Driver core: Unified interface for firmware node properties

Add new generic routines are provided for retrieving properties from
device description objects in the platform firmware in case there are
no struct device objects for them (either those objects have not been
created yet or they do not exist at all).

The following functions are provided:

fwnode_property_present()
fwnode_property_read_u8()
fwnode_property_read_u16()
fwnode_property_read_u32()
fwnode_property_read_u64()
fwnode_property_read_string()
fwnode_property_read_u8_array()
fwnode_property_read_u16_array()
fwnode_property_read_u32_array()
fwnode_property_read_u64_array()
fwnode_property_read_string_array()

in analogy with the corresponding functions for struct device added
previously.  For all of them, the first argument is a pointer to struct
fwnode_handle (new type) that allows a device description object
(depending on what platform firmware interface is in use) to be
obtained.

Add a new macro device_for_each_child_node() for iterating over the
children of the device description object associated with a given
device and a new function device_get_child_node_count() returning the
number of a given device's child nodes.

The interface covers both ACPI and Device Trees.

Suggested-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index f59cbf860658..a361f43b1974 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -27,6 +27,7 @@
 #define __ACPI_BUS_H__
 
 #include <linux/device.h>
+#include <linux/property.h>
 
 /* TBD: Make dynamic */
 #define ACPI_MAX_HANDLES	10
@@ -348,6 +349,7 @@ struct acpi_device_data {
 struct acpi_device {
 	int device_type;
 	acpi_handle handle;		/* no handle for fixed hardware */
+	struct fwnode_handle fwnode;
 	struct acpi_device *parent;
 	struct list_head children;
 	struct list_head node;
@@ -372,6 +374,21 @@ struct acpi_device {
 	void (*remove)(struct acpi_device *);
 };
 
+static inline bool is_acpi_node(struct fwnode_handle *fwnode)
+{
+	return fwnode && fwnode->type == FWNODE_ACPI;
+}
+
+static inline struct acpi_device *acpi_node(struct fwnode_handle *fwnode)
+{
+	return fwnode ? container_of(fwnode, struct acpi_device, fwnode) : NULL;
+}
+
+static inline struct fwnode_handle *acpi_fwnode_handle(struct acpi_device *adev)
+{
+	return &adev->fwnode;
+}
+
 static inline void *acpi_driver_data(struct acpi_device *d)
 {
 	return d->driver_data;