hynitron,cst8xx (on i2c bus)

Description

Hynitron CST8XX touchscreen sensor

Properties

Properties not inherited from the base binding file.

Name

Type

Details

irq-gpios

phandle-array

The irq signal defaults to active low as produced by the
sensor. The property value should ensure the flags properly
describe the signal that is presented to the driver.

rst-gpios

phandle-array

The reset signal defaults to active low to the
sensor. The property value should ensure the flags properly
describe the signal that is presented to the driver.

auto-wake-time

int

Auto-recalibration period during low-power mode in minutes. Range 1–5. The default value is specified in the data sheet.

Default value: 5

Legal values: 1, 2, 3, 4, 5

scan-th

int

Low-power scan wake-up threshold. Smaller = more sensitive. The default value is specified in the data sheet.

Default value: 48

Value range: 1 to 255

scan-win

int

Measurement range for low-power scan. Larger = more sensitive but higher consumption. The datasheet is mentiones values from 0 to 3 as valid options with 3 as default. But you can go higher as it is an 8-bit register and higher values than 3 seem to work fine. They improve the sensitivity further at the cost of power consumption.

Default value: 3

Value range: 0 to 255

scan-freq

int

Frequency for low-power scan. Smaller = more sensitive. The default value is specified in the data sheet.

Default value: 7

Value range: 1 to 255

scan-i-dac

int

Current for low-power scan. Smaller = more sensitive. The default value is not specified in the data sheet. Instead, 200 is chosen as a reasonable default based on typical usage.

Default value: 200

Value range: 1 to 255

auto-sleep-time

int

Time (in seconds) of inactivity after which the controller automatically enters standby / low-power mode. The default value is specified in the data sheet.

Default value: 2

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.

Default value: 0

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.

Default value: 0

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.

display

phandle

Optional handle to the display controller this touchscreen feeds. When set, output-width /
output-height are taken from the referenced node's width / height instead of the properties
below, so the panel resolution is not duplicated. Falls back to output-width / output-height
when this is not set.

output-width

int

Horizontal resolution of the display the touchscreen is bonded to. The two pairs name two
different spaces: screen-width / screen-height describe what the touch controller reports,
output-width / output-height describe the panel those reports should land on. When this
and output-height are both set, reported coordinates are scaled from the former into
the latter. Omitting them disables scaling, so coordinates are reported exactly as the
controller produced them. Ignored when display is set, which supplies these
dimensions instead.

Scaling is applied after inverting and swapping, and is what makes swapped-x-y usable on a
rotated panel whose two dimensions differ: the swapped axes carry each other's range, which
a bare swap would leave mismatched against the display.

output-height

int

Vertical resolution of the display the touchscreen is bonded to. See output-width.