From patchwork Mon Sep 14 15:48:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Baryshkov X-Patchwork-Id: 11774405 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C9559618 for ; Mon, 14 Sep 2020 15:58:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A887420756 for ; Mon, 14 Sep 2020 15:58:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Ah7wZk7H" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725976AbgINP6K (ORCPT ); Mon, 14 Sep 2020 11:58:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726475AbgINPsY (ORCPT ); Mon, 14 Sep 2020 11:48:24 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AD80C061355 for ; Mon, 14 Sep 2020 08:48:24 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id w3so99411ljo.5 for ; Mon, 14 Sep 2020 08:48:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=u+ec5e/iUjJ8qDBtGE9xKBCADcm1RI8srVHT5OLXlvU=; b=Ah7wZk7H4a1YXb3siR+1ZjnwbjtSkXQdarNonG4apXmKK1RU7RgA3q5ffNCULhdZvv szBF+ywo3gSiAmVakhVSgrzGXibgJEBf0zLpay43DWkEfJks/Sxn9RKntWuRWYaevQev lg3aSW2BNqdhGyZe/JNz3NltDhgf8++D85FQcp14KLyjLf7D4vi1YLxZTZvklHXZ9T8Y Un2iIgaxXMW8MTzeluqSCr7BmwGpo0sk+04aycaYPhknOLHiqpydFmz5ZYsXOE0v/Gbs S1YPClKB3VqmlDYAnn14//BI+/N1syiPKkvqMZDzc7xAJueJPfZwiiaWpHxrUtoA2par bnCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=u+ec5e/iUjJ8qDBtGE9xKBCADcm1RI8srVHT5OLXlvU=; b=UM/RZT71ySX7HPOn1qsa5OaTd7tGHrNUXoyMx3sl/fomV8759PS8/xNOHh+DOUrqnq dDFsryMPWl2SStJrXRC+AmnHup/b6e6HDWUUUIKlNnDANV2a1Wu28BQPGQGLZRJQlpjQ iMlEicRHSUjohkmLMXqZVapqWPYuxX9WDNnOakOodyB4FGknWuxWvof8kFfJ0AvF/K9l b3NIHYgGXL+pyA62E55eycQt8amDSss9xwwGqjPTBJnrf8H/oicUFcSQ66CZegCyfr/Q HWDE5ndEuHqOlxqJ5ZKvegePzHhFt7eMBrfvdNXz7R9g9tzbt9czL7vUW5g8n0zxftSD PQlw== X-Gm-Message-State: AOAM533T3btw0sLlIwCuAWTYEs8qBOGw9xBA+e/9Erfel1TtCH9kyTNA hor8QVIJHntlpKlp5USHwMUklw== X-Google-Smtp-Source: ABdhPJzURBwsNbRnRIeAcecDmShpK8ebYE54NKbCVaKVQd6J/us5aq97BPTZiiIzM3WGoHHWH2cIzQ== X-Received: by 2002:a2e:780d:: with SMTP id t13mr5681189ljc.324.1600098502656; Mon, 14 Sep 2020 08:48:22 -0700 (PDT) Received: from eriador.lan ([188.162.64.187]) by smtp.gmail.com with ESMTPSA id f19sm3834650lfs.85.2020.09.14.08.48.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2020 08:48:22 -0700 (PDT) From: Dmitry Baryshkov To: Andy Gross , Bjorn Andersson , Rob Herring , Zhang Rui , Daniel Lezcano , Amit Kucheria , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler Cc: linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-iio@vger.kernel.org, Manivannan Sadhasivam , Craig Tatlor , Jonathan Cameron Subject: [PATCH v5 2/9] fixp-arith: add a linear interpolation function Date: Mon, 14 Sep 2020 18:48:02 +0300 Message-Id: <20200914154809.192174-3-dmitry.baryshkov@linaro.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200914154809.192174-1-dmitry.baryshkov@linaro.org> References: <20200914154809.192174-1-dmitry.baryshkov@linaro.org> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Craig Tatlor Adds a function to interpolate against two points, this is carried arount as a helper function by tons of drivers. Signed-off-by: Craig Tatlor Signed-off-by: Dmitry Baryshkov Acked-by: Jonathan Cameron --- include/linux/fixp-arith.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/linux/fixp-arith.h b/include/linux/fixp-arith.h index 8396013785ef..281cb4f83dbe 100644 --- a/include/linux/fixp-arith.h +++ b/include/linux/fixp-arith.h @@ -141,4 +141,23 @@ static inline s32 fixp_sin32_rad(u32 radians, u32 twopi) #define fixp_cos32_rad(rad, twopi) \ fixp_sin32_rad(rad + twopi / 4, twopi) +/** + * fixp_linear_interpolate() - interpolates a value from two known points + * + * @x0: x value of point 0 + * @y0: y value of point 0 + * @x1: x value of point 1 + * @y1: y value of point 1 + * @x: the linear interpolant + */ +static inline int fixp_linear_interpolate(int x0, int y0, int x1, int y1, int x) +{ + if (y0 == y1 || x == x0) + return y0; + if (x1 == x0 || x == x1) + return y1; + + return y0 + ((y1 - y0) * (x - x0) / (x1 - x0)); +} + #endif