linux-kernel - Re: [PATCH 3/13] CLK: TI: DRA7: make return of 0 explicit

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Date:	Mon, 19 May 2014 11:08:44 +0300
From:	Tero Kristo <t-kristo@...com>
To:	Dan Carpenter <dan.carpenter@...cle.com>,
	Julia Lawall <Julia.Lawall@...6.fr>
CC:	Mike Turquette <mturquette@...aro.org>,
	<kernel-janitors@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	J Keerthy <j-keerthy@...com>
Subject: Re: [PATCH 3/13] CLK: TI: DRA7: make return of 0 explicit

On 05/19/2014 10:41 AM, Dan Carpenter wrote:
> This one does feel like a bug in the original code as you mention.  I
> have added the TI devs to the CC list so they can help us.

Yes this is a bug, the dra7_apll_enable() should return some sort of 
error code if the lock fails. EBUSY maybe?

-Tero

>
> regards,
> dan carpenter
>
> On Mon, May 19, 2014 at 06:31:05AM +0200, Julia Lawall wrote:
>> From: Julia Lawall <Julia.Lawall@...6.fr>
>>
>> Delete unnecessary local variable whose value is always 0 and that hides
>> the fact that the result is always 0.
>>
>> Additionally dropped some unneeded braces in an affected if.
>>
>> A simplified version of the semantic patch that fixes this problem is as
>> follows: (http://coccinelle.lip6.fr/)
>>
>> // <smpl>
>> @r exists@
>> local idexpression ret;
>> expression e;
>> position p;
>> @@
>>
>> -ret = 0;
>> ... when != ret = e
>> return
>> - ret
>> + 0
>>    ;
>> // </smpl>
>>
>> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
>>
>> ---
>> Alternatively, is an error code wanted in either of the MAX_APLL_WAIT_TRIES
>> cases?
>>
>>   drivers/clk/ti/apll.c |   13 +++++--------
>>   1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/clk/ti/apll.c b/drivers/clk/ti/apll.c
>> index b986f61..659032a 100644
>> --- a/drivers/clk/ti/apll.c
>> +++ b/drivers/clk/ti/apll.c
>> @@ -37,7 +37,7 @@
>>   static int dra7_apll_enable(struct clk_hw *hw)
>>   {
>>   	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
>> -	int r = 0, i = 0;
>> +	int i = 0;
>>   	struct dpll_data *ad;
>>   	const char *clk_name;
>>   	u8 state = 1;
>> @@ -55,7 +55,7 @@ static int dra7_apll_enable(struct clk_hw *hw)
>>   	v = ti_clk_ll_ops->clk_readl(ad->idlest_reg);
>>
>>   	if ((v & ad->idlest_mask) == state)
>> -		return r;
>> +		return 0;
>>
>>   	v = ti_clk_ll_ops->clk_readl(ad->control_reg);
>>   	v &= ~ad->enable_mask;
>> @@ -74,17 +74,14 @@ static int dra7_apll_enable(struct clk_hw *hw)
>>   		udelay(1);
>>   	}
>>
>> -	if (i == MAX_APLL_WAIT_TRIES) {
>> +	if (i == MAX_APLL_WAIT_TRIES)
>>   		pr_warn("clock: %s failed transition to '%s'\n",
>>   			clk_name, (state) ? "locked" : "bypassed");
>> -	} else {
>> +	else
>>   		pr_debug("clock: %s transition to '%s' in %d loops\n",
>>   			 clk_name, (state) ? "locked" : "bypassed", i);
>>
>> -		r = 0;
>> -	}
>> -
>> -	return r;
>> +	return 0;
>>   }
>>
>>   static void dra7_apll_disable(struct clk_hw *hw)
>>
>> --
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