[U-Boot] [PATCH v3 06/20] Add print_freq() to display frequencies nicely

[Bin Meng]

On Wed, Apr 29, 2015 at 9:56 PM, Simon Glass <sjg at chromium.org> wrote:
> Add a function similar to print_size() that works for frequencies. It can
> handle from Hz to GHz.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
Tested-by: Bin Meng <bmeng.cn at gmail.com>

> Changes in v3:
> - Only display 2 digits of the fractional part, and round up when needed
>
> Changes in v2:
> - Correct bugs in number output
>
>  include/display_options.h | 11 +++++++++++
>  lib/display_options.c     | 42 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 53 insertions(+)
>
> diff --git a/include/display_options.h b/include/display_options.h
> index 54bd41d..ac44c45 100644
> --- a/include/display_options.h
> +++ b/include/display_options.h
> @@ -23,6 +23,17 @@
>  void print_size(uint64_t size, const char *suffix);
>
>  /**
> + * print_freq() - Print a frequency with a suffix
> + *
> + * Print frequencies as "x.xx GHz", "xxx KHz", etc as needed; allow for
> + * optional trailing string (like "\n")
> + *
> + * @freq:      Frequency to print in Hz
> + * @suffix     String to print after the frequency
> + */
> +void print_freq(uint64_t freq, const char *suffix);
> +
> +/**
>   * print_buffer() - Print data buffer in hex and ascii form
>   *
>   * Data reads are buffered so that each memory address is only read once.
> diff --git a/lib/display_options.c b/lib/display_options.c
> index 3f32bcd..24d8f55 100644
> --- a/lib/display_options.c
> +++ b/lib/display_options.c
> @@ -7,6 +7,7 @@
>
>  #include <config.h>
>  #include <common.h>
> +#include <div64.h>
>  #include <inttypes.h>
>  #include <version.h>
>  #include <linux/ctype.h>
> @@ -22,6 +23,47 @@ int display_options (void)
>         return 0;
>  }
>
> +void print_freq(uint64_t freq, const char *s)
> +{
> +       unsigned long m = 0, n;
> +       uint32_t f;
> +       static const char names[] = {'G', 'M', 'K'};
> +       unsigned long d = 1e9;
> +       char c = 0;
> +       unsigned int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(names); i++, d /= 1000) {
> +               if (freq >= d) {
> +                       c = names[i];
> +                       break;
> +               }
> +       }
> +
> +       if (!c) {
> +               printf("%" PRIu64 " Hz%s", freq, s);
> +               return;
> +       }
> +
> +       f = do_div(freq, d);
> +       n = freq;
> +
> +       /* If there's a remainder, show the first few digits */
> +       if (f) {
> +               m = f;
> +               while (m > 1000)
> +                       m /= 10;
> +               while (m && !(m % 10))
> +                       m /= 10;
> +               if (m >= 100)
> +                       m = (m / 10) + (m % 100 >= 50);
> +       }
> +
> +       printf("%lu", n);
> +       if (m)
> +               printf(".%ld", m);
> +       printf(" %cHz%s", c, s);
> +}
> +
>  void print_size(uint64_t size, const char *s)
>  {
>         unsigned long m = 0, n;
> --

Regards,
Bin