v4l2_async_nf_add_fwnode(9)

💖 v4l2_async_nf_add_fwnode — Kernel API Manual, but make it a group chat 💖

okay so bestie, we're looking at v4l2_async_nf_add_fwnode(9) today and honestly? iconic kernel-API behavior. stay with me, this one's short but it matters. 🎀

---

✨ NAME ✨

v4l2_async_nf_add_fwnode — the function that allocates a fwnode async subdev and adds it to the notifier's master asc_list. slay, that's literally the whole job. 💅

---

🌸 SYNOPSIS 🌸

v4l2_async_nf_add_fwnode (notifier , fwnode , type );

three args, no cap. let's meet them 🫶

---

🦋 ARGUMENTS 🦋

• notifier — a pointer to struct v4l2_async_notifier. it's the notifier, bestie. the main character of this whole operation. ✨
• fwnode — the fwnode handle of the sub-device that's gonna get matched, i.e. a pointer to struct fwnode_handle. this is the thing we're hunting for a match with. 🔥
• type — the type of the driver's async sub-device, or the connection struct. the important bit: struct v4l2_async_connection shall be the first member of the driver's async struct, meaning both of them begin at the same memory address. lowkey that layout rule is non-negotiable, so don't be out here reordering your structs. 💀

---

🎀 DESCRIPTION 🎀

so what actually happens? the function allocates a fwnode-matched asc of size asc_struct_size, and adds it to the notifier's asc_list. that's it, that's the vibe. 🌈

it also grabs a reference of the fwnode, which gets released later at notifier cleanup time. so the reference is not just vibing forever — it's accounted for, and cleanup is where it gets let go. periodt. 👑

---

🌟 SEE ALSO 🌟

like, go read all of these too, they're the friend group:

• Kernel file ./include/media/v4l2-async.h
• enum v4l2_async_match_type(9)
• struct v4l2_async_match_desc(9)
• struct v4l2_async_connection(9)
• struct v4l2_async_notifier_operations(9)
• struct v4l2_async_notifier(9)
• struct v4l2_async_subdev_endpoint(9)
• v4l2_async_debug_init(9)
• v4l2_async_nf_init(9)
• v4l2_async_subdev_nf_init(9)
• v4l2_async_nf_add_fwnode_remote(9)
• v4l2_async_nf_add_i2c(9)
• v4l2_async_subdev_endpoint_add(9)
• v4l2_async_connection_unique(9)
• v4l2_async_nf_register(9)
• v4l2_async_nf_unregister(9)
• v4l2_async_nf_cleanup(9)
• v4l2_async_register_subdev(9)
• v4l2_async_register_subdev_sensor(9)
• v4l2_async_unregister_subdev(9)

---

💡 ok real talk: that struct-first-member rule in type is the kind of thing that will bite you if you forget it, and the fwnode reference is the kind of thing you must let cleanup release. no skipping cleanup. 🙈

---

and that's the page, bestie!! 🧚 this whole thing lives in ./include/media, it's dated October 2026, and it's page v4l2_async_nf_add_fwnode(9) of the Kernel API Manual. go forth and match your fwnodes responsibly 💜🌸✨