From patchwork Tue Jul 6 16:09:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liam Beguin X-Patchwork-Id: 12360873 X-Patchwork-Delegate: jic23@cam.ac.uk Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67E0FC07E96 for ; Tue, 6 Jul 2021 16:10:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53ACF619D2 for ; Tue, 6 Jul 2021 16:10:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230015AbhGFQMp (ORCPT ); Tue, 6 Jul 2021 12:12:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229891AbhGFQMj (ORCPT ); Tue, 6 Jul 2021 12:12:39 -0400 Received: from mail-qv1-xf2c.google.com (mail-qv1-xf2c.google.com [IPv6:2607:f8b0:4864:20::f2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3F7AC0613DB; Tue, 6 Jul 2021 09:09:55 -0700 (PDT) Received: by mail-qv1-xf2c.google.com with SMTP id w5so9967525qvu.10; Tue, 06 Jul 2021 09:09:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=D81pHYY9yUEhsRTAhZj3nTjKb2wFBFB7qiFvu4YjemA=; b=rW5rzAYGnvHaDagYm5Qp14n0N9osr/o0qshDyXcyYoaL22KUx5DtsvrZ0V1jRIDF5b Ucm76w7h3PjsPPwD/Wl8Msak/8BV5yFyMYMhXJoihnkKuD37wDy7rxP8KjskpERSs4fQ LaBNBRda7mXgnepvctO4uBvQfAKOFEpu6qvIgh59uktBphxzSUFSbdTXN/7jVxYZ1lX6 cejtN3sY9pOnjd4SHM7eoQ3S0JA08tZs8JDmadd1kGGZRMEp5aLtxxVdqU9HBsdK/4qr Q+WNbuqR4nViCgyNxm+jX/hD6FCFMiqNcmS6OtU+naOw2jM8jMhe6e42BY0irGRD3X7i sAcw== 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=D81pHYY9yUEhsRTAhZj3nTjKb2wFBFB7qiFvu4YjemA=; b=MKX6AZlgzDIWquR3ymM61bDHJtLmiYktkjmNLD2dsAoVvUNzngKrRQlm0cybMzUmxU QIfZWMDGTZjgGAALogSAxhFDkoWokmemE34qtsidy4JFI5tjzwXrplY2bUqPMZwyGg// udunwTIp9zpYxO4iuYiMAhyWCbdP8VYSMUqj/FBSlIK3BDKELuKRN3H6EjiCuzqIuCSw ynHHAEsxsE/Cx2f2qCUpf6PnlnZV+YkozUlEg9oh7tgh8l9SVKewnVfhMkuOT/aLh7UQ +CZ8c5+BS2ysO9fRk/vXuKp3jBZc8D/FryiJmD6t/XqsCTFAR8SSu+dvCFZmVrPjkvX8 K6fw== X-Gm-Message-State: AOAM533e1+b66w1nJzF5nP+2b4W4zJrtE6SwMa81o6cZyuVb6LAFUY63 gCW/viEZhYQNLUWvcWtDicU= X-Google-Smtp-Source: ABdhPJwZbp0uikDx06Z9stzIw6EGbH+gVsvGovd2mRn8vq2DHMfULg62s274VF9kUkyKNtjNtchBrA== X-Received: by 2002:a05:6214:d49:: with SMTP id 9mr19301224qvr.30.1625587794889; Tue, 06 Jul 2021 09:09:54 -0700 (PDT) Received: from shaak.xiphos.ca (198-48-202-89.cpe.pppoe.ca. [198.48.202.89]) by smtp.gmail.com with ESMTPSA id n64sm6995371qkd.79.2021.07.06.09.09.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jul 2021 09:09:54 -0700 (PDT) From: Liam Beguin To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org, lars@metafoo.de, pmeerw@pmeerw.net Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: [PATCH v4 06/10] iio: afe: rescale: add offset support Date: Tue, 6 Jul 2021 12:09:38 -0400 Message-Id: <20210706160942.3181474-7-liambeguin@gmail.com> X-Mailer: git-send-email 2.30.1.489.g328c10930387 In-Reply-To: <20210706160942.3181474-1-liambeguin@gmail.com> References: <20210706160942.3181474-1-liambeguin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Liam Beguin This is a preparatory change required for the addition of temperature sensing front ends. Signed-off-by: Liam Beguin --- drivers/iio/afe/iio-rescale.c | 72 +++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 1d0e24145d87..7b241e0d8638 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -32,6 +32,7 @@ struct rescale { bool chan_processed; s32 numerator; s32 denominator; + s32 offset; }; static int rescale_read_raw(struct iio_dev *indio_dev, @@ -39,6 +40,8 @@ static int rescale_read_raw(struct iio_dev *indio_dev, int *val, int *val2, long mask) { struct rescale *rescale = iio_priv(indio_dev); + int scale, scale2; + int schan_off = 0; s64 tmp, tmp2; u32 factor; int ret; @@ -100,6 +103,71 @@ static int rescale_read_raw(struct iio_dev *indio_dev, dev_err(&indio_dev->dev, "unsupported type %d\n", ret); return -EOPNOTSUPP; } + case IIO_CHAN_INFO_OFFSET: + /* + * Processed channels are scaled 1-to-1 and source offset is + * already taken into account. + * + * In other cases, real world measurement are expressed as: + * + * schan_scale * (raw + schan_offset) + * + * Given that the rescaler parameters are applied recursively: + * + * rescaler_scale * (schan_scale * (raw + schan_offset) + + * rescaler_offset) + * + * Or, + * + * (rescaler_scale * schan_scale) * (raw + + * (schan_offset + rescaler_offset / schan_scale) + * + * Thus, reusing the original expression the parameters exposed + * to userspace are: + * + * scale = schan_scale * rescaler_scale + * offset = schan_offset + rescaler_offset / schan_scale + */ + if (rescale->chan_processed) { + *val = rescale->offset; + return IIO_VAL_INT; + } + + if (iio_channel_has_info(rescale->source->channel, + IIO_CHAN_INFO_OFFSET)) { + ret = iio_read_channel_offset(rescale->source, + &schan_off, NULL); + if (ret != IIO_VAL_INT) + return ret < 0 ? ret : -EOPNOTSUPP; + } + + ret = iio_read_channel_scale(rescale->source, &scale, &scale2); + switch (ret) { + case IIO_VAL_FRACTIONAL: + tmp = (s64)rescale->offset * scale2; + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT: + *val = div_s64(rescale->offset, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_FRACTIONAL_LOG2: + tmp = (s64)rescale->offset * (1 << scale2); + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_NANO: + tmp = (s64)rescale->offset * 1000000000UL; + tmp2 = ((s64)scale * 1000000000UL) + scale2; + *val = div_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_MICRO: + tmp = (s64)rescale->offset * 1000000UL; + tmp2 = ((s64)scale * 1000000UL) + scale2; + *val = div_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + default: + dev_err(&indio_dev->dev, "unsupported type %d\n", ret); + return -EOPNOTSUPP; + } default: return -EINVAL; } @@ -176,6 +244,9 @@ static int rescale_configure_channel(struct device *dev, chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE); + if (rescale->offset) + chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET); + /* * Using .read_avail() is fringe to begin with and makes no sense * whatsoever for processed channels, so we make sure that this cannot @@ -340,6 +411,7 @@ static int rescale_probe(struct platform_device *pdev) rescale->cfg = of_device_get_match_data(dev); rescale->numerator = 1; rescale->denominator = 1; + rescale->offset = 0; ret = rescale->cfg->props(dev, rescale); if (ret)