worldsemi,ws2812-gpio
Vendor: Worldsemi Co., Limited
Note
An implementation of a driver matching this compatible is available in drivers/led_strip/ws2812_gpio.c.
Description
Worldsemi WS2812 LED strip, GPIO binding
Driver bindings for bit-banging a WS2812 or compatible LED strip.
The CPU driver uses inline assembly, and isn't available for all
boards. The timing is automatically derived from the CPU clock frequency,
or can be provided by setting the delay-txx properties in the device
tree, or can be manually provided by the Kconfig settings DELAY_Txx.
The four delays provided (calculated based on the clock frequency,
provided by a dts, or Kconfig file) determine the delays as depicted
below. The exact timings of the LED strip data line might vary on the
type of LEDs used, consult the data-sheet for the precise timings.
0 code
+-------+ +---
| | |
| T0H | T0L |
| | |
---+ +-----------------+
1 code
+---------------+ +---
| | |
| T1H | T1L |
| | |
---+ +---------+
Example dts file:
/ {
cpus {
cpu@0 {
clock-frequency = <64000000>;
};
};
rgb_led: ws2812 {
compatible = "worldsemi,ws2812-gpio";
chain-length = <1>;
color-mapping = <LED_COLOR_ID_GREEN
LED_COLOR_ID_RED
LED_COLOR_ID_BLUE>;
gpios = <&gpio0 16 0>;
};
};
Example dts file:
/ {
chosen {
zephyr,led-strip = &rgb_led;
};
rgb_led: ws2812 {
compatible = "worldsemi,ws2812-gpio";
chain-length = <1>;
color-mapping = <LED_COLOR_ID_GREEN
LED_COLOR_ID_RED
LED_COLOR_ID_BLUE>;
reset-delay = <50>;
gpios = <&gpio0 16 0>;
delay-t1h = <48>;
delay-t1l = <32>;
delay-t0h = <16>;
delay-t0l = <32>;
};
};
Properties
Node specific properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
|
|
Number of NOP assembly operations to create a delay for a 1 bit, high
voltage period (default 700 nsec)
|
|
|
Number of NOP assembly operations to create a delay for a 1 bit, low
voltage period (default 600 nsec)
|
|
|
Number of NOP assembly operations to create a delay for a 0 bit, high
voltage period (default 350 nsec)
|
|
|
Number of NOP assembly operations to create a delay for a 0 bit, low
voltage period (default 800 nsec)
|
|
|
GPIO phandle and specifier for the pin connected to the
led-strip. Exactly one pin should be given.
This property is required. |
|
|
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: |
|
|
The number of devices in the daisy-chain.
This property is required. |
|
|
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. |
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-gpio” compatible.
Name |
Type |
Details |
|---|---|---|
|
|
indicates the operational status of a device
Legal values: See Important properties for more information. |
|
|
compatible strings
This property is required. See Important properties for more information. |
|
|
register space
See Important properties for more information. |
|
|
name of each register space
|
|
|
interrupts for device
See Important properties for more information. |
|
|
extended interrupt specifier for device
|
|
|
name of each interrupt
|
|
|
phandle to interrupt controller node
|
|
|
Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
|
|
Clock gate information
|
|
|
name of each clock
|
|
|
number of address cells in reg property
|
|
|
number of size cells in reg property
|
|
|
DMA channels specifiers
|
|
|
Provided names of DMA channel specifiers
|
|
|
IO channels specifiers
|
|
|
Provided names of IO channel specifiers
|
|
|
mailbox / IPM channels specifiers
|
|
|
Provided names of mailbox / IPM channel specifiers
|
|
|
Power domain specifiers
|
|
|
Provided names of power domain specifiers
|
|
|
Number of cells in power-domains property
|
|
|
Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
|
|
|
Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
|
|
|
Automatically configure the device for runtime power management after the
init function runs.
|
|
|
List of power states that will disable this device power.
|