From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C57CD1E98EB; Wed, 30 Apr 2025 07:15:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.255.230.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745997320; cv=none; b=PfabmcDpVOG4am49wq4oU+V2q5+jhMqg4thaq5LZSCzoMVf7ru7QWDTrdW32Cx4GzuGargiApqWhs53yx9gD723VXFdniZgdCTLJdVatg9V7wNj5V0244IvhWUpuMY+GUhnhqlhYp9FGrQGTKvjJrLLoG0qJL8OxQX6thoOxkWA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745997320; c=relaxed/simple; bh=PAsD7NS4YVFutLoWr6jqj6AC3UU/UXuFp0b49PB+QGY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AFw/Du8NCVt/gLnX9f7F8NFS6sNkvBu4xtmJkglnXwWN+JrojRLkWAy4fB0MHlGE+IHPBGm69lg3R2hAN1ngQdpxhJYv+edPwUGAyiO4J5I8DjkvpqEApHEgBBqS+mTklOgJiM/9VMP5GWcatM9Nr4ScEOfLUPWLgvf8O+Pckew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ucw.cz; spf=pass smtp.mailfrom=ucw.cz; dkim=pass (1024-bit key) header.d=ucw.cz header.i=@ucw.cz header.b=e28nt/lV; arc=none smtp.client-ip=46.255.230.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ucw.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ucw.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ucw.cz header.i=@ucw.cz header.b="e28nt/lV" Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 52B511C01AA; Wed, 30 Apr 2025 09:15:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ucw.cz; s=gen1; t=1745997308; 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=0uWhUtB07fuy+20OaSmbXkXnv/vhP67L+RCQmHanEtY=; b=e28nt/lVW+XJbyWKMQHktS27mBX3qBE/5EeAl30/FlGEVNUc2OaCXyhF7sq4kn5mT435qz mAvgP9BJAL/CACX2+38yWS3M0okLMEpwve42TUFWG3jNK/B6/vwULbF1DxRtlHfz+omiWw eOmxtRcmWl1UOGZ3FqUoePo9R12vblc= Date: Wed, 30 Apr 2025 09:15:07 +0200 From: Pavel Machek To: Nam Tran Cc: andy@kernel.org, geert@linux-m68k.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, christophe.jaillet@wanadoo.fr, corbet@lwn.net, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, florian.fainelli@broadcom.com, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v8 0/5] auxdisplay: add support for TI LP5812 4x3 Matrix LED driver Message-ID: References: <20250429170220.8145-1-trannamatk@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Y8wJvSsTAszRr9tX" Content-Disposition: inline In-Reply-To: <20250429170220.8145-1-trannamatk@gmail.com> --Y8wJvSsTAszRr9tX Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > > > Is it intended to be used as a 4x3 matrix, or is this just an inter= nal > > > > wiring detail, and should it be exposed as 12 individual LEDs inste= ad? > > >=20 > > > The 4=C3=973 matrix is a real and fundamental aspect of the LP5812=E2= =80=99s operation. > > > It is not just an internal wiring detail. > > > The device adopts a Time-Cross-Multiplexing (TCM) structure, where 4 = output > > > pins control 12 LED dots individually through scanning. Each pin incl= udes > > > both high-side and low-side drive circuits, meaning matrix multiplexi= ng is > > > required for proper operation =E2=80=94 it cannot be treated as 12 co= mpletely > > > independent LEDs. > >=20 > > Scanning is really a detail. > >=20 > > If this is used as rectangular 4x3 display, then it goes to auxdisplay. > >=20 > > If this is used as a power LED, SD activity LED, capslock and numlock > > ... placed randomly all around the device, then it goes LED subsystem. >=20 > The LP5812 is used for LED status indication in devices like smart speake= rs, > wearables, and routers, not as a structured rectangular display. Well, IIRC it also supports automated animations, and that does not make sense on LED indicators. So... what device do _you_ have and how exactly is it used there? Best regards, Pavel --=20 I don't work for Nazis and criminals, and neither should you. Boycott Putin, Trump, and Musk! --Y8wJvSsTAszRr9tX Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCaBHN+wAKCRAw5/Bqldv6 8vbsAJ4yWVOLyewaLjKCy5K42zX2pr7vhQCfRwpEm2TX7CnFns8+ygH5cB6Wa/I= =tWxB -----END PGP SIGNATURE----- --Y8wJvSsTAszRr9tX--