linux-kernel - [PATCH v2 0/8] Add R-Car fuse support

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Date: Wed, 29 May 2024 11:29:29 +0200
From: Geert Uytterhoeven <geert+renesas@...der.be>
To: Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Magnus Damm <magnus.damm@...il.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc: devicetree@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org,
	linux-gpio@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH v2 0/8] Add R-Car fuse support

	Hi all,

R-Car Gen3/Gen4 SoCs contain fuses indicating hardware support or
hardware parameters.  Unfortunately the various SoCs require different
mechanisms to read the state of the fuses:
  - On R-Car Gen3, the fuse monitor registers are in the middle of the
    Pin Function Controller (PFC) register block,
  - On R-Car V3U and S4-8, the E-FUSE non-volatile memory is accessible
    through a separate register block in the PFC,
  - On R-Car V4H and V4M, the E-FUSE non-volatile memory is accessible
    through the second register block of OTP_MEM.

This patch series adds support for all 3 variants.  It provides an
in-kernel API to read the fuses' states, as well as userspace access
through the nvmem subsystem and sysfs:
  - R-Car Gen3:    /sys/bus/platform/devices/rcar_fuse/fuse/nvmem
  - R-Car V3U/S4:  /sys/bus/platform/devices/e6078800.fuse/fuse/nvmem 
  - R-Car V4H/V4M: /sys/bus/platform/devices/e61be000.otp/fuse/nvmem 

This has been tested on R-Car H3 ES2.0, M3-W and M3-W+, M3-N, V3M, V3H
and V3H2, D3, E3, V3U, S4-8 ES1.0 and ES1.2, V4H, and V4M.

For SoCs where E-FUSE is accessed through the PFC, it is not clear from
the documentation if any PFC module clock needs to be enabled for fuse
access.  According to experiments on R-Car S4-8, the module clock and
reset only impact the GPIO functionality of the PFC, not the pinmux or
fuse monitor functionalities.  So perhaps the clock/power-domains/resets
properties should be dropped from the DT bindings and DTS, as well as
the Runtime PM handling from the driver?

Changes compared to v1[1]:
  - Drop RFC state and broaden audience,
  - Fix typo in one-line summary,
  - Add Reviewed-by.

Thanks for your comments!

[1] https://lore.kernel.org/r/cover.1714642390.git.geert+renesas@glider.be

Geert Uytterhoeven (8):
  dt-bindings: fuse: Document R-Car E-FUSE / PFC
  dt-bindings: fuse: Document R-Car E-FUSE / OTP_MEM
  soc: renesas: Add R-Car fuse driver
  pinctrl: renesas: Add R-Car Gen3 fuse support
  arm64: dts: renesas: r8a779a0: Add E-FUSE node
  arm64: dts: renesas: r8a779f0: Add E-FUSE node
  arm64: dts: renesas: r8a779g0: Add OTP_MEM node
  arm64: dts: renesas: r8a779h0: Add OTP_MEM node

 .../bindings/fuse/renesas,rcar-efuse.yaml     |  55 +++++
 .../bindings/fuse/renesas,rcar-otp.yaml       |  38 ++++
 arch/arm64/boot/dts/renesas/r8a779a0.dtsi     |   8 +
 arch/arm64/boot/dts/renesas/r8a779f0.dtsi     |   8 +
 arch/arm64/boot/dts/renesas/r8a779g0.dtsi     |   5 +
 arch/arm64/boot/dts/renesas/r8a779h0.dtsi     |   5 +
 drivers/pinctrl/renesas/core.c                |  18 ++
 drivers/pinctrl/renesas/pfc-r8a77951.c        |   2 +
 drivers/pinctrl/renesas/pfc-r8a7796.c         |   4 +
 drivers/pinctrl/renesas/pfc-r8a77965.c        |   2 +
 drivers/pinctrl/renesas/pfc-r8a77970.c        |   2 +
 drivers/pinctrl/renesas/pfc-r8a77980.c        |  14 +-
 drivers/pinctrl/renesas/pfc-r8a77990.c        |   2 +
 drivers/pinctrl/renesas/pfc-r8a77995.c        |   2 +
 drivers/pinctrl/renesas/sh_pfc.h              |   4 +-
 drivers/soc/renesas/Kconfig                   |   8 +
 drivers/soc/renesas/Makefile                  |   1 +
 drivers/soc/renesas/rcar-fuse.c               | 201 ++++++++++++++++++
 include/linux/platform_data/rcar_fuse.h       |  11 +
 include/linux/soc/renesas/rcar-fuse.h         |  41 ++++
 20 files changed, 429 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/fuse/renesas,rcar-efuse.yaml
 create mode 100644 Documentation/devicetree/bindings/fuse/renesas,rcar-otp.yaml
 create mode 100644 drivers/soc/renesas/rcar-fuse.c
 create mode 100644 include/linux/platform_data/rcar_fuse.h
 create mode 100644 include/linux/soc/renesas/rcar-fuse.h

-- 
2.34.1

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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