ACPI / property: Extend device_get_next_child_node() to data-only nodes

Make device_get_next_child_node() work with ACPI data-only subnodes
introduced previously.

Namely, replace acpi_get_next_child() with acpi_get_next_subnode()
that can handle (and return) child device objects as well as child
data-only subnodes of the given device and modify the ACPI part
of the GPIO subsystem to handle data-only subnodes returned by it.

To that end, introduce acpi_node_get_gpiod() taking a struct
fwnode_handle pointer as the first argument.  That argument may
point to an ACPI device object as well as to a data-only subnode
and the function should do the right thing (ie. look for the matching
GPIO descriptor correctly) in either case.

Next, modify fwnode_get_named_gpiod() to use acpi_node_get_gpiod()
instead of acpi_get_gpiod_by_index() which automatically causes
devm_get_gpiod_from_child() to work with ACPI data-only subnodes
that may be returned by device_get_next_child_node() which in turn
is required by the users of that function (the gpio_keys_polled
and gpio-leds drivers).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 64 insertions, 9 deletions

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index a38cf16a5828..69a83626f1ae 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -453,7 +453,7 @@ static int acpi_gpio_resource_lookup(struct acpi_gpio_lookup *lookup,
 	return 0;
 }
 
-static int acpi_gpio_property_lookup(struct acpi_device *adev,
+static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
 				     const char *propname, int index,
 				     struct acpi_gpio_lookup *lookup)
 {
@@ -461,10 +461,16 @@ static int acpi_gpio_property_lookup(struct acpi_device *adev,
 	int ret;
 
 	memset(&args, 0, sizeof(args));
-	ret = acpi_dev_get_property_reference(adev, propname, index, &args);
-	if (ret && !acpi_get_driver_gpio_data(adev, propname, index, &args))
-		return ret;
+	ret = acpi_node_get_property_reference(fwnode, propname, index, &args);
+	if (ret) {
+		struct acpi_device *adev = to_acpi_device_node(fwnode);
 
+		if (!adev)
+			return ret;
+
+		if (!acpi_get_driver_gpio_data(adev, propname, index, &args))
+			return ret;
+	}
 	/*
 	 * The property was found and resolved, so need to lookup the GPIO based
 	 * on returned args.
@@ -518,7 +524,8 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 	if (propname) {
 		dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
 
-		ret = acpi_gpio_property_lookup(adev, propname, index, &lookup);
+		ret = acpi_gpio_property_lookup(acpi_fwnode_handle(adev),
+						propname, index, &lookup);
 		if (ret)
 			return ERR_PTR(ret);
 
@@ -535,6 +542,47 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 }
 
 /**
+ * acpi_node_get_gpiod() - get a GPIO descriptor from ACPI resources
+ * @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)
+ *
+ * If @fwnode is an ACPI device object, call %acpi_get_gpiod_by_index() for it.
+ * Otherwise (ie. it is a data-only non-device object), use the property-based
+ * GPIO lookup to get to the GPIO resource with the relevant information and use
+ * that to obtain the GPIO descriptor to return.
+ */
+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;
+}
+
+/**
  * acpi_dev_gpio_irq_get() - Find GpioInt and translate it to Linux IRQ number
  * @adev: pointer to a ACPI device to get IRQ from
  * @index: index of GpioInt resource (starting from %0)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f43e808a49d9..7d61b506c42f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2083,11 +2083,10 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
 						&flags);
 		if (!IS_ERR(desc))
 			active_low = flags & OF_GPIO_ACTIVE_LOW;
-	} else if (is_acpi_device_node(fwnode)) {
+	} else if (is_acpi_node(fwnode)) {
 		struct acpi_gpio_info info;
 
-		desc = acpi_get_gpiod_by_index(to_acpi_device_node(fwnode),
-					       propname, 0, &info);
+		desc = acpi_node_get_gpiod(fwnode, propname, 0, &info);
 		if (!IS_ERR(desc))
 			active_low = info.active_low;
 	}
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index bf343004b008..e69c7157cdad 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -42,6 +42,9 @@ void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 					  const char *propname, int index,
 					  struct acpi_gpio_info *info);
+struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
+				      const char *propname, int index,
+				      struct acpi_gpio_info *info);
 
 int acpi_gpio_count(struct device *dev, const char *con_id);
 #else
@@ -60,7 +63,12 @@ acpi_get_gpiod_by_index(struct acpi_device *adev, const char *propname,
 {
 	return ERR_PTR(-ENOSYS);
 }
-
+static inline struct gpio_desc *
+acpi_node_get_gpiod(struct fwnode_handle *fwnode, const char *propname,
+		    int index, struct acpi_gpio_info *info)
+{
+	return ERR_PTR(-ENXIO);
+}
 static inline int acpi_gpio_count(struct device *dev, const char *con_id)
 {
 	return -ENODEV;