gpiolib: acpi: teach acpi_find_gpio() to handle data-only nodes

In preparation of switching all ACPI-based GPIO lookups to go through
acpi_find_gpio() we need to make sure it can handle data-only ACPI
nodes, same as existing acpi_node_get_gpiod().

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -864,8 +864,9 @@ static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
  * function only returns the first.
  */
 static struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
-					  const char *propname, int index,
-					  struct acpi_gpio_info *info)
+						 const char *propname,
+						 int index,
+						 struct acpi_gpio_info *info)
 {
 	struct acpi_gpio_lookup lookup;
 	int ret;
@@ -896,6 +897,44 @@ static struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 	return ret ? ERR_PTR(ret) : lookup.desc;
 }
 
+/**
+ * acpi_get_gpiod_from_data() - get a GPIO descriptor from ACPI data node
+ * @fwnode: pointer to an ACPI firmware node to get the GPIO information from
+ * @propname: Property name of the GPIO
+ * @index: index of GpioIo/GpioInt resource (starting from %0)
+ * @info: info pointer to fill in (optional)
+ *
+ * This function uses the property-based GPIO lookup to get to the GPIO
+ * resource with the relevant information from a data-only ACPI firmware node
+ * and uses that to obtain the GPIO descriptor to return.
+ *
+ * If the GPIO cannot be translated or there is an error an ERR_PTR is
+ * returned.
+ */
+static struct gpio_desc *acpi_get_gpiod_from_data(struct fwnode_handle *fwnode,
+						  const char *propname,
+						  int index,
+						  struct acpi_gpio_info *info)
+{
+	struct acpi_gpio_lookup lookup;
+	int ret;
+
+	if (!is_acpi_data_node(fwnode))
+		return ERR_PTR(-ENODEV);
+
+	if (!propname)
+		return ERR_PTR(-EINVAL);
+
+	lookup.index = index;
+
+	ret = acpi_gpio_property_lookup(fwnode, propname, index, &lookup);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = acpi_gpio_resource_lookup(&lookup, info);
+	return ret ? ERR_PTR(ret) : lookup.desc;
+}
+
 static bool acpi_can_fallback_to_crs(struct acpi_device *adev,
 				     const char *con_id)
 {
@@ -912,16 +951,12 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
 				 enum gpiod_flags *dflags,
 				 unsigned long *lookupflags)
 {
-	struct acpi_device *adev;
+	struct acpi_device *adev = to_acpi_device_node(fwnode);
 	struct acpi_gpio_info info;
 	struct gpio_desc *desc;
 	char propname[32];
 	int i;
 
-	adev = to_acpi_device_node(fwnode);
-	if (!adev)
-		return ERR_PTR(-ENODEV);
-
 	/* Try first from _DSD */
 	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
 		if (con_id) {
@@ -932,7 +967,12 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
 				 gpio_suffixes[i]);
 		}
 
-		desc = acpi_get_gpiod_by_index(adev, propname, idx, &info);
+		if (adev)
+			desc = acpi_get_gpiod_by_index(adev,
+						       propname, idx, &info);
+		else
+			desc = acpi_get_gpiod_from_data(fwnode,
+						        propname, idx, &info);
 		if (!IS_ERR(desc))
 			break;
 		if (PTR_ERR(desc) == -EPROBE_DEFER)
@@ -941,7 +981,7 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
 
 	/* Then from plain _CRS GPIOs */
 	if (IS_ERR(desc)) {
-		if (!acpi_can_fallback_to_crs(adev, con_id))
+		if (!adev || !acpi_can_fallback_to_crs(adev, con_id))
 			return ERR_PTR(-ENOENT);
 
 		desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
@@ -979,29 +1019,13 @@ struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
 				      const char *propname, int index,
 				      struct acpi_gpio_info *info)
 {
-	struct acpi_gpio_lookup lookup;
 	struct acpi_device *adev;
-	int ret;
 
 	adev = to_acpi_device_node(fwnode);
 	if (adev)
 		return acpi_get_gpiod_by_index(adev, propname, index, info);
 
-	if (!is_acpi_data_node(fwnode))
-		return ERR_PTR(-ENODEV);
-
-	if (!propname)
-		return ERR_PTR(-EINVAL);
-
-	memset(&lookup, 0, sizeof(lookup));
-	lookup.index = index;
-
-	ret = acpi_gpio_property_lookup(fwnode, propname, index, &lookup);
-	if (ret)
-		return ERR_PTR(ret);
-
-	ret = acpi_gpio_resource_lookup(&lookup, info);
-	return ret ? ERR_PTR(ret) : lookup.desc;
+	return acpi_get_gpiod_from_data(fwnode, propname, index, info);
 }
 
 /**