Re: [PATCH v5 4/5] clk: add CLK_SET_RATE_NO_REPARENT flag

From: Sylwester Nawrocki
Date: Thu Jul 25 2013 - 08:34:24 EST


Hi James,

On 06/13/2013 06:06 PM, James Hogan wrote:
> Add a CLK_SET_RATE_NO_REPARENT clock flag, which will prevent muxes
> being reparented during clk_set_rate.
>
> To avoid breaking existing platforms, all callers of clk_register_mux()
> are adjusted to pass the new flag. Platform maintainers are encouraged
> to remove the flag if they wish to allow mux reparenting on set_rate.
[..]
> Changes in v3:
>
> * rename/invert CLK_SET_RATE_REMUX to CLK_SET_RATE_NO_REPARENT and move
> to this new patch.
> * patch 3: add CLK_SET_RATE_NO_REPARENT flag to all callers of
> clk_register_mux. If you don't mind your clocks being reparented in
> response to set_rate please let me know and I'll drop the relevant
> portion of the patch.

Why is this better to change current behaviour of the clock core
and modify all drivers instead of having, e.g. CLK_SET_RATE_REPARENT
set in drivers of hardware that supports clock re-parenting while
setting clock rate ?

Is there intention to just have the automatic clock re-parenting
as a default feature in the common clock API ?
My apologies if this has already been answered, I haven't been
following this thread.

Thanks,
Sylwester

> arch/arm/mach-imx/clk.h | 5 +-
> drivers/clk/mmp/clk-mmp2.c | 39 +++++---
> drivers/clk/mmp/clk-pxa168.c | 40 +++++---
> drivers/clk/mmp/clk-pxa910.c | 31 +++---
> drivers/clk/mxs/clk.h | 4 +-
> drivers/clk/samsung/clk.h | 2 +-
> drivers/clk/spear/spear1310_clock.c | 179 ++++++++++++++++++-----------------
> drivers/clk/spear/spear1340_clock.c | 97 ++++++++++---------
> drivers/clk/spear/spear3xx_clock.c | 57 +++++++----
> drivers/clk/spear/spear6xx_clock.c | 35 +++----
> drivers/clk/sunxi/clk-sunxi.c | 3 +-
> drivers/clk/tegra/clk-tegra114.c | 36 ++++---
> drivers/clk/tegra/clk-tegra20.c | 6 +-
> drivers/clk/tegra/clk-tegra30.c | 33 ++++---
> drivers/clk/versatile/clk-vexpress.c | 4 +-
> include/linux/clk-provider.h | 1 +
> 16 files changed, 334 insertions(+), 238 deletions(-)

--
Sylwester Nawrocki
Samsung R&D Institute Poland
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