From be193249b4178158c0f697cb452b2bbf0cb16361 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Nov 2012 10:15:19 +0530 Subject: [PATCH] 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: Viresh Kumar Reviewed-by: Stephen Warren Signed-off-by: Rob Herring --- 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 af3b22ac7627..f564e3107b3e 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -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, diff --git a/include/linux/of.h b/include/linux/of.h index 857dde984a6e..ab1af0e14659 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) -- 2.20.1