Some of the N-M-style clocks, namely the PLLs, support sigma-delta
modulation to do fractional-N frequency synthesis. This is used in
the audio PLL to generate the exact frequency the audio blocks need.
These frequencies can not be generated with integer N-M factors.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
The round_rate callback for N-M-factor style clocks does not check if
the requested clock rate is supported by the fractional clock mode.
While this doesn't affect usage in practice, since the clock rates
are also supported through N-M factors, it does not match the set_rate
code.
Add a check to the round_rate callback so it matches the set_rate
callback.
Fixes: 6174a1e24b ("clk: sunxi-ng: Add N-M-factor clock support")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Currently ccu_frac_helper_set_rate() doesn't wait for a lock bit to be
set before returning. Because of that, unstable clock may be used.
Add a wait for lock in the helper function.
Fixes: 89a3dfb787 ("clk: sunxi-ng: Add fractional lib")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
N-M factor clock driver is missing a call to ccu_frac_helper_enable()
when fractional mode is used. Additionally, most SoCs require that M
factor must be set to 0 when fractional mode is used.
Without this patch, clock keeps the old value and clk_set_rate() returns
without error.
Fixes: 6174a1e24b ("clk: sunxi-ng: Add N-M-factor clock support")
CC: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
In commit 2beaa601c8 ("clk: sunxi-ng: Implement minimum for
multipliers"), the multiplier minimums in the set_rate callback
for NM and NKMP style clocks were not updated.
This patch fixes them to match their round_rate callbacks.
Fixes: 2beaa601c8 ("clk: sunxi-ng: Implement minimum for multipliers")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
A zero multiplier does not make sense for clocks.
Use 1 as the minimum when a multiplier minimum isn't specified.
Fixes: 2beaa601c8 ("clk: sunxi-ng: Implement minimum for multipliers")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some multipliers have a maximum rate that is lower than what the register
width allows to. Add a field in the multiplier structure to allow CCU
driver to set that maximum.
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
The factors we've seen so far all had an offset of one. However, on the
earlier Allwinner SoCs, some factors could have no offset at all, meaning
that the value computed to reach the rate we want to use was the one we had
to program in the registers.
Implement an additional field for the factors that can have such an offset
(linears, not based on a power of two) to specify that offset.
This offset is not linked to the extremums that can be specified in those
structures too. The minimum and maximum are representing the range of
values we can use to try to compute the best rate. The offset comes later
on when we want to set the best value in the registers.
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Allow the CCU drivers to specify a multiplier for their clocks.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Modify the current clocks we have to be able to specify the minimum for
each clocks we support, just like we support the max.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
While the rational library works great, it doesn't really allow us to add
more constraints, like the minimum.
Remove that in order to be able to deal with the constraints we'll need.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Some dividers might have a maximum value that is lower than the width of
the register.
Add a field to _ccu_div to handle those case properly. If the field is set
to 0, the code will assume that the maximum value is the maximum one that
can be used with the field register width.
Otherwise, we'll use whatever value has been set.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
