From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751646AbcCNQ24 (ORCPT ); Mon, 14 Mar 2016 12:28:56 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:59598 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750815AbcCNQ2x (ORCPT ); Mon, 14 Mar 2016 12:28:53 -0400 Date: Mon, 14 Mar 2016 16:28:43 +0000 From: Mark Brown To: Laxman Dewangan Cc: robh+dt@kernel.org, pawel.moll@arm.com, lgirdwood@gmail.com, lee.jones@linaro.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20160314162843.GC2566@sirena.org.uk> References: <1457434405-30372-1-git-send-email-ldewangan@nvidia.com> <1457434405-30372-5-git-send-email-ldewangan@nvidia.com> <20160312060925.GW3898@sirena.org.uk> <56E565BE.5010703@nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="wxDdMuZNg1r63Hyj" Content-Disposition: inline In-Reply-To: <56E565BE.5010703@nvidia.com> X-Cookie: Walk softly and carry a megawatt laser. User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: 2a01:348:6:8808:fab::3 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH 4/5] regulator: pwm: Add support for voltage linear equal steps X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wxDdMuZNg1r63Hyj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Mar 13, 2016 at 06:36:06PM +0530, Laxman Dewangan wrote: > On Saturday 12 March 2016 11:39 AM, Mark Brown wrote: > >I can't see any reason why this would ever be preferable to just using > >the flat linear range (you certainly haven't articulated one, you're > >just stating it). This seems like you are bodging around a limited > >consumer driver, you should fix the consumer to cope with regulators > >with lots of voltages - PWM regulators aren't the only ones with high > >resolution steps. > The requirement is to have perfect linear steps interms of the period/pulse > time of PWM without loosing any voltage. > Continuous mode is pretty much near to what you said but here we are loosing > the perfect step as this divides the periods to 100 parts and then set > voltage. Could you be more specific about what the issue is? We've hopefully got errors of less than 1% in the values here... > If new mode is not accpetable then need to enhance the existing continuous > mode like before scaling for 100% of period, first look if we get the > perfect pulse time of of PWM period and if it is there then use this direct > instead of converting required voltage to 100% scale and then back > calculating duty time. That seems a lot better, what you're proposing is changing the ABI to fudge things for a client specific requirement where both the client requirement and the change you're proposing are specific to the current Linux implementation. That doesn't sound like a DT thing. --wxDdMuZNg1r63Hyj Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJW5ua6AAoJECTWi3JdVIfQqw0H/RQktJyRcNuIDmbziylrXQ5v czCa7zha6uSDIIizkU0pvwBI8tmrbgAUloRiACb8MlgEk1dsGShRjMjbShPeMLp8 rNe5FN5b3zRQQrOUzF40UzMwhiy+PuJhwPfMbE4GVwtE3nS5svbaonGD9SVjMiCB az0XrE1T28oef4tyhfbSxqq8C3w1JYgiNzbje09JLieMmFjYMaV5PKSId00eHGFg uMgNdUZ9Q4nhmA0zQPMUdMTUz8qu3XduLY0vHlICzY/Yc78mg3M/U3k8uNjztvRi r7zRGVt5bGfdkEdTeRbjJozx1sM6NGrBTCf0KqzUg9cv40fktFOqoJ3cY8G1zVM= =GJ61 -----END PGP SIGNATURE----- --wxDdMuZNg1r63Hyj--