Since commit 6f888e7bc7bd58 ("clk: meson: clk-pll: add enable bit") our
PLLs also support the "enable" bit. Currently meson_clk_pll_enable
unconditionally resets the PLL, enables it, takes it out of reset and
waits until it is locked.
This works fine for our current clock trees. However, there will be a
problem once we allow modifications to sys_pll on Meson8, Meson8b and
Meson8m2 (which will be required for CPU frequency scaling):
the CPU clock is derived from the sys_pll clock. Once clk_enable is
called on the CPU clock this will be propagated by the common clock
framework up until the sys_pll clock. If we reset the PLL
unconditionally in meson_clk_pll_enable the CPU will be stopped (on
Meson8, Meson8b and Meson8m2).
To prevent this we simply check if the PLL is already enabled and do
reset the PLL if it's already enabled and locked.
Now that we have a utility function to check whether the PLL is enabled
we can also pass that to our clk_ops to let the common clock framework
know about the status of the hardware clock.
For now this is of limited use since the only common clock framework's
internal "disabled unused clocks" mechanism checks for this. Everything
else still uses the ref-counting (internal to the common clock
framework) when clk_enable is called.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181115224048.13511-2-martin.blumenstingl@googlemail.com
Putting hard-coded rates inside the parameter tables assumes that
the parent is known and will never change. That's a big assumption
we should not make.
We have everything we need to recalculate the output rate using
the parent rate and the rest of the parameters. Let's do so and
drop the rates from the tables.
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Remove od parameters from pll clocks and add post dividers clocks
instead. Some clock, especially the one which feature several ods,
may provide output between those ods. Also, some drivers, such
as the hdmi driver, may require a more detailed control of the
clock dividers, compared to what CCF would perform automatically.
One added benefit of removing ods is that it also greatly reduce the
size of the rate parameter tables.
In the future, we could possibly take the predivider 'n' out of this
driver as well. To do so, we will need to understand the constraints
for the PLL to lock and whether or not it depends on the input clock
rate.
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Add the enable the bit of the pll clocks.
These pll clocks may be disabled but we can't model this as an external
gate since the pll needs to lock when enabled.
Adding this bit allows to drop the poke of the first register of PLL.
This will be useful to model the different components of the pll using
generic clocks elements
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Replace every license notices in drivers/clk/meson by SPDX license
identifiers, as described in license-rules.rst
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Provide an option for the pll driver to round to the rate closest to the
requested rate, instead of systematically rounding down.
This may allow the provided rate to be closer to the requested rate when
rounding up is not an issue
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Finding the appropriate settings of meson plls is too tricky to be done
entirely at runtime, using calculation only. Many combination of m, n
and od won't lock which is why we are using a table for this. However,
for plls having a fractional parameters, it is possible to improve on
the result provided by the table by calculating the frac parameter.
This change adds the calculation of frac when the parameter is available
and the rate provided by the table is not an exact match for the
requested rate.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
After testing, it appears that the gxl (and axg) does not require the
special locking/reset loop which was initially added for it.
All the values present in the gxl table can locked with the simple lock
checking loop.
The change switches the gxl and axg gp0 back to the simple lock checking
loop and removes the code no longer required.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Rework meson pll driver to use clk_regmap and move meson8b, gxbb and
axg's clock using meson_clk_pll to clk_regmap.
This rework is not just about clk_regmap, there a serious clean-up of
the driver code:
* Add lock and reset field: Previously inferred from the n field.
* Simplify the reset logic: Code seemed to apply reset differently but
in fact it was always the same -> assert reset, apply params,
de-assert reset. The 2 lock checking loops have been kept for now, as
they seem to be necessary.
* Do the sequence of init register pokes only at .init() instead of in
.set_rate(). Redoing the init on every set_rate() is not necessary
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
The rate of the parent should not be multiplied by 2 when the pll has a
fractional part. This is making the rate calculation of the gxl_hdmi_pll
wrong (and others as well). This multiplication is specific
to the hdmi_pll of gxbb and is most likely due to a multiplier sitting
in front of this particular pll.
Add a fixed factor clock in front on the gxbb pll and remove this constant
from the calculation to fix the problem
Fixes: 4a47295144 ("clk: meson: fractional pll support")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Some meson plls, such as the hdmi pll, are using a 3rd od parameter,
which is yet another "power of 2" post divider. Add it to fix the
calculation of the hdmi_pll rate
Fixes: 738f66d321 ("clk: gxbb: add AmLogic GXBB clk controller driver")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Use the fractional part width in the calculation instead of 12, which
happens to be the witdh right now. This is safer in case the field width
ever change in the future
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
The pll driver performs the rate calculation in Mhz, which adds an
unnecessary rounding down to the Mhz of the rate. Use 64bits long
integers to perform this calculation safely on meson8b and perform the
calculation in Hz instead
Fixes: 7a29a86943 ("clk: meson: Add support for Meson clock controller")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Make sure the rate param table is available before using it.
Some read-only plls don't provide it, which is ok since the
table is not used by read-only clocks. R/W clocks are supposed
to provide it, but it does not hurt check it.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
In recent Amlogic GXBB, GXL and GXM SoCs, the GP0 PLL needs some specific
parameters in order to initialize and lock correctly.
This patch adds an optional PARAM table used to initialize the PLL to a
default value with it's parameters in order to achieve to desired frequency.
The GP0 PLL in GXBB, GXL/GXM also needs some tweaks in the initialization
steps, and these are exposed along the PARAM table.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/1490178747-14837-2-git-send-email-narmstrong@baylibre.com
Fractional MPLLs are a superset of the existing AmLogic MPLLs. They add
in a couple of new bitfields for further dividing the clock rate to
achieve rates with fractional hertz.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Remove the pll registration function and helpers. Replace unnecessary
configuration struct with static initialization of the desired clock
type.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
This patchset adds the infrastructure for registering and managing the
core clocks found on Amlogic MesonX SoCs. In particular:
- PLLs
- CPU clock
- Fixed rate clocks, fixed factor clocks, ...
Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Martin Blumenstingl