From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: Lucas De Marchi <lucas.demarchi@intel.com>, linux-i2c@vger.kernel.org
Cc: christian.ruppert@alitech.com, linux-kernel@vger.kernel.org,
mika.westerberg@linux.intel.com,
"José Roberto de Souza" <jose.souza@intel.com>
Subject: Re: [PATCH v3 3/3] i2c: designware: do not disable adapter after transfer
Date: Tue, 16 Aug 2016 17:00:20 +0300 [thread overview]
Message-ID: <fb003fe4-2f85-6c37-6af5-b9ad7e0c06ab@linux.intel.com> (raw)
In-Reply-To: <1469743424-2480-4-git-send-email-lucas.demarchi@intel.com>
Hi, + Wolfram
On 07/29/2016 01:03 AM, Lucas De Marchi wrote:
> Disabling the adapter after each transfer adds additional delays
> for each I2C transfer. Even if we don't wait for it to be disabled
> anymore, on next transfer we will need to if we have several transfers
> in a row.
>
> Now during the transfer init we check if IC_TAR can be changed
> dynamically, the status register for no activity and TX buffer being
> empty. In this case we don't need to disable it
>
> When a transfer fails the adapter will still be disabled - this is a
> conservative approach. When transfers succeed, the adapter is left
> enabled and it's configured so to disable interrupts.
>
> Alternating register reads on 2 slaves:
> perf stat -r4 chrt -f 10 ./i2c-test /dev/i2c-1 25000 0x40 0x6 0x1e 0x00
>
> Before:
> 8.638705161 seconds time elapsed ( +- 5.90% )
> After:
> 7.516821591 seconds time elapsed ( +- 0.11% )
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 55 +++++++++++++++++++++-----------
> 1 file changed, 37 insertions(+), 18 deletions(-)
>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
next prev parent reply other threads:[~2016-08-16 14:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-28 22:03 [PATCH v3 0/3] i2c: designware: improve performance for transfers Lucas De Marchi
2016-07-28 22:03 ` [PATCH v3 1/3] i2c: designware: wait for disable/enable only if necessary Lucas De Marchi
2016-08-16 13:59 ` Jarkko Nikula
2016-07-28 22:03 ` [PATCH v3 2/3] i2c: designware: detect when dynamic tar update is possible Lucas De Marchi
2016-08-16 14:00 ` Jarkko Nikula
2016-08-16 14:07 ` De Marchi, Lucas
2016-08-17 8:05 ` Jarkko Nikula
2016-08-17 12:48 ` De Marchi, Lucas
2016-07-28 22:03 ` [PATCH v3 3/3] i2c: designware: do not disable adapter after transfer Lucas De Marchi
2016-08-16 14:00 ` Jarkko Nikula [this message]
2016-08-12 14:59 ` [PATCH v3 0/3] i2c: designware: improve performance for transfers Christian Ruppert
2016-08-15 12:34 ` De Marchi, Lucas
2016-08-16 12:14 ` Wolfram Sang
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