usb: gadget: uvc: configfs: Add interface number attributes

The video control and video streaming interface numbers are needed in
the UVC gadget userspace stack to reply to UVC requests. They are
hardcoded to fixed values at the moment, preventing configurations with
multiple functions.

To fix this, make them dynamically discoverable by userspace through
read-only configfs attributes in <function>/control/bInterfaceNumber and
<function>/streaming/bInterfaceNumber respectively.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index 9281e2a..490a013 100644 (file)
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -12,6 +12,10 @@ Date:                Dec 2014
 KernelVersion: 4.0
 Description:   Control descriptors
 
+               All attributes read only:
+               bInterfaceNumber        - USB interface number for this
+                                         streaming interface
+
 What:          /config/usb-gadget/gadget/functions/uvc.name/control/class
 Date:          Dec 2014
 KernelVersion: 4.0
@@ -109,6 +113,10 @@ Date:              Dec 2014
 KernelVersion: 4.0
 Description:   Streaming descriptors
 
+               All attributes read only:
+               bInterfaceNumber        - USB interface number for this
+                                         streaming interface
+
 What:          /config/usb-gadget/gadget/functions/uvc.name/streaming/class
 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 95cb1b5..4ea9877 100644 (file)
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -699,12 +699,14 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
        uvc_iad.bFirstInterface = ret;
        uvc_control_intf.bInterfaceNumber = ret;
        uvc->control_intf = ret;
+       opts->control_interface = ret;
 
        if ((ret = usb_interface_id(c, f)) < 0)
                goto error;
        uvc_streaming_intf_alt0.bInterfaceNumber = ret;
        uvc_streaming_intf_alt1.bInterfaceNumber = ret;
        uvc->streaming_intf = ret;
+       opts->streaming_interface = ret;
 
        /* Copy descriptors */
        f->fs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);

diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h
index 2ed292e..5242d48 100644 (file)
--- a/drivers/usb/gadget/function/u_uvc.h
+++ b/drivers/usb/gadget/function/u_uvc.h
@@ -25,6 +25,9 @@ struct f_uvc_opts {
        unsigned int                                    streaming_maxpacket;
        unsigned int                                    streaming_maxburst;
 
+       unsigned int                                    control_interface;
+       unsigned int                                    streaming_interface;
+
        /*
         * Control descriptors array pointers for full-/high-speed and
         * super-speed. They point by default to the uvc_fs_control_cls and

diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index ae72254..fa8d2e1 100644 (file)
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -713,9 +713,40 @@ static const struct uvcg_config_group_type uvcg_control_class_grp_type = {
  * control
  */
 
+static ssize_t uvcg_default_control_b_interface_number_show(
+       struct config_item *item, char *page)
+{
+       struct config_group *group = to_config_group(item);
+       struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+       struct config_item *opts_item;
+       struct f_uvc_opts *opts;
+       int result = 0;
+
+       mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+       opts_item = item->ci_parent;
+       opts = to_f_uvc_opts(opts_item);
+
+       mutex_lock(&opts->lock);
+       result += sprintf(page, "%u\n", opts->control_interface);
+       mutex_unlock(&opts->lock);
+
+       mutex_unlock(su_mutex);
+
+       return result;
+}
+
+UVC_ATTR_RO(uvcg_default_control_, b_interface_number, bInterfaceNumber);
+
+static struct configfs_attribute *uvcg_default_control_attrs[] = {
+       &uvcg_default_control_attr_b_interface_number,
+       NULL,
+};
+
 static const struct uvcg_config_group_type uvcg_control_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
+               .ct_attrs       = uvcg_default_control_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "control",
@@ -2259,9 +2290,40 @@ static const struct uvcg_config_group_type uvcg_streaming_class_grp_type = {
  * streaming
  */
 
+static ssize_t uvcg_default_streaming_b_interface_number_show(
+       struct config_item *item, char *page)
+{
+       struct config_group *group = to_config_group(item);
+       struct mutex *su_mutex = &group->cg_subsys->su_mutex;
+       struct config_item *opts_item;
+       struct f_uvc_opts *opts;
+       int result = 0;
+
+       mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+       opts_item = item->ci_parent;
+       opts = to_f_uvc_opts(opts_item);
+
+       mutex_lock(&opts->lock);
+       result += sprintf(page, "%u\n", opts->streaming_interface);
+       mutex_unlock(&opts->lock);
+
+       mutex_unlock(su_mutex);
+
+       return result;
+}
+
+UVC_ATTR_RO(uvcg_default_streaming_, b_interface_number, bInterfaceNumber);
+
+static struct configfs_attribute *uvcg_default_streaming_attrs[] = {
+       &uvcg_default_streaming_attr_b_interface_number,
+       NULL,
+};
+
 static const struct uvcg_config_group_type uvcg_streaming_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
+               .ct_attrs       = uvcg_default_streaming_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "streaming",