From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [nexus7-flo] backlight brightness Date: Mon, 2 May 2016 09:26:38 +0200 Message-ID: <20160502072638.GD27465@ulmo.ba.sec> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0776866905==" Return-path: Received: from mail-wm0-x234.google.com (mail-wm0-x234.google.com [IPv6:2a00:1450:400c:c09::234]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8F7AF6E331 for ; Mon, 2 May 2016 07:26:41 +0000 (UTC) Received: by mail-wm0-x234.google.com with SMTP id g17so20833917wme.0 for ; Mon, 02 May 2016 00:26:41 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Rob Clark Cc: "dri-devel@lists.freedesktop.org" , Bjorn Andersson , Vinay Simha , Archit Taneja List-Id: dri-devel@lists.freedesktop.org --===============0776866905== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Hf61M2y+wYpnELGG" Content-Disposition: inline --Hf61M2y+wYpnELGG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 29, 2016 at 08:04:09AM -0400, Rob Clark wrote: > On Fri, Apr 29, 2016 at 1:32 AM, Vinay Simha wrote: > > hi, > > > > In nx7, backlight brightness control is controlled by dcs commands of > > MIPI_DCS_SET_DISPLAY_BRIGHTNESS. > > there is no PWM going to panel interface directly as we have in ifc6410= /nx5 >=20 > afaiu it is not uncommon to need to control backlight via panel (ie, I > think basically all adaptive-backlight panels). I think the answer is > for these panels, the panel driver would register it's own backlight > driver, rather than get a (pwm, etc) backlight via dt bindings. Yes, that'd be my recommendation as well. > Possibly if the backlight commands are standardized enough then we > could implement a single drm_panel_dsi_backlight helper which could be > created by any of the dsi adaptive-backlight panels (ie. pass in a > 'struct mipi_dsi_device *').. something like: >=20 > struct drm_panel_dsi_backlight { > struct mipi_panel_dsi_device *link; > ... > } >=20 > struct backlight_device *drm_panel_create_dsi_backlight(struct > mipi_panel_dsi_device *link) > { > struct drm_panel_dsi_backlight *dsi_bl; > ... > return devm_backlight_device_register(&link->dev, ..., dsi_bl, > dsi_bl_ops, props); > } I agree it would make sense to have a DCS specific helper for backlight. I'm somewhat sceptical about the standardization, even though these seem to be part of DCS 1.3. But perhaps we can start by being optimistic. Thierry --Hf61M2y+wYpnELGG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJXJwEuAAoJEN0jrNd/PrOhM9wP/3qgeRR75DEYpi/kFhgoqk5O 5IA2HA4eLkcL+96We9k52dYY7BgtQaOCnRWM4j+8ytnrjX7ayrWj2TSbD31EV1lH P9Md+NlbDQkwdWpPtF9nyaHX07PTNCY60wut97wOy+CK6Eq21pL+/Xl0T0N4f7vZ IXUqnHqHAqO8gRTICwdlt8coHKm1UcgcdObG52ALUYK3yxiABzacejcLgqd/1AeC wteaeC0d7xaUg7f41b3ArYvhSTzxAsvNBC4lYbbnWYLHheO7qn9rBiDgv/osGJKb UCmD2FGlbq9RnbFLGvvU+S/hPvIw1HgYDQ0CUUQANaNTiHFZ1FSKOkWdQu+6G/UL YlonsQQ/cDHF4A5FR3djRCrxU+3NUixGnoedzKfZ0IRyo0aI3IBjAgMWy4vdEQ8g QyCMFhgxe8hd/wgG/0pVLLovP6CPVU7wVq+ZLeIfe5M+Iuxw+BRe1ovlI1dF5FhW IqEV1qBmbbNCZ+6fTlwXHybNcEZ1fJCEeolmznbHWmSd/n223jTTGwlcQ9YVb9zU JsnThvgcj8EsWZ89+p+H4p8PUhUsal4tM92qj3fiL+7UQf/jU/22NQBaOtqKrhqX LdK8MdAkzWwdQuEbayf4DCDaHIOadlCPyzwl+At15fNXEk/pJG0cuFSS9CFi+kUJ +dxFkNRE+1CgYhTkFrTU =aLI8 -----END PGP SIGNATURE----- --Hf61M2y+wYpnELGG-- --===============0776866905== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============0776866905==--