I think people might be reading differences into 'if' and 'depends on'
that aren't there, like maybe 'if' being needed to "hide" a symbol,
while 'depends on' just adds a dependency.
There are no differences between 'if' and 'depends on'. 'if' is just a
shorthand for 'depends on'. They work the same when it comes to creating
implicit menus too.
The way symbols get "hidden" is through their dependencies not being
satisfied ('if'/'depends on' get copied up as a dependency on the
prompt).
Since 'if' and 'depends on' are the same, an 'if' with just a single
symbol in it can be replaced with a 'depends on'. IMO, it's best to
avoid 'if' there as a style choice too, because it confuses people into
thinking there's deep Kconfig magic going on that requires 'if'.
Going for 'depends on' can also remove some nested 'if's, which
generates nicer symbol information and docs, because nested 'if's really
are so simple/dumb that they just add the dependencies from both 'if's
to all symbols within.
Replace a bunch of single-symbol 'if's with 'depends on' to despam the
Kconfig files a bit and make it clearer how things work. Also do some
other minor related dependency refactoring.
The replacement isn't complete. Will fix up the rest later. Splitting it
a bit to make it more manageable.
(Everything above is true for choices, menus, and comments as well.)
Detected by tweaking the Kconfiglib parsing code. It's impossible to
detect after parsing, because 'if' turns into 'depends on'.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Convert the GPIO based driver to the new GPIO API. (Only the
gpio_configure() call is affected).
Move configuration to DT where appropriate for both SPI and GPIO
drivers, only leaving the SPI vs. GPIO decision in Kconfig (in
addition to the basic enable for the driver.) Move some files around
to clean up as a result of this change.
led_ws2812 sample changes:
- make the pattern easier to look at by emitting less light
- use led_strip alias from DT to get strip device, allocate
appropriate struct led_rgb buffer, etc.
- move the pins around and remove 96b_carbon support (I have no board
to test with)
GPIO driver specific changes:
- str is required to write OUTSET/OUTCLR, not strb. The registers
are word-sized.
- the str[b] registers must all be in r0-r7, so "l" is the correct GCC
inline assembly constraint for both "base" and "pin"
SPI driver specific changes:
- match the GPIO driver in not supporting the update_channels API
method, which never made sense for this type of strip
- return -ENOMEM when the user tries to send more pixel data
than we have buffer space for instead of -EINVAL
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
Use this short header style in all Kconfig files:
# <description>
# <copyright>
# <license>
...
Also change all <description>s from
# Kconfig[.extension] - Foo-related options
to just
# Foo-related options
It's clear enough that it's about Kconfig.
The <description> cleanup was done with this command, along with some
manual cleanup (big letter at the start, etc.)
git ls-files '*Kconfig*' | \
xargs sed -i -E '1 s/#\s*Kconfig[\w.-]*\s*-\s*/# /'
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Clean up space errors and use a consistent style throughout the Kconfig
files. This makes reading the Kconfig files more distraction-free, helps
with grepping, and encourages the same style getting copied around
everywhere (meaning another pass hopefully won't be needed).
Go for the most common style:
- Indent properties with a single tab, including for choices.
Properties on choices work exactly the same syntactically as
properties on symbols, so not sure how the no-indentation thing
happened.
- Indent help texts with a tab followed by two spaces
- Put a space between 'config' and the symbol name, not a tab. This
also helps when grepping for definitions.
- Do '# A comment' instead of '#A comment'
I tweaked Kconfiglib a bit to find most of the stuff.
Some help texts were reflowed to 79 columns with 'gq' in Vim as well,
though not all, because I was afraid I'd accidentally mess up
formatting.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Define a SPI baud rate, as well as WS2812_STRIP_ONE_FRAME and
WS2812_STRIP_ZERO_FRAME values, that work for nRF5 devices.
Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
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>
At least on nRF52 devices, we are taking too much time between pixels
dealing with overhead inside the SPI driver transceive calls. This is
leading to dropped frames, because the dead time between frames is
long enough (5000ns+) to look like a reset pulse to the LED strip.
Given this SPI driver limitation, it seems this LED driver's design
decision to rely on SPI peripherals as efficient pulse generators
doesn't work well in practice.
The right way to handle this is probably to switch from SPI to
efficient inline assembly which bit-bangs the pulses with interrupts
disabled.
This is what other efficient libraries do to drive this type of
LED (e.g. FastLED uses C++ templates that expand into such
assembly). The Zephyr GPIO API doesn't support doing that in a
portable fashion, unfortunately.
For now, we'll cheat by pre-allocating enough buffer space to send the
entire strip's worth of data.
This is preposterously inefficient (8x memory overhead since there's
one byte to make a SPI frame for each bit of color), but makes the
driver work correctly.
(Note that using timer peripherals as pulse generators, when combined
with DMA for efficiency, would also lead to similar levels of
overhead.)
Signed-off-by: Marti Bolivar <marti@opensourcefoundries.com>
Bool symbols implicitly default to 'n'.
A 'default n' can make sense e.g. in a Kconfig.defconfig file, if you
want to override a 'default y' on the base definition of the symbol. It
isn't used like that on any of these symbols though, and is
inconsistent.
This will make the auto-generated Kconfig documentation have "No
defaults. Implicitly defaults to n." as well, which is clearer than
'default n if ...'
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
tx_bufs/tx_count and rx_bufs/rx_count can be hold in another dedicated
structure, thus reducing the number of parameters to transceive. This
permits to avoid using the stack when calling transceive.
Since we saved parameters, we can expose back the struct device pointer,
to stay consistent with other device driver APIs.
Fixes#5839
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
The WS2812 LED driver IC has a one-wire interface which encodes bit
values as pulse widths.
The ICs themselves are basically shift registers. Roughly speaking, a
"short" pulse shifts in a zero bit, a "long" pulse shifts in a one
bit, and an inter-pulse gap exceeding a reset time threshold causes a
pixel to latch the shifted-in color values. Each chip has an output
pin for daisy chaining. Refer to the chip datsheets and comments in
Kconfig.ws2812 for more details.
To meet timing without hogging the core, this driver generates pulses
using SPI. To work, this requires the MOSI line to stay low between
SPI frames, and for inter-frame delays to be less than the reset pulse
time.
There are other ways do it (PWM + DMA on some SoCs, GPIO bit-banging
if no other tasks need the core), but this is a reasonably
general-purpose implementation.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
