From: Lars-Peter Clausen Date: Fri, 14 Sep 2012 15:21:00 +0000 (+0100) Subject: iio: Introduce a new fractional value type X-Git-Tag: omap-for-v3.7-rc1/fixes-cpufreq-signed~75^2~161^2~10 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7985e7c1003bc5cdfa20755f8cfdada946ed8e18;p=pandora-kernel.git iio: Introduce a new fractional value type Currently IIO uses a decimal fixed point representations for real type numbers. This patch introduces a new representation for rational type numbers. The number will be expressed by specifying a numerator and denominator. For converting a raw value to a processed value multiply it by the numerator and divide it by the denominator. The reasoning for introducing this new type is that for a lot of devices the scale can be represented easily by a fractional number, but it is not possible to represent it as fixed point number without rounding. E.g. for a simple DAC the scale is often the reference voltage divided by the number of possible values (Usually 2**n_bits - 1). Each driver currently implements the conversion of this fraction to a fixed point number on its own. Also when it comes to the in-kernel interface this allows to directly use the fractional factors to convert a raw value to a processed value. This should on one hand require less instructions and on the other hand increase the precision. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- Reading git-diff-tree failed