[PATCH 00/16] clk: sunxi: introduce "modern" clock support

[Maxime Ripard]

Hi,

This is an attempt at introducing clock support for the Allwinner SoCs
following the current model used by pretty much all the other SoCs.

Such a conversion has been suggested on a regular basis by Mike and
Stephen, and here is a first implementation.

This new approach has a good number of advantages, some due to the new
binding itself, some due to the lessons learned with the current code
we have.

Beside from having a binding similar to the other SoCs, which helps
developper hopping from one SoC to the other, it also reduces the
amount of binding review that needs to be done, something that Rob
already complained about a few times.
Now that we are following the DT-as-an-ABI rule, the new binding will
also make our life way easier, since we reduce the exposed surface
greatly. The former binding, while making quite easy to mix and match
clocks when bringing up new SoCs, was also exposing way too much
implementation details that would hold us back when wanting to
refactor, consolidate, or fix some shortcomings in the current
implementation. In the new approach, the only thing that we're
exposing is the clock index, meaning that we can change the
implementation as much as we want.

This rewrite is also the occasion to layer things up quite differently
in our clock core.

The current code had a bunch of shortcomings. Most of the code was
relying on our clk-factor code, which was factoring away a few things
like the clock registration, ie boilerplate, but didn't factor the
logic to compute a clock rate, while the huge majority are computed
from some variation of a formula, which could actually be shared.

Which meant that every time we had to add new code to help clk-factors
compute the actual factors used, even though a clock with the same
formual was probably already supported. This eventually lead to a huge
number of clocks driver patches, and to review, which is also
something Stephen complained about.

The new approach takes a different approach by adding a bunch of clock
drivers based on the formula they use to compute their rate and / or
the features they have (mux, gate, etc.). The SoC will only have to
provide the data for the driver to know how many options it has,
without adding any extra code.

To reduce the amount of code duplication between those drivers, a
bunch of helpers have also been introduced to deal with the common
features (pre-dividers, gate, muxes, etc.). This will also be very
easy to extend to support new features missing for now (mostly the
fractional stuff as of today).

Since this is a complete rewrite, it probably has a bunch of bugs
and/or limitations not yet found. My plan would be to start using that
approach on the A64, A83T and H3 which are in their early support
stage to be the test-bed for this new framework, before switching the
older and more featureful SoCs to it eventually.

Because of the DT ABI, the older drivers will remain in-tree
obviously, otherwise things would break pretty badly.

The current code has been tested on the H3 and an Orange Pi PC,
including making sure that MMC still works, so the general approach
seems ok.

Let me know what you think,
Maxime

Maxime Ripard (16):
  clk: fix critical clock locking
  clk: sunxi-ng: Add common infrastructure
  clk: sunxi-ng: Add fixed factor clock support
  clk: sunxi-ng: Add gate clock support
  clk: sunxi-ng: Add mux clock support
  clk: sunxi-ng: Add divider table clock
  clk: sunxi-ng: Add phase clock support
  clk: sunxi-ng: Add M-factor clock support
  clk: sunxi-ng: Add P-factor clock support
  clk: sunxi-ng: Add M-P factor clock support
  clk: sunxi-ng: Add N-K-factor clock support
  clk: sunxi-ng: Add N-M-factor clock support
  clk: sunxi-ng: Add N-K-M Factor clock
  clk: sunxi-ng: Add N-K-M-P factor clock
  clk: sunxi-ng: Add H3 clocks
  ARM: dt: sun8i: switch the H3 to the new CCU driver

 arch/arm/boot/dts/sun8i-h3.dtsi         | 310 +++----------
 drivers/clk/Makefile                    |   1 +
 drivers/clk/clk.c                       |   7 +
 drivers/clk/sunxi-ng/Makefile           |  17 +
 drivers/clk/sunxi-ng/ccu-sun8i-h3.c     | 757 ++++++++++++++++++++++++++++++++
 drivers/clk/sunxi-ng/ccu_common.c       | 108 +++++
 drivers/clk/sunxi-ng/ccu_common.h       |  74 ++++
 drivers/clk/sunxi-ng/ccu_div_table.c    | 117 +++++
 drivers/clk/sunxi-ng/ccu_div_table.h    |  75 ++++
 drivers/clk/sunxi-ng/ccu_factor.h       |  15 +
 drivers/clk/sunxi-ng/ccu_fixed_factor.c |  42 ++
 drivers/clk/sunxi-ng/ccu_fixed_factor.h |  50 +++
 drivers/clk/sunxi-ng/ccu_gate.c         |  82 ++++
 drivers/clk/sunxi-ng/ccu_gate.h         |  53 +++
 drivers/clk/sunxi-ng/ccu_m.c            | 135 ++++++
 drivers/clk/sunxi-ng/ccu_m.h            | 101 +++++
 drivers/clk/sunxi-ng/ccu_mp.c           | 158 +++++++
 drivers/clk/sunxi-ng/ccu_mp.h           |  79 ++++
 drivers/clk/sunxi-ng/ccu_mux.c          | 187 ++++++++
 drivers/clk/sunxi-ng/ccu_mux.h          |  92 ++++
 drivers/clk/sunxi-ng/ccu_nk.c           | 147 +++++++
 drivers/clk/sunxi-ng/ccu_nk.h           |  44 ++
 drivers/clk/sunxi-ng/ccu_nkm.c          | 144 ++++++
 drivers/clk/sunxi-ng/ccu_nkm.h          |  42 ++
 drivers/clk/sunxi-ng/ccu_nkmp.c         | 157 +++++++
 drivers/clk/sunxi-ng/ccu_nkmp.h         |  43 ++
 drivers/clk/sunxi-ng/ccu_nm.c           | 103 +++++
 drivers/clk/sunxi-ng/ccu_nm.h           |  41 ++
 drivers/clk/sunxi-ng/ccu_p.c            | 141 ++++++
 drivers/clk/sunxi-ng/ccu_p.h            |  40 ++
 drivers/clk/sunxi-ng/ccu_phase.c        | 126 ++++++
 drivers/clk/sunxi-ng/ccu_phase.h        |  50 +++
 drivers/clk/sunxi-ng/ccu_reset.c        |  55 +++
 drivers/clk/sunxi-ng/ccu_reset.h        |  40 ++
 include/dt-bindings/clock/sun8i-h3.h    | 162 +++++++
 include/dt-bindings/reset/sun8i-h3.h    | 103 +++++
 36 files changed, 3646 insertions(+), 252 deletions(-)
 create mode 100644 drivers/clk/sunxi-ng/Makefile
 create mode 100644 drivers/clk/sunxi-ng/ccu-sun8i-h3.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_common.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_common.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_div_table.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_div_table.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_factor.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_fixed_factor.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_fixed_factor.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_gate.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_gate.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_m.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_m.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_mp.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_mp.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_mux.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_mux.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_nk.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_nk.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_nkm.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_nkm.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_nkmp.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_nkmp.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_nm.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_nm.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_p.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_p.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_phase.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_phase.h
 create mode 100644 drivers/clk/sunxi-ng/ccu_reset.c
 create mode 100644 drivers/clk/sunxi-ng/ccu_reset.h
 create mode 100644 include/dt-bindings/clock/sun8i-h3.h
 create mode 100644 include/dt-bindings/reset/sun8i-h3.h

-- 
2.8.2