st,stmpe811 (on i2c bus)
Vendor: STMicroelectronics N.V.
Note
An implementation of a driver matching this compatible is available in drivers/input/input_stmpe811.c.
Description
STMPE811 I2C touchscreen controller
Properties
Node specific properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
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Interrupt GPIO. Used by the controller to signal touch data is
available. Active low.
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Signed raw X axis start for scaling the reported coordinates.
No effect if screen size is not set.
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Signed raw Y axis start for scaling the reported coordinates.
No effect if screen size is not set.
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Raw X axis end for scaling the reported coordinates.
No effect if screen size is not set.
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Raw Y axis end for scaling the reported coordinates.
No effect if screen size is not set.
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Panel driver settling time (microseconds). For large panels (> 6"), a capacitor of 10 nF
is recommended at the touchscreen terminals for noise filtering.
As a general rule, 1-5 nF capacitors require around 500 us settling time, and 5-10 nF need
around 1 ms. When a larger capacitor is used, this value should be changed, as it can
lead to inaccuracy of the measurement.
This property is required. Legal values: |
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Touch detect delay (microseconds) is the delay from the activation of the pull-up resistor
in the X+ line to the time the device performs touch detection.
If no capacitor, or a smaller capacitor is used, this value can be lowered to
minimize detection latency, but it could lower the position stability.
This property is required. Legal values: |
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Average control (number of samples).
This parameter can be set to any of the possible values.
Higher values result in more filtering of noise, but also introduce
more latency in the touch detection process.
Use cases that require low touch detection latency
may benefit from using a lower value for this parameter,
at the cost of less noise filtering.
This property is required. Legal values: |
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Tracking index determines the minimal distance between
the current touch position and the previous touch position.
If the distance is shorter than the tracking index, it is discarded.
Lowering the tracking index increases the frequency of touch events,
but also increases the load on the system.
This property is required. Legal values: |
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GPIO specifier that controls power to the device.
This property should be provided when the device has a dedicated
switch that controls power to the device. The supply state is
entirely the responsibility of the device driver.
Contrast with vin-supply.
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Reference to the regulator that controls power to the device.
The referenced devicetree node must have a regulator compatible.
This property should be provided when device power is supplied
by a shared regulator. The supply state is dependent on the
request status of all devices fed by the regulator.
Contrast with supply-gpios. If both properties are provided
then the regulator must be requested before the supply GPIOS is
set to an active state, and the supply GPIOS must be set to an
inactive state before releasing the regulator.
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Horizontal resolution of touchscreen (maximum x coordinate reported + 1). The default
corresponds to a valid value for non-inverted axis, required for a display with an inverted x
axis.
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Vertical resolution of touchscreen (maximum y coordinate reported + 1). The default
corresponds to a valid value for non-inverted axis, required for a display with an inverted y
axis.
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X axis is inverted.
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Y axis is inverted.
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X and Y axis are swapped. Swapping is done after inverting the axis.
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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 “st,stmpe811” compatible.
Name |
Type |
Details |
|---|---|---|
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device address on i2c bus
This property is required. See Important properties for more information. |
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Indicates the operational status of the hardware or other
resource that the node represents. In particular:
- "okay" means the resource is operational and, for example,
can be used by device drivers
- "disabled" means the resource is not operational and the system
should treat it as if it is not present
For details, see "2.3.4 status" in Devicetree Specification v0.4.
Legal values: See Important properties for more information. |
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This property is a list of strings that essentially define what
type of hardware or other resource this devicetree node
represents. Each device driver checks for specific compatible
property values to find the devicetree nodes that represent
resources that the driver should manage.
The recommended format is "vendor,device", The "vendor" part is
an abbreviated name of the vendor. The "device" is usually from
the datasheet.
The compatible property can have multiple values, ordered from
most- to least-specific. Having additional values is useful when the
device is a specific instance of a more general family, to allow the
system to match the most specific driver available.
For details, see "2.3.1 compatible" in Devicetree Specification v0.4.
This property is required. See Important properties for more information. |
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Optional names given to each register block in the "reg" property.
For example:
/ {
soc {
#address-cells = <1>;
#size-cells = <1>;
uart@1000 {
reg = <0x1000 0x2000>, <0x3000 0x4000>;
reg-names = "foo", "bar";
};
};
};
The uart@1000 node has two register blocks:
- one with base address 0x1000, size 0x2000, and name "foo"
- another with base address 0x3000, size 0x4000, and name "bar"
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Information about interrupts generated by the device, encoded as an array
of one or more interrupt specifiers. The format of the data in this property
varies by where the device appears in the interrupt tree. Devices with the same
"interrupt-parent" will use the same format in their interrupts properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
See Important properties for more information. |
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Extended interrupt specifier for device, used as an alternative to
the "interrupts" property.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
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Optional names given to each interrupt generated by a device.
The interrupts themselves are defined in either "interrupts" or
"interrupts-extended" properties.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
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If present, this refers to the node which handles interrupts generated
by this device.
For details, see "2.4 Interrupts and Interrupt Mapping" in
Devicetree Specification v0.4.
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Human readable string describing the device. Use of this property is
deprecated except as needed on a case-by-case basis.
For details, see "4.1.2 Miscellaneous Properties" in Devicetree
Specification v0.4.
See Important properties for more information. |
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Information about the device's clock providers. In general, this property
should follow conventions established in the dt-schema binding:
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/clock/clock.yaml
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Optional names given to each clock provider in the "clocks" property.
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This property encodes the number of <u32> cells used by address fields
in "reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
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This property encodes the number of <u32> cells used by size fields in
"reg" properties in this node's children.
For details, see "2.3.5 #address-cells and #size-cells" in Devicetree
Specification v0.4.
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DMA channel specifiers relevant to the device.
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Optional names given to the DMA channel specifiers in the "dmas" property.
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IO channel specifiers relevant to the device.
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Optional names given to the IO channel specifiers in the "io-channels" property.
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Mailbox / IPM channel specifiers relevant to the device.
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Optional names given to the mbox specifiers in the "mboxes" property.
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Power domain specifiers relevant to the device.
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Optional names given to the power domain specifiers in the "power-domains" property.
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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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