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

[Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 11/19/2012 10:45 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()
> 
> 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 <viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Applied.

Rob

> ---
> V2->V3:
> - Expect u8 & u16 arrays to be passed using: /bits/ 8 or 16
> - remove common macro, as not much common now :(
> - Tested on ARM platform.
> 
>  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 af3b22a..f564e31 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -671,12 +671,89 @@ 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.
>   *
>   * @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 b4e50d5..bfdc130 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)
>