[PATCH] dt: add helper function to read u8 & u16 variables & arrays

From: Viresh Kumar
Date: Fri Oct 12 2012 - 14:01:38 EST


This adds following helper routines:
- of_property_read_u8_array()
- of_property_read_u16_array()
- of_property_read_u8()
- of_property_read_u16()

First two actually share most of the code with of_property_read_u32_array(), so
the common part is taken out into a macro, which can be used by all three
*_array() routines.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/of/base.c | 73 +++++++++++++++++++++++++++++++++++++++++++-----------
include/linux/of.h | 30 ++++++++++++++++++++++
2 files changed, 89 insertions(+), 14 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 38892a9..446fe7f 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -670,6 +670,64 @@ struct device_node *of_find_node_by_phandle(phandle handle)
}
EXPORT_SYMBOL(of_find_node_by_phandle);

+#define of_property_read_array(_np, _pname, _out, _sz, _type) \
+ struct property *_prop = of_find_property(_np, _pname, NULL); \
+ const __be32 *_val; \
+ \
+ if (!_prop) \
+ return -EINVAL; \
+ if (!_prop->value) \
+ return -ENODATA; \
+ if ((_sz * sizeof(*_out)) > _prop->length) \
+ return -EOVERFLOW; \
+ \
+ _val = _prop->value; \
+ while (_sz--) \
+ *_out++ = (_type)be32_to_cpup(_val++); \
+ return 0;
+
+/**
+ * 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.
+ * @propname: name of the property to be searched.
+ * @out_value: pointer to return value, modified only if return value is 0.
+ *
+ * Search for a property in a device node and read 8-bit value(s) 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 u8 value can be decoded.
+ */
+int of_property_read_u8_array(const struct device_node *np,
+ const char *propname, u8 *out_values, size_t sz)
+{
+ of_property_read_array(np, propname, out_values, sz, u8);
+}
+EXPORT_SYMBOL_GPL(of_property_read_u8_array);
+
+/**
+ * of_property_read_u16_array - Find and read an array of u16 from a property.
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ * @out_value: pointer to return value, modified only if return value is 0.
+ *
+ * Search for a property in a device node and read 16-bit value(s) 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 u16 value can be decoded.
+ */
+int of_property_read_u16_array(const struct device_node *np,
+ const char *propname, u16 *out_values, size_t sz)
+{
+ of_property_read_array(np, propname, out_values, sz, u16);
+}
+EXPORT_SYMBOL_GPL(of_property_read_u16_array);
+
/**
* of_property_read_u32_array - Find and read an array of 32 bit integers
* from a property.
@@ -689,20 +747,7 @@ int of_property_read_u32_array(const struct device_node *np,
const char *propname, u32 *out_values,
size_t sz)
{
- struct property *prop = of_find_property(np, propname, NULL);
- const __be32 *val;
-
- if (!prop)
- return -EINVAL;
- if (!prop->value)
- return -ENODATA;
- if ((sz * sizeof(*out_values)) > prop->length)
- return -EOVERFLOW;
-
- val = prop->value;
- while (sz--)
- *out_values++ = be32_to_cpup(val++);
- return 0;
+ of_property_read_array(np, propname, out_values, sz, u32);
}
EXPORT_SYMBOL_GPL(of_property_read_u32_array);

diff --git a/include/linux/of.h b/include/linux/of.h
index 72843b7..e2d9b40 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -223,6 +223,10 @@ 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_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,
+ const char *propname, u16 *out_values, size_t sz);
extern int of_property_read_u32_array(const struct device_node *np,
const char *propname,
u32 *out_values,
@@ -357,6 +361,18 @@ static inline struct device_node *of_find_compatible_node(
return NULL;
}

+static inline int of_property_read_u8_array(const struct device_node *np,
+ const char *propname, u8 *out_values, size_t sz)
+{
+ return -ENOSYS;
+}
+
+static inline int of_property_read_u16_array(const struct device_node *np,
+ const char *propname, u16 *out_values, size_t sz)
+{
+ return -ENOSYS;
+}
+
static inline int of_property_read_u32_array(const struct device_node *np,
const char *propname,
u32 *out_values, size_t sz)
@@ -463,6 +479,20 @@ static inline bool of_property_read_bool(const struct device_node *np,
return prop ? true : false;
}

+static inline int of_property_read_u8(const struct device_node *np,
+ const char *propname,
+ u8 *out_value)
+{
+ return of_property_read_u8_array(np, propname, out_value, 1);
+}
+
+static inline int of_property_read_u16(const struct device_node *np,
+ const char *propname,
+ u16 *out_value)
+{
+ return of_property_read_u16_array(np, propname, out_value, 1);
+}
+
static inline int of_property_read_u32(const struct device_node *np,
const char *propname,
u32 *out_value)
--
1.7.12.rc2.18.g61b472e

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