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drivers: led_strip: guard SPI defaults on stm32f4x kconfig

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The given defaults were chosen for 96b_carbon, which is an STM32F4X
board that supports the specified WS2812_STRIP_SPI_BAUD_RATE exactly.

Rather than assume the rest of the world works that way, guard the
Kconfig options accordingly.

This is preparation work for adding configuration for other hardware.

Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
This commit is contained in:
Marti Bolivar 2018-02-21 10:12:10 -05:00 • committed by Carles Cufí
commit 7cf2ce6751
1 changed files with 4 additions and 6 deletions
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10
drivers/led_strip/Kconfig.ws2812
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@ -49,19 +49,17 @@ config WS2812_STRIP_SPI_DEV_NAME
config WS2812_STRIP_SPI_BAUD_RATE
int "Baud rate to use to drive LED strip"
default 5250000
default 5250000 if SOC_SERIES_STM32F4X
help
SPI clock rate, in Hz, to use while driving the strip.
The baud rate must be chosen carefully together with the
WS2812_STRIP_SPI_ONE_FRAME and WS2812_STRIP_SPI_ZERO_FRAME
values so that the transmitted frames meet the chipset
pulse widths for one and zero bits. If unsure, keep the default,
but enable SPI debug logging for your device and make sure the
configuration is matched exactly at runtime.
pulse widths for one and zero bits.
config WS2812_STRIP_ONE_FRAME
hex "SPI frame to shift out to signal a one bit"
default 0x7c
default 0x7c if SOC_SERIES_STM32F4X
help
When shifted out at the configured clock frequency,
this must generate a pulse whose width fits within the chipset
@ -72,7 +70,7 @@ config WS2812_STRIP_ONE_FRAME
config WS2812_STRIP_ZERO_FRAME
hex "SPI frame to shift out to signal a zero bit"
default 0x60
default 0x60 if SOC_SERIES_STM32F4X
help
When shifted out at the configured clock frequency,
this must generate a pulse whose width fits within the chipset