From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Date: Mon, 10 Dec 2012 08:45:49 +0000 Subject: Re: [PATCHv15 3/7] video: add of helper for display timings/videomode Message-Id: <50C5A13D.7040908@ti.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="------------enigD5913F5C38A1C760756BBE03" List-Id: References: <1353920848-1705-1-git-send-email-s.trumtrar@pengutronix.de> <1353920848-1705-4-git-send-email-s.trumtrar@pengutronix.de> <50B37EEC.6090808@ti.com> <20121126161055.GB30791@pengutronix.de> <50B39F46.7050808@ti.com> <1354889568.2533.118.camel@pizza.hi.pengutronix.de> In-Reply-To: <1354889568.2533.118.camel-/rZezPiN1rtR6QfukMTsflXZhhPuCNm+@public.gmane.org> To: Philipp Zabel Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Florian Tobias Schandinat , David Airlie , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Laurent Pinchart , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, Steffen Trumtrar , Guennady Liakhovetski , linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --------------enigD5913F5C38A1C760756BBE03 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 2012-12-07 16:12, Philipp Zabel wrote: > Hi, >=20 > Am Montag, den 26.11.2012, 18:56 +0200 schrieb Tomi Valkeinen: >> So what does the pixelclk-inverted mean? Normally the SoC drives pixel= >> data on rising edge, and the panel samples it at falling edge? And >> vice-versa for inverted? Or the other way around? >> >> When is hsync/vsync set? On rising or falling edge of pclk? >> >> My point here is that the pixelclk-inverted is not crystal clear thing= , >> like the hsync/vsync/de-active values are. >> >> And while thinking about this, I realized that the meaning of >> pixelclk-inverted depends on what component is it applied to. Presumin= g >> normal pixclk means "pixel data on rising edge", the meaning of that >> depends on do we consider the SoC or the panel. The panel needs to >> sample the data on the other edge from the one the SoC uses to drive t= he >> data. >> >> Does the videomode describe the panel, or does it describe the setting= s >> programmed to the SoC? >=20 > How about calling this property pixelclk-active, active high meaning > driving pixel data on rising edges and sampling on falling edges (the > pixel clock is high between driving and sampling the data), and active > low meaning driving on falling edges and sampling on rising edges? > It is the same from the SoC perspective and from the panel perspective,= > and it mirrors the usage of the other *-active properties. This sounds good to me. It's not quite correct, as neither pixelclock or pixel data are not really "active" when the clock is high/low, but it still makes sense and is clear (at least with a short description). Tomi --------------enigD5913F5C38A1C760756BBE03 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQIcBAEBAgAGBQJQxaE9AAoJEPo9qoy8lh71tfkP/3hzeIGnvSuFoVrLGiV/IyGu 2Uk+qSL1REVac/EJZGngR5nMNur+E3nAc/VqdoFPxL3eUQN64aq2/tbD+sB1HzH1 oYz0mVwzowUkGCEM1DVgtVoO9KW4HGHX0//6Jn8w1LlUSvLwJJl1NXlirsfxS5Qu nr5XG/hzf+zfCF1lsRKxlBxY2Q0JBIL72CkPkCYdMNVpcKKNuqVNl0zGw2aGHm2M qvo9o00rAW23DKRJOY6GPls1JDMpo+f8RGJExXvJlbONZjouNQM5lHr/UxNVrZum Izzn7j2Q1pGupDluiNdFPXBKDn0o6aU27xSUTQCu5s3pKuJxiPKT/QBw60eueaPo 8VZvAmrxlC+zEEAwW+T+AXKWfUmnUE4fr4XmMWbg9zclOPf7pdJDJSU15pDG2TYy 5UV0TvuqeSA9MJaZnnhO7kI/YPi0KRCP3zwQf0LNestdxm+3VfpE2oINYJ2eoWq1 WxwQ7SnX/HDuaeCNIcaZB6U5dQ98M0ziyNy7P9aS0dN46CnSYTmLm+h2yhk6eFkS TvST+YWV+Be3BFVppoH31ICkNotKBI2qGfVH6GcCjXtp1S9N45tC5HbojBLlwze3 SGTb5ZkbV/SHib/OnZtzW+P/+bbmIOplySOf9RQ9zFlf/1mGThXgEEbp36U1lic6 Izb71Op2WrU2TebUsesg =BhOc -----END PGP SIGNATURE----- --------------enigD5913F5C38A1C760756BBE03--