clk: sunxi: rewrite sun9i_a80_get_pll4_factors()

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The old implementation of sun9i_a80_get_pll4_factors() has several issues,
it checks against 256 / 512 in various places where it should use 255 / 511,
it does the wrong thing for low frequencies which are an even multiple of
6 MHz, e.g. if you ask it for 72 MHz it will result in 144 Mhz, and it does
not take into account that n must be at least 12. Moreover it is quite hard
to read / follow it.

This commit rewrites it to be correct in all cases, and makes it much easier
to follow the code / to read.

Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

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Hans de Goede 2015-01-24 12:56:31 +01:00 • committed by Maxime Ripard

parent 7a6fca879f

commit 6424e0aeeb

1 changed files with 29 additions and 28 deletions

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drivers/clk/sunxi/clk-sun9i-core.c

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