diff mbox series

[v2,2/8] clk: renesas: rcar-gen3: Improve arithmetic divisions

Message ID 20190830134515.11925-3-geert+renesas@glider.be
State Mainlined
Commit b5dea62d34042d173ba1d1887c8dd40262423d68
Delegated to: Geert Uytterhoeven
Headers show
Series clk: renesas: rcar-gen2/gen3: Switch to .determine_rate() | expand

Commit Message

Geert Uytterhoeven Aug. 30, 2019, 1:45 p.m. UTC
- Use div64_ul() instead of div_u64() if the divisor is unsigned long,
    to avoid truncation to 32-bit on 64-bit platforms,
  - Use div_u64() for 64-by-32 divisions.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - New.
---
 drivers/clk/renesas/rcar-gen3-cpg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Niklas Söderlund Aug. 30, 2019, 9:57 p.m. UTC | #1
Hi Geert,

Thanks for your work.

On 2019-08-30 15:45:09 +0200, Geert Uytterhoeven wrote:
>   - Use div64_ul() instead of div_u64() if the divisor is unsigned long,
>     to avoid truncation to 32-bit on 64-bit platforms,
>   - Use div_u64() for 64-by-32 divisions.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

> ---
> v2:
>   - New.
> ---
>  drivers/clk/renesas/rcar-gen3-cpg.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
> index 043ab6ed9d550732..3480284a08308134 100644
> --- a/drivers/clk/renesas/rcar-gen3-cpg.c
> +++ b/drivers/clk/renesas/rcar-gen3-cpg.c
> @@ -122,10 +122,10 @@ static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
>  	unsigned int mult;
>  
>  	prate = *parent_rate / zclk->fixed_div;
> -	mult = div_u64(rate * 32ULL, prate);
> +	mult = div64_ul(rate * 32ULL, prate);
>  	mult = clamp(mult, 1U, 32U);
>  
> -	return (u64)prate * mult / 32;
> +	return div_u64((u64)prate * mult, 32);
>  }
>  
>  static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index 043ab6ed9d550732..3480284a08308134 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -122,10 +122,10 @@  static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 	unsigned int mult;
 
 	prate = *parent_rate / zclk->fixed_div;
-	mult = div_u64(rate * 32ULL, prate);
+	mult = div64_ul(rate * 32ULL, prate);
 	mult = clamp(mult, 1U, 32U);
 
-	return (u64)prate * mult / 32;
+	return div_u64((u64)prate * mult, 32);
 }
 
 static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,