linux-kernel - Re: [PATCH] clk: qcom: clk-alpha-pll: Replace divide operator with comparison

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Message-ID: <4d314b61-7483-4ceb-ac72-10dbd7e4522a@linaro.org>
Date: Tue, 13 Aug 2024 23:01:47 +0300
From: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>
To: Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
 Bjorn Andersson <andersson@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
 linux-kernel@...r.kernel.org, Ajit Pandey <quic_ajipan@...cinc.com>,
 Imran Shaik <quic_imrashai@...cinc.com>, Taniya Das <quic_tdas@...cinc.com>,
 Jagadeesh Kona <quic_jkona@...cinc.com>, kernel test robot <lkp@...el.com>,
 Dan Carpenter <dan.carpenter@...aro.org>
Subject: Re: [PATCH] clk: qcom: clk-alpha-pll: Replace divide operator with
 comparison

On 8/13/24 12:40, Satya Priya Kakitapalli wrote:
> In zonda_pll_adjust_l_val() replace the divide operator with comparison
> operator since comparisons are faster than divisions.
> 
> Fixes: f4973130d255 ("clk: qcom: clk-alpha-pll: Update set_rate for Zonda PLL")

Apparently the change is not a fix, therefore I believe the Fixes tag
shall be removed.

> Reported-by: kernel test robot <lkp@...el.com>
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> Closes: https://lore.kernel.org/r/202408110724.8pqbpDiD-lkp@intel.com/
> Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@...cinc.com>
> ---
>   drivers/clk/qcom/clk-alpha-pll.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index 2f620ccb41cb..fd8a82bb3690 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -2126,7 +2126,7 @@ static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32
>   	remainder = do_div(quotient, prate);
>   	*l = quotient;

Since it's not a fix, but a simplification, you may wish to remove
an unnecessary 'quotient' local variable:

remainder = do_div(rate, prate);

>   
> -	if ((remainder * 2) / prate)
> +	if ((remainder * 2) >= prate)
>   		*l = *l + 1;

*l = rate + (u32)(remainder * 2 >= prate);

I hope the assignment above is quite clear...

>   }
>   

With the review comments above implemented, feel free to add to v2

Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>

--
Best wishes,
Vladimir