linux-kernel - Re: [PATCH] i2c-omap: always send stop after nack

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Message-ID: <20130716090300.GG8880@arwen.pp.htv.fi>
Date:	Tue, 16 Jul 2013 12:03:14 +0300
From:	Felipe Balbi <balbi@...com>
To:	Hein Tibosch <hein_tibosch@...oo.es>
CC:	Tony Lindgren <tony@...mide.com>,
	linux-i2c <linux-i2c@...r.kernel.org>,
	linux-omap <linux-omap@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] i2c-omap: always send stop after nack

Hi,

On Tue, Jul 16, 2013 at 04:19:35PM +0800, Hein Tibosch wrote:
> Hi Vikram,
> 
> On a OMAP4460, i2c-bus-3:
> 
> A driver (lm75) is causing many 'timeout waiting for bus ready' errors.
> SDA remains high (as it should), but SCL remains low after a NACK.
> The bus becomes _unusable for other clients_.
> 
> While probing, "lm75" writes a command, followed by a read + stop,
> but the write command is NACK'd. The chip does accept other writes/reads,
> it just refuses to ack invalid commands.
> 
> Can you tell me if the patch below would make any sense? Or is it the
> responsibility of the client to reset the i2c_smbus?

patch below breaks repeated start.

-- 
balbi

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