gpio: shared: handle pins shared by child nodes of devices

Shared GPIOs may be assigned to child nodes of device nodes which don't
themselves bind to any struct device. We need to pass the firmware node
that is the actual consumer to gpiolib-shared and compare against it
instead of unconditionally using the fwnode of the consumer device.

Fixes: a060b8c511ab ("gpiolib: implement low-level, shared GPIO support")
Reported-by: Jon Hunter <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Tested-by: Jon Hunter <[e-mail]>
Acked-by: Jon Hunter <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpiolib-shared.c

···
 }
 #endif /* CONFIG_RESET_GPIO */
 
-int gpio_shared_add_proxy_lookup(struct device *consumer, const char *con_id,
-				 unsigned long lflags)
+int gpio_shared_add_proxy_lookup(struct device *consumer, struct fwnode_handle *fwnode,
+				 const char *con_id, unsigned long lflags)
 {
 	const char *dev_id = dev_name(consumer);
 	struct gpiod_lookup_table *lookup;
···
 			if (!ref->fwnode && device_is_compatible(consumer, "reset-gpio")) {
 				if (!gpio_shared_dev_is_reset_gpio(consumer, entry, ref))
 					continue;
-			} else if (!device_match_fwnode(consumer, ref->fwnode)) {
+			} else if (fwnode != ref->fwnode) {
 				continue;
 			}
 

drivers/gpio/gpiolib-shared.h

···
 struct gpio_device;
 struct gpio_desc;
 struct device;
+struct fwnode_handle;
 
 #if IS_ENABLED(CONFIG_GPIO_SHARED)
 
 int gpiochip_setup_shared(struct gpio_chip *gc);
 void gpio_device_teardown_shared(struct gpio_device *gdev);
-int gpio_shared_add_proxy_lookup(struct device *consumer, const char *con_id,
-				 unsigned long lflags);
+int gpio_shared_add_proxy_lookup(struct device *consumer,
+				 struct fwnode_handle *fwnode,
+				 const char *con_id, unsigned long lflags);
 
 #else
 
···
 static inline void gpio_device_teardown_shared(struct gpio_device *gdev) { }
 
 static inline int gpio_shared_add_proxy_lookup(struct device *consumer,
+					       struct fwnode_handle *fwnode,
 					       const char *con_id,
 					       unsigned long lflags)
 {

drivers/gpio/gpiolib.c

···
 			 * lookup table for the proxy device as previously
 			 * we only knew the consumer's fwnode.
 			 */
-			ret = gpio_shared_add_proxy_lookup(consumer, con_id,
-							   lookupflags);
+			ret = gpio_shared_add_proxy_lookup(consumer, fwnode,
+							   con_id, lookupflags);
 			if (ret)
 				return ERR_PTR(ret);