STRUCT COUNTER_DEVICE(9)

✨ STRUCT COUNTER_DEVICE(9) — like, the counter vibes manual ✨

okay bestie, welcome to the kernel API manual for struct counter_device(9) 💅 this is the literal blueprint for a Counter data structure, and honestly? it ate. let's get into it 🎀

💖 NAME 💖

struct counter_device — Counter data structure. that's it, that's the whole name, she's iconic and she knows it ✨

🦋 SYNOPSIS 🦋

here's the whole struct in all her glory — copy it exactly, don't you dare touch a character, she's perfect 😭

struct counter_device {
    const char *name;
    struct device *parent;
    const struct counter_ops *ops;
    struct counter_signal *signals;
    size_t num_signals;
    struct counter_count *counts;
    size_t num_counts;
    struct counter_comp *ext;
    size_t num_ext;
    struct device dev;
    struct cdev chrdev;
    struct list_head events_list;
    spinlock_t events_list_lock;
    struct list_head next_events_list;
    struct mutex n_events_list_lock;
    struct counter_event *events;
    wait_queue_head_t events_wait;
    spinlock_t events_in_lock;
    struct mutex events_out_lock;
    struct mutex ops_exist_lock;
 };

🌸 Members 🌸 — meet the whole squad, one by one 🫶

• name — the name of the device. her government name, if you will 👑
• parent — optional parent device providing the counters. optional! she can be independent, respect it 💅
• ops — callbacks from driver. the driver slides in with the actual moves 🔥
• signals — array of Signals. plural, bestie, there's a bunch 🌈
• num_signals — number of Signals specified in signals. gotta keep the count honest ngl 🧮
• counts — array of Counts. more arrays, more fun 💜
• num_counts — number of Counts specified in counts. yes, again, but for counts this time ⭐
• ext — optional array of Counter device extensions. optional! fancy extra flair ✨
• num_ext — number of Counter device extensions specified in ext. counting the extras, lowkey meta 🎀
• dev — internal device structure. the internal organs, don't poke at her 🙈
• chrdev — internal character device structure. more internals, also internal 🦋
• events_list — list of current watching Counter events. the current watch party list 👀
• events_list_lock — lock to protect Counter events list operations. bodyguard behavior, fr fr 🔒
• next_events_list — list of next watching Counter events. the next watch party, already queued up 💫
• n_events_list_lock — lock to protect Counter next events list operations. yes she has her own bodyguard too, they're matching 🫶
• events — queue of detected Counter events. detected! she noticed! 😭
• events_wait — wait queue to allow blocking reads of Counter events. the "hold on, let me get there" queue ⏳
• events_in_lock — lock to protect Counter events queue in operations. in! 🔐
• events_out_lock — lock to protect Counter events queue out operations. out! girl's got both sides covered 💅
• ops_exist_lock — lock to prevent use during removal. very "we're closed, please leave" energy, but make it safe 🚫

💀 SEE ALSO 💀

Kernel file ./include/linux/counter.h — go read it, it's giving required reading 📚 and also these lovelies:

• struct counter_comp(9)
• struct counter_signal(9)
• struct counter_synapse(9)
• struct counter_count(9)
• struct counter_event_node(9)
• struct counter_ops(9)

and that's the tea, bestie 🍓 this absolute queen of a page lives in ./include/linux, freshly dated October 2026, and yes — struct counter_device(9) is her handle if you ever need to @ her 💜 slay, bye! 😭🎀