From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754069Ab2GWIcs (ORCPT ); Mon, 23 Jul 2012 04:32:48 -0400 Received: from moutng.kundenserver.de ([212.227.17.10]:62315 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754019Ab2GWIcq (ORCPT ); Mon, 23 Jul 2012 04:32:46 -0400 Date: Mon, 23 Jul 2012 10:32:33 +0200 From: Thierry Reding To: "Philip, Avinash" Cc: "rpurdie@rpsys.net" , "linux-kernel@vger.kernel.org" , "Nori, Sekhar" , "Hebbar, Gururaja" Subject: Re: DT support for Low threshold brightness in backlight. Message-ID: <20120723083233.GB12868@avionic-0098.mockup.avionic-design.de> References: <518397C60809E147AF5323E0420B992E3E96A842@DBDE01.ent.ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ftEhullJWpWg/VHq" Content-Disposition: inline In-Reply-To: <518397C60809E147AF5323E0420B992E3E96A842@DBDE01.ent.ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Provags-ID: V02:K0:HCBNzGNcr0F+Bh+8WcFC625mZhKin/tdglIgXWscpJe YnnIx/YfCbWE2KahtynHh7Y5UTR3B2XCaJ1GpbfS2FeSqkLocM 3p1PuJ50A66zAnC4lyW/o7qGf/+h6kIsXOtdmsi+qKJK5VvLET GIm5kPlfzyvUBIV8D4HzYdahfgXc5UH0BbH6Mw4UqeDPhprG23 da7naktC+sV/fiyxSkrVJZ4/X2wm/cT/rBRSiIxvU8eIwWfb79 JvZZd8GrkHFj7FB3FTbgUv58zmKS1CtsmmlCpun/5p2FBhEZ4j nOsRSBiWoq+sSE7OQwB6JR4vH2SS4lxprtOkOHovqWNjukdcEe xAcdvW/EetJQCnbG0LBbGt3Cg7ltvkyzCpY5BXWlx6wlA80BPX +RljvbNtZfiyG7jU3dSxN9hATMd63cYlKg= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ftEhullJWpWg/VHq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 18, 2012 at 02:59:32PM +0000, Philip, Avinash wrote: > Hi, >=20 > In pwm-backlight driver low threshold brightness support in DT is not > present. Do you have any plans in such direction? >=20 > I am planning to add support for the same but want to avoid duplication > of work. >=20 > Below scenario describes need for it: > On some boards panel backlight is OFF at low end of brightness scale. > So with Low threshold brightness we can have linear scale in brightness > (Though the actual brightness scale is changes to Low threshold > brightness value instead of 0). >=20 > Example with Low threshold brightness > pwms =3D <&pwm 0 50000>; > brightness-levels =3D <0 2 4 8 16 32 64 128 255>; > default-brightness-level =3D <6>; > brightness_threshold_level =3D <50>; >=20 > It can also be achieved without Low threshold brightness as below >=20 > pwms =3D <&pwm 0 50000>; > brightness-levels =3D <0 51 53 56 62 75 101 152 255>;=20 > default-brightness-level =3D <6>; >=20 > But brightness-levels won't be uniformly divided. >=20 > So it is good to have low threshold DT support for backlight. >=20 > Thanks > Avinash Philip I have no plans to add it myself, but feel free to send a patch. There is a corresponding field in the platform data already, so adding DT support is probably a good idea. Thierry --ftEhullJWpWg/VHq Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIcBAEBAgAGBQJQDQwhAAoJEN0jrNd/PrOhp7oP/10brp9e+0+KY8KaqSURGI8O 1lAg/RRYi7mb1/zitXlc6fnVX/WQfML4N7RrJX0qcDl1Kp5cPTKHLZwREhVhV8P7 p8W7xzsxyGFRftie65Y3w0XjdbGsfSX7ylV/mAypMnq7G492fYZecLLt3lKeRDhW 32Ybsw30NfEIaxSi+zYT3VYQmr/YIpp0DbijrG31LDCyJqMZ/CmDiUmiZiJo1RgU 8F1t0UTm093cwyz89mgZ1lPvDtSKxnkLHfclagdTOE2Z4z0hlEyTDqBSsVS67vKj 7kq4sUqm1qMSSiJHREGj7JyoU8B/JZ7VzAOsbhkNM3eaysMcZe7QHUWE0zuwcVc5 WWZKgKxhCvT2ylsmpXx4pdpLBi4tEXSRmm2RBIWLmVvjnqwnlxK9D1B3kGt19s5x rNd905jmXIRg0HDbG49LE1oHS23keHJWjOKuAeVR8pTgZ19KhDxSV9QTjaLYcGJC mKUD8TGrYheOrLclkPBgnQOKciqOAtSMpEbOpo/lhm9fn/Ix0XEnFpusHhEaXkgz HRaPA8jCvRAOQw1w8dXGHuMulciCQAWAaT/ly/j46ohNRwr4QsKytzc513/68IJP NcU2D5AYZ4lWTVviZN78Zp+AT5ThkdBomjX9U/zZyTtM5kxfQEAVEy9jR0bfg+gb 93wILkEk+FrWTzIbYxsL =O7rd -----END PGP SIGNATURE----- --ftEhullJWpWg/VHq--