spi: mxc_spi: Update pre and post divider algorithm
authorDirk Behme <dirk.behme@gmail.com>
Sat, 11 May 2013 05:25:54 +0000 (07:25 +0200)
committerStefano Babic <sbabic@denx.de>
Wed, 26 Jun 2013 14:23:30 +0000 (16:23 +0200)
commit9a30903b44a63861de93d5beaaf4c91173bbac0c
tree5a4af903597414caf5d8f62d7725a32858709e78
parent8d4c4ffb95d528f6a709bf68da5e0beb0f4ee72f
spi: mxc_spi: Update pre and post divider algorithm

The spi clock divisor is of the form x * (2**y),  or  x  << y, where x is
1 to 16, and y is 0 to 15. Note the similarity with floating point numbers.
Convert the desired divisor to the smallest number which is >= desired divisor,
and can be represented in this form. The previous algorithm chose a divisor
which could be almost twice as large as needed.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
drivers/spi/mxc_spi.c