Re: [PATCH Resend V2] dt: add helper function to read u8 & u16 variables & arrays

On 10/25/2012 11:20 PM, Viresh Kumar wrote:

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

V1->V2:

• Use typeof() in of_property_read_array() macro instead of passing type to it

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 af3b22a..039e178 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) \

• 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++ = (typeof(*_out))be32_to_cpup(_val++);		\
  

This will not work. You are incrementing _out by 1, 2, or 4 bytes, but _val is always incremented by 4 bytes.

According to the dtc commit adding this feature, the values are packed:

With this patch the following property assignment:

property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;

is equivalent to:

property = <0x12345678 0x0000ffff>;

• 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.

Missing sz

• • 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);

+} +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.

Ditto.

• • 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);

+} +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);

} 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)