add the reset controller to the Meson8b clkc

Hi Neil,

Quoted 71 lines · Neil Armstrong

Quoted 70 lines · Jerome Brunet

Quoted 53 lines · Martin Blumenstingl

This registers the known (soft) reset lines provided by the clock controller's registers.

This is the first preparation step for SMP and CPU hotplug support on Meson8/Meson8b/Meson8m2. Booting the secondary cores on these SoCs requires asserting and de-asserting a reset line (one for each CPU core). These reset lines are provided by the clock controller.

The reset controller part of the meson8b clock controller has to be registered early (which I did through CLK_OF_DECLARE_DRIVER), because the secondary cores are started *very* early in the boot process (and meson8b_clkc_probe is invoked long after we need the reset controller to be available for booting the secondary CPU cores).

The user of the reset-controller (= the patches which enable SMP and CPU hotplug support) will follow in the next days. I decided to split this because the SMP series will probably consist of 6 patches alone (and may need to go through two separate trees).

Changes since v2 at [3]:
- move the reset line preprocessor defines into a separate file (affects patch #1 as this header file is part of the dt-binding)
- rename the reset line preprocessor macros from RESETID_ to CLKC_RESET_ to clearly indicate that these are provided by the clock controller (unlike the preprocessor macros for the reset lines in the standlone reset controller, which start with RESET_)
- updated patch #2 due to the changes mentioned above
- added Neil's Reviewed-by to all patches

Changes since v1 at [0]:
- updated cover letter description as we are now registering more than four reset lines
- split patch #1 into a dt-binding and clk driver patch
- slightly reworded the dt-binding documentation so it's now clear that the reset identifiers are preprocessor macros in dt-bindings/clock/meson8b-clkc.h (v1 of this series didn't have these macros at all)
- patch #2 (previously part of patch #1) now registers all known reset lines (see [1] and [2] for the results of my detective work)
- patch #3 is untouched

[0] http://lists.infradead.org/pipermail/linux-amlogic/2017-July/004283.html
[1] http://lists.infradead.org/pipermail/linux-amlogic/2017-July/004330.html
[2] http://lists.infradead.org/pipermail/linux-amlogic/2017-July/004347.html
[3] http://lists.infradead.org/pipermail/linux-amlogic/2017-July/004352.html

Martin Blumenstingl (3):
dt-bindings: clock: meson8b: describe the embedded reset controller
clk: meson: meson8b: register the built-in reset controller
ARM: dts: meson: mark the clock controller also as reset controller

Quoted 11 lines

 .../bindings/clock/amlogic,meson8b-clkc.txt        |   9 +-
 arch/arm/boot/dts/meson8.dtsi                      |   1 +
 arch/arm/boot/dts/meson8b.dtsi                     |   1 +
 drivers/clk/meson/Kconfig                          |   1 +
 drivers/clk/meson/meson8b.c                        | 159 +++++++++++++++++++-
-
 drivers/clk/meson/meson8b.h                        |   9 +-
 .../dt-bindings/reset/amlogic,meson8b-clkc-reset.h |  27 ++++
 7 files changed, 193 insertions(+), 14 deletions(-)
 create mode 100644 include/dt-bindings/reset/amlogic,meson8b-clkc-reset.h

Series looks good to me overall.

Acked-by Jerome Brunet <[email protected]>

Quoted 7 lines

Quoted 3 lines

Just one thing, which is not an issue really, I wonder if the dt-bindings documentation and the bindings them-self should be in separate patches ?

Hi Martin,

Anyway it's OK for me, I've applied patches 1 & 2 on the clk-meson's next branches.

thank you!
I'm also fine with either way - I chose to include it in the dt-bindings patch due to two reasons:
- my SMP series depends on this header file
- we typically send header updates with a dt-bindings patch (see your AO CEC clock for example)
with these I thought it makes sense to combine the documentation and the header in the dt-bindings patch - if it's an issue I can simply change it

may be the DT-maintainers can comment on this?

Quoted 1 line

Kevin, patch 3 is all yours !