[PATCH v8 0/7] Add syscon support for Renesas WDT driver

[Prabhakar]

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 strategy, as the WDT driver now includes renesas.h header file,
the driver patches can go via renesas-soc.

Note, patches have been rebased on top of next-20260930.

v7->v8:
- Dropped patch "watchdog: rzv2h: Drop enabling clocks in the
  restart handler" addressing Sashiko's comments

v6->v7:
- Added a new patch to introduce rzt2h_cpg_wdtdcr_count_start() function
- Added new patch to drop pm_runtime_resume_and_get() &
  pm_runtime_put_sync() calls while accessing the WDTDCR register.
- Dropped propagating WDTDCR access errors.
- Dropped converting WDTDCR handling to regmap as this would require
  resource address comparison to get WDT index to call
  rzt2h_cpg_wdtdcr_count_start().
- Made use of rzt2h_cpg_wdtdcr_count_start() in restart handler
- Added if regmap is available, use it for WDTDCR access
- Updated commit message

v5->v6:
- Used pm_runtime_put_sync() in rzv2h_wdt_stop() function.
- rebased on top of next-20260922

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 (7):
  clk: renesas: r9a09g077: Add helper to start WDTDCR counter
  watchdog: rzv2h: Use pm_runtime_put_sync()
  watchdog: rzv2h: Drop WDTRCR_RSTIRQS define
  watchdog: rzv2h: Drop runtime PM handling from WDTDCR init
  watchdog: rzv2h_wdt: Add syscon based WDTDCR access
  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/clk/renesas/r9a09g077-cpg.c        | 35 +++++++--
 drivers/watchdog/rzv2h_wdt.c               | 85 ++++++++++++++++++----
 include/linux/clk/renesas.h                |  6 ++
 5 files changed, 129 insertions(+), 45 deletions(-)

-- 
2.55.0