From patchwork Fri Jun 17 08:45:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean-Michel Hautbois X-Patchwork-Id: 583105 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 0F836C433EF for ; Fri, 17 Jun 2022 08:45:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381359AbiFQIp5 (ORCPT ); Fri, 17 Jun 2022 04:45:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381413AbiFQIpj (ORCPT ); Fri, 17 Jun 2022 04:45:39 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD3716A04B for ; Fri, 17 Jun 2022 01:45:28 -0700 (PDT) Received: from tatooine.ideasonboard.com (unknown [IPv6:2a01:e0a:169:7140:28e5:dce:57ec:634e]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 222652A5; Fri, 17 Jun 2022 10:45:27 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1655455527; bh=8fGsXJySfx/20YC9EMkhXuZx3a5LAzX5aBaucimZ4O4=; h=From:To:Cc:Subject:Date:From; b=FkLEWcn7W7/rKihafHx5k7MykmYd1qckMTQLNKQfjF4MoN1/G5FHRcTJjlPAY26GF K83F5YFwsm8cMJKuuoi9xvcvilsF445W+DMlqG2MOjUJHzHDwxgv9VjO5K+abGaC1e knoO74kJgMlI5ZwUJBrmDHRondp6Yohe+krFcvhk= From: Jean-Michel Hautbois To: linux-media@vger.kernel.org Cc: sakari.ailus@linux.intel.com, bingbu.cao@intel.com, tian.shu.qiu@intel.com, laurent.pinchart@ideasonboard.com, Jean-Michel Hautbois Subject: [PATCH] media: staging: ipu3-imgu: Fix BNR wb gain documentation Date: Fri, 17 Jun 2022 10:45:19 +0200 Message-Id: <20220617084519.32129-1-jeanmichel.hautbois@ideasonboard.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The documentation states that the BNR factor is a multiplier coded as u3.13 and with a range of (0, 8). This is not correct, as the isp is adding 1.0 to the gain applied, ie Pout = { Pin * (1 + Gx) }. It means that a gain of 1.0 should be coded as 0. Signed-off-by: Jean-Michel Hautbois --- drivers/staging/media/ipu3/include/uapi/intel-ipu3.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h index dbdd015ce220..caa358e0bae4 100644 --- a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h +++ b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h @@ -626,8 +626,11 @@ struct ipu3_uapi_stats_3a { * @b: white balance gain for B channel. * @gb: white balance gain for Gb channel. * - * Precision u3.13, range [0, 8). White balance correction is done by applying - * a multiplicative gain to each color channels prior to BNR. + * For BNR parameters WB gain factor for the three channels [Ggr, Ggb, Gb, Gr]. + * Their precision is U3.13 and the range is (0, 8) and the actual gain is + * Gx + 1, it is typically Gx = 1. + * + * Pout = {Pin * (1 + Gx)}. */ struct ipu3_uapi_bnr_static_config_wb_gains_config { __u16 gr;