[PATCH v5 00/11] Add XU support to UVC Gadget

[PATCH v5 00/11] Add XU support to UVC Gadget

[Daniel Scally]

Hello all

This series adds support for the definition of extension units in configfs for
the UVC Gadget. The XUs are modelled as config_items within a new "extensions"
group under control, which seemed like an appropriate place to put them.

To allow the XU's to be inserted in the function graph, the bSourceID attribute
for the default output terminal is made writeable - users will need to configure
it with the bUnitID of the XU that they want to use as the OT's source. This does
mean that the XUs can _only_ be placed immediately preceding the OT, but I think
that that's fine for now.

The XUs configured through this series have been tested via uvc-gadget, uvcvideo
and uvcdynctrl.

The series is based on usb-testing plus my recent "usb: gadget: uvc: Correct
documentation formatting" patch.

Thanks
Dan


Daniel Scally (11):
  usb: gadget: uvc: Make bSourceID read/write
  usb: gadget: uvc: Generalise helper functions for reuse
  usb: gadget: uvc: Allow definition of XUs in configfs
  usb: gadget: uvc: Copy XU descriptors during .bind()
  usb: gadget: configfs: Rename struct gadget_strings
  usb: gadget: configfs: Support arbitrary string descriptors
  usb: gadget: configfs: Attach arbitrary strings to cdev
  usb: gadget: uvc: Allow linking XUs to string descriptors
  usb: gadget: uvc: Pick up custom string descriptor IDs
  usb: gadget: uvc: Allow linking function to string descs
  usb: gadget: uvc: Use custom strings if available

 .../ABI/testing/configfs-usb-gadget-uvc       |  30 +-
 Documentation/usb/gadget_configfs.rst         |  10 +
 drivers/usb/gadget/configfs.c                 | 291 ++++++-
 drivers/usb/gadget/function/f_uvc.c           |  69 +-
 drivers/usb/gadget/function/u_uvc.h           |  15 +
 drivers/usb/gadget/function/uvc.h             |   1 +
 drivers/usb/gadget/function/uvc_configfs.c    | 771 ++++++++++++++++--
 drivers/usb/gadget/function/uvc_configfs.h    |  30 +
 include/linux/usb/composite.h                 |   1 +
 include/linux/usb/gadget.h                    |  11 +
 10 files changed, 1138 insertions(+), 91 deletions(-)

-- 
2.34.1

[PATCH v5 01/11] usb: gadget: uvc: Make bSourceID read/write

[Daniel Scally]

At the moment, the UVC function graph is hardcoded IT -> PU -> OT.
To add XU support we need the ability to insert the XU descriptors
into the chain. To facilitate that, make the output terminal's
bSourceID attribute writeable so that we can configure its source.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- None 

Changes in v2:

	- Updated the ABI Documentation to reflect the change.

 .../ABI/testing/configfs-usb-gadget-uvc       |  2 +-
 drivers/usb/gadget/function/uvc_configfs.c    | 59 ++++++++++++++++++-
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index 9c716dd3ae6f..c2323f2b069b 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -54,7 +54,7 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Default output terminal descriptors
 
-		All attributes read only:
+		All attributes read only except bSourceID:
 
 		==============	=============================================
 		iTerminal	index of string descriptor
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index e2ffddb969fd..b52aae924d66 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -484,11 +484,68 @@ UVC_ATTR_RO(uvcg_default_output_, cname, aname)
 UVCG_DEFAULT_OUTPUT_ATTR(b_terminal_id, bTerminalID, 8);
 UVCG_DEFAULT_OUTPUT_ATTR(w_terminal_type, wTerminalType, 16);
 UVCG_DEFAULT_OUTPUT_ATTR(b_assoc_terminal, bAssocTerminal, 8);
-UVCG_DEFAULT_OUTPUT_ATTR(b_source_id, bSourceID, 8);
 UVCG_DEFAULT_OUTPUT_ATTR(i_terminal, iTerminal, 8);
 
 #undef UVCG_DEFAULT_OUTPUT_ATTR
 
+static ssize_t uvcg_default_output_b_source_id_show(struct config_item *item,
+						    char *page)
+{
+	struct config_group *group = to_config_group(item);
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvc_output_terminal_descriptor *cd;
+	int result;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = group->cg_item.ci_parent->ci_parent->
+			ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+	cd = &opts->uvc_output_terminal;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%u\n", le8_to_cpu(cd->bSourceID));
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return result;
+}
+
+static ssize_t uvcg_default_output_b_source_id_store(struct config_item *item,
+						     const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item);
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvc_output_terminal_descriptor *cd;
+	int result;
+	u8 num;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = group->cg_item.ci_parent->ci_parent->
+			ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+	cd = &opts->uvc_output_terminal;
+
+	result = kstrtou8(page, 0, &num);
+	if (result)
+		return result;
+
+	mutex_lock(&opts->lock);
+	cd->bSourceID = num;
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return len;
+}
+UVC_ATTR(uvcg_default_output_, b_source_id, bSourceID);
+
 static struct configfs_attribute *uvcg_default_output_attrs[] = {
 	&uvcg_default_output_attr_b_terminal_id,
 	&uvcg_default_output_attr_w_terminal_type,
-- 
2.34.1

[PATCH v5 02/11] usb: gadget: uvc: Generalise helper functions for reuse

[Daniel Scally]

The __uvcg_*frm_intrv() helper functions can be helpful when adding
support for similar attributes. Generalise the functions and
move them higher in the file for better coverage.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3 (Laurent):

	- Spelling
	- Renamed the "interv" variable to "values"
	- Switched to functions taking a size argument rather than a macro that
	duplicated the implementation.
	
Changes in v2:

	- none

 drivers/usb/gadget/function/uvc_configfs.c | 120 ++++++++++++---------
 1 file changed, 67 insertions(+), 53 deletions(-)

diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index b52aae924d66..b32ecbdfd88d 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -47,6 +47,71 @@ static int uvcg_config_compare_u32(const void *l, const void *r)
 	return li < ri ? -1 : li == ri ? 0 : 1;
 }
 
+static inline int __uvcg_count_item_entries(char *buf, void *priv, unsigned int size)
+{
+	++*((int *)priv);
+	return 0;
+}
+
+static inline int __uvcg_fill_item_entries(char *buf, void *priv, unsigned int size)
+{
+	unsigned int num;
+	u8 **values;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &num);
+	if (ret)
+		return ret;
+
+	if (num != (num & GENMASK((size * 8) - 1, 0)))
+		return -ERANGE;
+
+	values = priv;
+	memcpy(*values, &num, size);
+	*values += size;
+
+	return 0;
+}
+
+static int __uvcg_iter_item_entries(const char *page, size_t len,
+				    int (*fun)(char *, void *, unsigned int),
+				    void *priv, unsigned int size)
+{
+	/* sign, base 2 representation, newline, terminator */
+	unsigned int bufsize = 1 + size * 8 + 1 + 1;
+	const char *pg = page;
+	int i, ret = 0;
+	char *buf;
+
+	if (!fun)
+		return -EINVAL;
+
+	buf = kzalloc(bufsize, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	while (pg - page < len) {
+		i = 0;
+		while (i < sizeof(buf) && (pg - page < len) &&
+		       *pg != '\0' && *pg != '\n')
+			buf[i++] = *pg++;
+		if (i == sizeof(buf)) {
+			ret = -EINVAL;
+			goto out_free_buf;
+		}
+		while ((pg - page < len) && (*pg == '\0' || *pg == '\n'))
+			++pg;
+		buf[i] = '\0';
+		ret = fun(buf, priv, size);
+		if (ret)
+			goto out_free_buf;
+	}
+
+out_free_buf:
+	kfree(buf);
+	return ret;
+}
+
 struct uvcg_config_group_type {
 	struct config_item_type type;
 	const char *name;
@@ -1336,57 +1401,6 @@ static ssize_t uvcg_frame_dw_frame_interval_show(struct config_item *item,
 	return result;
 }
 
