gpio-qdec
Vendor: Generic or vendor-independent
Note
An implementation of a driver matching this compatible is available in drivers/input/input_gpio_qdec.c.
Description
GPIO based QDEC input device
Implement an input device generating relative axis event reports for a rotary
encoder connected to two GPIOs. The driver is normally idling until it sees a
transition on any of the encoder signal lines, then switches to polling mode
and samples the two signal lines periodically to track the encoder position,
and goes back to idling after the specified timeout.
Example configuration:
#include <zephyr/dt-bindings/input/input-event-codes.h>
qdec {
compatible = "gpio-qdec";
gpios = <&gpio0 14 (GPIO_PULL_UP | GPIO_ACTIVE_HIGH)>,
<&gpio0 13 (GPIO_PULL_UP | GPIO_ACTIVE_HIGH)>;
steps-per-period = <4>;
zephyr,axis = <INPUT_REL_WHEEL>;
sample-time-us = <2000>;
idle-timeout-ms = <200>;
};
Properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
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GPIO for the A and B encoder signals.
This property is required. |
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GPIOs for LED or other components needed for sensing the AB signals.
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Time between enabling the led-gpios output pins and reading the encoder
state on the input pins, meant to give the state detector (such a
phototransistor) time to settle to right state. Required if led-gpios and
idle-poll-time-us are specified, can be explicitly set to 0 for no delay.
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How many steps to count before reporting an input event.
This property is required. |
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The input code for the axis to report for the device, typically any of
INPUT_REL_*.
This property is required. |
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How often to sample the A and B signal lines when tracking the encoder
movement.
This property is required. |
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How often to sample the A and B signal while idling. If unset then the
driver will use the GPIO interrupt to exit idle state, and any GPIO
specified in led-gpios will be enabled all the time. If non zero, then
the driver will poll every idle-poll-time-us microseconds while idle, and
only activate led-gpios before sampling the encoder state.
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Timeout for the last detected transition before stopping the sampling
timer and going back to idle state.
This property is required. |
Deprecated properties not inherited from the base binding file.
(None)
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 “gpio-qdec” compatible.
Name |
Type |
Details |
|---|---|---|
|
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indicates the operational status of a device
Legal values: See Important properties for more information. |
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compatible strings
This property is required. See Important properties for more information. |
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register space
See Important properties for more information. |
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name of each register space
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interrupts for device
See Important properties for more information. |
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extended interrupt specifier for device
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name of each interrupt
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phandle to interrupt controller node
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Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
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Clock gate information
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name of each clock
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number of address cells in reg property
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number of size cells in reg property
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DMA channels specifiers
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Provided names of DMA channel specifiers
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IO channels specifiers
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Provided names of IO channel specifiers
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mailbox / IPM channels specifiers
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Provided names of mailbox / IPM channel specifiers
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Power domain specifiers
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Provided names of power domain specifiers
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Number of cells in power-domains property
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Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
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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.
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Automatically configure the device for runtime power management after the
init function runs.
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List of power states that will disable this device power.
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