From mboxrd@z Thu Jan  1 00:00:00 1970
From: Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH/RFC v3 00/22] soc: renesas: Add R-Car RST driver for obtaining mode pin state
Date: Wed,  1 Jun 2016 21:20:58 +0200
Message-ID: <1464808880-343-1-git-send-email-geert+renesas@glider.be>
Return-path: <linux-renesas-soc-owner@vger.kernel.org>
Sender: linux-renesas-soc-owner@vger.kernel.org
To: Simon Horman <horms@verge.net.au>, Magnus Damm <magnus.damm@gmail.com>, Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>, Philipp Zabel <p.zabel@pengutronix.de>, Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@codeaurora.org>, Dirk Behme <dirk.behme@de.bosch.com>
Cc: linux-renesas-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Geert Uytterhoeven <geert+renesas@glider.be>
List-Id: devicetree@vger.kernel.org

	Hi all,

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

This RFC 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 R-Car RST driver.

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 3-10 add device nodes for the RST modules to the R-Car DTS
     files,
  C. Patches 11-16 convert the clock drivers to call into the new R-Car
     RST driver,
  D. Patches 17-19 remove passing mode pin state to the clock drivers
     from the board code,
  E. Patches 20-22 remove dead code from the clock drivers.

I've kept all parts together as this is an RFC, and to avoid losing the
bigger picture. I will split it in series per maintainer, when we have
decided how to handle the dependencies (see below).

After this, there are still a few users of rcar_gen2_read_mode_pins()
left in board code, which should be converted in one way or another.
However, 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 calling into
rcar_gen2_read_mode_pins().

As is usually the case with moving functionality from board 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,
  - 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.

This series has evolved over time, cfr.
  - "[PATCH/RFC 00/11] ARM: shmobile: Let CPG use syscon for MD pin
    values" (http://www.spinics.net/lists/linux-clk/msg01478.html),
  - "[PATCH 00/10] arm64: renesas: Obtain MD pin values using
    syscon/regmap".
    (http://www.spinics.net/lists/linux-sh/msg44757.html)

Changes compared to v2:
  - Use "renesas,<soctype>-rst" instead of "renesas,rst-<soctype>",
  - Drop "syscon" compatible value and "renesas,modemr" property, use a
    real driver instead,
  - Add support for R-Car M1A, H1, and M3-W.

Changes compared to v1:
  - Add support for R-Car H3.

An alternative and broader solution was proposed by Simon Horman as
"[PATCH/RFC 0/6] boot-mode-reg: Add core"
(http://www.spinics.net/lists/linux-sh/msg45969.html).

This patch series is against renesas-drivers.
It has been tested on r8a7778/bockw, r8a7779/marzen, r8a7791/koelsch,
and r8a7795/salvator-x.

Thanks for your comments!

Geert Uytterhoeven (22):
  reset: Add renesas,rst DT bindings
  soc: renesas: Add R-Car RST driver
  ARM: dts: r8a7778: Add device node for RESET/WDT module
  ARM: dts: r8a7779: Add device node for RESET/WDT module
  ARM: dts: r8a7790: Add device node for RST module
  ARM: dts: r8a7791: Add device node for RST module
  ARM: dts: r8a7793: Add device node for RST module
  ARM: dts: r8a7794: Add device node for RST module
  arm64: renesas: r8a7795 dtsi: Add device node for RST module
  arm64: renesas: r8a7796 dtsi: Add device node for RST module
  clk: renesas: r8a7778: Obtain mode pin values using R-Car RST driver
  clk: renesas: r8a7779: Obtain mode pin values from R-Car RST driver
  clk: renesas: rcar-gen2: Obtain mode pin values using RST driver
  clk: renesas: r8a7795: Obtain mode pin values from R-Car RST driver
  clk: renesas: r8a7796: Obtain mode pin values from R-Car RST driver
  clk: renesas: rcar-gen3-cpg: Remove obsolete
    rcar_gen3_read_mode_pins()
  ARM: shmobile: r8a7778: Stop passing mode pins state to clock driver
  ARM: shmobile: r8a7779: Stop passing mode pins state to clock driver
  ARM: shmobile: rcar-gen2: Stop passing mode pins state to clock driver
  clk: renesas: r8a7778: Remove obsolete r8a7778_clocks_init()
  clk: renesas: r8a7779: Remove obsolete r8a7779_clocks_init()
  clk: renesas: rcar-gen2: Remove obsolete rcar_gen2_clocks_init()

 .../devicetree/bindings/reset/renesas,rst.txt      | 35 ++++++++
 arch/arm/boot/dts/r8a7778.dtsi                     |  5 ++
 arch/arm/boot/dts/r8a7779.dtsi                     |  5 ++
 arch/arm/boot/dts/r8a7790.dtsi                     |  5 ++
 arch/arm/boot/dts/r8a7791.dtsi                     |  5 ++
 arch/arm/boot/dts/r8a7793.dtsi                     |  5 ++
 arch/arm/boot/dts/r8a7794.dtsi                     |  5 ++
 arch/arm/mach-shmobile/setup-r8a7778.c             | 15 ----
 arch/arm/mach-shmobile/setup-r8a7779.c             | 27 -------
 arch/arm/mach-shmobile/setup-rcar-gen2.c           |  6 +-
 arch/arm64/boot/dts/renesas/r8a7795.dtsi           |  5 ++
 arch/arm64/boot/dts/renesas/r8a7796.dtsi           |  5 ++
 drivers/clk/renesas/clk-r8a7778.c                  | 26 +++---
 drivers/clk/renesas/clk-r8a7779.c                  | 18 ++---
 drivers/clk/renesas/clk-rcar-gen2.c                | 17 ++--
 drivers/clk/renesas/r8a7795-cpg-mssr.c             |  8 +-
 drivers/clk/renesas/r8a7796-cpg-mssr.c             |  8 +-
 drivers/clk/renesas/rcar-gen3-cpg.c                | 17 ----
 drivers/clk/renesas/rcar-gen3-cpg.h                |  1 -
 drivers/soc/renesas/Makefile                       |  5 ++
 drivers/soc/renesas/rcar-rst.c                     | 94 ++++++++++++++++++++++
 include/linux/clk/renesas.h                        |  4 -
 include/linux/soc/renesas/rcar-rst.h               |  6 ++
 23 files changed, 227 insertions(+), 100 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reset/renesas,rst.txt
 create mode 100644 drivers/soc/renesas/rcar-rst.c
 create mode 100644 include/linux/soc/renesas/rcar-rst.h

-- 
1.9.1

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