-static inline int __uvcg_count_frm_intrv(char *buf, void *priv)
-{
-	++*((int *)priv);
-	return 0;
-}
-
-static inline int __uvcg_fill_frm_intrv(char *buf, void *priv)
-{
-	u32 num, **interv;
-	int ret;
-
-	ret = kstrtou32(buf, 0, &num);
-	if (ret)
-		return ret;
-
-	interv = priv;
-	**interv = num;
-	++*interv;
-
-	return 0;
-}
-
-static int __uvcg_iter_frm_intrv(const char *page, size_t len,
-				 int (*fun)(char *, void *), void *priv)
-{
-	/* sign, base 2 representation, newline, terminator */
-	char buf[1 + sizeof(u32) * 8 + 1 + 1];
-	const char *pg = page;
-	int i, ret;
-
-	if (!fun)
-		return -EINVAL;
-
-	while (pg - page < len) {
-		i = 0;
-		while (i < sizeof(buf) && (pg - page < len) &&
-				*pg != '\0' && *pg != '\n')
-			buf[i++] = *pg++;
-		if (i == sizeof(buf))
-			return -EINVAL;
-		while ((pg - page < len) && (*pg == '\0' || *pg == '\n'))
-			++pg;
-		buf[i] = '\0';
-		ret = fun(buf, priv);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
 static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
 						  const char *page, size_t len)
 {
@@ -1410,7 +1424,7 @@ static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
 		goto end;
 	}
 
-	ret = __uvcg_iter_frm_intrv(page, len, __uvcg_count_frm_intrv, &n);
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n, sizeof(u32));
 	if (ret)
 		goto end;
 
@@ -1420,7 +1434,7 @@ static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
 		goto end;
 	}
 
-	ret = __uvcg_iter_frm_intrv(page, len, __uvcg_fill_frm_intrv, &tmp);
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &tmp, sizeof(u32));
 	if (ret) {
 		kfree(frm_intrv);
 		goto end;
-- 
2.34.1

[PATCH v5 03/11] usb: gadget: uvc: Allow definition of XUs in configfs

[Daniel Scally]

The UVC gadget at present has no support for extension units. Add the
infrastructure to uvc_configfs.c that allows users to create XUs via
configfs. These will be stored in a new child of uvcg_control_grp_type
with the name "extensions".

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- Corrected table formatting (kernel test bot)

Changes in v4:

	- None

Changes in v3 (Laurent):

	- Spelling
	- Passed __GFP_ZERO to krealloc_array() instead of memsetting the new
	entries to zero afterwards.
	- Switched to using the bLength calculation macro instead of open coding
	the same thing
	- Fixed a return without mutex_unlock()

Changes in v2:

	- Updated the ABI documentation with the new elements.
	- Locked the su_mutex when appropriate.

 .../ABI/testing/configfs-usb-gadget-uvc       |  28 +
 drivers/usb/gadget/function/f_uvc.c           |   9 +
 drivers/usb/gadget/function/u_uvc.h           |   7 +
 drivers/usb/gadget/function/uvc_configfs.c    | 480 ++++++++++++++++++
 drivers/usb/gadget/function/uvc_configfs.h    |  29 ++
 5 files changed, 553 insertions(+)

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index c2323f2b069b..80b98a4a4d0f 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -113,6 +113,34 @@ Description:	Default processing unit descriptors
 		bUnitID		a non-zero id of this unit
 		===============	========================================
 
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/extensions
+Date:		Nov 2022
+KernelVersion:	6.1
+Description:	Extension unit descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/extensions/name
+Date:		Nov 2022
+KernelVersion:	6.1
+Description:	Extension Unit (XU) Descriptor
+
+		bLength, bUnitID and iExtension are read-only. All others are
+		read-write.
+
+		=================	========================================
+		bLength			size of the descriptor in bytes
+		bUnitID			non-zero ID of this unit
+		guidExtensionCode	Vendor-specific code identifying the XU
+		bNumControls		number of controls in this XU
+		bNrInPins		number of input pins for this unit
+		baSourceID		list of the IDs of the units or terminals
+					to which this XU is connected
+		bControlSize		size of the bmControls field in bytes
+		bmControls		list of bitmaps detailing which vendor
+					specific controls are supported
+		iExtension		index of a string descriptor that describes
+					this extension unit
+		=================	========================================
+
 What:		/config/usb-gadget/gadget/functions/uvc.name/control/header
 Date:		Dec 2014
 KernelVersion:	4.0
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 835e121a806f..443333471b4d 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -865,6 +865,13 @@ static struct usb_function_instance *uvc_alloc_inst(void)
 	od->bSourceID			= 2;
 	od->iTerminal			= 0;
 
+	/*
+	 * With the ability to add XUs to the UVC function graph, we need to be
+	 * able to allocate unique unit IDs to them. The IDs are 1-based, with
+	 * the CT, PU and OT above consuming the first 3.
+	 */
+	opts->last_unit_id		= 3;
+
 	/* Prepare fs control class descriptors for configfs-based gadgets */
 	ctl_cls = opts->uvc_fs_control_cls;
 	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
@@ -885,6 +892,8 @@ static struct usb_function_instance *uvc_alloc_inst(void)
 	opts->ss_control =
 		(const struct uvc_descriptor_header * const *)ctl_cls;
 
+	INIT_LIST_HEAD(&opts->extension_units);
+
 	opts->streaming_interval = 1;
 	opts->streaming_maxpacket = 1024;
 	snprintf(opts->function_name, sizeof(opts->function_name), "UVC Camera");
diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h
index 67cf319e9c2d..0345b8fc36ff 100644
--- a/drivers/usb/gadget/function/u_uvc.h
+++ b/drivers/usb/gadget/function/u_uvc.h
@@ -28,6 +28,7 @@ struct f_uvc_opts {
 	unsigned int					control_interface;
 	unsigned int					streaming_interface;
 	char						function_name[32];
+	unsigned int					last_unit_id;
 
 	bool						enable_interrupt_ep;
 
@@ -65,6 +66,12 @@ struct f_uvc_opts {
 	struct uvc_descriptor_header			*uvc_fs_control_cls[5];
 	struct uvc_descriptor_header			*uvc_ss_control_cls[5];
 
