pinctrl: stm32: improve debugfs information of pinconf-pins entry

Print the name of the selected alternate function in addition to its
number. Ex:
   "pin 135 (PI7): alternate 10 (SAI2_FS_A) - ..."

Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Link: https://lore.kernel.org/r/20220502152524.283374-1-fabien.dessenne@foss.st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/stm32/pinctrl-stm32.c

@@ -508,7 +508,7 @@ stm32_pctrl_find_group_by_pin(struct stm32_pinctrl *pctl, u32 pin)
 static bool stm32_pctrl_is_function_valid(struct stm32_pinctrl *pctl,
 		u32 pin_num, u32 fnum)
 {
-	int i;
+	int i, k;
 
 	for (i = 0; i < pctl->npins; i++) {
 		const struct stm32_desc_pin *pin = pctl->pins + i;
@@ -517,7 +517,7 @@ static bool stm32_pctrl_is_function_valid(struct stm32_pinctrl *pctl,
 		if (pin->pin.number != pin_num)
 			continue;
 
-		while (func && func->name) {
+		for (k = 0; k < STM32_CONFIG_NUM; k++) {
 			if (func->num == fnum)
 				return true;
 			func++;
@@ -1119,10 +1119,27 @@ static int stm32_pconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
 	return 0;
 }
 
+static struct stm32_desc_pin *
+stm32_pconf_get_pin_desc_by_pin_number(struct stm32_pinctrl *pctl,
+				       unsigned int pin_number)
+{
+	struct stm32_desc_pin *pins = pctl->pins;
+	int i;
+
+	for (i = 0; i < pctl->npins; i++) {
+		if (pins->pin.number == pin_number)
+			return pins;
+		pins++;
+	}
+	return NULL;
+}
+
 static void stm32_pconf_dbg_show(struct pinctrl_dev *pctldev,
 				 struct seq_file *s,
 				 unsigned int pin)
 {
+	struct stm32_pinctrl *pctl = pinctrl_dev_get_drvdata(pctldev);
+	const struct stm32_desc_pin *pin_desc;
 	struct pinctrl_gpio_range *range;
 	struct stm32_gpio_bank *bank;
 	int offset;
@@ -1172,7 +1189,12 @@ static void stm32_pconf_dbg_show(struct pinctrl_dev *pctldev,
 	case 2:
 		drive = stm32_pconf_get_driving(bank, offset);
 		speed = stm32_pconf_get_speed(bank, offset);
-		seq_printf(s, "%d - %s - %s - %s %s", alt,
+		pin_desc = stm32_pconf_get_pin_desc_by_pin_number(pctl, pin);
+		if (!pin_desc)
+			return;
+
+		seq_printf(s, "%d (%s) - %s - %s - %s %s", alt,
+			   pin_desc->functions[alt + 1].name,
 			   drive ? "open drain" : "push pull",
 			   biasing[bias],
 			   speeds[speed], "speed");
@@ -1386,7 +1408,8 @@ static int stm32_pctrl_create_pins_tab(struct stm32_pinctrl *pctl,
 		if (pctl->pkg && !(pctl->pkg & p->pkg))
 			continue;
 		pins->pin = p->pin;
-		pins->functions = p->functions;
+		memcpy((struct stm32_desc_pin *)pins->functions, p->functions,
+		       STM32_CONFIG_NUM * sizeof(struct stm32_desc_function));
 		pins++;
 		nb_pins_available++;
 	}

drivers/pinctrl/stm32/pinctrl-stm32.h

@@ -17,6 +17,7 @@
 #define STM32_PIN_GPIO		0
 #define STM32_PIN_AF(x)		((x) + 1)
 #define STM32_PIN_ANALOG	(STM32_PIN_AF(15) + 1)
+#define STM32_CONFIG_NUM	(STM32_PIN_ANALOG + 1)
 
 /*  package information */
 #define STM32MP_PKG_AA		BIT(0)
@@ -31,26 +32,26 @@ struct stm32_desc_function {
 
 struct stm32_desc_pin {
 	struct pinctrl_pin_desc pin;
-	const struct stm32_desc_function *functions;
+	const struct stm32_desc_function functions[STM32_CONFIG_NUM];
 	const unsigned int pkg;
 };
 
 #define STM32_PIN(_pin, ...)					\
 	{							\
 		.pin = _pin,					\
-		.functions = (struct stm32_desc_function[]){	\
-			__VA_ARGS__, { } },			\
+		.functions = {	\
+			__VA_ARGS__},			\
 	}
 
 #define STM32_PIN_PKG(_pin, _pkg, ...)					\
 	{							\
 		.pin = _pin,					\
 		.pkg  = _pkg,				\
-		.functions = (struct stm32_desc_function[]){	\
-			__VA_ARGS__, { } },			\
+		.functions = {	\
+			__VA_ARGS__},			\
 	}
 #define STM32_FUNCTION(_num, _name)		\
-	{							\
+	[_num] = {						\
 		.num = _num,					\
 		.name = _name,					\
 	}