gpiolib: generalize devprop_gpiochip_set_names() for device properties

devprop_gpiochip_set_names() is overly complicated with taking the
fwnode argument (which requires using dev_fwnode() & of_fwnode_handle()
in ACPI and OF GPIO code respectively). Let's just switch to using the
generic device properties.

This allows us to pull the code setting line names directly into
gpiochip_add_data_with_key() instead of handling it separately for
ACPI and OF.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/gpio/gpiolib-acpi.c

@@ -1221,9 +1221,6 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
 		return;
 	}
 
-	if (!chip->names)
-		devprop_gpiochip_set_names(chip, dev_fwnode(chip->parent));
-
 	acpi_gpiochip_request_regions(acpi_gpio);
 	acpi_gpiochip_scan_gpios(acpi_gpio);
 	acpi_walk_dep_device_list(handle);

drivers/gpio/gpiolib-devprop.c

@@ -17,25 +17,23 @@
 /**
  * devprop_gpiochip_set_names - Set GPIO line names using device properties
  * @chip: GPIO chip whose lines should be named, if possible
- * @fwnode: Property Node containing the gpio-line-names property
  *
  * Looks for device property "gpio-line-names" and if it exists assigns
  * GPIO line names for the chip. The memory allocated for the assigned
- * names belong to the underlying firmware node and should not be released
+ * names belong to the underlying software node and should not be released
  * by the caller.
  */
-void devprop_gpiochip_set_names(struct gpio_chip *chip,
-				const struct fwnode_handle *fwnode)
+int devprop_gpiochip_set_names(struct gpio_chip *chip)
 {
 	struct gpio_device *gdev = chip->gpiodev;
+	struct device *dev = chip->parent;
 	const char **names;
 	int ret, i;
 	int count;
 
-	count = fwnode_property_read_string_array(fwnode, "gpio-line-names",
-						  NULL, 0);
+	count = device_property_string_array_count(dev, "gpio-line-names");
 	if (count < 0)
-		return;
+		return 0;
 
 	if (count > gdev->ngpio) {
 		dev_warn(&gdev->dev, "gpio-line-names is length %d but should be at most length %d",
@@ -45,19 +43,21 @@ void devprop_gpiochip_set_names(struct gpio_chip *chip,
 
 	names = kcalloc(count, sizeof(*names), GFP_KERNEL);
 	if (!names)
-		return;
+		return -ENOMEM;
 
-	ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
+	ret = device_property_read_string_array(dev, "gpio-line-names",
 						names, count);
 	if (ret < 0) {
 		dev_warn(&gdev->dev, "failed to read GPIO line names\n");
 		kfree(names);
-		return;
+		return ret;
 	}
 
 	for (i = 0; i < count; i++)
 		gdev->descs[i].name = names[i];
 
 	kfree(names);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(devprop_gpiochip_set_names);

drivers/gpio/gpiolib-of.c

@@ -1026,11 +1026,6 @@ int of_gpiochip_add(struct gpio_chip *chip)
 	if (ret)
 		return ret;
 
-	/* If the chip defines names itself, these take precedence */
-	if (!chip->names)
-		devprop_gpiochip_set_names(chip,
-					   of_fwnode_handle(chip->of_node));
-
 	of_node_get(chip->of_node);
 
 	ret = of_gpiochip_scan_gpios(chip);

drivers/gpio/gpiolib.c

@@ -340,9 +340,6 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
 	struct gpio_device *gdev = gc->gpiodev;
 	int i;
 
-	if (!gc->names)
-		return 0;
-
 	/* First check all names if they are unique */
 	for (i = 0; i != gc->ngpio; ++i) {
 		struct gpio_desc *gpio;
@@ -621,7 +618,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
 
-	ret = gpiochip_set_desc_names(gc);
+	if (gc->names)
+		ret = gpiochip_set_desc_names(gc);
+	else
+		ret = devprop_gpiochip_set_names(gc);
 	if (ret)
 		goto err_remove_from_list;
 

include/linux/gpio/driver.h

@@ -756,8 +756,7 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc,
 					    enum gpiod_flags dflags);
 void gpiochip_free_own_desc(struct gpio_desc *desc);
 
-void devprop_gpiochip_set_names(struct gpio_chip *gc,
-				const struct fwnode_handle *fwnode);
+int devprop_gpiochip_set_names(struct gpio_chip *gc);
 
 #ifdef CONFIG_GPIOLIB