On Fri, Aug 30, 2019 at 03:48:27PM +0200, Geert Uytterhoeven wrote:
> div_u64() does a 64-by-32 division, while the divisor max2175.xtal_freq
> is unsigned long, thus 64-bit on 64-bit platforms. Hence the proper
> function to call is div64_ul().
>
> Note that this change does not have any functional impact, as the
> crystal frequency must be much lower than the 32-bit limit anyway.
> On 32-bit platforms, the generated code is the same. But at least on
> arm64, this saves an AND-instruction to truncate xtal_freq to 32-bit.
>
> Signed-off-by: Geert Uytterhoeven
Reviewed-by: Simon Horman
> ---
> drivers/media/i2c/max2175.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/max2175.c b/drivers/media/i2c/max2175.c
> index 19a3ceea3bc20f0f..506a30e69ced45c4 100644
> --- a/drivers/media/i2c/max2175.c
> +++ b/drivers/media/i2c/max2175.c
> @@ -591,8 +591,8 @@ static int max2175_set_lo_freq(struct max2175 *ctx, u32
> lo_freq)
> lo_freq *= lo_mult;
>
> int_desired = lo_freq / ctx->xtal_freq;
> - frac_desired = div_u64((u64)(lo_freq % ctx->xtal_freq) << 20,
> -ctx->xtal_freq);
> + frac_desired = div64_ul((u64)(lo_freq % ctx->xtal_freq) << 20,
> + ctx->xtal_freq);
>
> /* Check CSM is not busy */
> ret = max2175_poll_csm_ready(ctx);
> --
> 2.17.1
>
