From patchwork Fri Oct 28 02:35:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jammy Huang X-Patchwork-Id: 620164 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 60834FA373D for ; Fri, 28 Oct 2022 02:38:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236554AbiJ1CiL (ORCPT ); Thu, 27 Oct 2022 22:38:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236430AbiJ1Ch7 (ORCPT ); Thu, 27 Oct 2022 22:37:59 -0400 Received: from twspam01.aspeedtech.com (twspam01.aspeedtech.com [211.20.114.71]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BBF394A830; Thu, 27 Oct 2022 19:37:55 -0700 (PDT) Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 29S2D5KF054600; Fri, 28 Oct 2022 10:13:06 +0800 (GMT-8) (envelope-from jammy_huang@aspeedtech.com) Received: from JammyHuang-PC.aspeed.com (192.168.2.115) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 28 Oct 2022 10:35:59 +0800 From: Jammy Huang To: , , , , , , , , , , , , , , , , , Subject: [PATCH v11 3/5] media: Documentation: aspeed-video: Add user documentation for the aspeed-video driver Date: Fri, 28 Oct 2022 10:35:52 +0800 Message-ID: <20221028023554.928-4-jammy_huang@aspeedtech.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221028023554.928-1-jammy_huang@aspeedtech.com> References: <20221028023554.928-1-jammy_huang@aspeedtech.com> MIME-Version: 1.0 X-Originating-IP: [192.168.2.115] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 29S2D5KF054600 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add user documentation for the aspeed-video driver. Signed-off-by: Jammy Huang --- v11: - update the way to change format v10: - new --- .../media/drivers/aspeed-video.rst | 61 +++++++++++++++++++ .../userspace-api/media/drivers/index.rst | 1 + 2 files changed, 66 insertions(+) create mode 100644 Documentation/userspace-api/media/drivers/aspeed-video.rst diff --git a/Documentation/userspace-api/media/drivers/aspeed-video.rst b/Documentation/userspace-api/media/drivers/aspeed-video.rst new file mode 100644 index 000000000000..e5656a8d990e --- /dev/null +++ b/Documentation/userspace-api/media/drivers/aspeed-video.rst @@ -0,0 +1,65 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. include:: + +ASPEED video driver +=================== + +ASPEED Video Engine found on AST2400/2500/2600 SoC supports high performance +video compressions with a wide range of video quality and compression ratio +options. The adopted compressing algorithm is a modified JPEG algorithm. + +There are 2 types of compressions in this IP. + +* JPEG JFIF standard mode: for single frame and management compression +* ASPEED proprietary mode: for multi-frame and differential compression. + Support 2-pass (high quality) video compression scheme (Patent pending by + ASPEED). Provide visually lossless video compression quality or to reduce + the network average loading under intranet KVM applications. + +VIDIOC_S_FMT can be used to choose which format you want. V4L2_PIX_FMT_JPEG +stands for JPEG JFIF standard mode; V4L2_PIX_FMT_AJPG stands for ASPEED +proprietary mode. + +More details on the ASPEED video hardware operations can be found in +*chapter 6.2.16 KVM Video Driver* of SDK_User_Guide which available on +AspeedTech-BMC/openbmc/releases. + +The ASPEED video driver implements the following driver-specific control: + +``V4L2_CID_ASPEED_HQ_MODE`` +------------------------------- + Enable/Disable ASPEED's High quality mode. This is a private control + that can be used to enable high quality for aspeed proprietary mode. + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 1 4 + + * - ``(0)`` + - ASPEED HQ mode is disabled. + * - ``(1)`` + - ASPEED HQ mode is enabled. + +``V4L2_CID_ASPEED_HQ_JPEG_QUALITY`` +------------------------------- + Define the quality of ASPEED's High quality mode. This is a private control + that can be used to decide compression quality if High quality mode enabled + . Higher the value, better the quality and bigger the size. + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 1 4 + + * - ``(1)`` + - minimum + * - ``(12)`` + - maximum + * - ``(1)`` + - step + * - ``(1)`` + - default + +**Copyright** |copy| 2022 ASPEED Technology Inc. diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst index 32f82aed47d9..46a494e00b72 100644 --- a/Documentation/userspace-api/media/drivers/index.rst +++ b/Documentation/userspace-api/media/drivers/index.rst @@ -31,6 +31,7 @@ For more details see the file COPYING in the source distribution of Linux. :maxdepth: 5 :numbered: + aspeed-video ccs cx2341x-uapi dw100