linux-kernel - [PATCH 2/2] clk: imx8mp: Mark arm_a53

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Message-Id: <20260128-ops-parent-enable-fix-v1-2-ff39cc37f98d@collabora.com>
Date: Wed, 28 Jan 2026 19:38:51 +0100
From: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
To: Mark Brown <broonie@...nel.org>, 
 Alexander Stein <alexander.stein@...tq-group.com>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Chen-Yu Tsai <wenst@...omium.org>, Abel Vesa <abelvesa@...nel.org>, 
 Peng Fan <peng.fan@....com>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>
Cc: linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org, 
 kernel@...labora.com, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, 
 Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Subject: [PATCH 2/2] clk: imx8mp: Mark arm_a53_div as critical

It appears the i.MX8MP does not like when arm_a53_div, or rather the
parent it depends on, sys_pll2_500m, is briefly turned off during
__clk_core_init.

In the past, this clock driver could get away with not declaring the
clock as critical, as nothing ever fiddled with its parent that early
on. However, after Commit 669917676e93 ("clk: Respect
CLK_OPS_PARENT_ENABLE during recalc"), this changed.

In order to guarantee that it keeps its parent enabled during
__clk_core_init if it sets the flag CLK_OPS_PARENT_ENABLE, the clock
must be marked as critical.

Fixes: 669917676e93 ("clk: Respect CLK_OPS_PARENT_ENABLE during recalc")
Reported-by: Alexander Stein <alexander.stein@...tq-group.com>
Closes: https://lore.kernel.org/r/6239343.lOV4Wx5bFT@steina-w/
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
---
 drivers/clk/imx/clk-imx8mp.c | 4 +++-
 drivers/clk/imx/clk.h        | 4 ++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/imx/clk-imx8mp.c b/drivers/clk/imx/clk-imx8mp.c
index fe6dac70f1a1..ee10f845faff 100644
--- a/drivers/clk/imx/clk-imx8mp.c
+++ b/drivers/clk/imx/clk-imx8mp.c
@@ -655,7 +655,9 @@ static int imx8mp_clocks_probe(struct platform_device *pdev)
 	hws[IMX8MP_CLK_CLKOUT2_DIV] = imx_clk_hw_divider("clkout2_div", "clkout2_sel", anatop_base + 0x128, 16, 4);
 	hws[IMX8MP_CLK_CLKOUT2] = imx_clk_hw_gate("clkout2", "clkout2_div", anatop_base + 0x128, 24);
 
-	hws[IMX8MP_CLK_A53_DIV] = imx8m_clk_hw_composite_core("arm_a53_div", imx8mp_a53_sels, ccm_base + 0x8000);
+	hws[IMX8MP_CLK_A53_DIV] = imx8m_clk_hw_composite_core_critical("arm_a53_div",
+								       imx8mp_a53_sels,
+								       ccm_base + 0x8000);
 	hws[IMX8MP_CLK_A53_SRC] = hws[IMX8MP_CLK_A53_DIV];
 	hws[IMX8MP_CLK_A53_CG] = hws[IMX8MP_CLK_A53_DIV];
 	hws[IMX8MP_CLK_M7_CORE] = imx8m_clk_hw_composite_core("m7_core", imx8mp_m7_sels, ccm_base + 0x8080);
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index aa5202f284f3..97cac1d623ca 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -454,6 +454,10 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
 	_imx8m_clk_hw_composite(name, parent_names, reg, \
 			IMX_COMPOSITE_CORE, IMX_COMPOSITE_CLK_FLAGS_DEFAULT)
 
+#define imx8m_clk_hw_composite_core_critical(name, parent_names, reg)	\
+	_imx8m_clk_hw_composite(name, parent_names, reg, \
+			IMX_COMPOSITE_CORE, IMX_COMPOSITE_CLK_FLAGS_CRITICAL)
+
 #define imx8m_clk_hw_fw_managed_composite(name, parent_names, reg) \
 	_imx8m_clk_hw_composite(name, parent_names, reg, \
 			IMX_COMPOSITE_FW_MANAGED, \

-- 
2.52.0