+	/*
+	 * Control descriptors for extension units. There could be any number
+	 * of these, including none at all.
+	 */
+	struct list_head				extension_units;
+
 	/*
 	 * Streaming descriptors for full-speed, high-speed and super-speed.
 	 * Used by configfs only, must not be touched by legacy gadgets. The
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index b32ecbdfd88d..c365f323af45 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -662,6 +662,485 @@ static const struct uvcg_config_group_type uvcg_terminal_grp_type = {
 	},
 };
 
+/* -----------------------------------------------------------------------------
+ * control/extensions
+ */
+
+#define UVCG_EXTENSION_ATTR(cname, aname, ro...)			\
+static ssize_t uvcg_extension_##cname##_show(struct config_item *item,	\
+					     char *page)		\
+{									\
+	struct config_group *group = to_config_group(item->ci_parent);	\
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;		\
+	struct uvcg_extension *xu = to_uvcg_extension(item);		\
+	struct config_item *opts_item;					\
+	struct f_uvc_opts *opts;					\
+	int ret;							\
+									\
+	mutex_lock(su_mutex);						\
+									\
+	opts_item = item->ci_parent->ci_parent->ci_parent;		\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	ret = sprintf(page, "%u\n", xu->desc.aname);			\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+									\
+	return ret;							\
+}									\
+UVC_ATTR##ro(uvcg_extension_, cname, aname)
+
+UVCG_EXTENSION_ATTR(b_length, bLength, _RO);
+UVCG_EXTENSION_ATTR(b_unit_id, bUnitID, _RO);
+UVCG_EXTENSION_ATTR(i_extension, iExtension, _RO);
+
+static ssize_t uvcg_extension_b_num_controls_store(struct config_item *item,
+						   const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	int ret;
+	u8 num;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
+	mutex_lock(&opts->lock);
+	xu->desc.bNumControls = num;
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return len;
+}
+UVCG_EXTENSION_ATTR(b_num_controls, bNumControls);
+
+/*
+ * In addition to storing bNrInPins, this function needs to realloc the
+ * memory for the baSourceID array and additionally expand bLength.
+ */
+static ssize_t uvcg_extension_b_nr_in_pins_store(struct config_item *item,
+						 const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	void *tmp_buf;
+	int ret;
+	u8 num;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
+	mutex_lock(&opts->lock);
+
+	if (num == xu->desc.bNrInPins) {
+		ret = len;
+		goto unlock;
+	}
+
+	tmp_buf = krealloc_array(xu->desc.baSourceID, num, sizeof(u8),
+				 GFP_KERNEL | __GFP_ZERO);
+	if (!tmp_buf) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	xu->desc.baSourceID = tmp_buf;
+	xu->desc.bNrInPins = num;
+	xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
+						      xu->desc.bControlSize);
+
+	ret = len;
+
+unlock:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+UVCG_EXTENSION_ATTR(b_nr_in_pins, bNrInPins);
+
+/*
+ * In addition to storing bControlSize, this function needs to realloc the
+ * memory for the bmControls array and additionally expand bLength.
+ */
+static ssize_t uvcg_extension_b_control_size_store(struct config_item *item,
+						   const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	void *tmp_buf;
+	int ret;
+	u8 num;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		return ret;
+
+	mutex_lock(&opts->lock);
+
+	if (num == xu->desc.bControlSize) {
+		ret = len;
+		goto unlock;
+	}
+
+	tmp_buf = krealloc_array(xu->desc.bmControls, num, sizeof(u8),
+				 GFP_KERNEL | __GFP_ZERO);
+	if (!tmp_buf) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	xu->desc.bmControls = tmp_buf;
+	xu->desc.bControlSize = num;
+	xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
+						      xu->desc.bControlSize);
+
+	ret = len;
+
+unlock:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+UVCG_EXTENSION_ATTR(b_control_size, bControlSize);
+
+static ssize_t uvcg_extension_guid_extension_code_show(struct config_item *item,
+						       char *page)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	memcpy(page, xu->desc.guidExtensionCode, sizeof(xu->desc.guidExtensionCode));
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return sizeof(xu->desc.guidExtensionCode);
+}
+
+static ssize_t uvcg_extension_guid_extension_code_store(struct config_item *item,
+							const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	int ret;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	memcpy(xu->desc.guidExtensionCode, page,
+	       min(sizeof(xu->desc.guidExtensionCode), len));
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	ret = sizeof(xu->desc.guidExtensionCode);
+
+	return ret;
+}
+
+UVC_ATTR(uvcg_extension_, guid_extension_code, guidExtensionCode);
+
+static ssize_t uvcg_extension_ba_source_id_show(struct config_item *item,
+						char *page)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	char *pg = page;
+	int ret, i;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	for (ret = 0, i = 0; i < xu->desc.bNrInPins; ++i) {
+		ret += sprintf(pg, "%u\n", xu->desc.baSourceID[i]);
+		pg = page + ret;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return ret;
+}
+
+static ssize_t uvcg_extension_ba_source_id_store(struct config_item *item,
+						 const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	u8 *source_ids, *iter;
+	int ret, n = 0;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
+				       sizeof(u8));
+	if (ret)
+		goto unlock;
+
+	iter = source_ids = kcalloc(n, sizeof(u8), GFP_KERNEL);
+	if (!source_ids) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &iter,
+				       sizeof(u8));
+	if (ret) {
+		kfree(source_ids);
+		goto unlock;
+	}
+
+	kfree(xu->desc.baSourceID);
+	xu->desc.baSourceID = source_ids;
+	xu->desc.bNrInPins = n;
+	xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
+						      xu->desc.bControlSize);
+
+	ret = len;
+
+unlock:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+UVC_ATTR(uvcg_extension_, ba_source_id, baSourceID);
+
+static ssize_t uvcg_extension_bm_controls_show(struct config_item *item,
+					       char *page)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	char *pg = page;
+	int ret, i;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	for (ret = 0, i = 0; i < xu->desc.bControlSize; ++i) {
+		ret += sprintf(pg, "0x%02x\n", xu->desc.bmControls[i]);
+		pg = page + ret;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return ret;
+}
+
+static ssize_t uvcg_extension_bm_controls_store(struct config_item *item,
+						const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item->ci_parent);
+	struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	u8 *bm_controls, *iter;
+	int ret, n = 0;
+
+	mutex_lock(su_mutex);
+
+	opts_item = item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
+				       sizeof(u8));
+	if (ret)
+		goto unlock;
+
+	iter = bm_controls = kcalloc(n, sizeof(u8), GFP_KERNEL);
+	if (!bm_controls) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &iter,
+				       sizeof(u8));
+	if (ret) {
+		kfree(bm_controls);
+		goto unlock;
+	}
+
+	kfree(xu->desc.bmControls);
+	xu->desc.bmControls = bm_controls;
+	xu->desc.bControlSize = n;
+	xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
+						      xu->desc.bControlSize);
+
+	ret = len;
+
+unlock:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+UVC_ATTR(uvcg_extension_, bm_controls, bmControls);
+
+static struct configfs_attribute *uvcg_extension_attrs[] = {
+	&uvcg_extension_attr_b_length,
+	&uvcg_extension_attr_b_unit_id,
+	&uvcg_extension_attr_b_num_controls,
+	&uvcg_extension_attr_b_nr_in_pins,
+	&uvcg_extension_attr_b_control_size,
+	&uvcg_extension_attr_guid_extension_code,
+	&uvcg_extension_attr_ba_source_id,
+	&uvcg_extension_attr_bm_controls,
+	&uvcg_extension_attr_i_extension,
+	NULL,
+};
+
+static void uvcg_extension_release(struct config_item *item)
+{
+	struct uvcg_extension *xu = container_of(item, struct uvcg_extension, item);
+
+	kfree(xu);
+}
+
+static struct configfs_item_operations uvcg_extension_item_ops = {
+	.release	= uvcg_extension_release,
+};
+
+static const struct config_item_type uvcg_extension_type = {
+	.ct_item_ops	= &uvcg_extension_item_ops,
+	.ct_attrs	= uvcg_extension_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void uvcg_extension_drop(struct config_group *group, struct config_item *item)
+{
+	struct uvcg_extension *xu = container_of(item, struct uvcg_extension, item);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+
+	opts_item = group->cg_item.ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+
+	config_item_put(item);
+	list_del(&xu->list);
+	kfree(xu->desc.baSourceID);
+	kfree(xu->desc.bmControls);
+
+	mutex_unlock(&opts->lock);
+}
+
+static struct config_item *uvcg_extension_make(struct config_group *group, const char *name)
+{
+	struct config_item *opts_item;
+	struct uvcg_extension *xu;
+	struct f_uvc_opts *opts;
+
+	opts_item = group->cg_item.ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	xu = kzalloc(sizeof(*xu), GFP_KERNEL);
+	if (!xu)
+		return ERR_PTR(-ENOMEM);
+
+	xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(0, 0);
+	xu->desc.bDescriptorType = USB_DT_CS_INTERFACE;
+	xu->desc.bDescriptorSubType = UVC_VC_EXTENSION_UNIT;
+	xu->desc.bNumControls = 0;
+	xu->desc.bNrInPins = 0;
+	xu->desc.baSourceID = NULL;
+	xu->desc.bControlSize = 0;
+	xu->desc.bmControls = NULL;
+
+	mutex_lock(&opts->lock);
+
+	xu->desc.bUnitID = ++opts->last_unit_id;
+
+	config_item_init_type_name(&xu->item, name, &uvcg_extension_type);
+	list_add_tail(&xu->list, &opts->extension_units);
+
+	mutex_unlock(&opts->lock);
+
+	return &xu->item;
+}
+
+static struct configfs_group_operations uvcg_extensions_grp_ops = {
+	.make_item	= uvcg_extension_make,
+	.drop_item	= uvcg_extension_drop,
+};
+
+static const struct uvcg_config_group_type uvcg_extensions_grp_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_group_ops	= &uvcg_extensions_grp_ops,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "extensions",
+};
+
 /* -----------------------------------------------------------------------------
  * control/class/{fs|ss}
  */
@@ -909,6 +1388,7 @@ static const struct uvcg_config_group_type uvcg_control_grp_type = {
 		&uvcg_processing_grp_type,
 		&uvcg_terminal_grp_type,
 		&uvcg_control_class_grp_type,
+		&uvcg_extensions_grp_type,
 		NULL,
 	},
 };
diff --git a/drivers/usb/gadget/function/uvc_configfs.h b/drivers/usb/gadget/function/uvc_configfs.h
index 174ee691302b..5557813bcca9 100644
--- a/drivers/usb/gadget/function/uvc_configfs.h
+++ b/drivers/usb/gadget/function/uvc_configfs.h
@@ -142,6 +142,35 @@ static inline struct uvcg_mjpeg *to_uvcg_mjpeg(struct config_item *item)
 	return container_of(to_uvcg_format(item), struct uvcg_mjpeg, fmt);
 }
 
