STRUCT V4L2_DEVICE(9)

okay bestie, welcome to struct v4l2_device(9) from the Kernel API Manual ✨ this is the page for the main struct that V4L2 device drivers live in, and every single detail is still here — no cap, we’re not skipping the “boring” parts. 💅

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🎀 NAME 🎀

• struct v4l2_device — the main struct to for V4L2 device drivers. Yes bestie, that’s the NAME line, and it’s doing the absolute most 🫶

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✨ SYNOPSIS ✨

okay so here’s the whole struct, copied exactly, no edits, no vibes-based rewrites:

       struct v4l2_device {
           struct device *dev;
           struct media_device *mdev;
           struct list_head subdevs;
           spinlock_t lock;
           char name[36];
           void (*notify)(struct v4l2_subdev *sd, unsigned int notification,
       void *arg);
           struct v4l2_ctrl_handler *ctrl_handler;
           struct v4l2_prio_state prio;
           struct kref ref;
           void (*release)(struct v4l2_device *v4l2_dev);
        };

💅 Members 💅

• dev — pointer to struct device. that’s the one.
• mdev — pointer to struct media_device, and it may be NULL.
• subdevs — used to keep track of the registered subdevs. literally the subdev guest list.
• lock — lock this struct; it can be used by the driver as well if this struct is embedded into a larger struct.
• name — unique device name; by default it’s the driver name + bus ID.
• notify — notify operation called by some sub-devices.
• ctrl_handler — the control handler. May be NULL.
• prio — Device’s priority state.
• ref — Keep track of the references to this struct.
• release — Release function that is called when the ref count goes to 0.

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💖 DESCRIPTION 💖

okay so each instance of a V4L2 device should create the v4l2_device struct, either stand-alone or embedded in a larger struct. it’s giving main character energy, honestly.

it allows easy access to sub-devices (see v4l2-subdev.h) and provides basic V4L2 device-level support. slay.

💀 NOTE 💀

bestie, these two little notes are important, no cap:

1. dev->driver_data points to this struct.
2. dev might be NULL if there is no parent device.

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🌈 SEE ALSO 🌈

Kernel file ./include/media/v4l2-device.h — start there, then go bother these functions:

• v4l2_device_get(9)
• v4l2_device_put(9)
• v4l2_device_register(9)
• v4l2_device_set_name(9)
• v4l2_device_disconnect(9)
• v4l2_device_unregister(9)
• v4l2_device_register_subdev(9)
• v4l2_device_unregister_subdev(9)
• __v4l2_device_register_subdev_nodes(9)
• v4l2_device_register_subdev_nodes(9)
• v4l2_device_register_ro_subdev_nodes(9)
• v4l2_subdev_notify(9)
• v4l2_device_supports_requests(9)
• v4l2_device_for_each_subdev(9)
• __v4l2_device_call_subdevs_p(9)
• __v4l2_device_call_subdevs(9)
• __v4l2_device_call_subdevs_until_err_p(9)
• __v4l2_device_call_subdevs_until_err(9)
• v4l2_device_call_all(9)
• v4l2_device_call_until_err(9)
• v4l2_device_mask_call_all(9)
• v4l2_device_mask_call_until_err(9)
• v4l2_device_has_op(9)
• v4l2_device_mask_has_op(9)

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mwah 💋 — source/version line: ./include/media; date: October 2026; title: struct v4l2_device(9). bye bestie, go slay those drivers 🦋💖 periodt.