[PATCH] clocksource/drivers/time-armada-370-xp: Fix the clock reference

[PATCH] clocksource/drivers/time-armada-370-xp: Fix the clock reference

[Gregory CLEMENT]

While converting the init function to return an error, the wrong clock
was get. This lead to wrong clock rate and slow down the kernel. For
example, before the patch a typical boot was around 15s after it was 1
minute slower.

Fixes: 12549e27c63c ("clocksource/drivers/time-armada-370-xp: Convert init function to return error")

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
 drivers/clocksource/time-armada-370-xp.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index 719b478d136e..3c39e6f45971 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -338,7 +338,6 @@ static int __init armada_xp_timer_init(struct device_node *np)
 	struct clk *clk = of_clk_get_by_name(np, "fixed");
 	int ret;
 
-	clk = of_clk_get(np, 0);
 	if (IS_ERR(clk)) {
 		pr_err("Failed to get clock");
 		return PTR_ERR(clk);
-- 
2.8.1

Re: [PATCH] clocksource/drivers/time-armada-370-xp: Fix the clock reference

[Thomas Petazzoni]

Hello,

On Wed, 10 Aug 2016 10:09:08 +0200, Gregory CLEMENT wrote:
> While converting the init function to return an error, the wrong clock
> was get. This lead to wrong clock rate and slow down the kernel. For
> example, before the patch a typical boot was around 15s after it was 1
> minute slower.
> 
> Fixes: 12549e27c63c ("clocksource/drivers/time-armada-370-xp: Convert init function to return error")
> 
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
>  drivers/clocksource/time-armada-370-xp.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
> index 719b478d136e..3c39e6f45971 100644
> --- a/drivers/clocksource/time-armada-370-xp.c
> +++ b/drivers/clocksource/time-armada-370-xp.c
> @@ -338,7 +338,6 @@ static int __init armada_xp_timer_init(struct device_node *np)
>  	struct clk *clk = of_clk_get_by_name(np, "fixed");
>  	int ret;
>  
> -	clk = of_clk_get(np, 0);

I think to avoid this mistake, we should rewrite the code as:

	struct *clk;
	int ret;

	clk = of_clk_get_by_name(np, "fixed");
	if (IS_ERR(clk)) {
		...
	

Indeed, I find confusing a block that starts with error checking, and
it's probably what lead to this of_clk_get() being added here.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH] clocksource/drivers/time-armada-370-xp: Fix the clock reference

[Gregory CLEMENT]

Hi Thomas,
 
 On mer., août 10 2016, Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote:

> Hello,
>
> On Wed, 10 Aug 2016 10:09:08 +0200, Gregory CLEMENT wrote:
>> While converting the init function to return an error, the wrong clock
>> was get. This lead to wrong clock rate and slow down the kernel. For
>> example, before the patch a typical boot was around 15s after it was 1
>> minute slower.
>> 
>> Fixes: 12549e27c63c ("clocksource/drivers/time-armada-370-xp: Convert init function to return error")
>> 
>> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
>> ---
>>  drivers/clocksource/time-armada-370-xp.c | 1 -
>>  1 file changed, 1 deletion(-)
>> 
>> diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
>> index 719b478d136e..3c39e6f45971 100644
>> --- a/drivers/clocksource/time-armada-370-xp.c
>> +++ b/drivers/clocksource/time-armada-370-xp.c
>> @@ -338,7 +338,6 @@ static int __init armada_xp_timer_init(struct device_node *np)
>>  	struct clk *clk = of_clk_get_by_name(np, "fixed");
>>  	int ret;
>>  
>> -	clk = of_clk_get(np, 0);
>
> I think to avoid this mistake, we should rewrite the code as:
>
> 	struct *clk;
> 	int ret;
>
> 	clk = of_clk_get_by_name(np, "fixed");
> 	if (IS_ERR(clk)) {
> 		...
> 	
>

OK I can do it. it will be alos more coherent with the other _init
function.

Gregory

> Indeed, I find confusing a block that starts with error checking, and
> it's probably what lead to this of_clk_get() being added here.
>
> Thomas
> -- 
> Thomas Petazzoni, CTO, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com