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authorTony Prisk <linux@prisktech.co.nz>2013-03-23 17:02:15 +1300
committerTony Prisk <linux@prisktech.co.nz>2013-04-04 17:58:59 +1300
commit3daf37260e965aa4bb060db99c2ed10b28109e04 (patch)
treeea9a0908cf24622b29d21d16e30f995afe17a58a /drivers/of
parent8bb9660418e05bb1845ac1a2428444d78e322cc7 (diff)
of: Add support for reading a u32 from a multi-value property.
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>
Diffstat (limited to 'drivers/of')
-rw-r--r--drivers/of/base.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 321d3ef0500..f6c89ed38db 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -746,6 +746,39 @@ 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.
*
* @np: device node from which the property value is to be read.