Driver core: Unified device properties interface for platform firmware

Add a uniform interface by which device drivers can request device
properties from the platform firmware by providing a property name
and the corresponding data type.  The purpose of it is to help to
write portable code that won't depend on any particular platform
firmware interface.

The following general helper functions are added:

device_property_present()
device_property_read_u8()
device_property_read_u16()
device_property_read_u32()
device_property_read_u64()
device_property_read_string()
device_property_read_u8_array()
device_property_read_u16_array()
device_property_read_u32_array()
device_property_read_u64_array()
device_property_read_string_array()

The first one allows the caller to check if the given property is
present.  The next 5 of them allow single-valued properties of
various types to be retrieved in a uniform way.  The remaining 5 are
for reading properties with multiple values (arrays of either numbers
or strings).

The interface covers both ACPI and Device Trees.

This change set includes material from Mika Westerberg and Aaron Lu.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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, 32 insertions, 0 deletions

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index dcdf8738898..76d64d6a903 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -28,6 +28,7 @@
 #include <linux/errno.h>
 #include <linux/ioport.h>	/* for struct resource */
 #include <linux/device.h>
+#include <linux/property.h>
 
 #ifndef _LINUX
 #define _LINUX
@@ -677,6 +678,13 @@ int acpi_dev_get_property_array(struct acpi_device *adev, const char *name,
 int acpi_dev_get_property_reference(struct acpi_device *adev, const char *name,
 				    const char *cells_name, size_t index,
 				    struct acpi_reference_args *args);
+
+int acpi_dev_prop_get(struct acpi_device *adev, const char *propname,
+		      void **valptr);
+int acpi_dev_prop_read_single(struct acpi_device *adev, const char *propname,
+			      enum dev_prop_type proptype, void *val);
+int acpi_dev_prop_read(struct acpi_device *adev, const char *propname,
+		       enum dev_prop_type proptype, void *val, size_t nval);
 #else
 static inline int acpi_dev_get_property(struct acpi_device *adev,
 					const char *name, acpi_object_type type,
@@ -697,6 +705,30 @@ static inline int acpi_dev_get_property_reference(struct acpi_device *adev,
 {
 	return -ENXIO;
 }
+
+static inline int acpi_dev_prop_get(struct acpi_device *adev,
+				    const char *propname,
+				    void **valptr)
+{
+	return -ENXIO;
+}
+
+static inline int acpi_dev_prop_read_single(struct acpi_device *adev,
+					    const char *propname,
+					    enum dev_prop_type proptype,
+					    void *val)
+{
+	return -ENXIO;
+}
+
+static inline int acpi_dev_prop_read(struct acpi_device *adev,
+				     const char *propname,
+				     enum dev_prop_type proptype,
+				     void *val, size_t nval)
+{
+	return -ENXIO;
+}
+
 #endif
 
 #endif	/*_LINUX_ACPI_H*/