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From:   Emil Renner Berthing <emil.renner.berthing@canonical.com>
To:     linux-gpio@vger.kernel.org
Cc:     Jianlong Huang <jianlong.huang@starfivetech.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Michael Zhu <michael.zhu@starfivetech.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] pinctrl: starfive: Serialize adding groups and functions
Date:   Mon, 27 Jun 2022 10:53:33 +0200
Message-Id: <20220627085333.1774396-1-emil.renner.berthing@canonical.com>
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From: Jianlong Huang <jianlong.huang@starfivetech.com>

The pinctrl dt_node_to_map method may be called in parallel which leads
us to call pinconf_generic_add_group and pinconf_generic_add_function
in parallel. This is not supported though and leads to errors, so add a
mutex to serialize these calls.

Signed-off-by: Jianlong Huang <jianlong.huang@starfivetech.com>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
 drivers/pinctrl/pinctrl-starfive.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-starfive.c b/drivers/pinctrl/pinctrl-starfive.c
index 2a86c1035cc8..3eb40e230d98 100644
--- a/drivers/pinctrl/pinctrl-starfive.c
+++ b/drivers/pinctrl/pinctrl-starfive.c
@@ -207,6 +207,7 @@ struct starfive_pinctrl {
 	void __iomem *base;
 	void __iomem *padctl;
 	struct pinctrl_dev *pctl;
+	struct mutex mutex; /* serialize adding groups and functions */
 };
 
 static inline unsigned int starfive_pin_to_gpio(const struct starfive_pinctrl *sfp,
@@ -522,6 +523,7 @@ static int starfive_dt_node_to_map(struct pinctrl_dev *pctldev,
 
 	nmaps = 0;
 	ngroups = 0;
+	mutex_lock(&sfp->mutex);
 	for_each_child_of_node(np, child) {
 		int npins;
 		int i;
@@ -615,12 +617,14 @@ static int starfive_dt_node_to_map(struct pinctrl_dev *pctldev,
 
 	*maps = map;
 	*num_maps = nmaps;
+	mutex_unlock(&sfp->mutex);
 	return 0;
 
 put_child:
 	of_node_put(child);
 free_map:
 	pinctrl_utils_free_map(pctldev, map, nmaps);
+	mutex_unlock(&sfp->mutex);
 	return ret;
 }
 
@@ -1267,6 +1271,7 @@ static int starfive_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, sfp);
 	sfp->gc.parent = dev;
 	raw_spin_lock_init(&sfp->lock);
+	mutex_init(&sfp->mutex);
 
 	ret = devm_pinctrl_register_and_init(dev, &starfive_desc, sfp, &sfp->pctl);
 	if (ret)
-- 
2.36.1