Commit Graph

7 Commits

Author SHA1 Message Date
Stephen Boyd 8062b4aafc Allwinner clock patches for 4.12
Support for the new H5 SoC and the PRCM block found in a number of SoCs as
 well, plus the usual chunk of fixes and minor enhancements.
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Merge tag 'sunxi-clk-for-4.12' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux into clk-next

Pull Allwinner clock patches for 4.12 from Maxime Ripard:

Support for the new H5 SoC and the PRCM block found in a number of SoCs as
well, plus the usual chunk of fixes and minor enhancements.

* tag 'sunxi-clk-for-4.12' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux:
  clk: sunxi-ng: Display index when clock registration fails
  clk: sunxi-ng: a33: Add offset and minimum value for DDR1 PLL N factor
  clk: sunxi-ng: a80: Remodel CPU cluster PLLs as N-type multiplier clocks
  clk: sunxi-ng: mult: Support PLL lock detection
  clk: sunxi-ng: add support for PRCM CCUs
  dt-bindings: update device tree binding for Allwinner PRCM CCUs
  clk: sunxi-ng: sun5i: Fix mux width for csi clock
  clk: sunxi-ng: tighten SoC deps on explicit AllWinner SoCs
  clk: sunxi-ng: add Allwinner H5 CCU support for H3 CCU driver
  clk: sunxi-ng: gate: Support common pre-dividers
2017-04-19 09:02:00 -07:00
Chen-Yu Tsai 02ae2bc6fe clk: sunxi-ng: Add clk notifier to gate then ungate PLL clocks
In common PLL designs, changes to the dividers take effect almost
immediately, while changes to the multipliers (implemented as
dividers in the feedback loop) take a few cycles to work into
the feedback loop for the PLL to stablize.

Sometimes when the PLL clock rate is changed, the decrease in the
divider is too much for the decrease in the multiplier to catch up.
The PLL clock rate will spike, and in some cases, might lock up
completely. This is especially the case if the divider changed is
the pre-divider, which affects the reference frequency.

This patch introduces a clk notifier callback that will gate and
then ungate a clk after a rate change, effectively resetting it,
so it continues to work, despite any possible lockups. Care must
be taken to reparent any consumers to other temporary clocks during
the rate change, and that this notifier callback must be the first
to be registered.

This is intended to fix occasional lockups with cpufreq on newer
Allwinner SoCs, such as the A33 and the H3. Previously it was
thought that reparenting the cpu clock away from the PLL while
it stabilized was enough, as this worked quite well on the A31.

On the A33, hangs have been observed after cpufreq was recently
introduced. With the H3, a more thorough test [1] showed that
reparenting alone isn't enough. The system still locks up unless
the dividers are limited to 1.

A hunch was if the PLL was stuck in some unknown state, perhaps
gating then ungating it would bring it back to normal. Tests
done by Icenowy Zheng using Ondrej's test firmware shows this
to be a valid solution.

[1] http://www.spinics.net/lists/arm-kernel/msg552501.html

Reported-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Icenowy Zheng <icenowy@aosc.io>
Tested-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2017-04-13 11:22:02 +02:00
Priit Laes cb545960de clk: sunxi-ng: Display index when clock registration fails
Add clock index to clock registration failure message. Clock name
is sometimes not available, when things go really wrong.

Signed-off-by: Priit Laes <plaes@plaes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2017-04-06 09:10:30 +02:00
Stephen Boyd 5d806f9fc8 clk: sunxi-ng: Check kzalloc() for errors and cleanup error path
This kzalloc() could fail. Let's bail out with -ENOMEM here
instead of NULL dereferencing. That silences static checkers. We
should also cleanup on the error path even though this function
returning an error probably means the system won't boot.

Cc: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2017-02-06 14:48:32 -08:00
Chen-Yu Tsai 3de64bf187 clk: sunxi-ng: Support separately grouped PLL lock status register
On the Allwinner A80 SoC, the PLL lock status indicators are grouped
together in a separate register, as opposed to being scattered in each
PLL's configuration register.

Add a flag to support this.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2017-01-30 08:36:20 +01:00
Chen-Yu Tsai ed0ab11023 clk: sunxi-ng: Fix inverted test condition in ccu_helper_wait_for_lock
The condition passed to read*_poll_timeout() is the break condition,
i.e. wait for this condition to happen and return success.

The original code assumed the opposite, resulting in a warning when
the PLL clock rate was changed but never lost it's lock as far as
the readout indicated. This was verified by checking the read out
register value.

Fixes: 1d80c14248 ("clk: sunxi-ng: Add common infrastructure")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2016-08-10 15:07:01 -07:00
Maxime Ripard 1d80c14248 clk: sunxi-ng: Add common infrastructure
Start our new clock infrastructure by adding the registration code, common
structure and common code.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-3-maxime.ripard@free-electrons.com
2016-07-08 18:04:32 -07:00