STRUCT REALTEK_GPIO_CTRL(9)

💖 NAME 💖

struct realtek_gpio_ctrl — Realtek Otto GPIO driver data. Okay so this is the struct realtek_gpio_ctrl(9) page from the Kernel API Manual, and it is literally the driver-data struct for Realtek Otto GPIO. Bestie, we are getting into it. 💅

✨ SYNOPSIS ✨

struct realtek_gpio_ctrl {
    struct gpio_generic_chip chip;
    void __iomem *base;
    void __iomem *cpumask_base;
    struct cpumask cpu_irq_maskable;
    raw_spinlock_t lock;
    u8 intr_mask[REALTEK_GPIO_MAX];
    u8 intr_type[REALTEK_GPIO_MAX];
    u32 (*bank_read)(void __iomem *reg);
    void (*bank_write)(void __iomem *reg, u32 value);
    unsigned int (*line_imr_pos)(unsigned int line);
};

🫶 Members 🫶

• chip — the associated gpio_generic_chip instance, like its main-character companion.
• base — base address of the register block for a GPIO bank.
• cpumask_base — base address of the per-CPU interrupt mask registers.
• cpu_irq_maskable — the CPUs that can receive GPIO interrupts.
• lock — the lock for accessing the IRQ registers and values.
• intr_mask — mask for interrupt lines.
• intr_type — interrupt type selection.
• bank_read — read a bank setting as a single 32-bit value.
• bank_write — write a bank setting as a single 32-bit value.
• line_imr_pos — bit shift of an IRQ line's IMR value.

🌸 Description 🌸

Real talk: the DIR, DATA, and ISR registers are made of four 8-bit port values packed into a single 32-bit register. So use bank_read (bank_write) to get (assign) a value from (to) these registers. The IMR register is made of four 16-bit port values, packed into two 32-bit registers. Use imr_line_pos to get the bit shift of the 2-bit field for a line's IMR settings — and yes, the prose says imr_line_pos while the member above is line_imr_pos; keeping both exactly as written, bestie, iykyk. Shifts larger than 32 overflow into the second register. Mind the overflow, no cap. 😭

Because the interrupt mask register (IMR) combines the function of IRQ type selection and masking, two extra values are stored. intr_mask is used to mask/unmask the interrupts for a GPIO line, and intr_type is used to store the selected interrupt types. The logical AND of these values is written to IMR on changes. periodt. 💅

🔥 SEE ALSO 🔥

Kernel file ./drivers/gpio/gpio-realtek-otto.c — that is the one to peek at, bestie. 🦋

okay bye bestie 🫶 — source/version: ./drivers/gpio; date: October 2026; page: struct realtek_gpio_ctrl(9). mwah. 💖