zephyr,gpio-emul-sdl

Vendor: Zephyr-specific binding

Note

An implementation of a driver matching this compatible is available in drivers/gpio/gpio_emul_sdl.c.

Description

SDL keyboard GPIO input Emulator

Simulate GPIO state/interrupts using SDL keyboard events. This node has
to be a child of a `zephyr,gpio-emul` compatible.
Add a list of scancodes for the desired keys to be mapped.

This driver uses USB HID scancodes, they are different from linux key codes,
and thus do not match Zephyr code values as described in input-event-codes.h.
Refer to https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf
section Keyboard/Keypad (p53) for a list of scancode values.

The following example maps the first 3 numeric keys to GPIO pins:
- Scancode 30: "Keyboard 1 and !", mapped to gpio0 0
- Scancode 31: "Keyboard 2 and @", mapped to gpio0 1
- Scancode 32: "Keyboard 3 and \#", mapped to gpio0 2

The "typical position" column from HID table suggests to match them
with standard keycode values 2, 3 and 4, corresponding to
INPUT_KEY_1, INPUT_KEY_2 and INPUT_KEY_3 in input-event-codes.h.

/* gpio0 has to be a zephyr,gpio-emul device */
&gpio0 {
  ngpios = <3>;

  sdl_gpio {
    compatible = "zephyr,gpio-emul-sdl";
    scancodes = <30 31 32>;
  };
};

keypad: keypad {
  compatible = "gpio-keys";
  key1: key1 {
    gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
  };
  key2: key2 {
    gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
  };
  key3: key3 {
    gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
  };
};

The limitations of usage are:
- Only active high as we don't get events for keys that aren't pressed
- Pressing multiple keys is best effort, state will be kept but no events
  are generated once the last key is released

Properties

Node specific properties

Properties not inherited from the base binding file.

Name	Type	Details
scancodes	array	An array of SDL scancodes mapped to its GPIO index This property is required.

Deprecated node specific properties

Deprecated properties not inherited from the base binding file.

(None)

Base properties

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “zephyr,gpio-emul-sdl” compatible.

Name	Type	Details
status	string	indicates the operational status of a device Legal values: 'ok', 'okay', 'disabled', 'reserved', 'fail', 'fail-sss' See Important properties for more information.
compatible	string-array	compatible strings This property is required. See Important properties for more information.
reg	array	register space See Important properties for more information.
reg-names	string-array	name of each register space
interrupts	array	interrupts for device See Important properties for more information.
interrupts-extended	compound	extended interrupt specifier for device
interrupt-names	string-array	name of each interrupt
interrupt-parent	phandle	phandle to interrupt controller node
label	string	Human readable string describing the device (used as device_get_binding() argument) See Important properties for more information. This property is deprecated.
clocks	phandle-array	Clock gate information
clock-names	string-array	name of each clock
#address-cells	int	number of address cells in reg property
#size-cells	int	number of size cells in reg property
dmas	phandle-array	DMA channels specifiers
dma-names	string-array	Provided names of DMA channel specifiers
io-channels	phandle-array	IO channels specifiers
io-channel-names	string-array	Provided names of IO channel specifiers
mboxes	phandle-array	mailbox / IPM channels specifiers
mbox-names	string-array	Provided names of mailbox / IPM channel specifiers
power-domains	phandle-array	Power domain specifiers
power-domain-names	string-array	Provided names of power domain specifiers
#power-domain-cells	int	Number of cells in power-domains property
zephyr,deferred-init	boolean	Do not initialize device automatically on boot. Device should be manually initialized using device_init().
wakeup-source	boolean	Property to identify that a device can be used as wake up source. When this property is provided a specific flag is set into the device that tells the system that the device is capable of wake up the system. Wake up capable devices are disabled (interruptions will not wake up the system) by default but they can be enabled at runtime if necessary.
zephyr,pm-device-runtime-auto	boolean	Automatically configure the device for runtime power management after the init function runs.
zephyr,disabling-power-states	phandles	List of power states that will disable this device power.