[PATCHv2] pinctrl: rza2: embed pins in the priv struct

[Rosen Penev <rosenp@gmail.com>]

Turn the separately allocated pinctrl_pin_desc array into a flexible
array member of struct rza2_pinctrl_priv, annotated with
__counted_by(npins). The pin count is now computed before allocation so
struct_size() can size the combined object, collapsing two allocations
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>
---
 v2: use unsigned inr
 drivers/pinctrl/renesas/pinctrl-rza2.c | 28 ++++++++++++--------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/pinctrl/renesas/pinctrl-rza2.c b/drivers/pinctrl/renesas/pinctrl-rza2.c
index 8618f32ed26a..15ae5a88d705 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 +289,17 @@ 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;
+	struct pinctrl_pin_desc *pin;
 	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];
+		pin = &priv->pins[i];
+		pin->number = i;
+		pin->name = rza2_gpio_names[i];
 	}

 	ret = devm_pinctrl_register_and_init(priv->dev, &priv->desc, priv,
@@ -482,12 +478,17 @@ 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 +499,6 @@ 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;
--
2.54.0