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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84CE2C4727C for ; Fri, 25 Sep 2020 10:47:54 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B4ED121D91 for ; Fri, 25 Sep 2020 10:47:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4ED121D91 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=denx.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-kernel-mentees-bounces@lists.linuxfoundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 40E49204D8; Fri, 25 Sep 2020 10:47:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UZ7IFat0cUyK; Fri, 25 Sep 2020 10:47:51 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 1AE0F203BF; Fri, 25 Sep 2020 10:47:51 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0D734C0889; Fri, 25 Sep 2020 10:47:51 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 67608C0051 for ; Fri, 25 Sep 2020 10:47:49 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 5B6C086D95 for ; Fri, 25 Sep 2020 10:47:49 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8pVrdA0XGfcr for ; Fri, 25 Sep 2020 10:47:47 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by whitealder.osuosl.org (Postfix) with ESMTPS id 918F186D7B for ; Fri, 25 Sep 2020 10:47:47 +0000 (UTC) Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 88E5F1C0C46; Fri, 25 Sep 2020 12:47:40 +0200 (CEST) Date: Fri, 25 Sep 2020 12:47:39 +0200 From: Pavel Machek To: linux-kernel-mentees@lists.linuxfoundation.org, kernel list , linux-leds@vger.kernel.org Message-ID: <20200925104739.GA26609@amd> MIME-Version: 1.0 User-Agent: Mutt/1.5.23 (2014-03-12) Subject: [Linux-kernel-mentees] Help wanted in LED subsystem X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3911810675720999447==" Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" --===============3911810675720999447== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+QahgC5+KEYLbs62" Content-Disposition: inline --+QahgC5+KEYLbs62 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! In linux-next, I published TODO list for LED subsystem. Is that something linux-kernel-mentees could help with? Best regards, Pavel +++ b/drivers/leds/TODO @@ -0,0 +1,58 @@ +-*- org -*- + +* On/off LEDs should have max_brightness of 1 +* Get rid of enum led_brightness + +It is really an integer, as maximum is configurable. Get rid of it, or +make it into typedef or something. + +* Review atomicity requirements in LED subsystem + +Calls that may and that may not block are mixed in same structure, and +semantics is sometimes non-intuitive. (For example blink callback may +not sleep.) Review the requirements for any bugs and document them +clearly. + +* LED names are still a mess + +No two LEDs have same name, so the names are probably unusable for the +userland. Nudge authors into creating common LED names for common +functionality. + +? Perhaps check for known LED names during boot, and warn if there are +LEDs not on the list? + +* Split drivers into subdirectories + +The number of drivers is getting big, and driver for on/off LED on a +i/o port is really quite different from camera flash LED, which is +really different from driver for RGB color LED that can run its own +microcode. Split the drivers somehow. + +* Figure out what to do with RGB leds + +Multicolor is a bit too abstract. Yes, we can have +Green-Magenta-Ultraviolet LED, but so far all the LEDs we support are +RGB, and not even RGB-White or RGB-Yellow variants emerged. + +Multicolor is not a good fit for RGB LED. It does not really know +about LED color. In particular, there's no way to make LED "white". + +Userspace is interested in knowing "this LED can produce arbitrary +color", which not all multicolor LEDs can. + + Proposal: let's add "rgb" to led_colors in drivers/leds/led-core.c, + add corresponding device tree defines, and use that, instead of + multicolor for RGB LEDs. + + We really need to do that now; "white" stuff can wait. + +RGB LEDs are quite common, and it would be good to be able to turn LED +white and to turn it into any arbitrary color. It is essential that +userspace is able to set arbitrary colors, and it might be good to +have that ability from kernel, too... to allow full-color triggers. + +* Command line utility to manipulate the LEDs? + +/sys interface is not really suitable to use by hand, should we have +an utility to perform LED control? --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --+QahgC5+KEYLbs62 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl9tyssACgkQMOfwapXb+vJwYwCdG0auv9aF9khVFQIS3OPAAcqk mMkAniskimJAzmhYhVGKqTW4+k7j3T3f =IOvW -----END PGP SIGNATURE----- --+QahgC5+KEYLbs62-- --===============3911810675720999447== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees --===============3911810675720999447==--