ti,fdc2x1x (on i2c bus)

Vendor: Texas Instruments

Note

An implementation of a driver matching this compatible is available in drivers/sensor/ti/fdc2x1x/fdc2x1x.c.

Description

Texas Instruments FDC2X1X capacitive sensor

Properties

Top level properties

These property descriptions apply to “ti,fdc2x1x” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

Name

Type

Details

sd-gpios

phandle-array

 
The SD pin defaults to active high when consumed by the sensor.
The property value should ensure the flags properly describe
the signal that is presented to the driver.

intb-gpios

phandle-array

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

fdc2x14

boolean

 
Set to identify the sensor as FDC2114 or FDC2214 (4-channel version)

autoscan

boolean

 
Set the Auto-Scan Mode.

false = Continuous conversion on the single channel selected by
"active-channel" (single channel mode).

true = Auto-Scan conversions as selected by "rr-sequence"
(multichannel mode).

fref

int

 
Reference frequency of the used clock source in KHz.
The internal clock oscillates at around 43360 KHz (43.36 MHz)
at 20 degrees Celsius.
Recommended external clock source frequency is 40000 KHz (40 MHz).

This property is required.

rr-sequence

int

 
Auto-Scan Sequence Configuration.
The FDC will perform a single conversion on each channel
in the sequence selected, and then restart the sequence continuously.

The sensor performs conversion on Channel 0 to 1 by default after
power-on-reset. This setting only applies if autoscan=true
(multichannel mode).

0 = Ch0, Ch1
1 = Ch0, Ch1, Ch2 (FDC2114, FDC2214 only)
2 = Ch0, Ch1, Ch2, Ch3 (FDC2114, FDC2214 only)

Legal values: 0, 1, 2

active-channel

int

 
Selects channel for continuous conversions.

The sensor performs continuous conversion on Channel 0 by default after
power-on-reset. This setting only applies if autoscan=false
(single channel mode).

0 = Perform continuous conversions on Channel 0
1 = Perform continuous conversions on Channel 1
2 = Perform continuous conversions on Channel 2 (FDC2114, FDC2214 only)
3 = Perform continuous conversions on Channel 3 (FDC2114, FDC2214 only)

Legal values: 0, 1, 2, 3

deglitch

int

 
Input deglitch filter bandwidth. Select the lowest setting that exceeds
the oscillation tank oscillation frequency.

1 = 1MHz
4 = 3.3MHz
5 = 10MHz
7 = 33MHz

This property is required.

Legal values: 1, 4, 5, 7

sensor-activate-sel

string

 
Sensor Activation Mode Selection.

The sensor uses low-power activation mode by default after
power-on-reset.

full-current = the FDC will drive maximum
sensor current for a shorter sensor activation time.

low-power = the FDC uses the value programmed by "idrive" during
sensor activation to minimize power consumption.

Default value: low-power

Legal values: 'full-current', 'low-power'

ref-clk-src

string

 
Select Reference Frequency Source.

The sensor uses the internal clock by default after power-on-reset.

internal = Use Internal oscillator as reference frequency
external = Reference frequency is provided from CLKIN pin.

Default value: internal

Legal values: 'internal', 'external'

current-drive

string

 
Select Current Sensor Drive.

The sensor uses normal current drive by default after power-on-reset.
High current drive is not supported if autoscan=false and will default
to normal.

normal = The FDC will drive all channels with normal sensor current
(1.5mA max).

high = The FDC will drive channel 0 with current >1.5mA.

Default value: normal

Legal values: 'normal', 'high'

output-gain

int

 
Output gain control (FDC2112, FDC2114 only)

The default output gain is 0 after power-on-reset.

0 = Gain = 1   | Effective Resolution 12 bits | 100% full scale
1 = Gain = 4   | Effective Resolution 14 bits | 25% full scale
2 = Gain = 8   | Effective Resolution 15 bits | 12.5% full scale
3 = Gain = 16  | Effective Resolution 16 bits | 6.25% full scale

Legal values: 0, 1, 2, 3

friendly-name

string

 
Human readable string describing the sensor. It can be used to
distinguish multiple instances of the same model (e.g., lid accelerometer
vs. base accelerometer in a laptop) to a host operating system.

This property is defined in the Generic Sensor Property Usages of the HID
Usage Tables specification
(https://usb.org/sites/default/files/hut1_3_0.pdf, section 22.5).

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.

Child node properties

Name

Type

Details

rcount

int

 
Channel X Reference Count Conversion Interval Time.
Valid range: 256 - 65535

This property is required.

offset

int

 
Channel X Conversion Offset (FDC2112 and FDC2212 only).
The default offset value after power-on-reset is 0.
Valid range: 0 - 65535

settlecount

int

 
Channel X Conversion Settling.

The FDC will use this settling time to allow the LC sensor to
stabilize before initiation of a conversion on Channel X.
Valid range: 0 - 65535

This property is required.

fref-divider

int

 
Channel X Reference Divider.

Sets the divider for Channel X reference.
Use this to scale the maximum conversion frequency.
Valid range: 1 - 1023

This property is required.

idrive

int

 
Channel X Sensor drive current.

This field defines the Drive Current used during the settling +
conversion time of Channel X sensor clock.
Valid range: 0 - 31

This property is required.

fin-sel

int

 
Channel X Sensor frequency select.

For differential sensor configuration:
1 = divide by 1. Choose for sensor frequencies between
0.01MHz and 8.75MHz
2 = divide by 2. Choose for sensor frequencies between 5MHz
and 10MHz

For single-ended sensor configuration:
2 = divide by 2. Choose for sensor frequencies between
0.01MHz and 10MHz

This property is required.

Legal values: 1, 2

inductance

int

 
Inductor value used on the PCB for the sensing network of the
specific channel, which is usually 18uH.

This property is required.