usb: gadget: uvc: Add new enable_interrupt_ep attribute

Add a new attribute to the default control config group that allows
users to specify whether they want to enable the optional interrupt
endpoint for the VideoControl interface.

Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Link: https://lore.kernel.org/r/20230130105045.120886-3-dan.scally@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index f00cff6..eb13cc5 100644 (file)
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -15,11 +15,13 @@ Date:               Dec 2014
 KernelVersion: 4.0
 Description:   Control descriptors
 
-               All attributes read only:
+               All attributes read only except enable_interrupt_ep:
 
                ================        =============================
                bInterfaceNumber        USB interface number for this
                                        streaming interface
+               enable_interrupt_ep     flag to enable the interrupt
+                                       endpoint for the VC interface
                ================        =============================
 
 What:          /config/usb-gadget/gadget/functions/uvc.name/control/class

diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h
index 24b8681..9d15bc2 100644 (file)
--- a/drivers/usb/gadget/function/u_uvc.h
+++ b/drivers/usb/gadget/function/u_uvc.h
@@ -29,6 +29,8 @@ struct f_uvc_opts {
        unsigned int                                    streaming_interface;
        char                                            function_name[32];
 
+       bool                                            enable_interrupt_ep;
+
        /*
         * 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 e28becd..9ff4b19 100644 (file)
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -716,8 +716,61 @@ static ssize_t uvcg_default_control_b_interface_number_show(
 
 UVC_ATTR_RO(uvcg_default_control_, b_interface_number, bInterfaceNumber);
 
+static ssize_t uvcg_default_control_enable_interrupt_ep_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->enable_interrupt_ep);
+       mutex_unlock(&opts->lock);
+
+       mutex_unlock(su_mutex);
+
+       return result;
+}
+
+static ssize_t uvcg_default_control_enable_interrupt_ep_store(
+       struct config_item *item, const char *page, size_t len)
+{
+       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;
+       ssize_t ret;
+       u8 num;
+
+       ret = kstrtou8(page, 0, &num);
+       if (ret)
+               return ret;
+
+       mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+       opts_item = item->ci_parent;
+       opts = to_f_uvc_opts(opts_item);
+
+       mutex_lock(&opts->lock);
+       opts->enable_interrupt_ep = num;
+       mutex_unlock(&opts->lock);
+
+       mutex_unlock(su_mutex);
+
+       return len;
+}
+UVC_ATTR(uvcg_default_control_, enable_interrupt_ep, enable_interrupt_ep);
+
 static struct configfs_attribute *uvcg_default_control_attrs[] = {
        &uvcg_default_control_attr_b_interface_number,
+       &uvcg_default_control_attr_enable_interrupt_ep,
        NULL,
 };