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From: Laxman Dewangan <ldewangan@nvidia.com>
To: "Arnout Vandecappelle (Essensium/Mind)" <arnout@mind.be>,
	Samuel Ortiz <sameo@linux.intel.com>,
	Lee Jones <lee.jones@linaro.org>, Mark Brown <broonie@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: David Brown <davidb@codeaurora.org>
Subject: Re: [PATCH v2] tps65910: Work around silicon erratum SWCZ010
Date: Tue, 26 Aug 2014 15:44:08 +0530	[thread overview]
Message-ID: <53FC5DF0.2040205@nvidia.com> (raw)
In-Reply-To: <1408721456-8101-1-git-send-email-arnout@mind.be>

Because this patch is dropped from Mark's tree, here is opportunity to 
revisit patch.

On Friday 22 August 2014 09:00 PM, Arnout Vandecappelle (Essensium/Mind) 
wrote:
>  From http://www.ti.com/lit/pdf/SWCZ010 :
>
>
> Workaround:
> Repeat I2C access.

> A simpler workaround is to make a dummy transfer just before the first
> access to the tps65910 chip. This can be done unconditionally.
> >id = chip_id;
>   
> +	/* Work around silicon erratum SWCZ010: the tps65910 may miss the
> +	 * first I2C transfer. So issue a dummy transfer before the first
> +	 * real transfer.
> +	 */
> +	i2c_master_send(i2c, "", 1);

I think dummy read is more safe operation than dummy write.
Dummy write can create the write on any register which can damage the 
critical settings or it may be possible that it will be incomplete 
calls. Datasheet has not been explained this clearly.


>   	


  parent reply	other threads:[~2014-08-26 10:14 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-22 12:14 [PATCH] tps65910: Work around silicon erratum SWCZ010 Arnout Vandecappelle (Essensium/Mind)
2014-08-22 13:46 ` Laxman Dewangan
2014-08-22 14:01   ` Arnout Vandecappelle
2014-08-22 15:30 ` [PATCH v2] " Arnout Vandecappelle (Essensium/Mind)
2014-08-22 21:12   ` Mark Brown
2014-08-26  9:25     ` Lee Jones
2014-08-26  9:46       ` Mark Brown
2014-08-26 10:07         ` Arnout Vandecappelle
2014-08-26 10:14   ` Laxman Dewangan [this message]
2014-08-26 16:21     ` Arnout Vandecappelle
2014-08-29  7:31   ` Lee Jones

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