From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Shinya Kuribayashi <skuribay@pobox.com>
Cc: christian.ruppert@abilis.com, linux-i2c@vger.kernel.org,
wsa@the-dreams.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] i2c-designware: make *CNT values configurable
Date: Mon, 19 Aug 2013 14:36:04 +0300 [thread overview]
Message-ID: <20130819113604.GN4898@intel.com> (raw)
In-Reply-To: <520D8B30.9000602@pobox.com>
On Fri, Aug 16, 2013 at 11:15:12AM +0900, Shinya Kuribayashi wrote:
> >Actually, the I2C specification clearly defines f_SCL;max (and thus
> >implies t_SCL;min), both in the tables and the timing diagrams. Why can
> >we ignore this constraint while having to meet all the others?
>
> If we meet t_r, t_f, t_HIGH, t_LOW (and t_HIGH in this DW case),
> f_SCL;max will be met by itself. And again, all I2C master and
> slave devices in the bus don't care about f_SCL; what they do care
> are t_f, t_r, t_HIGH, t_LOW, and so on. That's why I'm saying
> f_SCL is pointless and has no value for HCNT/LCNT calculations.
One thing that comes to mind regarding the bus speed is that even if we
have all the minimal timing requirements met we still prefer resulting bus
speeds closer to 400kHz than 315.41kHz for the reasons that we get more
data transferred that way, no?
next prev parent reply other threads:[~2013-08-19 11:36 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-08 11:45 [PATCH 1/2] i2c-designware: make *CNT values configurable Mika Westerberg
[not found] ` <1373283927-21677-1-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2013-07-08 11:45 ` [PATCH 2/2] i2c-designware: configure *CNT values from ACPI Mika Westerberg
[not found] ` <1373283927-21677-2-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2013-07-10 13:01 ` Mika Westerberg
2013-07-08 13:42 ` [PATCH 1/2] i2c-designware: make *CNT values configurable Christian Ruppert
[not found] ` <20130708134216.GB6402-7oYq3qWSd+k@public.gmane.org>
2013-07-09 8:44 ` Mika Westerberg
[not found] ` <20130709084402.GF4898-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-07-09 16:19 ` Christian Ruppert
[not found] ` <20130709161927.GC30236-7oYq3qWSd+k@public.gmane.org>
2013-07-10 10:52 ` Mika Westerberg
[not found] ` <20130710105215.GY4898-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-07-10 16:56 ` Christian Ruppert
[not found] ` <20130710165634.GA30693-7oYq3qWSd+k@public.gmane.org>
2013-07-11 7:36 ` Mika Westerberg
2013-07-11 10:13 ` Mika Westerberg
[not found] ` <20130711101330.GP4898-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-07-12 7:56 ` Shinya Kuribayashi
[not found] ` <51DFB6C1.4040001-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2013-07-12 8:51 ` Mika Westerberg
[not found] ` <20130712085140.GY4898-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-07-13 5:36 ` Shinya Kuribayashi
[not found] ` <51E0E76B.1040304-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2013-07-16 11:16 ` Christian Ruppert
[not found] ` <20130716111616.GA25835-7oYq3qWSd+k@public.gmane.org>
2013-07-17 14:39 ` Shinya Kuribayashi
[not found] ` <51E6ACBE.7000509-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2013-07-22 13:17 ` Christian Ruppert
[not found] ` <20130722131706.GA24081-7oYq3qWSd+k@public.gmane.org>
2013-07-24 14:31 ` Shinya Kuribayashi
[not found] ` <51EFE550.1000507-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2013-08-05 9:31 ` Christian Ruppert
[not found] ` <20130805093126.GE20936-7oYq3qWSd+k@public.gmane.org>
2013-08-05 10:02 ` Wolfram Sang
2013-08-12 7:48 ` Christian Ruppert
[not found] ` <20130812074800.GA23792-7oYq3qWSd+k@public.gmane.org>
2013-08-12 11:09 ` Wolfram Sang
2013-08-16 2:15 ` Shinya Kuribayashi
2013-08-19 11:36 ` Mika Westerberg [this message]
[not found] ` <20130819113604.GN4898-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-08-19 12:22 ` Shinya Kuribayashi
2013-08-21 14:39 ` Christian Ruppert
[not found] ` <20130821143915.GA3046-7oYq3qWSd+k@public.gmane.org>
2013-08-24 4:58 ` Shinya Kuribayashi
[not found] ` <52183D87.40703-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2013-08-28 15:34 ` Christian Ruppert
2013-10-08 15:00 ` [PATCH 1/2] i2c designware make SCL and SDA falling time configurable Romain Baeriswyl
2013-10-09 7:55 ` Mika Westerberg
2013-10-10 0:54 ` Ryan Mallon
[not found] ` <5255FAB5.7080803-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-13 11:36 ` Shinya Kuribayashi
[not found] ` <525A85D6.3090608-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2014-01-16 19:43 ` Wolfram Sang
2014-01-20 16:43 ` [PATCH v2 " Romain Baeriswyl
[not found] ` <1390236223-22584-1-git-send-email-romainba-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
2014-03-09 8:20 ` Wolfram Sang
[not found] ` <20130828153429.GB7066-7oYq3qWSd+k@public.gmane.org>
2013-10-08 15:00 ` [PATCH 2/2] i2c designware add support of I2C standard mode Romain Baeriswyl
2013-10-09 7:56 ` Mika Westerberg
[not found] ` <20131009075632.GR3521-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2013-10-13 11:46 ` Shinya Kuribayashi
2014-01-16 19:33 ` Wolfram Sang
2014-01-20 16:45 ` [PATCH v2 " Romain Baeriswyl
[not found] ` <1390236338-21407-1-git-send-email-romainba-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
2014-03-09 8:07 ` Wolfram Sang
2013-08-19 6:39 ` [PATCH 1/2] i2c-designware: make *CNT values configurable Mika Westerberg
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