From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FC06C4332F for ; Tue, 13 Dec 2022 09:08:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234928AbiLMJIG (ORCPT ); Tue, 13 Dec 2022 04:08:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234955AbiLMJHk (ORCPT ); Tue, 13 Dec 2022 04:07:40 -0500 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 374511F2C1; Tue, 13 Dec 2022 01:04:28 -0800 (PST) Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id A49001C09F4; Tue, 13 Dec 2022 10:03:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ucw.cz; s=gen1; t=1670922228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PKQ9Pz0Sg+hh8pZuS0zpWK+jUO+h77QCipngpn+W/pk=; b=jXB0ntuWGEGdP/8/rfQBXXP2kl+RBzuEpAUQtUBAxd4NlLV4tfipS9l8Tpi6iQUPuwxoOz oI9xtqBCLTwfM+BZUMYgsgW8NLOekrxQNWZVJVLITJIN6GNCnJxNtVI8IduSaCjB5YXGFw 1OzPUycGqPqt1kgIiAEGX3SgcsyyEkQ= Date: Tue, 13 Dec 2022 10:03:48 +0100 From: Pavel Machek To: Chuanhong Guo Cc: linux-leds@vger.kernel.org, Rob Herring , Krzysztof Kozlowski , Stanislav Jakubek , Linus Walleij , Shawn Guo , Johan Hovold , Bjorn Andersson , Marijn Suijten , Sven Schwermer , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list Subject: Re: [PATCH v3 0/3] leds: add driver for SPI driven WorldSemi WS2812B RGB LEDs Message-ID: References: <20221207040904.582585-1-gch981213@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wzoAYKgdxjUTBF2S" Content-Disposition: inline In-Reply-To: <20221207040904.582585-1-gch981213@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wzoAYKgdxjUTBF2S Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > This patch adds support for driving a chain of WS2812B LED chips > using SPI bus. >=20 > WorldSemi WS2812B is a individually addressable LED chip that > can be chained together and controlled individually using a > single wire. The chip recognize a long pulse as a bit of 1 and > a short pulse as a bit of 0. Host sends a continuous stream > of 24-bits color values, each LED chip takes the first 3 byte > it receives as its color value and passes the leftover bytes to > the next LED on the chain. >=20 > This driver simulates this protocol using SPI bus by sending > a long pulse as 3'b110 and a short pulse as 3'b100. The SPI > frequency needs to be 2.105MHz~2.85MHz for the timing to be > correct and the controller needs to transfer all the bytes > continuously. Is this the same thing as NeoPixel? If so, that may be better-known name. Best regards, Pavel --=20 People of Russia, stop Putin before his war on Ukraine escalates. --wzoAYKgdxjUTBF2S Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCY5g/9AAKCRAw5/Bqldv6 8tN6AJ93PHkW9Duonvsv/KKmECxKZAL80wCcCpmNDVTpYtzGaSGC/710usYaxRs= =sCOx -----END PGP SIGNATURE----- --wzoAYKgdxjUTBF2S--