[PATCH RFC 2/2] pinctrl: bcm2835: implement hook for missing gpio-ranges

[Stefan Wahren <stefan.wahren@xxxxxxxx>]

The commit c8013355ead6 ("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 DTS files provided by the kernel
tree. Unfortunately it isn't guaranteed that these files are shipped to
all users.

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

Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
---
 drivers/pinctrl/bcm/pinctrl-bcm2835.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 47e433e..dad4530 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/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,
-- 
2.7.4