linux-kernel - [PATCH v2 1/5] clk: Respect CLK_OPS_PARENT

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Message-Id: <20251008-mtk-pll-rpm-v2-1-170ed0698560@collabora.com>
Date: Wed, 08 Oct 2025 18:05:35 +0200
From: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Dong Aisheng <aisheng.dong@....com>, 
 Matthias Brugger <matthias.bgg@...il.com>, 
 Yassine Oudjana <y.oudjana@...tonmail.com>, 
 Laura Nao <laura.nao@...labora.com>, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>, 
 Chia-I Wu <olvaffe@...il.com>, Chen-Yu Tsai <wenst@...omium.org>
Cc: kernel@...labora.com, linux-clk@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-mediatek@...ts.infradead.org, Stephen Boyd <sboyd@...eaurora.org>, 
 Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Subject: [PATCH v2 1/5] clk: Respect CLK_OPS_PARENT_ENABLE during recalc

When CLK_OPS_PARENT_ENABLE was introduced, it guarded various clock
operations, such as setting the rate or switching parents. However,
another operation that can and often does touch actual hardware state is
recalc_rate, which may also be affected by such a dependency.

Add parent enables/disables where the recalc_rate op is called directly.

Fixes: fc8726a2c021 ("clk: core: support clocks which requires parents enable (part 2)")
Fixes: a4b3518d146f ("clk: core: support clocks which requires parents enable (part 1)")
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
---
 drivers/clk/clk.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 85d2f2481acf360f0618a4a382fb51250e9c2fc4..1b0f9d567f48e003497afc98df0c0d2ad244eb90 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1921,7 +1921,14 @@ static unsigned long clk_recalc(struct clk_core *core,
 	unsigned long rate = parent_rate;

 	if (core->ops->recalc_rate && !clk_pm_runtime_get(core)) {
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_prepare_enable(core->parent);
+
 		rate = core->ops->recalc_rate(core->hw, parent_rate);
+
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_disable_unprepare(core->parent);
+
 		clk_pm_runtime_put(core);
 	}
 	return rate;
@@ -4031,6 +4038,9 @@ static int __clk_core_init(struct clk_core *core)
 	 */
 	clk_core_update_duty_cycle_nolock(core);

+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_prepare_enable(core->parent);
+
 	/*
 	 * Set clk's rate.  The preferred method is to use .recalc_rate.  For
 	 * simple clocks and lazy developers the default fallback is to use the
@@ -4046,6 +4056,9 @@ static int __clk_core_init(struct clk_core *core)
 		rate = 0;
 	core->rate = core->req_rate = rate;

+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_disable_unprepare(core->parent);
+
 	/*
 	 * Enable CLK_IS_CRITICAL clocks so newly added critical clocks
 	 * don't get accidentally disabled when walking the orphan tree and

-- 
2.51.0