gpiolib: Extend software-node support to support secondary software-nodes

When a software-node gets added to a device which already has another
fwnode as primary node it will become the secondary fwnode for that
device.

Currently if a software-node with GPIO properties ends up as the secondary
fwnode then gpiod_find_by_fwnode() will fail to find the GPIOs.

Add a new gpiod_fwnode_lookup() helper which falls back to calling
gpiod_find_by_fwnode() with the secondary fwnode if the GPIO was not
found in the primary fwnode.

Fixes: e7f9ff5dc90c ("gpiolib: add support for software nodes")
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hansg@kernel.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20250920200955.20403-1-hansg@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 0d2b470a252eebf70c888fc282e3c66d06b838ab..74d54513730a70814d84a4a84f2d8c8b7db3fe05 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4604,6 +4604,23 @@ static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode,
        return desc;
 }
 
+static struct gpio_desc *gpiod_fwnode_lookup(struct fwnode_handle *fwnode,
+                                            struct device *consumer,
+                                            const char *con_id,
+                                            unsigned int idx,
+                                            enum gpiod_flags *flags,
+                                            unsigned long *lookupflags)
+{
+       struct gpio_desc *desc;
+
+       desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx, flags, lookupflags);
+       if (gpiod_not_found(desc) && !IS_ERR_OR_NULL(fwnode))
+               desc = gpiod_find_by_fwnode(fwnode->secondary, consumer, con_id,
+                                           idx, flags, lookupflags);
+
+       return desc;
+}
+
 struct gpio_desc *gpiod_find_and_request(struct device *consumer,
                                         struct fwnode_handle *fwnode,
                                         const char *con_id,
@@ -4622,8 +4639,8 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer,
        int ret = 0;
 
        scoped_guard(srcu, &gpio_devices_srcu) {
-               desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
-                                           &flags, &lookupflags);
+               desc = gpiod_fwnode_lookup(fwnode, consumer, con_id, idx,
+                                          &flags, &lookupflags);
                if (gpiod_not_found(desc) && platform_lookup_allowed) {
                        /*
                         * Either we are not using DT or ACPI, or their lookup