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Date: Fri, 20 Dec 2013 09:52:22 +0500
From: "Zubair Lutfullah :" <zubair.lutfullah@gmail.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Zubair Lutfullah:  zubair.lutfullah@gmail.com,
	Lee Jones <lee.jones@linaro.org>,
	Samuel Ortiz <sameo@linux.intel.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Felipe Balbi <balbi@ti.com>, linux-iio@vger.kernel.org,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] mfd: input: iio: ti_amm335x: Rework TSC/ADC
 synchronization
Message-ID: <20131220045216.GA3853@gmail.com>
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 <1387466911-3732-6-git-send-email-bigeasy@linutronix.de>
 <20131219190126.GA5123@gmail.com>
 <52B3FC6C.1070105@linutronix.de>
 <20131220033634.GB2596@gmail.com>
 <52B405E9.2020304@linutronix.de>
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On Fri, Dec 20, 2013 at 09:55:05AM +0100, Sebastian Andrzej Siewior wrote:
> On 12/20/2013 04:36 AM, Zubair Lutfullah : wrote:
> > Indeed, due to the separation of TSC/ADC drivers, getting
> > them both to work simultaneously without fault is tricky.
> 
> The race window which leads to the lockup is (as I believe) when the
> hardware is finishing its work for the TSC (pre interrupt) and the ADC
> parts writes to the SE register. As long as you allow both parts to
> write to the register bad things can happen (as it seems). So it does
> not matter if you have two drivers or one :)
> 
Hmm. That makes sense. At the moment, the ADC/TSC handshake is
when the ADC wants to read samples.

Would it be wiser to have a handshake and wait for whenever ADC/TSC wants
to write to the SE register?

Thanks
Zubair