linux-kernel - Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the zonda_pll_adjust_l

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Message-ID: <87876873-1aa7-4435-90c1-02bc2e8d7316@quicinc.com>
Date: Fri, 30 Aug 2024 11:03:14 +0530
From: Satya Priya Kakitapalli <quic_skakitap@...cinc.com>
To: Bjorn Andersson <andersson@...nel.org>
CC: Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd
	<sboyd@...nel.org>, <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>,
        Vladimir Zapolskiy
	<vladimir.zapolskiy@...aro.org>
Subject: Re: [PATCH V2] clk: qcom: clk-alpha-pll: Simplify the
 zonda_pll_adjust_l_val()


On 8/16/2024 3:00 AM, Bjorn Andersson wrote:
> On Wed, Aug 14, 2024 at 03:50:05PM GMT, Satya Priya Kakitapalli wrote:
>> In zonda_pll_adjust_l_val() replace the divide operator with comparison
>> operator since comparisons are faster than divisions. Also, simplify the
>> logic and remove the unnecessary 'quotient' local variable.
>>
>> 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>
>> Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>
>> ---
>> Changes in V2:
>>   - Simplify the logic and remove unnecessary quotient variable.
>>   - Remove Fixes tag as this is just a simplification.
>>
>>   drivers/clk/qcom/clk-alpha-pll.c | 9 +++------
>>   1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
>> index 2f620ccb41cb..4ce3347beb39 100644
>> --- a/drivers/clk/qcom/clk-alpha-pll.c
>> +++ b/drivers/clk/qcom/clk-alpha-pll.c
>> @@ -2120,14 +2120,11 @@ static void clk_zonda_pll_disable(struct clk_hw *hw)
>>   
>>   static void zonda_pll_adjust_l_val(unsigned long rate, unsigned long prate, u32 *l)
>>   {
>> -	u64 remainder, quotient;
>> +	u64 remainder;
>>   
>> -	quotient = rate;
>> -	remainder = do_div(quotient, prate);
>> -	*l = quotient;
>> +	remainder = do_div(rate, prate);
> This does not compile on arm32 target.


Could you please confirm if it is because of the do_div? I see the 
do_div() API is used at multiple places in the same driver already.


> Regards,
> Bjorn
>
>>   
>> -	if ((remainder * 2) / prate)
>> -		*l = *l + 1;
>> +	*l = rate + (u32)(remainder * 2 >= prate);
>>   }
>>   
>>   static int clk_zonda_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>> -- 
>> 2.25.1
>>