linux-kernel - [PATCH] clk: at91: fix possible deadlock

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Message-Id: <20191128102531.817549-1-alexandre.belloni@bootlin.com>
Date:   Thu, 28 Nov 2019 11:25:31 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Stephen Boyd <sboyd@...nel.org>
Cc:     Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Michael Turquette <mturquette@...libre.com>,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Subject: [PATCH] clk: at91: fix possible deadlock

Lockdep warns about a possible circular locking dependency because using
syscon_node_to_regmap() will make the created regmap get and enable the
first clock it can parse from the device tree. This clock is not needed to
access the registers and should not be enabled at that time.

Use the recently introduced device_node_to_regmap to solve that as it looks
up the regmap in the same list but doesn't care about the clocks.

Reported-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/clk/at91/at91sam9260.c | 2 +-
 drivers/clk/at91/at91sam9rl.c  | 2 +-
 drivers/clk/at91/at91sam9x5.c  | 2 +-
 drivers/clk/at91/pmc.c         | 2 +-
 drivers/clk/at91/sama5d2.c     | 2 +-
 drivers/clk/at91/sama5d4.c     | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/at91/at91sam9260.c b/drivers/clk/at91/at91sam9260.c
index 0aabe49aed09..a9d4234758d7 100644
--- a/drivers/clk/at91/at91sam9260.c
+++ b/drivers/clk/at91/at91sam9260.c
@@ -348,7 +348,7 @@ static void __init at91sam926x_pmc_setup(struct device_node *np,
 		return;
 	mainxtal_name = of_clk_get_parent_name(np, i);
 
-	regmap = syscon_node_to_regmap(np);
+	regmap = device_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		return;
 
diff --git a/drivers/clk/at91/at91sam9rl.c b/drivers/clk/at91/at91sam9rl.c
index 0ac34cdaa106..77fe83a73bf4 100644
--- a/drivers/clk/at91/at91sam9rl.c
+++ b/drivers/clk/at91/at91sam9rl.c
@@ -83,7 +83,7 @@ static void __init at91sam9rl_pmc_setup(struct device_node *np)
 		return;
 	mainxtal_name = of_clk_get_parent_name(np, i);
 
-	regmap = syscon_node_to_regmap(np);
+	regmap = device_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		return;
 
diff --git a/drivers/clk/at91/at91sam9x5.c b/drivers/clk/at91/at91sam9x5.c
index 0855f3a80cc7..086cf0b4955c 100644
--- a/drivers/clk/at91/at91sam9x5.c
+++ b/drivers/clk/at91/at91sam9x5.c
@@ -146,7 +146,7 @@ static void __init at91sam9x5_pmc_setup(struct device_node *np,
 		return;
 	mainxtal_name = of_clk_get_parent_name(np, i);
 
-	regmap = syscon_node_to_regmap(np);
+	regmap = device_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		return;
 
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 0b03cfae3a9d..b71515acdec1 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -275,7 +275,7 @@ static int __init pmc_register_ops(void)
 
 	np = of_find_matching_node(NULL, sama5d2_pmc_dt_ids);
 
-	pmcreg = syscon_node_to_regmap(np);
+	pmcreg = device_node_to_regmap(np);
 	if (IS_ERR(pmcreg))
 		return PTR_ERR(pmcreg);
 
diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c
index 0de1108737db..ff7e3f727082 100644
--- a/drivers/clk/at91/sama5d2.c
+++ b/drivers/clk/at91/sama5d2.c
@@ -162,7 +162,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np)
 		return;
 	mainxtal_name = of_clk_get_parent_name(np, i);
 
-	regmap = syscon_node_to_regmap(np);
+	regmap = device_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		return;
 
diff --git a/drivers/clk/at91/sama5d4.c b/drivers/clk/at91/sama5d4.c
index 25b156d4e645..a6dee4a3b6e4 100644
--- a/drivers/clk/at91/sama5d4.c
+++ b/drivers/clk/at91/sama5d4.c
@@ -136,7 +136,7 @@ static void __init sama5d4_pmc_setup(struct device_node *np)
 		return;
 	mainxtal_name = of_clk_get_parent_name(np, i);
 
-	regmap = syscon_node_to_regmap(np);
+	regmap = device_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		return;
 
-- 
2.23.0