]> git.itanic.dy.fi Git - linux-stable/commit
clk: rockchip: fix frac settings of GPLL clock for rk3328
authorKatsuhiro Suzuki <katsuhiro@katsuster.net>
Sat, 22 Dec 2018 16:42:49 +0000 (01:42 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 5 Apr 2019 20:34:52 +0000 (22:34 +0200)
commite84e0a8c3f22dba823b33cfd38c65c3fe6e35dd5
treedf027ce6feb21e22ff87e1b7408eaa94de7da767
parent25fb6c323b55dbb7ec9227a174c36a13697bcb5d
clk: rockchip: fix frac settings of GPLL clock for rk3328

[ Upstream commit a0e447b0c50240a90ab84b7126b3c06b0bab4adc ]

This patch fixes settings of GPLL frequency in fractional mode for
rk3328. In this mode, FOUTVCO is calcurated by following formula:
  FOUTVCO = FREF * FBDIV / REFDIV + ((FREF * FRAC / REFDIV) >> 24)

The problem is in FREF * FRAC >> 24 term. This result always lacks
one from target value is specified by rate member. For example first
itme of rk3328_pll_frac_rate originally has
  - rate  : 1016064000
  - refdiv: 3
  - fbdiv : 127
  - frac  : 134217
  - FREF * FBDIV / REFDIV        = 1016000000
  - (FREF * FRAC / REFDIV) >> 24 = 63999
Thus calculated rate is 1016063999. It seems wrong.

If frac has 134218 (it is increased 1 from original value), second
term is 64000. All other items have same situation. So this patch
adds 1 to frac member in all items of rk3328_pll_frac_rate.

Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net>
Acked-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/clk/rockchip/clk-rk3328.c