+/* -----------------------------------------------------------------------------
+ * control/extensions/<NAME>
+ */
+
+struct uvcg_extension_unit_descriptor {
+	u8 bLength;
+	u8 bDescriptorType;
+	u8 bDescriptorSubType;
+	u8 bUnitID;
+	u8 guidExtensionCode[16];
+	u8 bNumControls;
+	u8 bNrInPins;
+	u8 *baSourceID;
+	u8 bControlSize;
+	u8 *bmControls;
+	u8 iExtension;
+} __packed;
+
+struct uvcg_extension {
+	struct config_item item;
+	struct list_head list;
+	struct uvcg_extension_unit_descriptor desc;
+};
+
+static inline struct uvcg_extension *to_uvcg_extension(struct config_item *item)
+{
+	return container_of(item, struct uvcg_extension, item);
+}
+
 int uvcg_attach_configfs(struct f_uvc_opts *opts);
 
 #endif /* UVC_CONFIGFS_H */
-- 
2.34.1

[PATCH v5 04/11] usb: gadget: uvc: Copy XU descriptors during .bind()

[Daniel Scally]

Now that extension unit support is available through configfs we need
to copy the descriptors for the XUs during uvc_function_bind() so that
they're exposed to the usb subsystem.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Laurent - I didn't add your tag because having switched it to a function I actually
decided I preferred it this way and switched it back; too many pointers to
pointers of things made it less easy to follow I think, but if you disagree let me
know and I'll go ahead.

Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:
	- Dropped a local variable.

Changes in v2:

	- none

 drivers/usb/gadget/function/f_uvc.c | 33 +++++++++++++++++++++++++++++
 drivers/usb/gadget/function/uvc.h   |  1 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 443333471b4d..f6fd5decdcb7 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -478,6 +478,25 @@ uvc_register_video(struct uvc_device *uvc)
 		} \
 	} while (0)
 
+#define UVC_COPY_XU_DESCRIPTOR(mem, dst, desc)					\
+	do {									\
+		*(dst)++ = mem;							\
+		memcpy(mem, desc, 22); /* bLength to bNrInPins */		\
+		mem += 22;							\
+										\
+		memcpy(mem, (desc)->baSourceID, (desc)->bNrInPins);		\
+		mem += (desc)->bNrInPins;					\
+										\
+		memcpy(mem, &(desc)->bControlSize, 1);				\
+		mem++;								\
+										\
+		memcpy(mem, (desc)->bmControls, (desc)->bControlSize);		\
+		mem += (desc)->bControlSize;					\
+										\
+		memcpy(mem, &(desc)->iExtension, 1);				\
+		mem++;								\
+	} while (0)
+
 static struct usb_descriptor_header **
 uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 {
@@ -489,6 +508,7 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 	const struct usb_descriptor_header * const *src;
 	struct usb_descriptor_header **dst;
 	struct usb_descriptor_header **hdr;
+	struct uvcg_extension *xu;
 	unsigned int control_size;
 	unsigned int streaming_size;
 	unsigned int n_desc;
@@ -556,6 +576,13 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 		bytes += (*src)->bLength;
 		n_desc++;
 	}
+
+	list_for_each_entry(xu, uvc->desc.extension_units, list) {
+		control_size += xu->desc.bLength;
+		bytes += xu->desc.bLength;
+		n_desc++;
+	}
+
 	for (src = (const struct usb_descriptor_header **)uvc_streaming_cls;
 	     *src; ++src) {
 		streaming_size += (*src)->bLength;
@@ -582,6 +609,10 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
 	uvc_control_header = mem;
 	UVC_COPY_DESCRIPTORS(mem, dst,
 		(const struct usb_descriptor_header **)uvc_control_desc);
+
+	list_for_each_entry(xu, uvc->desc.extension_units, list)
+		UVC_COPY_XU_DESCRIPTOR(mem, dst, &xu->desc);
+
 	uvc_control_header->wTotalLength = cpu_to_le16(control_size);
 	uvc_control_header->bInCollection = 1;
 	uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;
@@ -1025,6 +1056,8 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 		return ERR_PTR(-EBUSY);
 	}
 
