From 9dbf8ccde1b810a59b684e1d1aec7f9d2d007162 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Mon, 15 Oct 2012 10:35:00 +0100 Subject: [PATCH] iio: Add some helper macros for unit conversion Some datasheets use a different unit to specify the channel scale than what IIO expects it to be. This patch adds two helper macros which allow to convert units commonly used in datasheets to IIO units: * acceleration: g -> meter / second**2 * angular velocity: degree (/ second) -> rad (/ second) This makes it much more convenient to specify and also easier to verify a channel's scale attribute. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- include/linux/iio/iio.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index c0ae76ac4e0b..7806c24e5bc8 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -618,4 +618,20 @@ static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev) }; #endif +/** + * IIO_DEGREE_TO_RAD() - Convert degree to rad + * @deg: A value in degree + * + * Returns the given value converted from degree to rad + */ +#define IIO_DEGREE_TO_RAD(deg) (((deg) * 314159ULL + 9000000ULL) / 18000000ULL) + +/** + * IIO_G_TO_M_S_2() - Convert g to meter / second**2 + * @g: A value in g + * + * Returns the given value converted from g to meter / second**2 + */ +#define IIO_G_TO_M_S_2(g) ((g) * 980665ULL / 100000ULL) + #endif /* _INDUSTRIAL_IO_H_ */