嵌入式linux/鸿蒙开发板(IMX6ULL）开发（三十一）驱动进化之路：设备树的引入及简明教程（下）

static inline struct device_node *of_find_node_by_path(const char *path);

extern struct device_node *of_find_node_by_name(struct device_node *from,
  const char *name);

extern struct device_node *of_find_node_by_type(struct device_node *from,
  const char *type);

extern struct device_node *of_find_compatible_node(struct device_node *from,
  const char *type, const char *compat);

extern struct device_node *of_find_node_by_phandle(phandle handle);

extern struct device_node *of_get_parent(const struct device_node *node);

of_node_put(node);

extern struct device_node *of_get_next_parent(struct device_node *node);

extern struct device_node *of_get_next_child(const struct device_node *node,
          struct device_node *prev);

struct device_node *of_get_next_available_child(const struct device_node *node,
  struct device_node *prev);

extern struct device_node *of_get_child_by_name(const struct device_node *node,
      const char *name);

extern struct property *of_find_property(const struct device_node *np,
      const char *name,
      int *lenp);

xxx_node {
    xxx_pp_name = “hello”;
};

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
const void *of_get_property(const struct device_node *np, const char *name,
       int *lenp)

* of_property_count_elems_of_size - Count the number of elements in a property
 *
 * @np:  device node from which the property value is to be read.
 * @propname: name of the property to be searched.
 * @elem_size:  size of the individual element
 *
 * Search for a property in a device node and count the number of elements of
 * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
 * property does not exist or its length does not match a multiple of elem_size
 * and -ENODATA if the property does not have a value.
 */
int of_property_count_elems_of_size(const struct device_node *np,
    const char *propname, int elem_size)

return prop->length / elem_size;

xxx_node {
    xxx_pp_name = <0x50000000 1024>  <0x60000000  2048>;
};

static inline int of_property_read_u32(const struct device_node *np,
           const char *propname,
           u32 *out_value);
extern int of_property_read_u64(const struct device_node *np,
    const char *propname, u64 *out_value);

xxx_node {
    name1 = <0x50000000>;
    name2 = <0x50000000  0x60000000>;
};

extern int of_property_read_u32_index(const struct device_node *np,
           const char *propname,
           u32 index, u32 *out_value);

xxx_node {
    name2 = <0x50000000  0x60000000>;
};

int of_property_read_variable_u8_array(const struct device_node *np,
      const char *propname, u8 *out_values,
      size_t sz_min, size_t sz_max);
int of_property_read_variable_u16_array(const struct device_node *np,
      const char *propname, u16 *out_values,
      size_t sz_min, size_t sz_max);
int of_property_read_variable_u32_array(const struct device_node *np,
          const char *propname, u32 *out_values,
          size_t sz_min, size_t sz_max);
int of_property_read_variable_u64_array(const struct device_node *np,
          const char *propname, u64 *out_values,
          size_t sz_min, size_t sz_max);

xxx_node {
    name2 = <0x50000012  0x60000034>;
};

int of_property_read_string(const struct device_node *np, const char *propname,
    const char **out_string);