gpio_keys_device

gpio_keys_device is a kernel module for registering a gpio_keys device.

Usage

modprobe gpio_keys_device arguments

Keys argument

This is a comma separated list of keys. Each key can have several configuration values. If values are left out, the default is used.
gpio and code is required.
Format: gpio:code:type:active_low:debounce_interval:can_disable:value:wakeup:irq
Example setting debounce_interval: 23:108:::10

• gpio
  GPIO number
• code
  input event code (KEY_, SW_)
  Find values under the Keys and buttons heading in include/uapi/linux/input-event-codes.h
• type
  input event type (EV_KEY=1, EV_SW=5, EV_ABS=3)
• active_low
  The key is active LOW. HIGH is the default.
• debounce_interval
  debounce ticks interval in msecs
• can_disable
  Key can be disabled
• value
  axis value for EV_ABS
• wakeup
  configure the button as a wake-up source
• irq
  Use to override default irq (not used by polled driver)

Other arguments

• poll_interval
  polling interval in msecs - for polling driver only (default=20)
• repeat
  enable input subsystem auto repeat
• polled
  use polled driver: gpio_keys_polled instead of interrupt driven: gpio_keys
• active_low
  Set active_low=1 as default
• debounce_interval
  Set default debounce_interval (default=5)
• type
  Set default event type (default=EV_KEY)
• pullup
  Enable internal pull up resistor for all (only on Raspberry Pi)
• pulldown
  Enable internal pull down resistor for all (only on Raspberry Pi)
• verbose
  0 - silent (default)
  1 - print values to kernel log
  2 - more output
  3 - even more output

Example

Switches are active LOW and uses the internal pullup resistors. Keys is arrow keys and Enter key.

modprobe gpio_keys_device pullup active_low keys=23:103,17:108,18:105,21:106,22:28

References

• include/linux/gpio_keys.h
• drivers/input/keyboard/gpio_keys.c
• drivers/input/keyboard/gpio_keys_polled.c