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DMGPIO API Reference

Types

dmgpio_mode_t

GPIO pin operating mode.

typedef enum
{
    dmgpio_mode_input = 0,      // Digital input
    dmgpio_mode_output_pp,      // Output push-pull
    dmgpio_mode_output_od,      // Output open-drain
    dmgpio_mode_af_pp,          // Alternate function push-pull
    dmgpio_mode_af_od,          // Alternate function open-drain
    dmgpio_mode_analog,         // Analog mode (ADC/DAC)
} dmgpio_mode_t;

dmgpio_pull_t

Internal pull resistor configuration.

typedef enum
{
    dmgpio_pull_none = 0,       // No pull resistor
    dmgpio_pull_up,             // Pull-up resistor
    dmgpio_pull_down,           // Pull-down resistor
} dmgpio_pull_t;

dmgpio_speed_t

GPIO output slew rate.

typedef enum
{
    dmgpio_speed_low = 0,       // Low speed (~2 MHz)
    dmgpio_speed_medium,        // Medium speed (~25 MHz)
    dmgpio_speed_high,          // High speed (~50 MHz)
    dmgpio_speed_very_high,     // Very high speed (~100 MHz)
} dmgpio_speed_t;

dmgpio_pin_state_t

GPIO pin logic level.

typedef enum
{
    dmgpio_pin_reset = 0,       // Logic low (0)
    dmgpio_pin_set,             // Logic high (1)
} dmgpio_pin_state_t;

dmgpio_ioctl_cmd_t

IOCTL command codes for dmgpio_dmdrvi_ioctl.

typedef enum
{
    dmgpio_ioctl_cmd_get_state = 1, // Read current pin state -> dmgpio_pin_state_t*
    dmgpio_ioctl_cmd_set_state,     // Write pin state <- dmgpio_pin_state_t*
    dmgpio_ioctl_cmd_toggle,        // Toggle pin (arg = NULL)
    dmgpio_ioctl_cmd_get_mode,      // Read pin mode -> dmgpio_mode_t*
    dmgpio_ioctl_cmd_set_mode,      // Write pin mode <- dmgpio_mode_t*
    dmgpio_ioctl_cmd_get_pull,      // Read pull config -> dmgpio_pull_t*
    dmgpio_ioctl_cmd_set_pull,      // Write pull config <- dmgpio_pull_t*
    dmgpio_ioctl_cmd_get_speed,     // Read output speed -> dmgpio_speed_t*
    dmgpio_ioctl_cmd_set_speed,     // Write output speed <- dmgpio_speed_t*
    dmgpio_ioctl_cmd_reconfigure,   // Reapply current configuration (arg = NULL)
    dmgpio_ioctl_cmd_max
} dmgpio_ioctl_cmd_t;

DMDRVI Functions

dmgpio_dmdrvi_create

Create a new GPIO device context by reading configuration from an INI file.

dmdrvi_context_t dmgpio_dmdrvi_create(dmini_context_t config, dmdrvi_dev_num_t* dev_num);

Parameters:

  • config – INI configuration context (see Configuration Guide)
  • dev_num – Device number output

Returns: New context on success, NULL on failure.

dmgpio_dmdrvi_free

Free the GPIO device context and deinitialize the pin.

void dmgpio_dmdrvi_free(dmdrvi_context_t context);

dmgpio_dmdrvi_open

Open a handle to the GPIO device.

void* dmgpio_dmdrvi_open(dmdrvi_context_t context, int flags);

Parameters:

  • context – DMDRVI context
  • flags – Open flags (e.g., DMDRVI_O_RDWR)

Returns: Device handle on success, NULL on failure.

dmgpio_dmdrvi_close

Close the device handle.

void dmgpio_dmdrvi_close(dmdrvi_context_t context, void* handle);

dmgpio_dmdrvi_read

Read the current high-state pin bitmask as a hex string, with pread-style byte offset support.

size_t dmgpio_dmdrvi_read(dmdrvi_context_t context, void* handle, void* buffer, size_t size, uint32_t offset);

The device is modelled as a 6-byte virtual file whose content is always the current high-state bitmask formatted as "0x%04X" (e.g. "0x000A"). offset is a byte offset into that content, enabling standard pread()-style access. An offset at or beyond 6 returns 0 bytes (EOF).

Example:

// offset=0, size=16 → "0x000A"  (6 bytes, pin 1 and 3 are high)
// offset=6, size=16 → ""        (0 bytes, EOF)
// offset=2, size=2  → "00"      (mid-string slice)

Returns: Number of bytes copied into buffer, or 0 at EOF.

dmgpio_dmdrvi_write

Write the desired high-state pin bitmask to the device.

size_t dmgpio_dmdrvi_write(dmdrvi_context_t context, void* handle, const void* buffer, size_t size, uint32_t offset);

Accepts a decimal ("10") or hex ("0x000A") string. Trailing whitespace and newlines (e.g. appended by the shell's echo) are automatically stripped. Each bit in the value corresponds to a pin within the configured pins mask: a 1 sets the pin high, a 0 sets it low.

offset is not meaningful for GPIO (the state is a single atomic value) and is ignored.

dmgpio_dmdrvi_ioctl

Perform control and query operations on the GPIO device.

int dmgpio_dmdrvi_ioctl(dmdrvi_context_t context, void* handle, int command, void* arg);

Parameters:

  • command – IOCTL command from dmgpio_ioctl_cmd_t
  • arg – Command-specific argument (see command descriptions above)

Returns: 0 on success, negative errno on failure.

dmgpio_dmdrvi_stat

Get device statistics.

int dmgpio_dmdrvi_stat(dmdrvi_context_t context, void* handle, dmdrvi_stat_t* stat);

Port API

The port layer defines hardware-specific functions. See include/dmgpio_port.h.

dmgpio_port_init

Initialize a GPIO pin.

int dmgpio_port_init(dmgpio_port_t port, dmgpio_pin_t pin,
                     dmgpio_mode_t mode, dmgpio_pull_t pull,
                     dmgpio_speed_t speed, uint8_t alternate);

dmgpio_port_deinit

Deinitialize (reset) a GPIO pin.

int dmgpio_port_deinit(dmgpio_port_t port, dmgpio_pin_t pin);

dmgpio_port_read_pin

Read the current logical state of a GPIO pin.

dmgpio_pin_state_t dmgpio_port_read_pin(dmgpio_port_t port, dmgpio_pin_t pin);

dmgpio_port_write_pin

Set the logical state of a GPIO output pin.

void dmgpio_port_write_pin(dmgpio_port_t port, dmgpio_pin_t pin, dmgpio_pin_state_t state);

dmgpio_port_toggle_pin

Toggle the logical state of a GPIO output pin.

void dmgpio_port_toggle_pin(dmgpio_port_t port, dmgpio_pin_t pin);