From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [RFC/PATCH 02/13] media: s5p-csis: Add device tree support Date: Tue, 31 Jul 2012 23:37:20 +0200 Message-ID: <1964196.hivxX7VrnL@avalon> References: <4FBFE1EC.9060209@samsung.com> <4835930.8zRiqxUPR0@avalon> <5017D1CB.80709@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <5017D1CB.80709@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Sylwester Nawrocki Cc: Guennadi Liakhovetski , Sylwester Nawrocki , linux-media@vger.kernel.org, kyungmin.park@samsung.com, m.szyprowski@samsung.com, riverful.kim@samsung.com, sw0312.kim@samsung.com, devicetree-discuss@lists.ozlabs.org, linux-samsung-soc@vger.kernel.org, b.zolnierkie@samsung.com List-Id: devicetree@vger.kernel.org Hi Sylwester, On Tuesday 31 July 2012 14:38:35 Sylwester Nawrocki wrote: > On 07/31/2012 01:05 PM, Laurent Pinchart wrote: > >>>>> What about CSI receivers that can reroute the lanes internally ? We > >>>>> would need to specify lane indices for each lane then, maybe with > >>>>> something like > >>>>> > >>>>> clock-lane =<0>; > >>>>> data-lanes =<2 3 1>; > >>>> > >>>> Sounds good to me. And the clock-lane could be made optional, as not > >>>> all devices would need it. > >>>> > >>>> However, as far as I can see, there is currently no generic API for > >>>> handling this kind of data structure. E.g. number of cells for the > >>>> "interrupts" property is specified with an additional > >>>> "#interrupt-cells" property. > >>>> > >>>> It would have been much easier to handle something like: > >>>> > >>>> data-lanes = <2>, <3>, <1>; > >>>> > >>>> i.e. an array of the lane indexes. > >>> > >>> I'm fine with that. > >> > >> ...on a second thought: shouldn't this be handled by pinctrl? Or is it > >> some CSI-2 module internal lane switching, not the global SoC pin > >> function configuration? > > > > On the hardware I came across, it's handled by the CSI2 receiver, not the > > SoC pinmux feature. > > Same here. Is there any hardware known to mux those MIPI-CSI > D-PHY high speed differential signals with general purpose IO pins ? > > Or are there mostly dedicated pins used ? The OMAP3 multiplexes the CSI pins with other functions. > However, if there are cases the lane configuration is done solely at CSI2 > receiver level, there seems little point in involving the pinctrl API. The OMAP3 handles lane routing in the CSI2 receiver. -- Regards, Laurent Pinchart