STRUCT GPIO_DEVICE(9)

💖 struct gpio_device(9) 💖

okay bestie, so this is a page from the Kernel API Manual — yes, the Kernel API Manual — and honestly? it's giving backstage-pass energy. pull up a chair, we're going behind the scenes of a GPIO device 🎀

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✨ NAME ✨

struct gpio_device — the internal state container for GPIO devices. like, the little handbag where the kernel keeps all its stuff, iykyk 💅

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🌸 SYNOPSIS 🌸

struct gpio_device {
    struct device           dev;
    struct cdev             chrdev;
    int id;
    struct module           *owner;
    struct gpio_chip *chip;
    struct gpio_desc        *descs;
    unsigned long           *valid_mask;
    struct srcu_struct      desc_srcu;
    unsigned int            base;
    u16 ngpio;
    bool can_sleep;
    const char              *label;
    void *data;
    struct list_head        list;
    struct raw_notifier_head line_state_notifier;
    rwlock_t line_state_lock;
    struct workqueue_struct *line_state_wq;
    struct blocking_notifier_head device_notifier;
    struct srcu_struct      srcu;
  #ifdef CONFIG_PINCTRL;
    struct list_head pin_ranges;
  #endif;
 };

no cap, that #ifdef CONFIG_PINCTRL; is literally how it's written in the original, semicolons and all — do not come for me, I just work here 😭

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🦋 Members 🦋

• dev — the GPIO device struct. the main character, lowkey 🫶
• chrdev — the character device for the GPIO device. userspace says hi through this one.
• id — the numerical ID number for the GPIO chip.
• owner — helps prevent removal of modules that are exporting active GPIOs. a bodyguard module fr fr.
• chip — pointer to the corresponding gpiochip, which holds the static data for this device. the chill, doesn't-change part.
• descs — array of ngpio descriptors. one entry per line, bestie.
• valid_mask — if it's not NULL, it holds a bitmask of the GPIOs which are valid to be used from the chip. think VIP list 🌈
• desc_srcu — ensures consistent state of the GPIO descriptors exposed to users. so nobody catches a descriptor mid-glowup.
• base — the GPIO base in the DEPRECATED global Linux GPIO numberspace, assigned at device creation time. ⚠️ deprecated, bestie — noted, respected, moving on.
• ngpio — the number of GPIO lines on this GPIO device, equal to the size of the descs array. math checks out ✨
• can_sleep — tells you whether the GPIO chip driver's callbacks can sleep, which implies they cannot be used from atomic context. important!! do not ignore 🚨
• label — a descriptive name for the GPIO device, like the part number or the name of the IP component in a System on Chip. its whole identity, honestly.
• data — per-instance data assigned by the driver. the driver's personal stash.
• list — links gpio_devices together for traversal. a little linked-list friend group 🫂
• line_state_notifier — used to notify subscribers about lines being requested, released or reconfigured. the group chat notif 🍓
• line_state_lock — an RW-spinlock protecting the line state notifier. don't touch without it, periodt.
• line_state_wq — used to emit line state events from a separate thread in process context. delegation queen 👑
• device_notifier — used to notify character device wait queues about the GPIO device being unregistered. the "we're so over" announcement, but polite.
• srcu — protects the pointer to the underlying GPIO chip. 🛡️
• pin_ranges — the range of pins served by the GPIO driver.

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💜 Description 💜

So this state container holds most of the runtime variable data for a GPIO device — like, the live, moving parts. and here's the iconic bit: it can hold references and live on after the GPIO chip has been removed, if it's still being used from userspace. not me surviving the breakup 😭💀 it literally stays booked and busy after the chip is gone.

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🧚 SEE ALSO 🧚

• Kernel file ./drivers/gpio/gpiolib.h
• struct gpio_array(9)
• struct gpio_desc(9)

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go read those if you want the full lore, bestie. iykyk 💖

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okay that's the whole page!! this one came from ./drivers/gpio, dated October 2026, and it's the struct gpio_device(9) page — ily, go touch some GPIOs responsibly 🌸✨💅