From: Chuanhong Guo <gch981213@gmail.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Sebastian Reichel <sre@kernel.org>,
linux-leds@vger.kernel.org, Pavel Machek <pavel@ucw.cz>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Stanislav Jakubek <stano.jakubek@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
Shawn Guo <shawnguo@kernel.org>,
Johan Hovold <johan+linaro@kernel.org>,
Bjorn Andersson <andersson@kernel.org>,
Marijn Suijten <marijn.suijten@somainline.org>,
Sven Schwermer <sven.schwermer@disruptive-technologies.com>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] dt-bindings: leds: add dt schema for worldsemi,ws2812b-spi
Date: Wed, 30 Nov 2022 16:38:39 +0800 [thread overview]
Message-ID: <CAJsYDVJHa9qoBp0Em+Waj1TpAgHy0N504zHGkFEf+3VNA42omw@mail.gmail.com> (raw)
In-Reply-To: <08bd485b-51f6-8249-63a7-a6864a431276@linaro.org>
Hi!
On Wed, Nov 30, 2022 at 4:33 PM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
> >> What controls the intensity? Don't you have PWM there?
> >
> > WS2812 is a RGB led, which contains a small Microcontroller. The µC
> > takes 24 byte intensity data from a serial input and then passes on
> > any following bits to the next LED. SPI clk and chip-select are
> > ignored (chip-select support can be trivially added though).
> >
> > You can find them everywhere nowadays, since they are quite cheap
> > (a few cents per LED) and need only one MOSI pin to control hundreds
> > of LEDs.
>
> OK. This should be anyway existing property, so default-brightness.
default-intensity is a different property. Intensity controls only the
color for a multicolor led. The final brightness is calculated with
this intensity value with the single brightness value of the current
LED. (See my previous mail.)
--
Regards,
Chuanhong Guo
next prev parent reply other threads:[~2022-11-30 8:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-29 14:09 [PATCH 0/3] leds: add driver for SPI driven WorldSemi WS2812B RGB LEDs Chuanhong Guo
2022-11-29 14:09 ` [PATCH 1/3] dt-bindings: vendor-prefixes: add an entry for WorldSemi Chuanhong Guo
2022-11-29 16:46 ` Krzysztof Kozlowski
2022-11-30 2:13 ` Chuanhong Guo
2022-11-29 14:09 ` [PATCH 2/3] dt-bindings: leds: add dt schema for worldsemi,ws2812b-spi Chuanhong Guo
2022-11-29 16:54 ` Krzysztof Kozlowski
2022-11-30 0:14 ` Sebastian Reichel
2022-11-30 8:33 ` Krzysztof Kozlowski
2022-11-30 8:38 ` Chuanhong Guo [this message]
2022-11-30 8:36 ` Chuanhong Guo
2022-11-30 9:08 ` Krzysztof Kozlowski
2022-11-30 9:25 ` Chuanhong Guo
2022-11-30 11:59 ` Krzysztof Kozlowski
2022-12-01 12:41 ` Chuanhong Guo
2022-11-29 14:09 ` [PATCH 3/3] leds: add driver for SPI driven WorldSemi WS2812B RGB LEDs Chuanhong Guo
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