pinctrl: bcm2835: implement hook for missing gpio-ranges

The commit c8013355ea ("ARM: dts: gpio-ranges property is now required")
fixed the GPIO probing issues caused by "pinctrl: bcm2835: Change init
order for gpio hogs". This changed only the kernel DTS files. Unfortunately
it isn't guaranteed that these files are shipped to all users.

So implement the necessary backward compatibility for BCM2835 and
BCM2711 platform.

Fixes: 266423e60e ("pinctrl: bcm2835: Change init order for gpio hogs")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220409095129.45786-3-stefan.wahren@i2se.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/bcm/pinctrl-bcm2835.c

@@ -358,6 +358,22 @@ static int bcm2835_gpio_direction_output(struct gpio_chip *chip,
 	return 0;
 }
 
+static int bcm2835_of_gpio_ranges_fallback(struct gpio_chip *gc,
+					   struct device_node *np)
+{
+	struct pinctrl_dev *pctldev = of_pinctrl_get(np);
+
+	of_node_put(np);
+
+	if (!pctldev)
+		return 0;
+
+	gpiochip_add_pin_range(gc, pinctrl_dev_get_devname(pctldev), 0, 0,
+			       gc->ngpio);
+
+	return 0;
+}
+
 static const struct gpio_chip bcm2835_gpio_chip = {
 	.label = MODULE_NAME,
 	.owner = THIS_MODULE,
@@ -372,6 +388,7 @@ static const struct gpio_chip bcm2835_gpio_chip = {
 	.base = -1,
 	.ngpio = BCM2835_NUM_GPIOS,
 	.can_sleep = false,
+	.of_gpio_ranges_fallback = bcm2835_of_gpio_ranges_fallback,
 };
 
 static const struct gpio_chip bcm2711_gpio_chip = {
@@ -388,6 +405,7 @@ static const struct gpio_chip bcm2711_gpio_chip = {
 	.base = -1,
 	.ngpio = BCM2711_NUM_GPIOS,
 	.can_sleep = false,
+	.of_gpio_ranges_fallback = bcm2835_of_gpio_ranges_fallback,
 };
 
 static void bcm2835_gpio_irq_handle_bank(struct bcm2835_pinctrl *pc,