From patchwork Sun Mar 18 13:36:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Veenstra X-Patchwork-Id: 10291171 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3E4E7600F6 for ; Sun, 18 Mar 2018 13:36:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2D44728E11 for ; Sun, 18 Mar 2018 13:36:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 21BAA2900F; Sun, 18 Mar 2018 13:36:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A90DD28E11 for ; Sun, 18 Mar 2018 13:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753930AbeCRNg4 (ORCPT ); Sun, 18 Mar 2018 09:36:56 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33466 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372AbeCRNgz (ORCPT ); Sun, 18 Mar 2018 09:36:55 -0400 Received: by mail-wm0-f65.google.com with SMTP id s206so9006622wme.0 for ; Sun, 18 Mar 2018 06:36:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=o0PUeP+pT+Uo1d41zQVhqZS8FIR8+5F46+Ay1XDoK1I=; b=D61U+2+98nhNlL2AYmdIRA/yM26wvFmpVXmKxKvBzbAN7uAge3UMaMrsIbKyETtWrk +HwQh1VmVXovurHFv8NWY1MD0aAKnC/FrA4MqhxFpss3BnfsVVa3KMtFokf9vvuGRhAD 2GpLJNxFrVMILLeYXP6GWWl8oDjnldEMYHuDS2wdZ8cPTJlxfsA0b6M8BnCIwurXSgx+ XbHMkK/GyyR09feijKr035CL4ix8WtuJH/t62AtHRMmbpVxhFmhoyXT9emZ+rO2/KtIR knEyXFj7soM1TwjvuIAVHMMeiFp5i2mg1Bd9YUxaMIbXrJYYUfw2XSmUJFCGX+EPc/br Rpzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=o0PUeP+pT+Uo1d41zQVhqZS8FIR8+5F46+Ay1XDoK1I=; b=MUgXCazWuOCxaofoPajDddhal0R8Z7tBonX7reej5uHFTDGhlX011ehrF8YXD3Pg/X NcDrooEgL1zsdAO660mSPHVtDkNgPEBr3yORG4Dm1aiAL/qWtqyZ1dlr4k91bkOaYMSP GXl2fCWaPdv3HzIdBqgMVAnep8L42bpjUNPBFXLvmXBRs7d3T1X556RxlbcXT3mm+X1/ cY125Pt5BZBTtHBKM9QSs2QGjyKsOo9TBSxiJE9kwppL+AqyxdAS28UXXksA1wDBmugL dJAVFmXkfI+BikbjeLXMtjRMEvkz7ON4s0+iys+bjnQNue7x/q71sIMuyskvoJLuoc3i YjHw== X-Gm-Message-State: AElRT7HqXBOXztVogTktkdQk8CAGi799je14//kIjIe+1sqfjmTq/lwC IFebAP0dt68SuunU/YzCbBc= X-Google-Smtp-Source: AG47ELuNSlFLZsCQwucGUmFmrktNk807Ymf+W/JwCvDrIGAPexQ2q3Gp+5YZ411taKA+hAG+DVeZ1Q== X-Received: by 10.80.183.166 with SMTP id h35mr10052989ede.124.1521380214279; Sun, 18 Mar 2018 06:36:54 -0700 (PDT) Received: from zenbook-arch (s559434a1.adsl.online.nl. [85.148.52.161]) by smtp.gmail.com with ESMTPSA id i48sm8028699ede.39.2018.03.18.06.36.53 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 18 Mar 2018 06:36:53 -0700 (PDT) Date: Sun, 18 Mar 2018 14:36:51 +0100 From: David Veenstra To: lars@metafoo.de, jic23@kernel.org Cc: Michael.Hennerich@analog.com, knaack.h@gmx.de, linux-iio@vger.kernel.org, devel@driverdev.osuosl.org Subject: [PATCH 09/11] staging: iio: ad2s1200: Add scaling factor for IIO_ANGL_VEL channel Message-ID: <02a7cb757f8c61a274ee499d3b458ca09a569917.1521379685.git.davidjulianveenstra@gmail.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The sysfs iio ABI states that a unit of radians per second is expected, but the 12-bit angular velocity register has rps as its unit. So a fractional scaling factor of approximately 2 * Pi is added to the angular velocity channel. Signed-off-by: David Veenstra --- drivers/staging/iio/resolver/ad2s1200.c | 82 ++++++++++++++++++++++----------- 1 file changed, 56 insertions(+), 26 deletions(-) diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c index 7ee1d9f76dfb..4b97a106012c 100644 --- a/drivers/staging/iio/resolver/ad2s1200.c +++ b/drivers/staging/iio/resolver/ad2s1200.c @@ -61,40 +61,69 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev, int ret = 0; u16 vel; - mutex_lock(&st->lock); - gpiod_set_value(st->sample, 0); + switch (m) { + case IIO_CHAN_INFO_SCALE: + switch (chan->type) { + case IIO_ANGL_VEL: + /* + * 2 * Pi is almost equal to + * 2 * 103993 / 33102 = 103993 / (33102 / 2) + * This fraction is based on OEIS series of + * of nominator/denominator of convergents to Pi + * (A002485 and A002486). + * + * iio_convert_raw_to_processed_unlocked uses integer + * division. This will cause at most 5% error + * (for very small values). But for 99.5% of the values + * it will cause less that 1% error. + */ + *val = 103993; + *val2 = 33102 / 2; + return IIO_VAL_FRACTIONAL; + default: + return -EINVAL; + } + break; + case IIO_CHAN_INFO_RAW: + mutex_lock(&st->lock); + gpiod_set_value(st->sample, 0); + + /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ + udelay(1); + gpiod_set_value(st->sample, 1); + gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL)); + + ret = spi_read(st->sdev, st->rx, 2); + if (ret < 0) { + mutex_unlock(&st->lock); + return ret; + } - /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */ - udelay(1); - gpiod_set_value(st->sample, 1); - gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL)); + vel = be16_to_cpup((__be16 *)st->rx); + switch (chan->type) { + case IIO_ANGL: + *val = vel >> 4; + ret = IIO_VAL_INT; + break; + case IIO_ANGL_VEL: + *val = sign_extend32((s16)vel >> 4, 11); + ret = IIO_VAL_INT; + break; + default: + ret = -EINVAL; + break; + } - ret = spi_read(st->sdev, st->rx, 2); - if (ret < 0) { + /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */ + udelay(1); mutex_unlock(&st->lock); - return ret; - } - vel = be16_to_cpup((__be16 *)st->rx); - switch (chan->type) { - case IIO_ANGL: - *val = vel >> 4; - ret = IIO_VAL_INT; - break; - case IIO_ANGL_VEL: - *val = sign_extend32((s16)vel >> 4, 11); - ret = IIO_VAL_INT; - break; + return ret; default: - ret = -EINVAL; break; } - /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */ - udelay(1); - mutex_unlock(&st->lock); - - return ret; + return -EINVAL; } static const struct iio_chan_spec ad2s1200_channels[] = { @@ -108,6 +137,7 @@ static const struct iio_chan_spec ad2s1200_channels[] = { .indexed = 1, .channel = 0, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), } };