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of: Add support for reading a u32 from a multi-value property.

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This patch adds an of_property_read_u32_index() function to allow
reading a single indexed u32 value from a property containing multiple
u32 values.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
This commit is contained in:
Tony Prisk 2013-03-23 17:02:15 +13:00
parent 8bb9660418
commit 3daf37260e
2 changed files with 42 additions and 0 deletions
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33
drivers/of/base.c
View File

@ -745,6 +745,39 @@ struct device_node *of_find_node_by_phandle(phandle handle)
}
EXPORT_SYMBOL(of_find_node_by_phandle);
/**
* of_property_read_u32_index - Find and read a u32 from a multi-value property.
*
* @np: device node from which the property value is to be read.
* @propname: name of the property to be searched.
* @index: index of the u32 in the list of values
* @out_value: pointer to return value, modified only if no error.
*
* Search for a property in a device node and read nth 32-bit value from
* it. Returns 0 on success, -EINVAL if the property does not exist,
* -ENODATA if property does not have a value, and -EOVERFLOW if the
* property data isn't large enough.
*
* The out_value is modified only if a valid u32 value can be decoded.
*/
int of_property_read_u32_index(const struct device_node *np,
const char *propname,
u32 index, u32 *out_value)
{
struct property *prop = of_find_property(np, propname, NULL);
if (!prop)
return -EINVAL;
if (!prop->value)
return -ENODATA;
if (((index + 1) * sizeof(*out_value)) > prop->length)
return -EOVERFLOW;
*out_value = be32_to_cpup(((__be32 *)prop->value) + index);
return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_u32_index);
/**
* of_property_read_u8_array - Find and read an array of u8 from a property.
*

9
include/linux/of.h
View File

@ -235,6 +235,9 @@ extern struct device_node *of_find_node_with_property(
extern struct property *of_find_property(const struct device_node *np,
const char *name,
int *lenp);
extern int of_property_read_u32_index(const struct device_node *np,
const char *propname,
u32 index, u32 *out_value);
extern int of_property_read_u8_array(const struct device_node *np,
const char *propname, u8 *out_values, size_t sz);
extern int of_property_read_u16_array(const struct device_node *np,
@ -394,6 +397,12 @@ static inline struct device_node *of_find_compatible_node(
return NULL;
}
static inline int of_property_read_u32_index(const struct device_node *np,
const char *propname, u32 index, u32 *out_value)
{
return -ENOSYS;
}
static inline int of_property_read_u8_array(const struct device_node *np,
const char *propname, u8 *out_values, size_t sz)
{