mkdir cfg
mount none cfg -t configfs
mkdir cfg/usb_gadget/g1
cd cfg/usb_gadget/g1
mkdir configs/c.1
mkdir functions/uac2.0
mkdir strings/0x409
mkdir configs/c.1/strings/0x409
echo 0x0101 > idProduct
echo 0x1d6b > idVendor
echo my-serial-num > strings/0x409/serialnumber
echo my-manufacturer > strings/0x409/manufacturer
echo "Test gadget" > strings/0x409/product
echo "Conf 1" > configs/c.1/strings/0x409/configuration
echo 120 > configs/c.1/MaxPower
ln -s functions/uac2.0 configs/c.1
echo musb-hdrc.0.auto > UDC


uac_1 (new api)
-------------
mkdir cfg
mount none cfg -t configfs
mkdir cfg/usb_gadget/g1
cd cfg/usb_gadget/g1
mkdir configs/c.1
mkdir functions/uac1_newapi.0
mkdir strings/0x409
mkdir configs/c.1/strings/0x409
echo 0x0101 > idProduct
echo 0x1d6b > idVendor
echo my-serial-num > strings/0x409/serialnumber
echo my-manufacturer > strings/0x409/manufacturer
echo "Test gadget" > strings/0x409/product
echo "Conf 1" > configs/c.1/strings/0x409/configuration
echo 120 > configs/c.1/MaxPower
ln -s functions/uac1_newapi.0 configs/c.1
echo musb-hdrc.0.auto > UDC


>
>
> Console output:
> root@imx6qdlsolo:~# arecord -f dat -t wav -D hw:1,0 | aplay -D hw:0,0 &
> [1] 859
> root@imx6qdlsolo:~#
> root@imx6qdlsolo:~# Recording WAVE 'stdin' : Signed 16 bit Little
> Endian, Rate 48000 Hz, Stereo
> Playing WAVE 'stdin' : Signed 16 bit Little Endian, Rate 48000 Hz,
> Stereo
> underrun!!! (at least 36.634 ms long)
> underrun!!! (at least 36.117 ms long)
> underrun!!! (at least 42.132 ms long)
> underrun!!! (at least 40.157 ms long)
> underrun!!! (at least 36.207 ms long)
> underrun!!! (at least 39.173 ms long)
> underrun!!! (at least 36.119 ms long)
> underrun!!! (at least 36.164 ms long)
>
>

I use alsaloop tool that is more powerful than just arecord/aplay
through pipe. It is compiled with libsamplerate so can do
resampling on the fly. Also it has few clever algorithms for
processing overruns/underruns. There are many possible
configuration option combinations. For example, one of used
by me (but I use other combinations as well) was:
$ alsaloop -C hw:0,0 -P hw:1,0 -t 10000  -A 3 -S 1 -b -v

This is for routing audio from gadget to real ALSA card

Hope this may be helpful for you and for other people
who want to try this new u_audio API.

Best regards,
Ruslan

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