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In-Reply-To: <08bd485b-51f6-8249-63a7-a6864a431276@linaro.org>
From:   Chuanhong Guo <gch981213@gmail.com>
Date:   Wed, 30 Nov 2022 16:38:39 +0800
Message-ID: <CAJsYDVJHa9qoBp0Em+Waj1TpAgHy0N504zHGkFEf+3VNA42omw@mail.gmail.com>
Subject: Re: [PATCH 2/3] dt-bindings: leds: add dt schema for worldsemi,ws2812b-spi
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>
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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 =C2=B5=
C
> > 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.)

--=20
Regards,
Chuanhong Guo