From patchwork Wed Sep 9 14:42:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Baryshkov X-Patchwork-Id: 11765793 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 AF7BC138E for ; Wed, 9 Sep 2020 16:43:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9408B2166E for ; Wed, 9 Sep 2020 16:43:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="OqjBqEAW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726920AbgIIQm4 (ORCPT ); Wed, 9 Sep 2020 12:42:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730783AbgIIQMt (ORCPT ); Wed, 9 Sep 2020 12:12:49 -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 1C155C0612A5 for ; Wed, 9 Sep 2020 07:43:07 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id b19so3855212lji.11 for ; Wed, 09 Sep 2020 07:43:06 -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=wcVYXgQ5pttw1IKCDgQFlSKYdGXdwjbBjMlIEbUjqiQ=; b=OqjBqEAWPDnfTgGoQjNBjYeKg4K9GLkX+Bw8XJ40eGAnEnptk7yRupxf6JWaCD3JmN 5RsG/GLVMzpJiJHXxHhGdf2uNA8I5Ti9uw3PbTjKXGjl7tXt/Lh+00q2uqsGRLua4bpz c0xwDeKX8dqKrNq1y6poqRfUh+qMciJUiOGJ1aEbPxjGGqtUdA1xchxaDu0XrEBPxg2t 2EtWKUuNJThIs44LYt4kbj5pee+7qcsqeQorMdD1UcHjN5e7IFGFQAW4kqhOXP47C5sS sq40F/txN46g5H8AVsWXBkPwPDLuurGMmnKh5rU/9dl2kro650tFs24zR8g1lE8OeIOt cn7g== 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=wcVYXgQ5pttw1IKCDgQFlSKYdGXdwjbBjMlIEbUjqiQ=; b=aJ5mU8j2yKPSNzXfWMkfmQ2WYF9oyvzdd9bqY2kTWbYFUkH1wfkHt1o797tSzJBUz3 M8DOHICf/evU/FhR3l3QBilbbbyWjs5JQZn18yR4yr0h9KYIuxfxoyEz/BELnohrhpVa 8yFjMADcv0i0dpUojw5znqmjJ94CewPXlhq6MdVDd8oTsKDmOJJWjlI+mcHo2PSHMGbg tXMLzmG0s9JhoaxS3lMaNCfnxZHKecLEdPS3NcuBYuUL/BBCOyUO7iCp8KzYDvKlt52+ Libsxie23EHFuc36fhNgDdvrKiXVNnHBfz1mEXS18ah/NJuZe/BtCT6KC5HxwSsrsdTk 8IZw== X-Gm-Message-State: AOAM530JTo1qvVvAKJV1mOBO8CFYeStkH6HxEUqw9+zR1pIxdV3Bg5aq D8XWFKcZo6UFS8yvrFNvUjdS1A== X-Google-Smtp-Source: ABdhPJyWwfksQxPk2Tnm2ER0m9k37Twox0OGJe88A6KO3gv3HM/BUcjQ+SFEmloMY+FO5ietjnqs7A== X-Received: by 2002:a2e:6c08:: with SMTP id h8mr2031092ljc.66.1599662584166; Wed, 09 Sep 2020 07:43:04 -0700 (PDT) Received: from eriador.lan ([188.162.64.155]) by smtp.gmail.com with ESMTPSA id t12sm621665lfk.26.2020.09.09.07.43.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Sep 2020 07:43:03 -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 Subject: [PATCH v3 03/10] fixp-arith: add a linear interpolation function Date: Wed, 9 Sep 2020 17:42:41 +0300 Message-Id: <20200909144248.54327-4-dmitry.baryshkov@linaro.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200909144248.54327-1-dmitry.baryshkov@linaro.org> References: <20200909144248.54327-1-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 --- 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