Currently MP clocks don't consider adjusting parent rate even if they
are allowed to do so. Such behaviour considerably lowers amount of
possible rates, which is very inconvenient when such clock is used for
pixel clock, for example.
In order to improve the situation, adjusting parent rate is considered
when allowed.
This code is inspired by clk_divider_bestdiv() function, which does
basically the same thing for different clock type.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
On the A64, the MMC module clocks are fixed in the new timing mode,
i.e. they do not have a bit to select the mode. These clocks have
a 2x divider somewhere between the clock and the MMC module.
To be consistent with other SoCs supporting the new timing mode,
we model the 2x divider as a fixed post-divider on the MMC module
clocks.
To do this, we first add fixed post-divider to the MP style clocks,
which the MMC module clocks are.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
All of our MMC clocks are of the MP clock type. A few MMC clocks on some
SoCs, such as MMC2 on the A83T, support new/old timing mode switching.
>From a clock rate point of view, when the new timing mode is active. the
output clock rate is halved.
This patch adds a special wrapper class of clocks, MP_MMC, around the
generic MP type clocks. The rate related callbacks in ccu_mp_mmc_ops
for this class look at the timing mode bit and apply the /2 post-divider
when needed, before passing it through to the generic class ops,
ccu_mp_ops.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The current function name is a bit confusing, and doesn't really allow to
create an explicit function to reverse the operation.
We also for now change the parent rate through a pointer, while we don't
return anything.
In order to be less confusing, and easier to use for downstream users,
change the function name to something hopefully clearer, and return the
adjusted rate instead of changing the pointer.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
The clocks might need to modify their parent clocks. In order to make that
possible, give them access to the parent clock being evaluated, and to a
pointer to the parent rate so that they can modify it if needed.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
The MP style clocks support an mux with pre-dividers. While the driver
correctly accounted for them in the .determine_rate callback, it did
not in the .recalc_rate and .set_rate callbacks.
This means when calculating the factors in the .set_rate callback, they
would be off by a factor of the active pre-divider. Same goes for
reading back the clock rate after it is set.
Cc: stable@vger.kernel.org
Fixes: 2ab836db50 ("clk: sunxi-ng: Add M-P factor clock support")
Signed-off-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>
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>
Introduce support for the clocks that combine a linear divider and a
power-of-two based one.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-9-maxime.ripard@free-electrons.com
