linux-kernel - [PATCH v2 2/5] clk: renesas: rzg2l: Re-assert reset on deassert timeout

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Message-ID: <20250903082757.115778-3-tommaso.merciai.xr@bp.renesas.com>
Date: Wed,  3 Sep 2025 10:27:51 +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 v2 2/5] clk: renesas: rzg2l: 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.

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

 drivers/clk/renesas/rzg2l-cpg.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 1143ce0afed47..8e9fea7f7dccb 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -1667,9 +1667,15 @@ static int __rzg2l_cpg_assert(struct reset_controller_dev *rcdev,
 		return 0;
 	}
 
-	return readl_poll_timeout_atomic(priv->base + reg, value,
-					 assert == !!(value & mask),
-					 10, 200);
+	ret = readl_poll_timeout_atomic(priv->base + reg, value,
+					assert == !!(value & mask),
+					10, 200);
+	if (ret && !assert) {
+		value = mask << 16;
+		writel(value, priv->base + CLK_RST_R(info->resets[id].off));
+	}
+
+	return ret;
 }
 
 static int rzg2l_cpg_assert(struct reset_controller_dev *rcdev,
-- 
2.43.0