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[85.148.52.161]) by smtp.gmail.com with ESMTPSA id q19sm4020212edd.39.2018.04.20.12.31.49 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 20 Apr 2018 12:31:50 -0700 (PDT) Date: Fri, 20 Apr 2018 21:31:48 +0200 From: David Veenstra To: lars@metafoo.de, jic23@kernel.org, pmeerw@pmeerw.net Cc: robh+dt@kernel.org, Michael.Hennerich@analog.com, knaack.h@gmx.de, daniel.baluta@nxp.com, linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, devicetree@vger.kernel.org Subject: [PATCH v2 12/13] staging: iio: ad2s1200: Add scaling factor for angle channel Message-ID: <9352ade3afee830795315b5931dfb316853dc094.1524247563.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 A fractional scaling factor of approximately 2 * Pi / (2^12 -1) is added, to scale the 12-bits angular position to radians. Signed-off-by: David Veenstra --- Changes in v2: - This patch replaces the patch that changed the the channel for angular position to inclination channel. drivers/staging/iio/resolver/ad2s1200.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c index 6c56257be3b1..4f5dd28b174a 100644 --- a/drivers/staging/iio/resolver/ad2s1200.c +++ b/drivers/staging/iio/resolver/ad2s1200.c @@ -71,6 +71,17 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev, switch (m) { case IIO_CHAN_INFO_SCALE: switch (chan->type) { + case IIO_ANGL: + /* + * 2 * Pi / (2^12 - 1) ~= 2 * 103993 / (33102 * 0xFFF) + * + * Since there only fit 3 whole radians in 360 degrees, + * usage of iio_convert_raw_to_processed for this + * channel will be highly inaccurate. + */ + *val = 103993; + *val2 = 16551 * 0xFFF; + return IIO_VAL_FRACTIONAL; case IIO_ANGL_VEL: /* * 2 * Pi ~= 2 * 103993 / 33102 @@ -133,6 +144,7 @@ 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), }, { .type = IIO_ANGL_VEL, .indexed = 1,