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

* [PATCH] dt: add helper function to read u8 & u16 variables & arrays
@ 2012-10-12 18:01 Viresh Kumar
  2012-10-15  7:56 ` Shevchenko, Andriy
  2012-10-25  7:03 ` Viresh Kumar
  0 siblings, 2 replies; 12+ messages in thread
From: Viresh Kumar @ 2012-10-12 18:01 UTC (permalink / raw)
  To: rob.herring, grant.likely
  Cc: spear-devel, devicetree-discuss, linux-kernel, andriy.shevchenko,
	Viresh Kumar

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@linaro.org>
---
 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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