clk: sprd: Composite driver support offset config

The composite interface support the offset configuration,
which is used to support mux and div in different registers.
Because some sprd projects, the divider has different
addresses from mux for one composite clk.

Signed-off-by: Zhifeng Tang <zhifeng.tang@unisoc.com>
Reviewed-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/20230913115211.11512-1-zhifeng.tang@unisoc.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sprd: composite: Simplify determine_rate implementation

The sprd_div_helper_round_rate() function calls divider_round_rate()
which calls divider_round_rate_parent() which calls
divider_determine_rate(). This call chain converts back and forth from
the rate request structure to make a determine_rate clk_op fit with a
round_rate clk_op. Simplify the code here by directly calling
divider_determine_rate() instead.

This fixes a smatch warning where an unsigned long is compared to less
than zero, which is impossible. This makes sprd_div_helper_round_rate()
unnecessary as well so simply remove it and fold it into the only caller
left.

Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Closes: https://lore.kernel.org/r/45fdc54e-7ab6-edd6-d55a-473485608473@oracle.com
Cc: Maxime Ripard <maxime@cerno.tech>
Fixes: 302d2f836d78 ("clk: sprd: composite: Switch to determine_rate")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20230613195443.1555132-1-sboyd@kernel.org
Reviewed-by: Maxime Ripard <mripard@kernel.org>

clk: sprd: add divider clock support

This is a feature that can also be found in sprd composite clocks,
provide a bunch of helpers that can be reused later on.

Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>