+	uvc->desc.extension_units = &opts->extension_units;
+
 	++opts->refcnt;
 	mutex_unlock(&opts->lock);
 
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index daf226610f49..100475b1363e 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -143,6 +143,7 @@ struct uvc_device {
 		const struct uvc_descriptor_header * const *fs_streaming;
 		const struct uvc_descriptor_header * const *hs_streaming;
 		const struct uvc_descriptor_header * const *ss_streaming;
+		struct list_head *extension_units;
 	} desc;
 
 	unsigned int control_intf;
-- 
2.34.1

[PATCH v5 05/11] usb: gadget: configfs: Rename struct gadget_strings

[Daniel Scally]

The struct gadget_strings really represents a single language in
configfs. Rename it to make that more clear.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- New patch

 drivers/usb/gadget/configfs.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index e89aa2877a33..3beeafcf2e3b 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -86,7 +86,7 @@ static inline struct gadget_info *cfg_to_gadget_info(struct config_usb_cfg *cfg)
 	return container_of(cfg->c.cdev, struct gadget_info, cdev);
 }
 
-struct gadget_strings {
+struct gadget_language {
 	struct usb_gadget_strings stringtab_dev;
 	struct usb_string strings[USB_GADGET_FIRST_AVAIL_IDX];
 	char *manufacturer;
@@ -372,9 +372,9 @@ static struct configfs_attribute *gadget_root_attrs[] = {
 	NULL,
 };
 
-static inline struct gadget_strings *to_gadget_strings(struct config_item *item)
+static inline struct gadget_language *to_gadget_language(struct config_item *item)
 {
-	return container_of(to_config_group(item), struct gadget_strings,
+	return container_of(to_config_group(item), struct gadget_language,
 			 group);
 }
 
@@ -768,20 +768,20 @@ static const struct config_item_type config_desc_type = {
 	.ct_owner       = THIS_MODULE,
 };
 
-GS_STRINGS_RW(gadget_strings, manufacturer);
-GS_STRINGS_RW(gadget_strings, product);
-GS_STRINGS_RW(gadget_strings, serialnumber);
+GS_STRINGS_RW(gadget_language, manufacturer);
+GS_STRINGS_RW(gadget_language, product);
+GS_STRINGS_RW(gadget_language, serialnumber);
 
-static struct configfs_attribute *gadget_strings_langid_attrs[] = {
-	&gadget_strings_attr_manufacturer,
-	&gadget_strings_attr_product,
-	&gadget_strings_attr_serialnumber,
+static struct configfs_attribute *gadget_language_langid_attrs[] = {
+	&gadget_language_attr_manufacturer,
+	&gadget_language_attr_product,
+	&gadget_language_attr_serialnumber,
 	NULL,
 };
 
-static void gadget_strings_attr_release(struct config_item *item)
+static void gadget_language_attr_release(struct config_item *item)
 {
-	struct gadget_strings *gs = to_gadget_strings(item);
+	struct gadget_language *gs = to_gadget_language(item);
 
 	kfree(gs->manufacturer);
 	kfree(gs->product);
@@ -791,8 +791,8 @@ static void gadget_strings_attr_release(struct config_item *item)
 	kfree(gs);
 }
 
-USB_CONFIG_STRING_RW_OPS(gadget_strings);
-USB_CONFIG_STRINGS_LANG(gadget_strings, gadget_info);
+USB_CONFIG_STRING_RW_OPS(gadget_language);
+USB_CONFIG_STRINGS_LANG(gadget_language, gadget_info);
 
 static inline struct gadget_info *webusb_item_to_gadget_info(
 		struct config_item *item)
@@ -1472,7 +1472,7 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
 
 	/* init all strings */
 	if (!list_empty(&gi->string_list)) {
-		struct gadget_strings *gs;
+		struct gadget_language *gs;
 
 		i = 0;
 		list_for_each_entry(gs, &gi->string_list, list) {
@@ -1761,7 +1761,7 @@ static struct config_group *gadgets_make(
 	configfs_add_default_group(&gi->configs_group, &gi->group);
 
 	config_group_init_type_name(&gi->strings_group, "strings",
-			&gadget_strings_strings_type);
+			&gadget_language_strings_type);
 	configfs_add_default_group(&gi->strings_group, &gi->group);
 
 	config_group_init_type_name(&gi->os_desc_group, "os_desc",
-- 
2.34.1

[PATCH v5 06/11] usb: gadget: configfs: Support arbitrary string descriptors

[Daniel Scally]

Add a framework to allow users to define arbitrary string descriptors
for a USB Gadget. This is modelled as a new type of config item rather
than as hardcoded attributes so as to be as flexible as possible.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- Added some explanatory documentation (Alan)

Changes in v3:

	- Moved this functionality from the UVC function to usb gadget core.

Changes in v2:

	- New patch

 Documentation/usb/gadget_configfs.rst |  10 ++
 drivers/usb/gadget/configfs.c         | 172 +++++++++++++++++++++++++-
 include/linux/usb/gadget.h            |  11 ++
 3 files changed, 191 insertions(+), 2 deletions(-)

diff --git a/Documentation/usb/gadget_configfs.rst b/Documentation/usb/gadget_configfs.rst
index e4566ffb223f..868e118a2644 100644
--- a/Documentation/usb/gadget_configfs.rst
+++ b/Documentation/usb/gadget_configfs.rst
@@ -90,6 +90,16 @@ Then the strings can be specified::
 	$ echo <manufacturer> > strings/0x409/manufacturer
 	$ echo <product> > strings/0x409/product
 
+Further custom string descriptors can be created as directories within the
+language's directory, with the string text being written to the "s" attribute
+within the string's directory:
+
+	$ mkdir strings/0x409/xu.0
+	$ echo <string text> > strings/0x409/xu.0/s
+
+Where function drivers support it, functions may allow symlinks to these custom
+string descriptors to associate those strings with class descriptors.
+
 2. Creating the configurations
 ------------------------------
 
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 3beeafcf2e3b..ac275855eeb6 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -95,6 +95,8 @@ struct gadget_language {
 
 	struct config_group group;
 	struct list_head list;
+	struct list_head gadget_strings;
+	unsigned int nstrings;
 };
 
 struct gadget_config_name {
@@ -791,8 +793,174 @@ static void gadget_language_attr_release(struct config_item *item)
 	kfree(gs);
 }
 
