On Mon, Sep 14, 2015 at 11:47 AM, Kuninori Morimoto
<[email protected]> wrote:
> +static int cs2000_ratio_set(struct i2c_client *client,
> + int ch, u32 rate_in, u32 rate_out)
> +{
> + u64 val;
> + unsigned int i;
> + int ret;
> +
> + if (CH_SIZE_ERR(ch))
> + return -EINVAL;
> +
> + /*
> + * ratio = rate_out / rate_in * 2^20
> + *
> + * To avoid over flow, rate_out is u64
> + * The result should be u32
> + */
> +
> + val = rate_out;
> + val *= (1 << 20);
val <<= 20
Or
val = (u64)rate_out << 20;
> + do_div(val, rate_in);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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