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Commit be193249 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rob Herring
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dt: add helper function to read u8 & u16 variables & arrays 



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: default avatarViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
parent 9846210b

drivers/of/base.c

+77 −0
Original line number Diff line number Diff line
@@ -670,6 +670,82 @@ 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.
@@ -677,6 +753,7 @@ EXPORT_SYMBOL(of_find_node_by_phandle); 
 * @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,

include/linux/of.h

+30 −0
Original line number Diff line number Diff line
@@ -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)