linux-kernel - [PATCH 3/4] clk: renesas: rzv2h: Re-assert reset on deassert timeout

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Message-ID: <20250820100428.233913-4-tommaso.merciai.xr@bp.renesas.com>
Date: Wed, 20 Aug 2025 12:04:24 +0200
From: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
To: tomm.merciai@...il.com
Cc: linux-renesas-soc@...r.kernel.org,
	biju.das.jz@...renesas.com,
	Tommaso Merciai <tommaso.merciai.xr@...renesas.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] clk: renesas: rzv2h: Re-assert reset on deassert timeout

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.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
---
 drivers/clk/renesas/rzv2h-cpg.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index 58ccbae0f904..469f40894c43 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 +866,16 @@ 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) {
+		dev_warn(rcdev->dev, "deassert timeout, re-asserting reset id %ld\n", id);
+		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