From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B7BA379CD; Mon, 6 Oct 2025 01:18:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759713518; cv=none; b=mKsQlkxJ5cR4kSyHaMgIDB7pcKPgFu4wxrEpWcKh5amXgD/A9ynQUZn3iUdru5i3u+pQa2oKL/GgBn42kq6KwkQRCLx3JoccDfHhjLyu0jWCUydeA3EN3nR3L+N5ktAFviIPhh84lGHS6LjNPf/P6COfTMBywZpuhVozo3sDkRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759713518; c=relaxed/simple; bh=2Z3QGL4wAK5QOKF4a4Gd1Zf6tzhgZNVyrlQQhXpXGKk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=teX0wzXhL+u7ugN5l/reIahqWtXThEtAGtsdNiNpFeQrzQQL365wfrFMmtnmVoYbT7nli47m7N+RUROgxiUIlZ+yjp4XeNX5TyjKlDBT/diRPVmTdu4kE61RAhiZFgTIPj/vzRasQKgDSqlAMVAYaJBV7nX/w+JH8gv+qDE8EOE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=oanwC028; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="oanwC028" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id F02C51741; Mon, 6 Oct 2025 03:17:02 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1759713423; bh=2Z3QGL4wAK5QOKF4a4Gd1Zf6tzhgZNVyrlQQhXpXGKk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oanwC028YZpnPsTnwkl1LQCcnvaR8MtpmUk6cIVMc6kA665gVCey2NZMxby19QMWy zAFyjhFWAYeHd1rhftu7IW8AbSkPSyVRVqRGumsipm5wMMjssDv6jOhIf9gau0ml8a 0ScVaWyji7biGZa+E2M1dARpaXYDOONpEDjpYQUw= Date: Mon, 6 Oct 2025 04:18:29 +0300 From: Laurent Pinchart To: Jacopo Mondi Cc: Dafna Hirschfeld , Keke Li , Mauro Carvalho Chehab , Heiko Stuebner , Dan Scally , Sakari Ailus , Antoine Bouyer , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v5 8/8] media: Documentation: kapi: Add v4l2 generic ISP support Message-ID: <20251006011829.GC29231@pendragon.ideasonboard.com> References: <20250915-extensible-parameters-validation-v5-0-e6db94468af3@ideasonboard.com> <20250915-extensible-parameters-validation-v5-8-e6db94468af3@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250915-extensible-parameters-validation-v5-8-e6db94468af3@ideasonboard.com> Hi Jacopo, Thank you for the patch. On Mon, Sep 15, 2025 at 07:18:17PM +0200, Jacopo Mondi wrote: > Add to the driver-api documentation the v4l2-isp.h types and > helpers documentation. > > Reviewed-by: Daniel Scally > Signed-off-by: Jacopo Mondi > --- > Documentation/driver-api/media/v4l2-core.rst | 1 + > Documentation/driver-api/media/v4l2-isp.rst | 37 ++++++++++++++++++++++++++++ > MAINTAINERS | 1 + > 3 files changed, 39 insertions(+) > > diff --git a/Documentation/driver-api/media/v4l2-core.rst b/Documentation/driver-api/media/v4l2-core.rst > index ad987c34ad2a8460bb95e97adc4d850d624e0b81..a5f5102c64cca57b57b54ab95882b26286fb27de 100644 > --- a/Documentation/driver-api/media/v4l2-core.rst > +++ b/Documentation/driver-api/media/v4l2-core.rst > @@ -27,3 +27,4 @@ Video4Linux devices > v4l2-common > v4l2-tveeprom > v4l2-jpeg > + v4l2-isp At what point we should structure the documentation. At one point :-) > diff --git a/Documentation/driver-api/media/v4l2-isp.rst b/Documentation/driver-api/media/v4l2-isp.rst > new file mode 100644 > index 0000000000000000000000000000000000000000..d778aa799347bfd0a95bd6887dd944ddad0fe4d1 > --- /dev/null > +++ b/Documentation/driver-api/media/v4l2-isp.rst > @@ -0,0 +1,37 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +V4L2 generic ISP parameters and statistics support > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + > +ISP configuration parameters and statistics are processed and collected by > +drivers and exchanged with userspace through data types that usually > +reflect the ISP peripheral registers layout. > + > +Each ISP driver defines its own metadata format for parameters and statistics, > +and exposing the registers layout in the format definition, part of the Linux > +kernel uAPI/uABI interface, makes it really hard, if not impossible, to extend > +the format in a backward compatible way to support new hardware blocks or > +different revisions of the same peripheral IP. > + > +For these reasons Video4Linux2 defines generic types for ISP configuration > +parameters and statistics with a set of associated helpers to support drivers > +and users using generic types. > + > +Generic ISP configuration parameters > +==================================== > + > +Drivers can use the generic and extensible configuration parameters format by > +re-using the types defined in the include/uapi/linux/media/v4l2-isp.h uAPI > +header file. > + > +The uAPI header defines generic types which the driver is expected to re-use and > +provide definitions for the types of supported ISP blocks, their control > +flags and the expected maximum size of a buffer of parameters. > + > +When a driver receives a buffer of parameters from userspace it shall validate > +it by using the helper functions and types available in include/media/v4l2-isp.h > +before accessing the buffer to apply the parameters to the hardware registers. > + Same comments are for the UAPI, I think this will need a full rewrite later. > +Generic ISP support driver documentation > +======================================== > +.. kernel-doc:: include/media/v4l2-isp.h > diff --git a/MAINTAINERS b/MAINTAINERS > index 5e0e4208ebe6c58a9ea0834e1ebb36abd2de06e1..b0c5e6c2b21a5d5ebc63d2ae8b5c1b68fa912b33 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -26414,6 +26414,7 @@ V4L2 GENERIC ISP PARAMETERS AND STATISTIC FORMATS > M: Jacopo Mondi > L: linux-media@vger.kernel.org > S: Maintained > +F: Documentation/driver-api/media/v4l2-isp.rst > F: Documentation/userspace-api/media/v4l/extensible-parameters.rst > F: drivers/media/v4l2-core/v4l2-isp.c > F: include/media/v4l2-isp.h -- Regards, Laurent Pinchart