[0/4] clk: meson: g12a: add support for DVFS

Message

Neil Armstrong July 29, 2019, 1:16 p.m. UTC

The G12A/G12B Socs embeds a specific clock tree for each CPU cluster :
cpu_clk / cpub_clk
|   \- cpu_clk_dyn
|      |  \- cpu_clk_premux0
|      |        |- cpu_clk_postmux0
|      |        |    |- cpu_clk_dyn0_div
|      |        |    \- xtal/fclk_div2/fclk_div3
|      |        \- xtal/fclk_div2/fclk_div3
|      \- cpu_clk_premux1
|            |- cpu_clk_postmux1
|            |    |- cpu_clk_dyn1_div
|            |    \- xtal/fclk_div2/fclk_div3
|            \- xtal/fclk_div2/fclk_div3
\ sys_pll / sys1_pll

This patchset adds notifiers on cpu_clk / cpub_clk, cpu_clk_dyn,
cpu_clk_premux0 and sys_pll / sys1_pll to permit change frequency of
the CPU clock in a safe way as recommended by the vendor Documentation
and reference code.

This patchset :
- introduces needed core and meson clk changes
- adds the clock notifiers

Dependencies:
- None

This patchset is split from the v3 RFC/RFC patchset at [3]

Changes from RFT/RFC v3 at [3]:
- Rebased on clk-meson v5.4/drivers tree with Alexandre's patches
- Removed the eeclk setup() callback, moved to a toplevel g12a-data struct

Changes since RFT/RFC v2 at [2]:
- Rebased on clk-meson v5.3/drivers trees
- added Kevin's review tags

Changes since RFT/RFC v1 at [1]:
- Added EXPORT_SYMBOL_GPL() to clk_hw_set_parent
- Added missing static to g12b_cpub_clk_mux0_div_ops and g12a_cpu_clk_mux_nb
- Simplified g12a_cpu_clk_mux_notifier_cb() without switch/case
- Fixed typo in "this the current path" in g12a.c
- Fixed various checkpatch errors

[1] https://patchwork.kernel.org/cover/11006929/
[2] https://patchwork.kernel.org/cover/11017273/
[3] https://patchwork.kernel.org/cover/11025309/

Neil Armstrong (4):
  clk: core: introduce clk_hw_set_parent()
  clk: meson: regmap: export regmap_div ops functions
  clk: meson: g12a: add notifiers to handle cpu clock change
  clk: meson: g12a: expose CPUB clock ID for G12B

 drivers/clk/clk.c                     |   6 +
 drivers/clk/meson/clk-regmap.c        |  10 +-
 drivers/clk/meson/clk-regmap.h        |   5 +
 drivers/clk/meson/g12a.c              | 567 +++++++++++++++++++++++---
 include/dt-bindings/clock/g12a-clkc.h |   1 +
 include/linux/clk-provider.h          |   1 +
 6 files changed, 540 insertions(+), 50 deletions(-)