On the A83T, the AHB1 clock has a shared pre-divider on the two
PLL-PERIPH clock parents. To support such instances of shared
pre-dividers, this patch extends the mux clock type to support
multiple variable pre-dividers.
As the pre-dividers are only used to calculate the rate, but
do not participate in the factorization process, this is fairly
straightforward.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Currently, the parent rate given back to the clock framework in our
request is the original parent rate we calculated before trying to round
the rate of our clock.
This works fine unless our clock also changes its parent rate, in which
case we will simply ignore that change and still use the previous parent
rate.
Create a new function to re-adjust the parent rate to take the pre-dividers
into account, and give that back to the clock framework.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.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 pre-divider retrieval code was merged into the function to apply the
current pre-divider onto the parent clock rate so that we can use that
adjusted value to do our factors computation.
However, since we'll need to do the reverse operation, we need to split out
that code into a function that will be shared.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
The current code only rely on the parent to change its rate in the case
where CLK_SET_RATE_PARENT is set.
However, some clock rates might be obtained only through a modification of
the parent and the clock divider. Just rely on the round rate of the clocks
to give us the best computation that might be achieved for a given rate.
round_rate functions now need to honor CLK_SET_RATE_PARENT, but either the
functions already do that if they modify the parent, or don't modify the
praents at all.
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>
If the CLK_SET_RATE_PARENT flag is set, we want to try getting the
closest parent rate.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
This patch adds support for the CLK_SET_RATE_NO_REPARENT flag to the
mux determine_rate helper, based on examples from clk-composite and
clk-mux.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
The determine_rate helper used ccu_mux_helper_adjust_parent_for_prediv()
to adjust the parent_rate to account for pre-dividers, but then passed
the pristine parent clock rate from clk_hw_get_rate() to the round()
callback, thereby ignoring the pre-divider adjustment. In addition,
it was saving the adjusted parent rate back into struct
clk_rate_request.
This patch fixes this by saving the pristine parent clock rate, and
adding a copy that is adjusted and passed to the round() callback.
The pristine copy, if it is the best solution, would be saved back
to struct clk_rate_request.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some clocks have a global pre-divider that applies to all their parents.
Since it might also apply to clocks that have a single parent, this is
merged in the ccu_common structure, unlike the other pre-divider settings
that are tied to a specific index, and thus a specific parent.
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
On sunxi we support cpufreq by changing the clock rate of PLL-CPU.
It's possible the clock output of the PLL goes out of the CPU's
operational limits when the PLL's multipliers / dividers are changed
and it hasn't stabilized yet. This would result in the CPU hanging.
To circumvent this, we temporarily switch the CPU mux clock to another
stable clock before the rate change, and switch it back after the PLL
stabilizes. This is done with clk notifiers registered on the PLL.
This patch adds common functions for notifiers to reparent mux clocks.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some clocks on the A31 have fixed pre-dividers on multiple parents.
Add support for them.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some clock muxes have holes, i.e. invalid or unconnected inputs,
between parent mux values.
Add support for specifying a mux table to map clock parents to
mux values.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some clocks have a predivider value that is larger than what u8 can
store. One such example is the OUT clk found on A20/A31, which has
a /750 pre-divider on one of the osc24M parents.
Increase the size of the div field to u16.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Some clocks in the Allwinner SoCs clocks unit are just muxes.
However, those muxes might also be found in some other complicated clocks
that would benefit from the code in there to deal with "advanced" features,
like pre-dividers.
Introduce a set of helpers to reduce the code duplication in such cases.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-6-maxime.ripard@free-electrons.com
Stephen Boyd
Chen-Yu Tsai
Maxime Ripard