From patchwork Mon Nov 2 17:49:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Baryshkov X-Patchwork-Id: 11874741 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 759FE92C for ; Mon, 2 Nov 2020 17:50:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5008422226 for ; Mon, 2 Nov 2020 17:50:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="pF6nXloP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725926AbgKBRuC (ORCPT ); Mon, 2 Nov 2020 12:50:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725911AbgKBRuC (ORCPT ); Mon, 2 Nov 2020 12:50:02 -0500 Received: from mail-lf1-x141.google.com (mail-lf1-x141.google.com [IPv6:2a00:1450:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B826C061A47 for ; Mon, 2 Nov 2020 09:50:02 -0800 (PST) Received: by mail-lf1-x141.google.com with SMTP id i6so18566793lfd.1 for ; Mon, 02 Nov 2020 09:50:02 -0800 (PST) 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=pF6nXloPlqM6obPwi75GDJ4k5kNTxmZBNAdxptXASLgJmKW8WWkBtqq1Wp1Ce1erYq cUIYfWu8TfzFoMmt32WTIcuwBtthMZOLo4y9bj4/a4v75KrpU1FEumUwjy0jYvxoKlGH etmg4jGm6GDjteZt6JgXGbEdlmEgBfjRmJh7G49/TxpyfoBS4pTnNnVBsBIl2vLK6nBm GbDF7Q8X5Yqnc/qx6sDhiGjG9tGrIcG3aa/M8fWVnpJv7Afk9M5FK8BjkpnN6ZK/Yr0T 6x5lBglGJ0VFL3uCu2+8tvYLDJMh9PY2/CszYvVXVOlxWltI3RXlnqB2TyxsLrF7xMgM IEiA== 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=rF1ME/qlN2IQ8hTLBnY5FQYmmpRbfLQeFlDP46YuZsu1doGFcGhT7/dnIeNij/hdsP s2/Gz5Kt2XtBD+5gYYv85Mzqvc1AI2hLDwENe77HC40s3FEwbx1oiKI7SVL+wdrOH2VA g/5/QA2leKjJcjR73NZ1j9493M9Xa7ZuZ8J9oTb2veFtg0PmfcDoiIgmuVi5ZkKAtPZY 0VVEQdK+3hPNbBcYhpnWDhCbjkNopRbdIqQVZjN2JFRyYBHuo7RQ0C8THDOg2j4fLpKU ljuB1vGTayEk21/cBiNKPFHuHRFZRIzcIG0nGRcnoAJmbqyHzgv3Pd7+64MFlOx4NVyU Cmkg== X-Gm-Message-State: AOAM532xbx+S++wW4zWcQK+OqdblNEmT7VrMVE6h48iy6KiCa2M5eIPS kcJhcexe2HHLkVahD8F/TW5qPA== X-Google-Smtp-Source: ABdhPJwT4c3XpWr9RF86PfA6UGPomdWMztywNoqE5xFatshmIo3gmkhsLHkWkfoZqYB+xOSFBXGteA== X-Received: by 2002:a19:407:: with SMTP id 7mr5928439lfe.291.1604339400716; Mon, 02 Nov 2020 09:50:00 -0800 (PST) Received: from eriador.lan ([94.25.229.254]) by smtp.gmail.com with ESMTPSA id r7sm2516163lfc.206.2020.11.02.09.49.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Nov 2020 09:50:00 -0800 (PST) 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 , Jishnu Prakash , Craig Tatlor , Jonathan Cameron Subject: [PATCH v9 02/15] fixp-arith: add a linear interpolation function Date: Mon, 2 Nov 2020 20:49:37 +0300 Message-Id: <20201102174950.1148498-3-dmitry.baryshkov@linaro.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201102174950.1148498-1-dmitry.baryshkov@linaro.org> References: <20201102174950.1148498-1-dmitry.baryshkov@linaro.org> MIME-Version: 1.0 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