pinctrl: renesas: rza2: Add lock around pinctrl_generic{{add,remove}_group,{add,remove}_function}

The pinctrl group and function creation/remove calls expect
caller to take care of locking. Add lock around these functions.

Fixes: b59d0e7 ("pinctrl: Add RZ/A2 pin and gpio controller")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230815131558.33787-4-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: bijudas

drivers/pinctrl/renesas/pinctrl-rza2.c

@@ -14,6 +14,7 @@
 #include <linux/gpio/driver.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of_device.h>
 #include <linux/pinctrl/pinmux.h>
 
@@ -46,6 +47,7 @@ struct rza2_pinctrl_priv {
 	struct pinctrl_dev *pctl;
 	struct pinctrl_gpio_range gpio_range;
 	int npins;
+	struct mutex mutex; /* serialize adding groups and functions */
 };
 
 #define RZA2_PDR(port)		(0x0000 + (port) * 2)	/* Direction 16-bit */
@@ -358,10 +360,14 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 		psel_val[i] = MUX_FUNC(value);
 	}
 
+	mutex_lock(&priv->mutex);
+
 	/* Register a single pin group listing all the pins we read from DT */
 	gsel = pinctrl_generic_add_group(pctldev, np->name, pins, npins, NULL);
-	if (gsel < 0)
-		return gsel;
+	if (gsel < 0) {
+		ret = gsel;
+		goto unlock;
+	}
 
 	/*
 	 * Register a single group function where the 'data' is an array PSEL
@@ -390,6 +396,8 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 	(*map)->data.mux.function = np->name;
 	*num_maps = 1;
 
+	mutex_unlock(&priv->mutex);
+
 	return 0;
 
 remove_function:
@@ -398,6 +406,9 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 remove_group:
 	pinctrl_generic_remove_group(pctldev, gsel);
 
+unlock:
+	mutex_unlock(&priv->mutex);
+
 	dev_err(priv->dev, "Unable to parse DT node %s\n", np->name);
 
 	return ret;
@@ -473,6 +484,8 @@ static int rza2_pinctrl_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
+	mutex_init(&priv->mutex);
+
 	platform_set_drvdata(pdev, priv);
 
 	priv->npins = (int)(uintptr_t)of_device_get_match_data(&pdev->dev) *