From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26857C433EF for ; Mon, 25 Apr 2022 06:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229834AbiDYHAS (ORCPT ); Mon, 25 Apr 2022 03:00:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229757AbiDYHAR (ORCPT ); Mon, 25 Apr 2022 03:00:17 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44F23193E0; Sun, 24 Apr 2022 23:57:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2FBEBB80ED5; Mon, 25 Apr 2022 06:57:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFAE8C385A4; Mon, 25 Apr 2022 06:57:08 +0000 (UTC) Message-ID: Date: Mon, 25 Apr 2022 08:57:07 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v4 6/9] media: uapi: Add a control for DW100 driver Content-Language: en-US To: Xavier Roumegue , mchehab@kernel.org, stanimir.varbanov@linaro.org, laurent.pinchart@ideasonboard.com, tomi.valkeinen@ideasonboard.com, robh+dt@kernel.org, nicolas@ndufresne.ca, alexander.stein@ew.tq-group.com Cc: linux-media@vger.kernel.org, devicetree@vger.kernel.org References: <20220328141309.177611-1-xavier.roumegue@oss.nxp.com> <20220328141309.177611-7-xavier.roumegue@oss.nxp.com> From: Hans Verkuil In-Reply-To: <20220328141309.177611-7-xavier.roumegue@oss.nxp.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 28/03/2022 16:13, Xavier Roumegue wrote: > The DW100 driver gets the dewarping mapping as a binary blob from the > userspace application through a custom control. > The blob format is hardware specific so create a dedicated control for > this purpose. > > Signed-off-by: Xavier Roumegue > --- > Documentation/userspace-api/media/drivers/dw100.rst | 12 ++++++++++++ > include/uapi/linux/dw100.h | 11 +++++++++++ > 2 files changed, 23 insertions(+) > create mode 100644 include/uapi/linux/dw100.h > > diff --git a/Documentation/userspace-api/media/drivers/dw100.rst b/Documentation/userspace-api/media/drivers/dw100.rst > index 4cd55c75628e..f6d684cadf26 100644 > --- a/Documentation/userspace-api/media/drivers/dw100.rst > +++ b/Documentation/userspace-api/media/drivers/dw100.rst > @@ -20,4 +20,16 @@ match the expected size inherited from the destination image resolution. > More details on the DW100 hardware operations can be found in > *chapter 13.15 DeWarp* of IMX8MP_ reference manuel. > > +The Vivante DW100 m2m driver implements the following driver-specific control: > + > +``V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP (integer)`` (integer) -> (__u32 array) But should this be a __u32 array at all? Wouldn't a __u16 array make more sense? > + Specifies to DW100 driver its dewarping map (aka LUT) blob as described in > + *chapter 13.15.2.3 Dewarping Remap* of IMX8MP_ reference manual as an U32 > + dynamic array. The image is divided into many small 16x16 blocks. If the > + width of the image is not divisible by 16, the size of the rightmost block > + is the remainder. Isn't the same true for the height? The dewarping map only saves the vertex coordinates of the > + block. The dewarping grid map is comprised of vertex coordinates for x and y. > + Each x, y coordinate register uses 16 bits (UQ12.4) to record the coordinate As mentioned before, UQ12.4 is not necessarily a standard notation. 'unsigned 12.4 fixed point' is better, but you also need to specify exactly where the bits are stored inside the __u16. I.e.: 'the integer part is stored in the 12 most significant bits, and the fractional part is stored in the 4 least significant bits of the __u16.' > + address, with the Y coordinate in the upper bits and X in the lower bits. And with a __u16 array this becomes: 'The array contains pairs of X, Y coordinates.' Or something along those lines. > + > .. _IMX8MP: https://www.nxp.com/webapp/Download?colCode=IMX8MPRM > diff --git a/include/uapi/linux/dw100.h b/include/uapi/linux/dw100.h > new file mode 100644 > index 000000000000..7fdcf2bf42e5 > --- /dev/null > +++ b/include/uapi/linux/dw100.h > @@ -0,0 +1,11 @@ > +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ > +/* Copyright 2022 NXP */ > + > +#ifndef __UAPI_DW100_H__ > +#define __UAPI_DW100_H__ > + > +#include > + Add a comment referring to the Documentation/userspace-api/media/drivers/dw100.rst documentation so users of this control know where to find the associated documentation. > +#define V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP (V4L2_CID_USER_DW100_BASE + 1) > + > +#endif Regards, Hans