Re: [PATCH 0/3] Meson8b: add the CPU clock post-dividers

From: Jerome Brunet
Date: Thu Nov 22 2018 - 04:05:56 EST


On Fri, 2018-11-16 at 21:53 +0100, Martin Blumenstingl wrote:
> This is the successor to my previous series "meson8b: add the CPU_DIV16
> clock for the ARM TWD" from [0]. I decided to not send this as v2 of
> the original series because the PERIPH clock is not the CPU_DIV16 clock.
> It's not clear whether a CPU_DIV16 clock exists.
>
> With this series we get all the CPU_CLK post-dividers as listed in the
> public S805 datasheet [1] on pages 31 and 32:
> - ABP
> - PERIPH (used as input for the ARM global timer and ARM TWD timer)
> - AXI
> - L2 DRAM
>
> Each of these clocks has a register called "..._CLK_DIS" which is
> documented as a "just in case" bit:
> "Set to 1 to manually disable the [...] clock when changing the mux
> selection. Typically this bit is set to 0 since the clock muxes can
> switch without glitches."
> Since we're not supposed to touch that register we're setting
> CLK_IS_CRITICAL for these clocks in the driver.

If we are not supposed to touch the register, I'd prefer if you used RO ops
instead of using CLK_IS_CRITICAL.

>
> The result of this is that we can use the PERIPH clock which clocks
> the ARM TWD timer. I will send a separate series to add the TWD timer.
>
>
> [0] http://lists.infradead.org/pipermail/linux-amlogic/2018-July/007890.html
> [1]
> https://dn.odroid.com/S805/Datasheet/S805_Datasheet%20V0.8%2020150126.pdf
>
> Martin Blumenstingl (3):
> dt-bindings: clock: meson8b: export the CPU post dividers
> clk: meson: meson8b: rename cpu_div2/cpu_div3 to
> cpu_in_div2/cpu_in_div3
> clk: meson: meson8b: add the CPU clock post divider clocks
>
> drivers/clk/meson/meson8b.c | 268 ++++++++++++++++++++++-
> drivers/clk/meson/meson8b.h | 17 +-
> include/dt-bindings/clock/meson8b-clkc.h | 4 +
> 3 files changed, 276 insertions(+), 13 deletions(-)
>

With CLK_IS_CRITICAL removed, looks good to me:

Acked-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>