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Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state

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Hi Mike, Stephen,

On Fri, Oct 21, 2016 at 3:17 PM, Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> 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).
>
> ***

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

Is this OK for you?

I'd like to move forward with this, as this is a prerequisite for adding
support for new SoCs (RZ/G) without adding more copies of
rcar_gen2_read_mode_pins(), and removing that function from platform code
for good.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.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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[PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining mode pin state Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 05/23] ARM: dts: r8a7790: Add device node for RST module Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 01/23] reset: Add renesas,rst DT bindings Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
    Re: [PATCH v4 01/23] reset: Add renesas,rst DT bindings Philipp Zabel <p.zabel@pengutronix.de> - 2016-10-21 17:50 +0200
  [PATCH v4 09/23] ARM: dts: r8a7794: Add device node for RST module Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 17/23] clk: renesas: rcar-gen3-cpg: Remove obsolete rcar_gen3_read_mode_pins() Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 03/23] ARM: dts: r8a7778: Add device node for RESET/WDT module Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 13/23] clk: renesas: r8a7779: Obtain mode pin values from R-Car RST driver Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 19/23] ARM: shmobile: r8a7779: Stop passing mode pins state to clock driver Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 15/23] clk: renesas: r8a7795: Obtain mode pin values from R-Car RST driver Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 23/23] clk: renesas: rcar-gen2: Remove obsolete rcar_gen2_clocks_init() Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 18/23] ARM: shmobile: r8a7778: Stop passing mode pins state to clock driver Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 20/23] ARM: shmobile: rcar-gen2: Stop passing mode pins state to clock driver Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 07/23] ARM: dts: r8a7792: Add device node for RST module Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  [PATCH v4 22/23] clk: renesas: r8a7779: Remove obsolete r8a7779_clocks_init() Geert Uytterhoeven <geert+renesas@glider.be> - 2016-10-21 15:30 +0200
  Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for  obtaining mode pin state Philipp Zabel <p.zabel@pengutronix.de> - 2016-10-21 17:50 +0200
    Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for  obtaining mode pin state Philipp Zabel <p.zabel@pengutronix.de> - 2016-10-21 17:50 +0200
    Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining  mode pin state Geert Uytterhoeven <geert@linux-m68k.org> - 2016-10-26 14:00 +0200
  Re: [PATCH v4 00/23] soc: renesas: Add R-Car RST driver for obtaining  mode pin state Geert Uytterhoeven <geert@linux-m68k.org> - 2016-10-26 14:10 +0200

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