[PATCH] dt: add helper function to read u8 & u16 variables & arrays
From: Viresh Kumar
Date: Mon Nov 19 2012 - 23:45:16 EST
This adds following helper routines:
- of_property_read_u8_array()
- of_property_read_u16_array()
- of_property_read_u8()
- of_property_read_u16()
This expects arrays from DT to be passed as:
- u8 array:
property = /bits/ 8 <0x50 0x60 0x70>;
- u16 array:
property = /bits/ 16 <0x5000 0x6000 0x7000>;
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
V2->V3:
- Expect u8 & u16 arrays to be passed using: /bits/ 8 or 16
- remove common macro, as not much common now :(
- Tested on ARM platform.
drivers/of/base.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of.h | 30 +++++++++++++++++++++
2 files changed, 107 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index af3b22a..f564e31 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -671,12 +671,89 @@ struct device_node *of_find_node_by_phandle(phandle handle)
EXPORT_SYMBOL(of_find_node_by_phandle);
/**
+ * 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.
+ * @sz: number of array elements to read
+ *
+ * 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.
+ *
+ * dts entry of array should be like:
+ * property = /bits/ 8 <0x50 0x60 0x70>;
+ *
+ * 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)
+{
+ struct property *prop = of_find_property(np, propname, NULL);
+ const u8 *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++ = *val++;
+ return 0;
+}
+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.
+ * @sz: number of array elements to read
+ *
+ * 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.
+ *
+ * dts entry of array should be like:
+ * property = /bits/ 16 <0x5000 0x6000 0x7000>;
+ *
+ * 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)
+{
+ struct property *prop = of_find_property(np, propname, NULL);
+ const __be16 *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++ = be16_to_cpup(val++);
+ return 0;
+}
+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.
*
* @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.
+ * @sz: number of array elements to read
*
* Search for a property in a device node and read 32-bit value(s) from
* it. Returns 0 on success, -EINVAL if the property does not exist,
diff --git a/include/linux/of.h b/include/linux/of.h
index b4e50d5..bfdc130 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,
@@ -364,6 +368,18 @@ 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)
@@ -470,6 +486,20 @@ 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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