Hi Srinivas, On Wed, May 29, 2024 at 11:29 AM Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > 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@xxxxxxxxx > > 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 Arnd pointed out on IRC this should probably be an nvmem driver instead of an soc driver. I had mimicked this after the Tegra fuse driver, which is also an soc driver. The in-kernel user would be its main user. The nvmem interface exists just because the tegra driver did the same. After some investigation, it looks like this should use Documentation/devicetree/bindings/nvmem/nvmem-consumer.yaml instead, and handle it like e.g. Documentation/devicetree/bindings/nvmem/sprd-efuse.txt? Thanks for your guidance! Link to this series: https://lore.kernel.org/all/cover.1716974502.git.geert+renesas@xxxxxxxxx/ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx 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
