From: Wolfram Sang <wsa@the-dreams.de>
To: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-i2c@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Jukka Laitinen <jukka.laitinen@intel.com>
Subject: Re: [PATCH] i2c: designware: Avoid aborted transfers with fast reacting I2C slaves
Date: Tue, 25 Oct 2016 12:10:14 +0200 [thread overview]
Message-ID: <20161025101014.GI1597@katana> (raw)
In-Reply-To: <20160929130459.11345-1-jarkko.nikula@linux.intel.com>
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On Thu, Sep 29, 2016 at 04:04:59PM +0300, Jarkko Nikula wrote:
> I2C DesignWare may abort transfer with arbitration lost if I2C slave pulls
> SDA down quickly after falling edge of SCL. Reason for this is unknown but
> after trial and error it was found this can be avoided by enabling non-zero
> SDA RX hold time for the receiver.
>
> By the specification SDA RX hold time extends incoming SDA low to high
> transition by n * ic_clk cycles but only when SCL is high. However it
> seems to help avoid above faulty arbitration lost error.
>
> Bits 23:16 in IC_SDA_HOLD register define the SDA RX hold time for the
> receiver. Be conservative and enable 1 ic_clk cycle long hold time in
> case boot firmware hasn't set it up.
>
> Reported-by: Jukka Laitinen <jukka.laitinen@intel.com>
> Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Applied to for-current, thanks!
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prev parent reply other threads:[~2016-10-25 10:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 13:04 [PATCH] i2c: designware: Avoid aborted transfers with fast reacting I2C slaves Jarkko Nikula
2016-09-30 7:05 ` Jukka Laitinen
2016-10-25 10:10 ` Wolfram Sang [this message]
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