Hi Stephen,

Thanks for your answers!

On Tue, Nov 1, 2016 at 12:25 AM, Stephen Boyd [off-list ref] wrote:

On 10/31, Geert Uytterhoeven wrote:

quoted

Hi Mike, Stephen, Arnd, Olof, Kevin,

Is the merge strategy [see ##### below] OK for you?
Thanks a lot!

On Mon, Oct 31, 2016 at 9:19 AM, Simon Horman [off-list ref] wrote:

quoted

On Wed, Oct 26, 2016 at 02:00:24PM +0200, Geert Uytterhoeven wrote:

quoted

On Fri, Oct 21, 2016 at 3:17 PM, Geert Uytterhoeven
[off-list ref] wrote:

quoted

Currently the R-Car Clock Pulse Generator (CPG) drivers obtains the
state of the mode pins either by a call from the platform code, or
directly by using a hardcoded register access. This is a bit messy, and
creates a dependency between driver and platform code.

This patch series converts the various Renesas R-Car clock drivers
and support code from reading the mode pin states using a hardcoded
register access to using a new minimalistic R-Car RST driver.

All R-Car clock drivers will rely on the presence in DT of a device node
for the RST module.  Backwards compatibility with old DTBs is retained
only for R-Car Gen2, which has fallback code using its own private copy
of rcar_gen2_read_mode_pins().

After this, there is still one remaining user of
rcar_gen2_read_mode_pins() left in platform code. A patch series to
remove that user has already been posted, though ("[PATCH/RFT 0/4] ARM:
shmobile: R-Car Gen2: Allow booting secondary CPU cores in debug mode").
Since v3, the other user has been removed in commit 9f5ce39ddb8f68b3
("ARM: shmobile: rcar-gen2: Obtain extal frequency from DT").

This series consists of 5 parts:
  A. Patches 1 and 2 add DT bindings and driver code for the R-Car RST
     driver,
  B. Patches 3-11 add device nodes for the RST modules to the R-Car DTS
     files,
  C. Patches 12-17 convert the clock drivers to call into the new R-Car
     RST driver,
  D. Patches 18-20 remove passing mode pin state to the clock drivers
     from the platform code,
  E. Patches 21-23 remove dead code from the clock drivers.

As is usually the case with moving functionality from platform code to
DT, there are lots of hard dependencies:
  - The DT updates in Part B can be merged as soon as the DT bindings in
    Part A have been approved,
  - The clock driver updates in Part C depend functionally on the driver
    code in Part A, and on the DT updates in Part B,
  - The board code cleanups in Part D depend on the clock driver updates
    in Part C,
  - The block driver cleanups in part E depend on the board code
    cleanups in part D.

Hence to maintain the required lockstep between SoC driver, clock
drivers, shmobile platform code, and shmobile DT, I propose to queue up
all patches in a single branch against v4.9-rc1, and send pull requests
to both Mike/Stephen (clock) and Simon (rest).

***

quoted

  - Mike/Stephen/Simon/Magnus: Are you OK with the suggested merge
    approach above?

Is this OK for you?

#####

(link to the full series at
 https://groups.google.com/forum/#!topic/linux.kernel/fLSFsjOgPT8)

Would the pull requests for clk also have dts changes at the base
of the tree? Perhaps clk side can just ack the clk patches and

Yes they would: this is moving functionality from platform code to DT.
Without the DT updates, it will break bisection (except for R-Car Gen2,
where we have fallback code to handle old DTBs).

then have it all routed through arm-soc? The only worry I have is
if we need to make some sort of change in clk side that conflicts
with these changes. I don't usually like taking dts changes
through clk tree, so I'd like to avoid that if possible.

Everything could go through arm-soc only with your Acked-by.
However, there are new clock drivers pending on this series.
Either they have to go through arm-soc, too, or this series would
be pulled into the clk tree with these new clock drivers.

Part E could happen anytime after everything else happens, so
that doesn't seem like a concern.

Part E can indeed by postponed.
But if parts A-D are applied together, there's no reason to postpone part E.

Part C could also be made to
only call into the new reset drivers if the reset dts nodes are
present? If that's done then we could merge clk patches anytime
and remove the dead code and the node search at some later time
when everything has settled?

That would require adding more backwards compatibility code for
old DTBs, even for platform where we're not interested in maintaining
that. In addition, Part C depends on the header file for the reset driver
to compile the clock driver, even if you would add some DT detection,
and on the reset driver to link. So I'm afraid this is not feasible.

Thanks again!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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