Re: [PATCH v2 0/3] Meson8/Meson8b: introduce a HHI syscon node

[Rob Herring <robh@kernel.org>]

On Sun, Oct 28, 2018 at 01:08:56PM +0100, Martin Blumenstingl wrote:
> The Meson8/Meson8b/Meson8m2 SoCs are suffering from a similar problem
> as the GXBB/GXL/GXM SoCs (see the GX series from Jerome: [0]):
> There is a register area called "HHI" which is used for multiple IP
> blocks of the SoC:
> - the system clock controller
> - a few reset lines (there is a separate reset controller, these reset
>   lines are not part of the other reset controller). this reset
>   controller is currently implemented in the clock controller driver
> - a HDMI controller

Does this have it's own clocks, resets or other resources?

> - temperature sensor calibration data (by "data" I really mean data,
>   the ADC driver has four bits for the TSC data in it's own register
>   space, however on Meson8b and Meson8m2 there is a fifth TSC bit which
>   is stored in the HHI register area)
> 
> The first three could be implemented with a single node (either in one
> big driver, or using a MFD driver which would register function-
> specific drivers).
> However, the TSC data is a big problem, because the ADC has it's own
> set of registers but needs to write one bit in the HHI register area.

Generally, that would be solved with a phandle to the HHI and maybe an 
offset cell in the ADC node. I don't see why that's a big problem.

> 
> NOTE: this series has multiple dependencies:
> - the clock controller changes depend "meson8b: add the CPU_DIV16 clock
>   for the ARM TWD" as well as "meson8b: register the clock controller
>   early" [2]
> - the dts changes depend on "fix clock controller register size on
>   Meson8/Meson8b" [3]
> 
> 
> Changes since v1 at [4]:
> - added a "amlogic,meson-hhi-sysctrl" compatible to the syscon node
>   (which is the parent of the clock controller) in patch #1 and #3
> - added Neil's Acked-by
> - rebased on top of clk-meson's meson-clk-4.20-1 tag and my other
>   series "Meson8b: fixes for the cpu_scale_div clock" from [5]
> 
> 
> [0] http://lists.infradead.org/pipermail/linux-amlogic/2018-March/006733.html
> [1] http://lists.infradead.org/pipermail/linux-amlogic/2018-July/007890.html
> [2] http://lists.infradead.org/pipermail/linux-amlogic/2018-July/007900.html
> [3] http://lists.infradead.org/pipermail/linux-amlogic/2018-July/007897.html
> [4] https://patchwork.kernel.org/cover/10539051/
> [5] https://patchwork.kernel.org/cover/10617617/
> 
> 
> Martin Blumenstingl (3):
>   dt-bindings: clock: meson8b: use the registers from the HHI syscon
>   clk: meson: meson8b: use the HHI syscon if available
>   ARM: dts: meson: switch the clock controller to the HHI register area
> 
>  .../bindings/clock/amlogic,meson8b-clkc.txt   | 13 ++++------
>  arch/arm/boot/dts/meson.dtsi                  |  7 ++++++
>  arch/arm/boot/dts/meson8.dtsi                 | 15 ++++++------
>  arch/arm/boot/dts/meson8b.dtsi                | 15 ++++++------
>  drivers/clk/meson/meson8b.c                   | 24 ++++++++++++-------
>  5 files changed, 43 insertions(+), 31 deletions(-)
> 
> -- 
> 2.19.1
>