[PATCH v2 3/5] clk: renesas: rzv2h: Re-assert reset on deassert timeout

Tommaso Merciai
2025-09-03T08:28:45Z

Prevent issues during reset deassertion by re-asserting the reset if a
timeout occurs when trying to deassert. This ensures the reset line is in a
known state and improves reliability for hardware that may not immediately
clear the reset monitor bit.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
v1->v2:
- Collected GUytterhoeven tag
- Removed dev_warn() in __rzg2l_cpg_assert()

drivers/clk/renesas/rzv2h-cpg.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index 58ccbae0f9046..35c5ff38e231e 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -854,6 +854,7 @@ static int __rzv2h_cpg_assert(struct reset_controller_dev *rcdev,
u32 mask = BIT(priv->resets[id].reset_bit);
u8 monbit = priv->resets[id].mon_bit;
u32 value = mask << 16;
+ int ret;

dev_dbg(rcdev->dev, "%s id:%ld offset:0x%x\n",
assert ? "assert" : "deassert", id, reg);
@@ -865,9 +866,15 @@ static int __rzv2h_cpg_assert(struct reset_controller_dev *rcdev,
reg = GET_RST_MON_OFFSET(priv->resets[id].mon_index);
mask = BIT(monbit);

- return readl_poll_timeout_atomic(priv->base + reg, value,
- assert ? (value & mask) : !(value & mask),
- 10, 200);
+ ret = readl_poll_timeout_atomic(priv->base + reg, value,
+ assert ? (value & mask) : !(value & mask),
+ 10, 200);
+ if (ret && !assert) {
+ value = mask << 16;
+ writel(value, priv->base + GET_RST_OFFSET(priv->resets[id].reset_index));
+ }
+
+ return ret;
}

static int rzv2h_cpg_assert(struct reset_controller_dev *rcdev,
--
2.43.0