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Driver core: Unified device properties interface for platform firmware

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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>
This commit is contained in:
Rafael J. Wysocki
2014-11-04 01:28:56 +01:00
parent ffdcd955c3
commit b31384fa5d
7 changed files with 514 additions and 1 deletions
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12
include/linux/of.h
View File

@@ -23,6 +23,7 @@
#include <linux/spinlock.h>
#include <linux/topology.h>
#include <linux/notifier.h>
#include <linux/property.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
@@ -263,6 +264,10 @@ extern int of_property_read_u32_array(const struct device_node *np,
size_t sz);
extern int of_property_read_u64(const struct device_node *np,
const char *propname, u64 *out_value);
extern int of_property_read_u64_array(const struct device_node *np,
const char *propname,
u64 *out_values,
size_t sz);
extern int of_property_read_string(struct device_node *np,
const char *propname,
@@ -477,6 +482,13 @@ static inline int of_property_read_u32_array(const struct device_node *np,
return -ENOSYS;
}
static inline int of_property_read_u64_array(const struct device_node *np,
const char *propname,
u64 *out_values, size_t sz)
{
return -ENOSYS;
}
static inline int of_property_read_string(struct device_node *np,
const char *propname,
const char **out_string)