-USB_CONFIG_STRING_RW_OPS(gadget_language);
-USB_CONFIG_STRINGS_LANG(gadget_language, gadget_info);
+static struct configfs_item_operations gadget_language_langid_item_ops = {
+	.release                = gadget_language_attr_release,
+};
+
+static ssize_t gadget_string_id_show(struct config_item *item, char *page)
+{
+	struct gadget_string *string = to_gadget_string(item);
+	int ret;
+
+	ret = sprintf(page, "%u\n", string->usb_string.id);
+	return ret;
+}
+CONFIGFS_ATTR_RO(gadget_string_, id);
+
+static ssize_t gadget_string_s_show(struct config_item *item, char *page)
+{
+	struct gadget_string *string = to_gadget_string(item);
+	int ret;
+
+	ret = snprintf(page, sizeof(string->string), "%s\n", string->string);
+	return ret;
+}
+
+static ssize_t gadget_string_s_store(struct config_item *item, const char *page,
+				     size_t len)
+{
+	struct gadget_string *string = to_gadget_string(item);
+	int size = min(sizeof(string->string), len + 1);
+	int ret;
+
+	if (len > USB_MAX_STRING_LEN)
+		return -EINVAL;
+
+	ret = strscpy(string->string, page, size);
+	return len;
+}
+CONFIGFS_ATTR(gadget_string_, s);
+
+static struct configfs_attribute *gadget_string_attrs[] = {
+	&gadget_string_attr_id,
+	&gadget_string_attr_s,
+	NULL,
+};
+
+static void gadget_string_release(struct config_item *item)
+{
+	struct gadget_string *string = to_gadget_string(item);
+
+	kfree(string);
+}
+
+static struct configfs_item_operations gadget_string_item_ops = {
+	.release	= gadget_string_release,
+};
+
+static const struct config_item_type gadget_string_type = {
+	.ct_item_ops	= &gadget_string_item_ops,
+	.ct_attrs	= gadget_string_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item *gadget_language_string_make(struct config_group *group,
+						       const char *name)
+{
+	struct gadget_language *language;
+	struct gadget_string *string;
+
+	language = to_gadget_language(&group->cg_item);
+
+	string = kzalloc(sizeof(*string), GFP_KERNEL);
+	if (!string)
+		return ERR_PTR(-ENOMEM);
+
+	string->usb_string.id = language->nstrings++;
+	string->usb_string.s = string->string;
+	list_add_tail(&string->list, &language->gadget_strings);
+
+	config_item_init_type_name(&string->item, name, &gadget_string_type);
+
+	return &string->item;
+}
+
+static void gadget_language_string_drop(struct config_group *group,
+					struct config_item *item)
+{
+	struct gadget_language *language;
+	struct gadget_string *string;
+	unsigned int i = USB_GADGET_FIRST_AVAIL_IDX;
+
+	language = to_gadget_language(&group->cg_item);
+	string = to_gadget_string(item);
+
+	list_del(&string->list);
+	language->nstrings--;
+
+	/* Reset the ids for the language's strings to guarantee a continuous set */
+	list_for_each_entry(string, &language->gadget_strings, list)
+		string->usb_string.id = i++;
+}
+
+static struct configfs_group_operations gadget_language_langid_group_ops = {
+	.make_item		= gadget_language_string_make,
+	.drop_item		= gadget_language_string_drop,
+};
+
+static struct config_item_type gadget_language_type = {
+	.ct_item_ops	= &gadget_language_langid_item_ops,
+	.ct_group_ops	= &gadget_language_langid_group_ops,
+	.ct_attrs	= gadget_language_langid_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *gadget_language_make(struct config_group *group,
+						 const char *name)
+{
+	struct gadget_info *gi;
+	struct gadget_language *gs;
+	struct gadget_language *new;
+	int langs = 0;
+	int ret;
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		return ERR_PTR(-ENOMEM);
+
+	ret = check_user_usb_string(name, &new->stringtab_dev);
+	if (ret)
+		goto err;
+	config_group_init_type_name(&new->group, name,
+				    &gadget_language_type);
+
+	gi = container_of(group, struct gadget_info, strings_group);
+	ret = -EEXIST;
+	list_for_each_entry(gs, &gi->string_list, list) {
+		if (gs->stringtab_dev.language == new->stringtab_dev.language)
+			goto err;
+		langs++;
+	}
+	ret = -EOVERFLOW;
+	if (langs >= MAX_USB_STRING_LANGS)
+		goto err;
+
+	list_add_tail(&new->list, &gi->string_list);
+	INIT_LIST_HEAD(&new->gadget_strings);
+
+	/* We have the default manufacturer, product and serialnumber strings */
+	new->nstrings = 3;
+	return &new->group;
+err:
+	kfree(new);
+	return ERR_PTR(ret);
+}
+
+static void gadget_language_drop(struct config_group *group,
+				 struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations gadget_language_group_ops = {
+	.make_group     = &gadget_language_make,
+	.drop_item      = &gadget_language_drop,
+};
+
+static struct config_item_type gadget_language_strings_type = {
+	.ct_group_ops   = &gadget_language_group_ops,
+	.ct_owner       = THIS_MODULE,
+};
 
 static inline struct gadget_info *webusb_item_to_gadget_info(
 		struct config_item *item)
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index dc3092cea99e..00750f7020f3 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -15,6 +15,7 @@
 #ifndef __LINUX_USB_GADGET_H
 #define __LINUX_USB_GADGET_H
 
+#include <linux/configfs.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/init.h>
@@ -821,6 +822,16 @@ int usb_gadget_get_string(const struct usb_gadget_strings *table, int id, u8 *bu
 /* check if the given language identifier is valid */
 bool usb_validate_langid(u16 langid);
 
+struct gadget_string {
+	struct config_item item;
+	struct list_head list;
+	char string[USB_MAX_STRING_LEN];
+	struct usb_string usb_string;
+};
+
+#define to_gadget_string(str_item)\
+container_of(str_item, struct gadget_string, item)
+
 /*-------------------------------------------------------------------------*/
 
 /* utility to simplify managing config descriptors */
-- 
2.34.1

[PATCH v5 07/11] usb: gadget: configfs: Attach arbitrary strings to cdev

[Daniel Scally]

Attach any arbitrary strings that are defined to the composite dev.
We handle the old-style manufacturer, product and serialnumbers
strings in the same function for simplicity.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- Replaced IS_ERR_OR_NULL() with IS_ERR() (Dan)

Changes in v3:

	- Was 7/9 in version 2, moved the same functionality from the UVC
	function to usb gadget core.

