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* [PATCH 0/2] arm64: dts: renesas: Increase CANFD clock rates
@ 2025-08-13 13:37 Geert Uytterhoeven
  2025-08-13 13:37 ` [PATCH 1/2] arm64: dts: renesas: rcar-gen3: " Geert Uytterhoeven
  2025-08-13 13:37 ` [PATCH 2/2] arm64: dts: renesas: rzg2: " Geert Uytterhoeven
  0 siblings, 2 replies; 3+ messages in thread
From: Geert Uytterhoeven @ 2025-08-13 13:37 UTC (permalink / raw)
  To: Magnus Damm, Biju Das
  Cc: linux-renesas-soc, linux-arm-kernel, Geert Uytterhoeven

	Hi all,

Currently, all R-Car Gen3 and RZ/G2 .dtsi files configure the CANFD core
clocks to 40 MHz, which limits CAN-FD data transfer rates to 4 Mbps.
However, all R-Car Gen3 and RZ/G2 SoCs except for R-Car D3 support CANFD
clock rates up to 80 MHz.

Now the R-Car CAN-FD driver has gained support for Transceiver Delay
Compensation in v6.17-rc1, increase all appropriate CANFD clock rates to
the documented maximum, to support data rates up to 8 Mbps.

The R-Car Gen3 boards that have CAN-FD enabled use CAN transceivers
that support transfer rates up to 8 (Ebisu) or 5 (Condor(-I), Eagle)
Mbps.  None of the RZ/G2 boards have CAN-FD enabled.

The Draak board, and some of the RZ/G2 boards have CAN enabled instead
of CAN-FD.  None of these are affected by this series, as they either
rely on the default value of zero for the "renesas,can-clock-select"
property, or configure it explicitly to zero, thus not using the CANFD
core clock as CAN clock source.

All .dtsi files for SoCs in the RZ/G2L family configure the P0_DIV2
clock to 50 Mhz, which should be sufficient for the maximum supported
transfer rates of 4 Mbps (my board has no CAN transceiver mounted...).
RZ/G3E already configures its can_clk to 80 MHz.

This series has been tested on Ebisu-4D (R-Car E3).
I plan to queue it in renesas-devel for v6.18.

Thanks for your comments!

Geert Uytterhoeven (2):
  arm64: dts: renesas: rcar-gen3: Increase CANFD clock rates
  arm64: dts: renesas: rzg2: Increase CANFD clock rates

 arch/arm64/boot/dts/renesas/r8a774a1.dtsi | 2 +-
 arch/arm64/boot/dts/renesas/r8a774b1.dtsi | 2 +-
 arch/arm64/boot/dts/renesas/r8a774c0.dtsi | 2 +-
 arch/arm64/boot/dts/renesas/r8a774e1.dtsi | 2 +-
 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 +-
 arch/arm64/boot/dts/renesas/r8a77970.dtsi | 2 +-
 arch/arm64/boot/dts/renesas/r8a77980.dtsi | 2 +-
 arch/arm64/boot/dts/renesas/r8a77990.dtsi | 2 +-
 11 files changed, 11 insertions(+), 11 deletions(-)

-- 
2.43.0

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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2025-08-13 13:37 [PATCH 0/2] arm64: dts: renesas: Increase CANFD clock rates Geert Uytterhoeven
2025-08-13 13:37 ` [PATCH 1/2] arm64: dts: renesas: rcar-gen3: " Geert Uytterhoeven
2025-08-13 13:37 ` [PATCH 2/2] arm64: dts: renesas: rzg2: " Geert Uytterhoeven

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