adc-keys

Note

An implementation of a driver matching this compatible is available in drivers/input/input_adc_keys.c.

Description

Input driver for ADC attached resistor ladder buttons.

The driver itself does not calculate each possible combination of resistor
values. Instead, users are required to specify the voltage for each single
key press or for combinations of key presses.

Example:

#include <dt-bindings/input/input-event-codes.h>

/ {
        buttons {
                compatible = "adc-keys";
                io-channels = <&adc 2>;
                keyup-threshold-mv = <0>;

                key_0 {
                        press-thresholds-mv = <1650>,  /* KEY0 */
                                              <2536>;  /* KEY0 + KEY1 */
                        zephyr,code = <INPUT_KEY_0>;
                };

                key_1 {
                        press-thresholds-mv = <2300>,  /* KEY1 */
                                              <2536>;  /* KEY0 + KEY1 */
                        zephyr,code = <INPUT_KEY_1>;
                };
        };
};

Properties

Top level properties

These property descriptions apply to “adc-keys” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

Name	Type	Details
`sample-period-ms`	`int`	Sample period in milliseconds. If not specified defaults to 20. Default value: `20`
`keyup-threshold-mv`	`int`	Millivolt value to which all the keys are considered up. This property is required.

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 “adc-keys” compatible.

Name	Type	Details
`io-channels`	`phandle-array`	Phandle to an ADC channel. This property is required.
`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-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.

Child node properties

Name	Type	Details
`press-thresholds-mv`	`array`	Array of millivolt values to consider a key pressed. This property is required.
`zephyr,code`	`int`	Key code to emit. This property is required.