st,stmpe811 (on i2c bus)

Vendor: STMicroelectronics

Description

STMPE811 I2C touchscreen controller

Properties

Properties not inherited from the base binding file.

Name

Type

Details

supply-gpios

phandle-array

 
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.

vin-supply

phandle

 
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.

screen-width

int

 
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.

screen-height

int

 
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.

inverted-x

boolean

 
X axis is inverted.

inverted-y

boolean

 
Y axis is inverted.

swapped-x-y

boolean

 
X and Y axis are swapped. Swapping is done after inverting the axis.

int-gpios

phandle-array

 
Interrupt GPIO. Used by the controller to signal touch data is
available. Active low.

raw-x-min

int

 
Signed raw X axis start for scaling the reported coordinates.
No effect if screen size is not set.

raw-y-min

int

 
Signed raw Y axis start for scaling the reported coordinates.
No effect if screen size is not set.

raw-x-max

int

 
Raw X axis end for scaling the reported coordinates.
No effect if screen size is not set.

raw-y-max

int

 
Raw Y axis end for scaling the reported coordinates.
No effect if screen size is not set.

panel-driver-settling-time-us

int

 
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: 10, 100, 500, 1000, 5000, 10000, 50000, 100000

touch-detect-delay-us

int

 
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: 10, 50, 100, 500, 1000, 5000, 10000, 50000

touch-average-control

int

 
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: 1, 2, 4, 8

tracking-index

int

 
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: 0, 4, 8, 16, 32, 64, 92, 127