Re: [PATCH v10 05/11] iio: core: add decimal value formatting into 64-bit value

[Rodrigo Alencar]

On 26/04/15 10:51AM, Rodrigo Alencar wrote:
> Create new format types for iio values (IIO_VAL_DECIMAL64_*), which
> defines the representation of fixed decimal point values into a single
> 64-bit number. This new format increases the range of represented values,
> allowing for integer parts greater than 2^32, as bits are not "wasted"
> in the fractional part, which can be seen in IIO_VAL_INT_PLUS_MICRO and
> IIO_VAL_INT_PLUS_NANO. Helper macros are created to compose and decompose
> 64-bit decimals into integer values used in IIO formatting interfaces,
> which creates consistency and avoid error-prone manual assignments when
> using wordpart macros. When doing the parsing, kstrtodec64() is used with
> the scale defined by the specific decimal format type.
> 
> Signed-off-by: Rodrigo Alencar <rodrigo.alencar@xxxxxxxxxx>

...

> --- a/include/linux/iio/types.h
> +++ b/include/linux/iio/types.h
> @@ -7,6 +7,7 @@
>  #ifndef _IIO_TYPES_H_
>  #define _IIO_TYPES_H_
>  
> +#include <linux/wordpart.h>
>  #include <uapi/linux/iio/types.h>
>  
>  enum iio_event_info {
> @@ -34,6 +35,38 @@ enum iio_event_info {
>  #define IIO_VAL_FRACTIONAL_LOG2 11
>  #define IIO_VAL_CHAR 12
>  
> +#define IIO_VAL_DECIMAL64_BASE		100
> +#define IIO_VAL_DECIMAL64_MILLI		(IIO_VAL_DECIMAL64_BASE + 3)
> +#define IIO_VAL_DECIMAL64_MICRO		(IIO_VAL_DECIMAL64_BASE + 6)
> +#define IIO_VAL_DECIMAL64_NANO		(IIO_VAL_DECIMAL64_BASE + 9)
> +#define IIO_VAL_DECIMAL64_PICO		(IIO_VAL_DECIMAL64_BASE + 12)
> +
> +#define iio_val_s64_compose(_val0, _val1)				\
> +	({ (s64)((((u64)(_val1)) << 32) | (u32)(_val0)); })
> +
> +#define iio_val_s64_from_array(_vals)					\
> +	({								\
> +		const int *_arr = (const int *)(_vals);			\
> +		s64 _dec64 = iio_val_s64_compose(_arr[0], _arr[1]);	\
> +									\
> +		_dec64;							\
> +	})
> +
> +#define iio_val_s64_decompose(_dec64, _val0, _val1)			\
> +	do {								\
> +		s64 _tmp64 = (s64)(_dec64);				\
> +									\
> +		*(_val0) = lower_32_bits(_tmp64);			\
> +		*(_val1) = upper_32_bits(_tmp64);			\
> +	} while (0)
> +
> +#define iio_val_s64_array_populate(_dec64, _vals)			\
> +	do {								\
> +		int *_arr = (int *)(_vals);				\
> +									\
> +		iio_val_s64_decompose((_dec64), &_arr[0], &_arr[1]);	\
> +	} while (0)

Hi Jonathan,

Are those macros ok? in terms of where they are declared or whether they
should be static inline functions? any preferences?

> +
>  enum iio_available_type {
>  	IIO_AVAIL_LIST,
>  	IIO_AVAIL_RANGE,
> 
> -- 
> 2.43.0
> 

-- 
Kind regards,

Rodrigo Alencar