In some cases firmware brings up plls with different parameters than the ones
noted in the rate table for the specific frequency. These firmware-selected
parameters are worse than the tested ones in the pll rate tables but cannot
be changed by a simple clk_set_rate call when the rate stays the same.
Therefore add a ROCKCHIP_PLL_SYNC_RATE flag and implement an init callback
that checks the runtime-parameters against the matching rate table entry
and adjusts them to the table-ones if necessary.
If no rate table is set or the current rate does not match any rate-table
entry no changes are made.
Being able to limit this adjustment to specific plls is necessary to not
touch the ones supplying core components like the apll and dpll supplying
the armcores and dram.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
In some cases we might need to access the data of the pll mux before the actual
mux gets registered - like in the following patch adding an init-callback.
Therefore populate pll_mux before registering the core pll-clock.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
This adds a flag parameter to plls that allows us to create
special flags to tweak the behaviour of the plls if necessary.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
The Rockchip PLL code switches into slow mode (AKA bypass more AKA
24MHz mode) before actually changing the PLL. This keeps anyone from
using the PLL while it's changing. However, in all known Rockchip
SoCs nobody should ever see the 24MHz when changing the PLL supplying
the armclk because we should reparent children to an alternate
(faster than 24MHz) PLL.
One problem is that the code to switch to an alternate parent was
running in PRE_RATE_CHANGE. ...and the code to switch to slow mode
was _also_ running in PRE_RATE_CHANGE. That meant there was no real
guarantee that we would switch to an alternate parent before switching
to 24MHz mode.
Let's move the switch to "slow mode" straight into
rockchip_rk3066_pll_set_rate(). That means we're guaranteed that the
24MHz is really a last-resort.
Note that without this change on real systems we were the code to
switch to an alternate parent at 24MHz. In some older versions of
that code we'd appy a (temporary) / 5 to the 24MHz causing us to run
at 4.8MHz. That wasn't enough to service USB interrupts in some cases
and could lead to a system hang.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
All known Rockchip SoCs down to the RK28xx (ARM9) use a similar pattern to
handle their plls:
|--\
xin32k ----------------|mux\
xin24m -----| pll |----|pll|--- pll output
\---------------|src/
|--/
The pll output is sourced from 1 of 3 sources, the actual pll being one of
them. To change the pll frequency it is imperative to remux it to another
source beforehand. This is done by adding a clock-listener to the pll that
handles the remuxing before and after the rate change.
The output mux is implemented as a separate clock to make use of already
existing common-clock features for disabling the pll if one of the other
two sources is used.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-By: Max Schwarz <max.schwarz@online.de>
Tested-By: Max Schwarz <max.schwarz@online.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
