On Sat, Jan 18, 2014 at 6:02 AM, Heiko Stübner <heiko@xxxxxxxxx> wrote: > The need to know the number of array elements in a property is > a common pattern. To prevent duplication of open-coded implementations > add a helper static function that also centralises strict sanity > checking and DTB format details, as well as a set of wrapper functions > for u8, u16, u32 and u64. > > Suggested-by: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx> > --- Looks good. Do you plan to convert some users to use this? Rob > changes since v3: > address more comments from Rob Herring > - export the base function and inline the type-specific wrappers > changes since v2: > address more comments from Mark Rutland > - switch to of_property_count_elems_of_size > - use full_name instead of name in error message > changes since v1: > address comments from Rob Herring and Mark Rutland: > - provide a helper and a set of wrappers for u8-u64 > - get rid of extra len variable, prop->length is enough > - include node name in error message > > Mark, does your Reviewed-by holds for this variant too? > > drivers/of/base.c | 32 ++++++++++++++++++++++ > include/linux/of.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 108 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index f807d0e..21646c0 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -862,6 +862,38 @@ struct device_node *of_find_node_by_phandle(phandle handle) > EXPORT_SYMBOL(of_find_node_by_phandle); > > /** > + * 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 u16 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) > +{ > + struct property *prop = of_find_property(np, propname, NULL); > + > + if (!prop) > + return -EINVAL; > + if (!prop->value) > + return -ENODATA; > + > + if (prop->length % elem_size != 0) { > + pr_err("size of %s in node %s is not a multiple of %d\n", > + propname, np->full_name, elem_size); > + return -EINVAL; > + } > + > + return prop->length / elem_size; > +} > +EXPORT_SYMBOL_GPL(of_property_count_elems_of_size); > + > +/** > * of_find_property_value_of_size > * > * @np: device node from which the property value is to be read. > diff --git a/include/linux/of.h b/include/linux/of.h > index 276c546..293920d 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -250,6 +250,8 @@ 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_count_elems_of_size(const struct device_node *np, > + const char *propname, int elem_size); > extern int of_property_read_u32_index(const struct device_node *np, > const char *propname, > u32 index, u32 *out_value); > @@ -426,6 +428,12 @@ static inline struct device_node *of_find_compatible_node( > return NULL; > } > > +static inline int of_property_count_elems_of_size(const struct device_node *np, > + const char *propname, int elem_size) > +{ > + return -ENOSYS; > +} > + > static inline int of_property_read_u32_index(const struct device_node *np, > const char *propname, u32 index, u32 *out_value) > { > @@ -565,6 +573,74 @@ static inline int of_node_to_nid(struct device_node *device) { return 0; } > #endif > > /** > + * of_property_count_u8_elems - Count the number of u8 elements in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u8 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u8 and -ENODATA if the > + * property does not have a value. > + */ > +static inline int of_property_count_u8_elems(const struct device_node *np, > + const char *propname) > +{ > + return of_property_count_elems_of_size(np, propname, sizeof(u8)); > +} > + > +/** > + * of_property_count_u16_elems - Count the number of u16 elements in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u16 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u16 and -ENODATA if the > + * property does not have a value. > + */ > +static inline int of_property_count_u16_elems(const struct device_node *np, > + const char *propname) > +{ > + return of_property_count_elems_of_size(np, propname, sizeof(u16)); > +} > + > +/** > + * of_property_count_u32_elems - Count the number of u32 elements in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u32 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u32 and -ENODATA if the > + * property does not have a value. > + */ > +static inline int of_property_count_u32_elems(const struct device_node *np, > + const char *propname) > +{ > + return of_property_count_elems_of_size(np, propname, sizeof(u32)); > +} > + > +/** > + * of_property_count_u64_elems - Count the number of u64 elements in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u64 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u64 and -ENODATA if the > + * property does not have a value. > + */ > +static inline int of_property_count_u64_elems(const struct device_node *np, > + const char *propname) > +{ > + return of_property_count_elems_of_size(np, propname, sizeof(u64)); > +} > + > +/** > * of_property_read_bool - Findfrom a property > * @np: device node from which the property value is to be read. > * @propname: name of the property to be searched. > -- > 1.7.10.4 > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html