Changes in v2:

	- New patch

 drivers/usb/gadget/configfs.c | 93 +++++++++++++++++++++++++++++------
 include/linux/usb/composite.h |  1 +
 2 files changed, 78 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index ac275855eeb6..06a0b73e0546 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -1597,6 +1597,80 @@ static void purge_configs_funcs(struct gadget_info *gi)
 	}
 }
 
+static struct usb_string *
+configfs_attach_gadget_strings(struct gadget_info *gi)
+{
+	struct usb_gadget_strings **gadget_strings;
+	struct gadget_language *language;
+	struct gadget_string *string;
+	unsigned int nlangs = 0;
+	struct list_head *iter;
+	struct usb_string *us;
+	unsigned int i = 0;
+	int nstrings = -1;
+	unsigned int j;
+
+	list_for_each(iter, &gi->string_list)
+		nlangs++;
+
+	/* Bail out early if no languages are configured */
+	if (!nlangs)
+		return NULL;
+
+	gadget_strings = kcalloc(nlangs + 1, /* including NULL terminator */
+				 sizeof(struct usb_gadget_strings *), GFP_KERNEL);
+	if (!gadget_strings)
+		return ERR_PTR(-ENOMEM);
+
+	list_for_each_entry(language, &gi->string_list, list) {
+		struct usb_string *stringtab;
+
+		if (nstrings == -1) {
+			nstrings = language->nstrings;
+		} else if (nstrings != language->nstrings) {
+			pr_err("languages must contain the same number of strings\n");
+			us = ERR_PTR(-EINVAL);
+			goto cleanup;
+		}
+
+		stringtab = kcalloc(language->nstrings + 1, sizeof(struct usb_string),
+				    GFP_KERNEL);
+		if (!stringtab) {
+			us = ERR_PTR(-ENOMEM);
+			goto cleanup;
+		}
+
+		stringtab[USB_GADGET_MANUFACTURER_IDX].id = USB_GADGET_MANUFACTURER_IDX;
+		stringtab[USB_GADGET_MANUFACTURER_IDX].s = language->manufacturer;
+		stringtab[USB_GADGET_PRODUCT_IDX].id = USB_GADGET_PRODUCT_IDX;
+		stringtab[USB_GADGET_PRODUCT_IDX].s = language->product;
+		stringtab[USB_GADGET_SERIAL_IDX].id = USB_GADGET_SERIAL_IDX;
+		stringtab[USB_GADGET_SERIAL_IDX].s = language->serialnumber;
+
+		j = USB_GADGET_FIRST_AVAIL_IDX;
+		list_for_each_entry(string, &language->gadget_strings, list) {
+			memcpy(&stringtab[j], &string->usb_string, sizeof(struct usb_string));
+			j++;
+		}
+
+		language->stringtab_dev.strings = stringtab;
+		gadget_strings[i] = &language->stringtab_dev;
+		i++;
+	}
+
+	us = usb_gstrings_attach(&gi->cdev, gadget_strings, nstrings);
+
+cleanup:
+	list_for_each_entry(language, &gi->string_list, list) {
+		kfree(language->stringtab_dev.strings);
+		language->stringtab_dev.strings = NULL;
+	}
+
+	kfree(gadget_strings);
+
+	return us;
+}
+
 static int configfs_composite_bind(struct usb_gadget *gadget,
 		struct usb_gadget_driver *gdriver)
 {
@@ -1640,22 +1714,7 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
 
 	/* init all strings */
 	if (!list_empty(&gi->string_list)) {
-		struct gadget_language *gs;
-
-		i = 0;
-		list_for_each_entry(gs, &gi->string_list, list) {
-
-			gi->gstrings[i] = &gs->stringtab_dev;
-			gs->stringtab_dev.strings = gs->strings;
-			gs->strings[USB_GADGET_MANUFACTURER_IDX].s =
-				gs->manufacturer;
-			gs->strings[USB_GADGET_PRODUCT_IDX].s = gs->product;
-			gs->strings[USB_GADGET_SERIAL_IDX].s = gs->serialnumber;
-			i++;
-		}
-		gi->gstrings[i] = NULL;
-		s = usb_gstrings_attach(&gi->cdev, gi->gstrings,
-				USB_GADGET_FIRST_AVAIL_IDX);
+		s = configfs_attach_gadget_strings(gi);
 		if (IS_ERR(s)) {
 			ret = PTR_ERR(s);
 			goto err_comp_cleanup;
@@ -1664,6 +1723,8 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
 		gi->cdev.desc.iManufacturer = s[USB_GADGET_MANUFACTURER_IDX].id;
 		gi->cdev.desc.iProduct = s[USB_GADGET_PRODUCT_IDX].id;
 		gi->cdev.desc.iSerialNumber = s[USB_GADGET_SERIAL_IDX].id;
+
+		gi->cdev.usb_strings = s;
 	}
 
 	if (gi->use_webusb) {
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 7ef8cea67f50..608dc962748b 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -494,6 +494,7 @@ struct usb_composite_dev {
 	struct usb_composite_driver	*driver;
 	u8				next_string_id;
 	char				*def_manufacturer;
+	struct usb_string		*usb_strings;
 
 	/* the gadget driver won't enable the data pullup
 	 * while the deactivation count is nonzero.
-- 
2.34.1

[PATCH v5 08/11] usb: gadget: uvc: Allow linking XUs to string descriptors

[Daniel Scally]

Add .allow_link() and .drop_link() callbacks to allow users to link
an extension unit descriptor to a string descriptor.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- Changed the target of the links to in <gadget root>/strings

Changes in v2:

	- New patch

 drivers/usb/gadget/function/uvc_configfs.c | 52 ++++++++++++++++++++++
 drivers/usb/gadget/function/uvc_configfs.h |  1 +
 2 files changed, 53 insertions(+)

diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index c365f323af45..3ac27838514c 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -1064,8 +1064,60 @@ static void uvcg_extension_release(struct config_item *item)
 	kfree(xu);
 }
 
+static int uvcg_extension_allow_link(struct config_item *src, struct config_item *tgt)
+{
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(src);
+	struct config_item *gadget_item;
+	struct gadget_string *string;
+	struct config_item *strings;
+	int ret = 0;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	/* Validate that the target of the link is an entry in strings/<langid> */
+	gadget_item = src->ci_parent->ci_parent->ci_parent->ci_parent->ci_parent;
+	strings = config_group_find_item(to_config_group(gadget_item), "strings");
+	if (!strings || tgt->ci_parent->ci_parent != strings) {
+		ret = -EINVAL;
+		goto put_strings;
+	}
+
+	string = to_gadget_string(tgt);
+	xu->string_descriptor_index = string->usb_string.id;
+
+put_strings:
+	config_item_put(strings);
+	mutex_unlock(su_mutex);
+
+	return ret;
+}
+
+static void uvcg_extension_drop_link(struct config_item *src, struct config_item *tgt)
+{
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvcg_extension *xu = to_uvcg_extension(src);
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = src->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+
+	xu->string_descriptor_index = 0;
+
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+}
+
 static struct configfs_item_operations uvcg_extension_item_ops = {
 	.release	= uvcg_extension_release,
+	.allow_link	= uvcg_extension_allow_link,
+	.drop_link	= uvcg_extension_drop_link,
 };
 
 static const struct config_item_type uvcg_extension_type = {
diff --git a/drivers/usb/gadget/function/uvc_configfs.h b/drivers/usb/gadget/function/uvc_configfs.h
index 5557813bcca9..c6a690158138 100644
--- a/drivers/usb/gadget/function/uvc_configfs.h
+++ b/drivers/usb/gadget/function/uvc_configfs.h
@@ -163,6 +163,7 @@ struct uvcg_extension_unit_descriptor {
 struct uvcg_extension {
 	struct config_item item;
 	struct list_head list;
+	u8 string_descriptor_index;
 	struct uvcg_extension_unit_descriptor desc;
 };
 
-- 
2.34.1

[PATCH v5 09/11] usb: gadget: uvc: Pick up custom string descriptor IDs

[Daniel Scally]

