From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:33419 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753009Ab2BRBn5 (ORCPT ); Fri, 17 Feb 2012 20:43:57 -0500 From: Laurent Pinchart To: Sylwester Nawrocki Cc: Sylwester Nawrocki , linux-media@vger.kernel.org, g.liakhovetski@gmx.de, sakari.ailus@iki.fi, m.szyprowski@samsung.com, riverful.kim@samsung.com, sw0312.kim@samsung.com, Kyungmin Park Subject: Re: [RFC/PATCH 3/6] V4L: Add g_embedded_data subdev callback Date: Sat, 18 Feb 2012 02:43:52 +0100 Message-ID: <4603092.UUnjJ05PXI@avalon> In-Reply-To: <4F3EE3C3.6070605@gmail.com> References: <1329416639-19454-1-git-send-email-s.nawrocki@samsung.com> <6366737.ZEMB1VQOcD@avalon> <4F3EE3C3.6070605@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Sylwester, On Saturday 18 February 2012 00:33:23 Sylwester Nawrocki wrote: > On 02/18/2012 12:23 AM, Laurent Pinchart wrote: > >> struct v4l2_subdev_video_ops { > >> > >> int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 > >> > >> config); @@ -321,6 +329,8 @@ struct v4l2_subdev_video_ops { > >> > >> struct v4l2_mbus_config *cfg); > >> > >> int (*s_mbus_config)(struct v4l2_subdev *sd, > >> > >> const struct v4l2_mbus_config *cfg); > >> > >> + int (*g_embedded_data)(struct v4l2_subdev *sd, unsigned int *size, > >> + void **buf); > >> > >> }; > > > > How is the embedded data transferred from the sensor to the host in your > > case ? Over I2C ? > > It's transferred over MIPI-CSI2 bus and is intercepted by the MIPI-CSI2 > receiver, before the image data DMA. The MIPI-CSI2 doesn't have its own > DMA engine. More details can be found in patch 6/6. As the data is transmitted by the device without any polling from the host, shouldn't it just go to a metadata plane in the V4L2 buffer ? -- Regards, Laurent Pinchart