From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793725807; b=wxnB6ct+gL17gxCXerl976+abL7vWA+Zez7+UHz4JIKkgEbTzbS9VRXz0mutwGat29he rfvbrOhYe1enX/IDv6JeqEtYZznGrHU1z3b2fO0a5GeUCbVP85kGZCr3Cv8wFirKjjeWL BPsrFJ6QTv9hvlkkJRUOy1p/97vTaLiCBUTgLtGjpjRpZfJkz/P/QHPSpaAIGufjVlNZW DY65Z84acB/QPoxxLZczQpNFpEDHbb2un2MvAUZH+7QzrFfkPHdLd0DXcr5WxvdWhYwOi a+IVPBbxe3zd52Vaelpn+KD9TDjczA9g8eUQ1YdS5no1VBXUWuJ1XrnoHfLbRza4rcg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793725807; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=4yXF2qH2dZlH5NaZeOXrAhyY/aCMSbLE9DiPJAinWiM=; b=C5vvE1rh4OSw1SSrEuoRF0skIcXa7//b3V22wLpapTnBStzwqMMS2ygx/RLo5TtiIAev OtkMsSF5W5ZfMU1egaQSmDJflw3hfPGaUrBmtICjtj9hh3p0dTIsv9q7RDmECUuSMWgI8 OkglLk6zdFmOAeJ5n6ecOLUy1QlWlCIswDnUbHw5tkTsOXttBqCjOfgpgbis2Rw6QFUwV Qvlz80zwc1d3C6gRP/RH0ivjRjtqTwdRCVWOm5omEhzjnvrOAqB24sw8TpnfaLZJed4Oz P9hAv79bYkm06o4h7gpcp3EJzCNbZoQXX9BhvNYCybudxDvtqX8fIiaCASYMW1ftViA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=H2GtedTK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7270D606A328; Tue, 3 Nov 2026 17:10:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=H2GtedTK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 841171F000C1; Tue, 3 Nov 2026 17:10:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793725807; bh=4yXF2qH2dZlH5NaZeOXrAhyY/aCMSbLE9DiPJAinWiM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=H2GtedTKni4UU2EY3qobMS0Dg3+Qmas82D0rV3NG1oUmo/Ml8rDNYcCcm0B0ET+Yp 9SCFdcnz4ahrGyyNSCy9b16+wLKDB+Gj4iVSBMsQFv5KW95uzWSOSxkwyDlbif19V+ ZO09Z7FBbVo/mZpUvU807tA1ga8DQw5UgYbs1RyYaMZDI0mc45lBdybYIoOx67hGdu NIuyZczUueXbJoZQFi3Gw3+zxdgfZBwoMyjRIBqzddkNHAq1ZN6xjWy2ZHYwhHuWsd lOvsHMTguvX2mYrABptuiCFjUf9QaiywEvoTmtZJJqivuMh2WT0E5HclqIBPMl2V95 w4QhY8zlKUGMg== Date: Tue, 3 Nov 2026 17:10:01 +0000 From: Daniel Thompson To: Roman Vivchar Cc: Lee Jones , Jingoo Han , Pavel Machek , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Helge Deller , dri-devel@lists.freedesktop.org, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org Subject: Re: [PATCH 1/2] dt-bindings: leds: backlight: add Kinetic KTD3137 Message-ID: References: <20261102-6768-ktd3137-v1-0-b5b4f903c56e@protonmail.com> <20261102-6768-ktd3137-v1-1-b5b4f903c56e@protonmail.com> <_kyk4j6fx0PX5QqVrjAIGH-5fzUhj-fKhD8YT4F734mCOnQCDXui6wQB77AOka69_gblWOJN2SxzC5OSrH1lXiQeciLfVnWuPHS0JfaMKD4=@protonmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Nov 03, 2026 at 03:21:45PM +0000, Roman Vivchar wrote: > On Tuesday, November 3rd, 2026 at 4:42 PM, Daniel Thompson wrote: > > > On Tue, Nov 03, 2026 at 02:34:02PM +0000, Roman Vivchar wrote: > > > Hi Daniel, > > > > > > On Tuesday, November 3rd, 2026 at 4:05 PM, Daniel Thompson wrote: > > > > On Mon, Nov 02, 2026 at 09:58:48PM +0200, Roman Vivchar via B4 Relay wrote: > > > > > + led-max-microamp: > > > > > + minimum: 5000 > > > > > + maximum: 29800 > > > > > + default: 20200 > > > > > + > > > > > + vin-supply: true > > > > > + > > > > > +required: > > > > > + - compatible > > > > > + - reg > > > > > + - vin-supply > > > > > > > > Why is vin-supply required? > > > > > > > > > > The chip cannot function without VIN power supply. Even if it's on the > > > always-on power rail on certain board, there's always a chance it might be > > > accidentally left disabled on the other. It's better to document supply in > > > the bindings as far as I understand. > > > > You haven't just documented the binding, you have also made the property > > mandatory by adding it to required. > > > > So what I am asking is why is this property listed as required. You > > didn't implement the driver in a way that makes the supply mandatory. > > Not sure I follow. > > In the driver I've used devm_regulator_get_enable(), rather than _optional(), > since my understanding is that the non-optional helper is a standard kernel > API for required supplies (with regulator core warning and fallback to dummy > regulator in case DT omits it). That dummy fallback essentially makes it optional. On a board with an always-on supply then there is no need to include vin-supply in the DTB. The driver will work just fine without it. > Do you suggest dropping vin-supply from required: ? On my board it's connected > to an always-on supply, though I can't tell about others. I can proceed with > this if the DT maintainers are okay with that. Given your answers then, yes, vin-supply should not be in the required: list (e.g. we don't want DT validation to fail for a DT that does not include a vin-supply). Daniel.