worldsemi,ws2812-rpi_pico-pio

Vendor: Worldsemi Co., Limited

Note

An implementation of a driver matching this compatible is available in drivers/led_strip/ws2812_rpi_pico_pio.c.

Description

The pio node configured for ws2812.

Properties

Top level properties

These property descriptions apply to “worldsemi,ws2812-rpi_pico-pio” nodes themselves. This page also describes child node properties in the following sections.

Node specific properties

Properties not inherited from the base binding file.

Name

Type

Details

bit-waveform

array

 
This property defines the waveform for sending 1-bit data.
The program uses the first three elements of the array.
The T0 is equal to T0H in the datasheet.
The T2 is equal to T1L in the datasheet.
The T1 is equal to (T1H-T0H) or (T0L-T1L) in the datasheet.

Code-0
   +------+                 +---
   |      |                 |
   |  T0  |      T1+T2      |
   |      |                 |
---+      +-----------------+

Code-1
   +---------------+        +---
   |               |        |
   |     T0+T1     |   T2   |
   |               |        |
---+               +--------+


The frequency determines the wave period.
The T0～T2 means ratio in one period.

For example, T0=3, T1=3, T2=4 and the frequency is 800kHz case,
T0H is
  (1 / 800kHz) * (3/10) = 375ns
T0L is
  (1 / 800kHz) * ((4+3)/10) = 875ns

pinctrl-0

phandles

 
Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.

pinctrl-1

phandles

 
Pin configuration/s for the second state. See pinctrl-0.

pinctrl-2

phandles

 
Pin configuration/s for the third state. See pinctrl-0.

pinctrl-3

phandles

 
Pin configuration/s for the fourth state. See pinctrl-0.

pinctrl-4

phandles

 
Pin configuration/s for the fifth state. See pinctrl-0.

pinctrl-names

string-array

 
Names for the provided states. The number of names needs to match the
number of states.

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 “worldsemi,ws2812-rpi_pico-pio” compatible.

(None)

Child node properties

Name

Type

Details

gpios

phandle-array

 
Inherited from ws2812-gpio.yaml.

Note: This driver does not configure the output pin.
You need to configure the pin with pinctrl that is in the parent node configuration
for use by PIO. This property only uses the GPIO pin number and ignores flags.

This property is required.

frequency

int

 
Specify the number of times a waveform representing 1 bit is
transmitted per second. It is same meaning as bit-per-seconds.
WS2812 works with 800000. Set the value 400000 if use with WS2811.

reset-delay

int

 
Minimum delay to wait (in microseconds) to make sure that the strip has
latched the signal. If omitted, a default value of 8 microseconds is used.
This default is good for the WS2812 controllers. Note that despite the
WS2812 datasheet states that a 50 microseconds delay is required, it seems
6 microseconds is enough. The default is set to 8 microseconds just to be
safe.

Default value: 8

chain-length

int

 
The number of devices in the daisy-chain.

This property is required.

color-mapping

array

 
Channel to color mapping (or pixel order).

For example a GRB channel to color mapping would be

   color-mapping = <LED_COLOR_ID_GREEN
                    LED_COLOR_ID_RED
                    LED_COLOR_ID_BLUE>;

This property is required.