[PATCH v4] gpiolib: match secondary fwnode too in gpio_device_find_by_fwnode()

[Bartosz Golaszewski]

In GPIOLIB, during fwnode lookup, after having resolved the consumer's
reference to a specific fwnode, we only match it against the primary
node of the controllers. Let's extend that to also the secondary node by
reworking gpio_chip_match_by_fwnode()

Suggested-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Reviewed-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@xxxxxxxxxx>
Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
Link: https://lore.kernel.org/all/aZUIFiOYt6GOlDQx@xxxxxxxxxx/
---
Changes in v4:
- Drop redundant !IS_ERR(node->secondary) check
- Link to v3: https://patch.msgid.link/20260225-device-match-secondary-fwnode-v3-1-a7152054135a@xxxxxxxxxxxxxxxx

Changes in v3:
- Remove the controversial patch 1/2 in favor of hand-coding its
  functionality in patch 2/2
- Link to v2: https://patch.msgid.link/20260223-device-match-secondary-fwnode-v2-0-966c00c9eeeb@xxxxxxxxxxxxxxxx

Changes in v2:
- Fold the code initially put into driver code into GPIOLIB as advised
  by Rafael
- Rework the logic as suggested by Andy
- To that end: make fwnode_is_primary() public
- Link to v1: https://patch.msgid.link/20260219-device-match-secondary-fwnode-v1-0-a64e8d4754bc@xxxxxxxxxxxxxxxx
---
 drivers/gpio/gpiolib.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c52200eaaaff82b12f22dd1ee8459bdd8ec10d81..780e30a033859578dabe3eda984e74db200507f7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -11,6 +11,7 @@
 #include <linux/errno.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/fwnode.h>
 #include <linux/idr.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
@@ -1395,7 +1396,16 @@ EXPORT_SYMBOL_GPL(gpio_device_find_by_label);
 
 static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, const void *fwnode)
 {
-	return device_match_fwnode(&gc->gpiodev->dev, fwnode);
+	struct device *dev = &gc->gpiodev->dev;
+	struct fwnode_handle *node = dev_fwnode(dev);
+
+	if (IS_ERR(fwnode))
+		return 0;
+
+	if (device_match_fwnode(dev, fwnode))
+		return 1;
+
+	return node && node->secondary == fwnode;
 }
 
 /**

---
base-commit: 50f68cc7be0a2cbf54d8f6aaf17df32fb01acc3f
change-id: 20260219-device-match-secondary-fwnode-4cc163ec47ee

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>