123 lines
3.8 KiB
Plaintext
123 lines
3.8 KiB
Plaintext
#
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# Copyright (c) 2017 Linaro Limited
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#
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# SPDX-License-Identifier: Apache-2.0
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#
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# The following blog post is an excellent resource about pulse timing:
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#
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# https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/
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menuconfig WS2812_STRIP
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bool "Enable WS2812 (and compatible) LED strip driver"
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depends on SPI
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depends on !SPI_LEGACY_API
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default n
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help
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Enable LED strip driver for daisy chains of WS2812-ish
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(or WS2812B, WS2813, SK6812, or compatible) devices.
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These devices have a one-wire communications interface
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which encodes bits using pulses. Short pulses indicate
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zero bits, and long pulses indicate ones; refer to the
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chip datsheets for precise specifications. To implement
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this in a multitasking operating system, this driver
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generates the pulses using a SPI peripheral.
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if WS2812_STRIP
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config WS2812_STRIP_NAME
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string "Driver name"
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default "ws2812_strip"
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help
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Device name for WS2812 LED strip.
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config WS2812_STRIP_SPI_DEV_NAME
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string "SPI master to use to drive the strip"
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default ""
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help
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Specify the device name of the SPI master which the
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WS2812 driver should use to control the LED strip.
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The MOSI pin of this SPI peripheral should be connected
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to the signal pin for the first chip in the strip.
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Examples: SPI_0, SPI_1, etc.
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config WS2812_STRIP_SPI_BAUD_RATE
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int "Baud rate to use to drive LED strip"
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default 5250000
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help
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SPI clock rate, in Hz, to use while driving the strip.
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The baud rate must be chosen carefully together with the
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WS2812_STRIP_SPI_ONE_FRAME and WS2812_STRIP_SPI_ZERO_FRAME
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values so that the transmitted frames meet the chipset
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pulse widths for one and zero bits. If unsure, keep the default,
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but enable SPI debug logging for your device and make sure the
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configuration is matched exactly at runtime.
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config WS2812_STRIP_ONE_FRAME
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hex "SPI frame to shift out to signal a one bit"
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default 0x7c
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help
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When shifted out at the configured clock frequency,
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this must generate a pulse whose width fits within the chipset
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specifications for T1H, and whose interpulse timing meets low
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times. It is recommended that the first and last bits in the
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frame be zero; this "encourages" SPI IPs to leave MOSI low
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between frames.
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config WS2812_STRIP_ZERO_FRAME
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hex "SPI frame to shift out to signal a zero bit"
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default 0x60
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help
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When shifted out at the configured clock frequency,
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this must generate a pulse whose width fits within the chipset
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specifications for T0H, and whose interpulse timing meets low
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times. It is recommended that the first and last bits in the
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frame be zero; this "encourages" SPI IPs to leave MOSI low
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between frames.
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# By default, we use GRBW [sic] (and ignore W).
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comment "The following options determine channel data order on the wire."
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config WS2812_RED_ORDER
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int "Order in which a red pixel should be shifted out"
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default 1
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range 0 3
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help
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If the red channel is shifted out first, specify 0.
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If second, specify 1, and so on.
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config WS2812_GRN_ORDER
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int "Order in which a green pixel should be shifted out"
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default 0
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range 0 3
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help
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If the green channel is shifted out first, specify 0.
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If second, specify 1, and so on.
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config WS2812_BLU_ORDER
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int "Order in which a blue pixel should be shifted out"
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default 2
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range 0 3
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help
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If the blue channel is shifted out first, specify 0.
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If second, specify 1, and so on.
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config WS2812_HAS_WHITE_CHANNEL
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bool "Does the chip have a white channel on wire?"
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default y
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help
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If the chipset has a white channel, say y. White channels
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are not used by the driver, but must be declared if expected
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by the chip.
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config WS2812_WHT_ORDER
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int "Order in which a white pixel should be shifted out"
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default 3
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range 0 3
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depends on WS2812_HAS_WHITE_CHANNEL
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help
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If the blue channel is shifted out first, specify 0.
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If second, specify 1, and so on.
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endif # WS2812_STRIP
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