gpiolib: provide gpio_device_find_by_fwnode()

One of the ways of looking up GPIO devices is using their fwnode.
Provide a helper for that to avoid every user implementing their
own matching function.

Reviewed-by: Dipen Patel <dipenp@nvidia.com>
Tested-by: Dipen Patel <dipenp@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20231010151709.4104747-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: andy-shev

drivers/gpio/gpiolib.c

@@ -1145,6 +1145,26 @@ struct gpio_device *gpio_device_find_by_label(const char *label)
 }
 EXPORT_SYMBOL_GPL(gpio_device_find_by_label);
 
+static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, void *fwnode)
+{
+	return device_match_fwnode(&gc->gpiodev->dev, fwnode);
+}
+
+/**
+ * gpio_device_find_by_fwnode() - wrapper around gpio_device_find() finding
+ *                                the GPIO device by its fwnode
+ * @fwnode: Firmware node to lookup
+ *
+ * Returns:
+ * Reference to the GPIO device or NULL. Reference must be released with
+ * gpio_device_put().
+ */
+struct gpio_device *gpio_device_find_by_fwnode(const struct fwnode_handle *fwnode)
+{
+	return gpio_device_find((void *)fwnode, gpio_chip_match_by_fwnode);
+}
+EXPORT_SYMBOL_GPL(gpio_device_find_by_fwnode);
+
 /**
  * gpio_device_get() - Increase the reference count of this GPIO device
  * @gdev: GPIO device to increase the refcount for

include/linux/gpio/driver.h

@@ -611,6 +611,7 @@ struct gpio_chip *gpiochip_find(void *data,
 struct gpio_device *gpio_device_find(void *data,
 				int (*match)(struct gpio_chip *gc, void *data));
 struct gpio_device *gpio_device_find_by_label(const char *label);
+struct gpio_device *gpio_device_find_by_fwnode(const struct fwnode_handle *fwnode);
 
 struct gpio_device *gpio_device_get(struct gpio_device *gdev);
 void gpio_device_put(struct gpio_device *gdev);