pinctrl: renesas: rza2: Embed pins in the priv struct

Turn the separately allocated pinctrl_pin_desc array into a flexible
array member of struct rza2_pinctrl_priv, annotated with
__counted_by(npins).  Compute the pin count before allocation so
struct_size() can size the combined object, and the two allocations can
be collapsed into one.

Change npins to unsigned int to avoid potential overflow/underflow
errors.

Assisted-by: Claude:Opus-4.7
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260527202317.5347-1-rosenp@gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

1 files changed, 11 insertions, 15 deletions

diff --git a/drivers/pinctrl/renesas/pinctrl-rza2.c b/drivers/pinctrl/renesas/pinctrl-rza2.c
index 8618f32ed26a..4cab641c3350 100644
--- a/drivers/pinctrl/renesas/pinctrl-rza2.c
+++ b/drivers/pinctrl/renesas/pinctrl-rza2.c
@@ -44,12 +44,12 @@ struct rza2_pinctrl_priv {
 	struct device *dev;
 	void __iomem *base;
 
-	struct pinctrl_pin_desc *pins;
 	struct pinctrl_desc desc;
 	struct pinctrl_dev *pctl;
 	struct pinctrl_gpio_range gpio_range;
-	int npins;
+	unsigned int npins;
 	struct mutex mutex; /* serialize adding groups and functions */
+	struct pinctrl_pin_desc pins[] __counted_by(npins);
 };
 
 #define RZA2_PDR(port)		(0x0000 + (port) * 2)	/* Direction 16-bit */
@@ -289,21 +289,15 @@ static int rza2_gpio_register(struct rza2_pinctrl_priv *priv)
 
 static int rza2_pinctrl_register(struct rza2_pinctrl_priv *priv)
 {
-	struct pinctrl_pin_desc *pins;
 	unsigned int i;
 	int ret;
 
-	pins = devm_kcalloc(priv->dev, priv->npins, sizeof(*pins), GFP_KERNEL);
-	if (!pins)
-		return -ENOMEM;
-
-	priv->pins = pins;
-	priv->desc.pins = pins;
+	priv->desc.pins = priv->pins;
 	priv->desc.npins = priv->npins;
 
 	for (i = 0; i < priv->npins; i++) {
-		pins[i].number = i;
-		pins[i].name = rza2_gpio_names[i];
+		priv->pins[i].number = i;
+		priv->pins[i].name = rza2_gpio_names[i];
 	}
 
 	ret = devm_pinctrl_register_and_init(priv->dev, &priv->desc, priv,
@@ -482,12 +476,17 @@ static const struct pinmux_ops rza2_pinmux_ops = {
 static int rza2_pinctrl_probe(struct platform_device *pdev)
 {
 	struct rza2_pinctrl_priv *priv;
+	unsigned int npins;
 	int ret;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	npins = (uintptr_t)of_device_get_match_data(&pdev->dev) *
+		      RZA2_PINS_PER_PORT;
+
+	priv = devm_kzalloc(&pdev->dev, struct_size(priv, pins, npins), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
+	priv->npins = npins;
 	priv->dev = &pdev->dev;
 
 	priv->base = devm_platform_ioremap_resource(pdev, 0);
@@ -498,9 +497,6 @@ static int rza2_pinctrl_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	priv->npins = (int)(uintptr_t)of_device_get_match_data(&pdev->dev) *
-		      RZA2_PINS_PER_PORT;
-
 	priv->desc.name		= DRIVER_NAME;
 	priv->desc.pctlops	= &rza2_pinctrl_ops;
 	priv->desc.pmxops	= &rza2_pinmux_ops;