[PATCH v5 0/8] Add syscon support for Renesas WDT driver

From: Prabhakar

Date: Fri Sep 11 2026 - 07:25:08 EST


From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

Hi all,

This series adds syscon support for the Renesas RZ/T2H and RZ/N2H SoCs in
the WDT driver. The WDTDCR register is part of the CPG/MSSR block for
which the CPG driver registers SYSC regmap. WDT driver now uses this
syscon to access the WDTDCR register.

These patches were part of two seprate series [0] and [1], out of which
certain patches have been queued separately, so I have included rest of
the patches into this single series.

Merge startegy, as the WDT driver and DTSI changes are interdependent
maybe the driver patches can go via renesas-soc.

v4->v5:
- patch #1 is new addressing Sashiko's comments to avoid potential deadlock
- patch #4 is new addressing Sashiko's comments
- Dropped checking rzt2h_wdt_wdtdcr_count_start() return value in
restart path.
- Handled the regmap locking in the driver and introduced nolock
version to be used in the restart path.
- Added review-by tag.

[0] https://lore.kernel.org/all/20260817192540.423994-1-prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx/
[1] https://lore.kernel.org/all/20260814191415.2110732-1-prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx/

Cheers,
Prabhakar

Lad Prabhakar (8):
watchdog: rzv2h: Drop enabling clocks in the restart handler
watchdog: rzv2h: Drop WDTRCR_RSTIRQS define
watchdog: rzv2h: Propagate WDTDCR access errors
watchdog: rzv2h: Use pm_runtime_put_sync()
watchdog: rzv2h: Convert WDTDCR handling to regmap
watchdog: rzv2h: Add syscon support for WDTDCR
arm64: dts: renesas: r9a09g077: Use CPG/MSSR syscon for WDTDCR access
arm64: dts: renesas: r9a09g087: Use CPG/MSSR syscon for WDTDCR access

arch/arm64/boot/dts/renesas/r9a09g077.dtsi | 24 ++--
arch/arm64/boot/dts/renesas/r9a09g087.dtsi | 24 ++--
drivers/watchdog/Kconfig | 1 +
drivers/watchdog/rzv2h_wdt.c | 134 +++++++++++++++------
4 files changed, 122 insertions(+), 61 deletions(-)

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2.55.0