pinctrl: stm32: fix the reported number of GPIO lines per bank

[ Upstream commit 67e2996 ]

Each GPIO bank supports a variable number of lines which is usually 16, but
is less in some cases : this is specified by the last argument of the
"gpio-ranges" bank node property.
Report to the framework, the actual number of lines, so the libgpiod
gpioinfo command lists the actually existing GPIO lines.

Fixes: 1dc9d28 ("pinctrl: stm32: add possibility to use gpio-ranges to declare bank range")
Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Link: https://lore.kernel.org/r/20210617144629.2557693-1-fabien.dessenne@foss.st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/pinctrl/stm32/pinctrl-stm32.c

@@ -1229,7 +1229,7 @@ static int stm32_gpiolib_register_bank(struct stm32_pinctrl *pctl,
 	struct device *dev = pctl->dev;
 	struct resource res;
 	int npins = STM32_GPIO_PINS_PER_BANK;
-	int bank_nr, err;
+	int bank_nr, err, i = 0;
 
 	if (!IS_ERR(bank->rstc))
 		reset_control_deassert(bank->rstc);
@@ -1251,9 +1251,14 @@ static int stm32_gpiolib_register_bank(struct stm32_pinctrl *pctl,
 
 	of_property_read_string(np, "st,bank-name", &bank->gpio_chip.label);
 
-	if (!of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &args)) {
+	if (!of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, i, &args)) {
 		bank_nr = args.args[1] / STM32_GPIO_PINS_PER_BANK;
 		bank->gpio_chip.base = args.args[1];
+
+		npins = args.args[2];
+		while (!of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+							 ++i, &args))
+			npins += args.args[2];
 	} else {
 		bank_nr = pctl->nbanks;
 		bank->gpio_chip.base = bank_nr * STM32_GPIO_PINS_PER_BANK;