[PATCH v2 00/19] clk: meson: use regmap in clock controllers

[Jerome Brunet]

This changeset is a rework of meson's clock controllers to use regmap
instead of directly using io memory. It based clk-meson next/drivers
and depends on few core clock patches, mainly to export generic clocks
helpers: [0],[1]. The line count is pretty high but the changes are
actually fairly simple and repetitive.

This work has been triggered by the fact that the HHI register space on
gxbb and axg provides more than just clocks. The display driver already
uses a syscon for HHI on gxbb. This is why gxbb did not use
devm_ioremap_resource() to map the registers, since it would have
reserved the memory region, preventing another driver from re-mapping
it. The cleaner solution is, of course, to use syscon to handle. The
purpose of this changeset is to allow it. Even if meson8b does not need
this ATM, there is real reason to leave it behind. It is actually easier
to migrate it as well, so all meson clock drivers may support regmap
only.

The rework starts with a few easy clean-ups. The real deal starts with
patch 5, which adds meson's clk_regmap. This will be used as common
structure to implement all the controller clocks. Having this replaces
the gxbb AO controller specific regmap gate. This structure will also be
re-used in upcoming controllers, such as the axg's AO and audio
controllers.  Each clock type is then migrated, one at a time, to this
new structure.

While at it, the meson clock drivers have been cleaned-up a bit,
removing the gate embedded in the mpll driver, simplifying the pll
driver and removing the legacy cpu_clk of meson8b.

The new code around the cpu clk of the meson8b is just re-implementation,
using simple elements, of the old cpu_clk. As explained by Martin, the
old cpu_clk would hang quite often when changing the rate of the cpu
clock. Surprisingly, the new implementation improved the situation a bit,
but still hangs from time to time. As this is not acceptable, the cpu
clk subtree as been switched to a read-only mode, preventing any change
of the cpu rate, until an acceptable solution is found.

With this series applied, the clock controllers of the gxbb, gxl and axg
SoC will try get regmap from their parent DT node. If this fails, they
will fallback to mapping the register themselves. This fallback will be
kept until platform DTs have changed so clock controllers is a child of
the HHI system controller.

Based on this changeset, more patches are coming. For those interested,
the WIP is available here [2]

Changes since v1 [3]:
* Fixed a few typos in patches descriptions
* Fixed cpu clock names on meson8b, as suggested by Martin
* Switched cpu clock subtree to reead-only mode
* Fix clk_regmap mux documentation, as reported by Yixun

[0]: https://lkml.kernel.org/r/20180118110144.30619-1-jbrunet@baylibre.com
[1]: https://lkml.kernel.org/r/20180122105759.12206-1-jbrunet@baylibre.com
[2]: https://github.com/jeromebrunet/linux/tree/v4.17/meson/clk-regmap
[1]: https://lkml.kernel.org/r/20180131180945.18025-1-jbrunet@baylibre.com

Jerome Brunet (19):
  clk: meson: use dev pointer where possible
  clk: meson: use devm_of_clk_add_hw_provider
  clk: meson: only one loop index is necessary in probe
  clk: meson: remove obsolete comments
  clk: meson: add regmap clocks
  clk: meson: switch gxbb ao_clk to clk_regmap
  clk: meson: remove superseded aoclk_gate_regmap
  clk: meson: add regmap to the clock controllers
  clk: meson: migrate gates to clk_regmap
  clk: meson: migrate dividers to clk_regmap
  clk: meson: migrate muxes to clk_regmap
  clk: meson: add regmap helpers for parm
  clk: meson: migrate mplls clocks to clk_regmap
  clk: meson: migrate the audio divider clock to clk_regmap
  clk: meson: migrate plls clocks to clk_regmap
  clk: meson: split divider and gate part of mpll
  clk: meson: rework meson8b cpu clock
  clk: meson: remove obsolete cpu_clk
  clk: meson: use hhi syscon if available

 drivers/clk/meson/Kconfig             |    9 +
 drivers/clk/meson/Makefile            |    5 +-
 drivers/clk/meson/axg.c               |  722 +++++++++--------
 drivers/clk/meson/axg.h               |    6 +-
 drivers/clk/meson/clk-audio-divider.c |   63 +-
 drivers/clk/meson/clk-cpu.c           |  178 -----
 drivers/clk/meson/clk-mpll.c          |  132 +---
 drivers/clk/meson/clk-pll.c           |  243 +++---
 drivers/clk/meson/clk-regmap.c        |  166 ++++
 drivers/clk/meson/clk-regmap.h        |  111 +++
 drivers/clk/meson/clkc.h              |   93 +--
 drivers/clk/meson/gxbb-aoclk-regmap.c |   46 --
 drivers/clk/meson/gxbb-aoclk.c        |   20 +-
 drivers/clk/meson/gxbb-aoclk.h        |   11 -
 drivers/clk/meson/gxbb.c              | 1402 ++++++++++++++++++---------------
 drivers/clk/meson/gxbb.h              |    5 +-
 drivers/clk/meson/meson8b.c           |  588 ++++++++------
 drivers/clk/meson/meson8b.h           |   11 +-
 18 files changed, 1978 insertions(+), 1833 deletions(-)
 delete mode 100644 drivers/clk/meson/clk-cpu.c
 create mode 100644 drivers/clk/meson/clk-regmap.c
 create mode 100644 drivers/clk/meson/clk-regmap.h
 delete mode 100644 drivers/clk/meson/gxbb-aoclk-regmap.c

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2.14.3