From patchwork Thu Sep 10 13:59:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Baryshkov X-Patchwork-Id: 11769271 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 C558159D for ; Thu, 10 Sep 2020 21:04:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B98521D90 for ; Thu, 10 Sep 2020 21:04:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="WcGgdaRR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727052AbgIJVEf (ORCPT ); Thu, 10 Sep 2020 17:04:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730690AbgIJOhg (ORCPT ); Thu, 10 Sep 2020 10:37:36 -0400 Received: from mail-lj1-x244.google.com (mail-lj1-x244.google.com [IPv6:2a00:1450:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6EBDC0617BB for ; Thu, 10 Sep 2020 07:00:16 -0700 (PDT) Received: by mail-lj1-x244.google.com with SMTP id a15so8360151ljk.2 for ; Thu, 10 Sep 2020 07:00:16 -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=WcGgdaRRvCVMPOMrzk8F0zJKKmXYDnx/T+2PstZPMVXOPjqh8utA+6+vILfHsug244 UlvTF+Cv7GA993X7lv/AnHiWokjLhHCdY/o/MAk/lHwbyu0dMRyCZIjZlZo1x5Mj3v3e j5B78FNoLh0JLl6S4aIr4wYfyAwpqAqX1E9RVHyrZlTjH/NSufy6X1HFlExrh+i7NTMI 4u16BTA6G+MhSDCVH/h07hI04tVXg4+T8S5BPo5F/PfZ8kYtuz3S5wWEK2/OFJWxvMHJ jjfiehwrYb1S+Pv9uTyiFpLE+BssJdGiBHGnGElC4KiOFrNr6tp6EXQIFi5enObhytNB lSGQ== 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=cmHx9TYy0kZW9PbpGVkgVeQnehCh3Pb1RP+Q2iWO93YQjUyQc46M/HHV5z7kBtLhgu l0wUXQEAGkwgJGblyqNHuEVzpHhjcu811tuq6GeYa3POgNJsvxler5r5DPPIN/6SnW5S eT4M3nXlIbh8HZcLVeMKb61EBOOz+9anauB9CEXgwlbGtVj4y6iLrdjF3z7TqZxP1oTT QsodrQWu/5fi9iutxao+9vpZoUq4ObKnnoaWi3xf8RkfBoxFmwOv5wBCjoZ5KQrgP+0e v/wV54Wpdcp1babJSMtBifo4fbIzG6d826SYKA/DI2nsQ1fbovOstXy54t9SAayeyqSX 67Aw== X-Gm-Message-State: AOAM531UTno8Bz4B4Z6/BqdoUb6n9zTNrfEVVnPZj8M1ro5BA3eeBzGp M+6hPYlRWSMFpND6gFv2pLl62A== X-Google-Smtp-Source: ABdhPJxBUWMazHhh0NVRcv5in/kVk015eZcEEP/gzP/tFVbk7+tflyjNHMBiyncgOgFctGYV3Bn5zg== X-Received: by 2002:a2e:8506:: with SMTP id j6mr4109652lji.176.1599746415305; Thu, 10 Sep 2020 07:00:15 -0700 (PDT) Received: from eriador.lan ([188.162.64.156]) by smtp.gmail.com with ESMTPSA id t82sm1367646lff.43.2020.09.10.07.00.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 07:00:14 -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 v4 03/10] fixp-arith: add a linear interpolation function Date: Thu, 10 Sep 2020 16:59:53 +0300 Message-Id: <20200910140000.324091-4-dmitry.baryshkov@linaro.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200910140000.324091-1-dmitry.baryshkov@linaro.org> References: <20200910140000.324091-1-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