maxim,max30101 (on i2c bus)

Description

MAX30101 heart rate sensor

Properties

Properties not inherited from the base binding file.

Name

Type

Details

irq-gpios

phandle-array

Active low interrupt signal. It is an open drain signal, so it
require either hardware or software pull-up.

fifo-rollover-en

boolean

Controls the behavior of the FIFO when the FIFO becomes completely
filled with data. If set, the FIFO address rolls over to zero and the
FIFO continues to fill with new data. If not set, then the FIFO is
not updated until FIFO_DATA is read or the WRITE/READ pointer
positions are changed.

fifo-watermark

int

Configure the trigger for the FIFO_WATERMARK interrupt (e.g. if set to 2,
then the flag is set when the 30th word is written to the FIFO).
Default set to 0, same as after Power Reset. Range: 0 - 15.

Legal values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

acq-mode

string

Set the operation mode of the MAX30101.

This property is required.

Legal values: 'multi-led', 'heart-rate', 'spo2'

smp-ave

int

To reduce the amount of data throughput, adjacent samples (in each
individual channel) can be averaged and decimated on the chip.
Default set to 1 for no averaging, same as after Power Reset.

Default value: 1

Legal values: 1, 2, 4, 8, 16, 32

adc-rge

int

Set the ADC's full-scale range at 18 bits resolution.
Default set to 8192, compromise between precision and consumption.

Default value: 8192

Legal values: 2048, 4096, 8192, 16384

smp-sr

int

Set the effective sampling rate with one sample consisting of one
pulse/conversion per active LED channel. In SpO2 mode, these means
one IR pulse/conversion and one red pulse/conversion per sample
period. Only one RED pulse/conversion in HR mode.
Default set to 50 Hz, same as after Power Reset.

Default value: 50

Legal values: 50, 100, 200, 400, 800, 1000, 1600, 3200

led-pw

int

Set the pulse width for each LED to control the integration time
of the ADC in us. The ADC resolution is directly related to the
integration time.
Default set to 69 us, same as after Power Reset.

Default value: 69

Legal values: 69, 118, 215, 411

led-pa

uint8-array

Set the pulse amplitude to control the LED current. The actual
measured LED current for each part can vary significantly due to the
trimming methodology.
[0]: Red LED
[1]: IR LED
[2]: Green LED
Default set to [0xff, 0xff, 0xff], activate any chosen LED channel.
Value range: 0x00 - 0xFF | 0.0 mA - 50.0 mA

Default value: [255, 255, 255]

led-slot

array

Set which LED are active in each time slot for Multi-LED mode only.
0: None (Disabled)
1: Red LED
2: InfraRed LED
3: Green LED
Default set to [0, 0, 0, 0], no LED activated in multi-LED mode.
User needs to choose wich LED is active for each slot.
NOTE: If a LED is present on multiple slots, `sensor_channel_get`
will result in the averaging of the values.

Default value: [0, 0, 0, 0]

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.