If any custom string descriptors have been linked to from the
extension unit, pick up the string ID that was returned when
the strings were attached to the composite dev and use it to
set the iExtension field of the Extension Unit Descriptor.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- New patch

 drivers/usb/gadget/function/f_uvc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index f6fd5decdcb7..7588ab21f952 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -644,6 +644,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
+	struct uvcg_extension *xu;
 	struct usb_string *us;
 	unsigned int max_packet_mult;
 	unsigned int max_packet_size;
@@ -736,6 +737,14 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	uvc_hs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
 	uvc_ss_streaming_ep.bEndpointAddress = uvc->video.ep->address;
 
+	/*
+	 * XUs can have an arbitrary string descriptor describing them. If they
+	 * have one pick up the ID.
+	 */
+	list_for_each_entry(xu, &opts->extension_units, list)
+		if (xu->string_descriptor_index)
+			xu->desc.iExtension = cdev->usb_strings[xu->string_descriptor_index].id;
+
 	uvc_en_us_strings[UVC_STRING_CONTROL_IDX].s = opts->function_name;
 	us = usb_gstrings_attach(cdev, uvc_function_strings,
 				 ARRAY_SIZE(uvc_en_us_strings));
-- 
2.34.1

[PATCH v5 10/11] usb: gadget: uvc: Allow linking function to string descs

[Daniel Scally]

Currently the string descriptors for the IAD and VideoStreaming
Interfaces are hardcoded into f_uvc. Now that we can create arbitrary
string descriptors, add a mechanism to define string descriptors for
the IAD, VC and VS interfaces by linking to the appropriate directory
at function level.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- Changed target of link to be within <gadget root>/strings
	- Dropped the VideoControl description since there's an attribute for
	that now

Changes in v2:

	- New patch

 drivers/usb/gadget/function/u_uvc.h        |  8 +++
 drivers/usb/gadget/function/uvc_configfs.c | 60 ++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h
index 0345b8fc36ff..1ce58f61253c 100644
--- a/drivers/usb/gadget/function/u_uvc.h
+++ b/drivers/usb/gadget/function/u_uvc.h
@@ -82,6 +82,14 @@ struct f_uvc_opts {
 	struct uvc_descriptor_header			**uvc_hs_streaming_cls;
 	struct uvc_descriptor_header			**uvc_ss_streaming_cls;
 
+	/*
+	 * Indexes into the function's string descriptors allowing users to set
+	 * custom descriptions rather than the hard-coded defaults.
+	 */
+	u8						iad_index;
+	u8						vs0_index;
+	u8						vs1_index;
+
 	/*
 	 * Read/write access to configfs attributes is handled by configfs.
 	 *
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index 3ac27838514c..18c6a1461b7e 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -3174,8 +3174,68 @@ static void uvc_func_item_release(struct config_item *item)
 	usb_put_function_instance(&opts->func_inst);
 }
 
+static int uvc_func_allow_link(struct config_item *src, struct config_item *tgt)
+{
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct gadget_string *string;
+	struct config_item *strings;
+	struct f_uvc_opts *opts;
+	int ret = 0;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	/* Validate that the target is an entry in strings/<langid> */
+	strings = config_group_find_item(to_config_group(src->ci_parent->ci_parent),
+					 "strings");
+	if (!strings || tgt->ci_parent->ci_parent != strings) {
+		ret = -EINVAL;
+		goto put_strings;
+	}
+
+	string = to_gadget_string(tgt);
+
+	opts = to_f_uvc_opts(src);
+	mutex_lock(&opts->lock);
+
+	if (!strcmp(tgt->ci_name, "iad_desc"))
+		opts->iad_index = string->usb_string.id;
+	else if (!strcmp(tgt->ci_name, "vs0_desc"))
+		opts->vs0_index = string->usb_string.id;
+	else if (!strcmp(tgt->ci_name, "vs1_desc"))
+		opts->vs1_index = string->usb_string.id;
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&opts->lock);
+
+put_strings:
+	config_item_put(strings);
+	mutex_unlock(su_mutex);
+
+	return ret;
+}
+
+static void uvc_func_drop_link(struct config_item *src, struct config_item *tgt)
+{
+	struct f_uvc_opts *opts;
+
+	opts = to_f_uvc_opts(src);
+	mutex_lock(&opts->lock);
+
+	if (!strcmp(tgt->ci_name, "iad_desc"))
+		opts->iad_index = 0;
+	else if (!strcmp(tgt->ci_name, "vs0_desc"))
+		opts->vs0_index = 0;
+	else if (!strcmp(tgt->ci_name, "vs1_desc"))
+		opts->vs1_index = 0;
+
+	mutex_unlock(&opts->lock);
+}
+
 static struct configfs_item_operations uvc_func_item_ops = {
 	.release	= uvc_func_item_release,
+	.allow_link	= uvc_func_allow_link,
+	.drop_link	= uvc_func_drop_link,
 };
 
 #define UVCG_OPTS_ATTR(cname, aname, limit)				\
-- 
2.34.1

[PATCH v5 11/11] usb: gadget: uvc: Use custom strings if available

[Daniel Scally]

If the user has defined a custom string descriptor for the IAD or the
VideoStreaming interfaces then set their index field to point to the
custom descriptor instead of the hardcoded defaults. If no custom
descriptors have been linked to, then use the default ones.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v5:

	- None

Changes in v4:

	- None

Changes in v3:

	- Dropped the VideoControl description since there's an attribute for
	that now

Changes in v2:

	- New patch

 drivers/usb/gadget/function/f_uvc.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 7588ab21f952..5e919fb65833 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -745,6 +745,10 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 		if (xu->string_descriptor_index)
 			xu->desc.iExtension = cdev->usb_strings[xu->string_descriptor_index].id;
 
+	/*
+	 * We attach the hard-coded defaults incase the user does not provide
+	 * any more appropriate strings through configfs.
+	 */
 	uvc_en_us_strings[UVC_STRING_CONTROL_IDX].s = opts->function_name;
 	us = usb_gstrings_attach(cdev, uvc_function_strings,
 				 ARRAY_SIZE(uvc_en_us_strings));
@@ -752,11 +756,15 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 		ret = PTR_ERR(us);
 		goto error;
 	}
-	uvc_iad.iFunction = us[UVC_STRING_CONTROL_IDX].id;
-	uvc_control_intf.iInterface = us[UVC_STRING_CONTROL_IDX].id;
-	ret = us[UVC_STRING_STREAMING_IDX].id;
-	uvc_streaming_intf_alt0.iInterface = ret;
-	uvc_streaming_intf_alt1.iInterface = ret;
+
+	uvc_iad.iFunction = opts->iad_index ? cdev->usb_strings[opts->iad_index].id :
+			    us[UVC_STRING_CONTROL_IDX].id;
+	uvc_streaming_intf_alt0.iInterface = opts->vs0_index ?
+					     cdev->usb_strings[opts->vs0_index].id :
+					     us[UVC_STRING_STREAMING_IDX].id;
+	uvc_streaming_intf_alt1.iInterface = opts->vs1_index ?
+					     cdev->usb_strings[opts->vs1_index].id :
+					     us[UVC_STRING_STREAMING_IDX].id;
 
 	/* Allocate interface IDs. */
 	if ((ret = usb_interface_id(c, f)) < 0)
-- 
2.34.1