usb_add_function(9)

🌈 usb_add_function(9) 💅 Kernel API Manual 🌈

🎀 NAME 🎀

usb_add_function — add a function to a configuration. That's the whole quest, bestie: you're attaching a function to a config. Slay.

✨ SYNOPSIS ✨

int usb_add_function (struct usb_configuration *config , struct usb_function *function );

🦋 ARGUMENTS 🦋

• config — the configuration. The one getting a shiny new function.
• function — the function being added. Yes, the actual function.

💜 CONTEXT 💜

Okay so context check: this is single threaded during gadget setup. No chaotic parallel energy here — it's giving calm, orderly setup vibes. 🧚

🔥 DESCRIPTION 🔥

After initialization, each configuration must have one or more functions added to it. Periodt.

Adding a function involves calling its bind method to allocate resources such as interface and string identifiers and endpoints. Not me being the glue that makes the setup happen. 💅

This function returns the value of the function's bind, which is zero for success else a negative errno value. So like, 0 = yay, negative errno = bestie, something went sideways. 😭

🌸 SEE ALSO 🌸

• Kernel file: ./drivers/usb/gadget/composite.c
• struct usb_os_string(9)
• function_descriptors(9)
• next_desc(9)
• config_ep_by_speed_and_alt(9)
• config_ep_by_speed(9)
• usb_function_deactivate(9)
• usb_function_activate(9)
• usb_interface_id(9)
• usb_func_wakeup(9)
• bos_desc(9)
• usb_add_config(9)
• usb_string_id(9)
• usb_string_ids_tab(9)
• usb_gstrings_attach(9)
• usb_string_ids_n(9)
• usb_composite_probe(9)
• usb_composite_unregister(9)
• usb_composite_setup_continue(9)

okay that's the page, bestie 💖 cute little footer sign-off: source/version ./drivers/usb/gadget, date October 2026, page tag usb_add_function(9). mwah 💋✨