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[PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values

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  [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values Jan Glauber <jglauber@cavium.com> - 2016-03-18 09:50 +0100
    Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry  default values Wolfram Sang <wsa@the-dreams.de> - 2016-03-23 21:00 +0100
      Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry  default values Jan Glauber <jan.glauber@caviumnetworks.com> - 2016-03-31 12:20 +0200

#1360425 — [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values

Convert the adapter timeout to 2 ms instead of a fixed number of
jiffies and set retries to 10.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
 drivers/i2c/busses/i2c-octeon.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 9240037..e616e4c 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -414,7 +414,6 @@ static struct i2c_adapter octeon_i2c_ops = {
 	.owner = THIS_MODULE,
 	.name = "OCTEON adapter",
 	.algo = &octeon_i2c_algo,
-	.timeout = HZ / 50,
 };
 
 /* calculate and set clock divisors */
@@ -541,6 +540,8 @@ static int octeon_i2c_probe(struct platform_device *pdev)
 	octeon_i2c_set_clock(i2c);
 
 	i2c->adap = octeon_i2c_ops;
+	i2c->adap.timeout = msecs_to_jiffies(2);
+	i2c->adap.retries = 10;
 	i2c->adap.dev.parent = &pdev->dev;
 	i2c->adap.dev.of_node = node;
 	i2c_set_adapdata(&i2c->adap, i2c);
-- 
1.9.1

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#1363651 — Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values

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On Fri, Mar 18, 2016 at 09:46:28AM +0100, Jan Glauber wrote:
> Convert the adapter timeout to 2 ms instead of a fixed number of
> jiffies and set retries to 10.

You describe what you change, but not why this is needed. Why 10
retries? And shouldn't that be 20ms seeing the HZ/50 ?

Also, please use "i2c: octeon: " as prefix in the subject.

Thanks,

   Wolfram

> 
> Signed-off-by: Jan Glauber <jglauber@cavium.com>
> ---
>  drivers/i2c/busses/i2c-octeon.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
> index 9240037..e616e4c 100644
> --- a/drivers/i2c/busses/i2c-octeon.c
> +++ b/drivers/i2c/busses/i2c-octeon.c
> @@ -414,7 +414,6 @@ static struct i2c_adapter octeon_i2c_ops = {
>  	.owner = THIS_MODULE,
>  	.name = "OCTEON adapter",
>  	.algo = &octeon_i2c_algo,
> -	.timeout = HZ / 50,
>  };
>  
>  /* calculate and set clock divisors */
> @@ -541,6 +540,8 @@ static int octeon_i2c_probe(struct platform_device *pdev)
>  	octeon_i2c_set_clock(i2c);
>  
>  	i2c->adap = octeon_i2c_ops;
> +	i2c->adap.timeout = msecs_to_jiffies(2);
> +	i2c->adap.retries = 10;
>  	i2c->adap.dev.parent = &pdev->dev;
>  	i2c->adap.dev.of_node = node;
>  	i2c_set_adapdata(&i2c->adap, i2c);
> -- 
> 1.9.1
> 

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#1368139 — Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values

On Wed, Mar 23, 2016 at 08:55:18PM +0100, Wolfram Sang wrote:
> On Fri, Mar 18, 2016 at 09:46:28AM +0100, Jan Glauber wrote:
> > Convert the adapter timeout to 2 ms instead of a fixed number of
> > jiffies and set retries to 10.
> 
> You describe what you change, but not why this is needed. Why 10
> retries? And shouldn't that be 20ms seeing the HZ/50 ?

The timeout value is not changed, i2c-octeon is bound to Octeon SOC
which has CONFIG_HZ=100. I would prefer to use an absolute value for
a timeout that should not change with the value of CONFIG_HZ.

For the retries, I'll change it to 5 which is what many i2c drivers
use. I thought the reason to use a non-zero value for retries might
be obvious, like "retry in case of a failed operation" ?!

With the updated driver I do not see retry attempts, but it might
not hurt the robustness of the driver to benefit from i2c core
retry logic, or am I missing something?

> Also, please use "i2c: octeon: " as prefix in the subject.

OK.

Thanks,
Jan

> Thanks,
> 
>    Wolfram
> 
> > 
> > Signed-off-by: Jan Glauber <jglauber@cavium.com>
> > ---
> >  drivers/i2c/busses/i2c-octeon.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
> > index 9240037..e616e4c 100644
> > --- a/drivers/i2c/busses/i2c-octeon.c
> > +++ b/drivers/i2c/busses/i2c-octeon.c
> > @@ -414,7 +414,6 @@ static struct i2c_adapter octeon_i2c_ops = {
> >  	.owner = THIS_MODULE,
> >  	.name = "OCTEON adapter",
> >  	.algo = &octeon_i2c_algo,
> > -	.timeout = HZ / 50,
> >  };
> >  
> >  /* calculate and set clock divisors */
> > @@ -541,6 +540,8 @@ static int octeon_i2c_probe(struct platform_device *pdev)
> >  	octeon_i2c_set_clock(i2c);
> >  
> >  	i2c->adap = octeon_i2c_ops;
> > +	i2c->adap.timeout = msecs_to_jiffies(2);
> > +	i2c->adap.retries = 10;
> >  	i2c->adap.dev.parent = &pdev->dev;
> >  	i2c->adap.dev.of_node = node;
> >  	i2c_set_adapdata(&i2c->adap, i2c);
> > -- 
> > 1.9.1
> > 

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