[PATCH/RFC 0/5] ravb: Add support for explicit internal clock delay configuration

[Geert Uytterhoeven <geert+renesas@glider.be>]

	Hi all,

Some Renesas EtherAVB variants support internal clock delay
configuration, which can add larger delays than the delays that are
typically supported by the PHY (using an "rgmii-*id" PHY mode, and/or
"[rt]xc-skew-ps" properties).

Historically, the EtherAVB driver configured these delays based on the
"rgmii-*id" PHY mode.  This caused issues with PHY drivers that
implement PHY internal delays properly[1].  Hence a backwards-compatible
workaround was added by masking the PHY mode[2].

This RFC patch series implements the next step of the plan outlined in
[3], and adds proper support for explicit configuration of the MAC
internal clock delays using new "renesas,[rt]xc-delay-ps" properties.
If none of these properties is present, the driver falls back to the old
handling.

The series consists of 4 parts:
  1. DT binding update documenting the new properties,
  2. A preparatory improvement,
  3. Driver update implementing support for the new properties,
  4. DT updates, one for R-Car Gen3 and RZ/G2 SoC families each.

Note that patches 4 and 5 depend on patch 3, and must not be applied
before that dependency has hit upstream.

Impacted, tested:
  - Salvator-X(S) with R-Car H3 ES1.0 and ES2.0, M3-W, and M3-N.

Not impacted, tested:
  - Ebisu with R-Car E3.

Impacted, not tested:
  - Salvator-X(S) with other SoC variants,
  - ULCB with R-Car H3/M3-W/M3-N variants,
  - V3MSK and Eagle with R-Car V3M,
  - Draak with R-Car V3H,
  - HiHope RZ/G2[MN] with RZ/G2M or RZ/G2N.

Thanks for your comments!

References:
  [1] Commit bcf3440c6dd78bfe ("net: phy: micrel: add phy-mode support
      for the KSZ9031 PHY")
  [2] Commit 9b23203c32ee02cd ("ravb: Mask PHY mode to avoid inserting
      delays twice").
      https://lore.kernel.org/r/20200529122540.31368-1-geert+renesas@glider.be/
  [3] https://lore.kernel.org/r/CAMuHMdU+MR-2tr3-pH55G0GqPG9HwH3XUd=8HZxprFDMGQeWUw@mail.gmail.com/

Geert Uytterhoeven (5):
  dt-bindings: net: renesas,ravb: Document internal clock delay
    properties
  ravb: Split delay handling in parsing and applying
  ravb: Add support for explicit internal clock delay configuration
  arm64: dts: renesas: rcar-gen3: Convert EtherAVB to explicit delay
    handling
  arm64: dts: renesas: rzg2: Convert EtherAVB to explicit delay handling

 .../devicetree/bindings/net/renesas,ravb.txt  | 29 ++++++-----
 .../boot/dts/renesas/hihope-rzg2-ex.dtsi      |  2 +-
 arch/arm64/boot/dts/renesas/r8a774a1.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a774b1.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a774c0.dtsi     |  1 +
 arch/arm64/boot/dts/renesas/r8a77951.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a77960.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a77961.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a77965.dtsi     |  2 +
 .../arm64/boot/dts/renesas/r8a77970-eagle.dts |  3 +-
 .../arm64/boot/dts/renesas/r8a77970-v3msk.dts |  3 +-
 arch/arm64/boot/dts/renesas/r8a77970.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a77980.dtsi     |  2 +
 arch/arm64/boot/dts/renesas/r8a77990.dtsi     |  1 +
 arch/arm64/boot/dts/renesas/r8a77995.dtsi     |  1 +
 .../boot/dts/renesas/salvator-common.dtsi     |  2 +-
 arch/arm64/boot/dts/renesas/ulcb.dtsi         |  2 +-
 drivers/net/ethernet/renesas/ravb.h           |  5 +-
 drivers/net/ethernet/renesas/ravb_main.c      | 52 ++++++++++++++-----
 19 files changed, 86 insertions(+), 31 deletions(-)

-- 
2.17.1

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