From: Jan Glauber <jan.glauber@caviumnetworks.com> To: Wolfram Sang <wsa@the-dreams.de> Cc: <linux-kernel@vger.kernel.org>, <linux-i2c@vger.kernel.org>, David Daney <ddaney@caviumnetworks.com> Subject: Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values Date: Thu, 31 Mar 2016 12:13:19 +0200 [thread overview] Message-ID: <20160331101319.GA31112@hardcore> (raw) In-Reply-To: <20160323195517.GE19849@katana> 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 > >
WARNING: multiple messages have this Message-ID (diff)
From: Jan Glauber <jan.glauber@caviumnetworks.com> To: Wolfram Sang <wsa@the-dreams.de> Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, David Daney <ddaney@caviumnetworks.com> Subject: Re: [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values Date: Thu, 31 Mar 2016 12:13:19 +0200 [thread overview] Message-ID: <20160331101319.GA31112@hardcore> (raw) In-Reply-To: <20160323195517.GE19849@katana> 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 > >
next prev parent reply other threads:[~2016-03-31 10:13 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-03-18 8:46 [PATCH v4 00/14] i2c-octeon and i2c-thunderx drivers Jan Glauber 2016-03-18 8:46 ` [PATCH v4 01/14] i2c-octeon: Cleanup i2c-octeon driver Jan Glauber 2016-03-23 19:51 ` Wolfram Sang 2016-03-18 8:46 ` [PATCH v4 02/14] i2c-octeon: Cleanup resource allocation code Jan Glauber 2016-03-23 19:52 ` Wolfram Sang 2016-03-18 8:46 ` [PATCH v4 03/14] i2c-octeon: Change adapter timeout and retry default values Jan Glauber 2016-03-23 19:55 ` Wolfram Sang 2016-03-31 10:13 ` Jan Glauber [this message] 2016-03-31 10:13 ` Jan Glauber 2016-03-18 8:46 ` [PATCH v4 04/14] i2c-octeon: Support I2C_M_RECV_LEN Jan Glauber 2016-03-23 19:52 ` Wolfram Sang 2016-03-18 8:46 ` [PATCH v4 05/14] i2c-octeon: Enable high-level controller and improve on bus contention Jan Glauber 2016-03-23 20:32 ` Wolfram Sang 2016-03-31 10:24 ` Jan Glauber 2016-03-31 10:24 ` Jan Glauber 2016-03-18 8:46 ` [PATCH v4 06/14] dt-bindings: i2c: Add Octeon cn78xx TWSI Jan Glauber 2016-03-18 8:46 ` [PATCH v4 07/14] i2c-octeon: Add support for cn78xx chips Jan Glauber 2016-03-18 8:46 ` [PATCH v4 08/14] i2c-octeon: Flush TWSI writes with readback Jan Glauber 2016-03-18 8:46 ` [PATCH v4 09/14] i2c-octeon: Faster operation when IFLG signals late Jan Glauber 2016-03-18 8:46 ` [PATCH v4 10/14] i2c-octeon: Add workaround for broken irqs on CN3860 Jan Glauber 2016-03-18 8:46 ` [PATCH v4 11/14] i2c-octeon: Rename driver to prepare for split Jan Glauber 2016-03-18 17:11 ` David Daney 2016-03-18 17:11 ` David Daney 2016-03-18 8:46 ` [PATCH v4 12/14] i2c-octeon: Split the driver into two parts Jan Glauber 2016-03-18 8:46 ` [PATCH v4 13/14] i2c-thunderx: Add i2c driver for ThunderX SOC Jan Glauber 2016-03-18 8:46 ` [PATCH v4 14/14] i2c-thunderx: Add smbus alert support Jan Glauber
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