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
Date: Fri, 20 Dec 2013 09:52:22 +0500 [thread overview]
Message-ID: <20131220045216.GA3853@gmail.com> (raw)
In-Reply-To: <52B405E9.2020304@linutronix.de>
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
next prev parent reply other threads:[~2013-12-20 4:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-19 15:28 am335x: IIO/ADC fixes if used together with TSC, v2 Sebastian Andrzej Siewior
2013-12-19 15:28 ` [PATCH 1/5] iio: ti_am335x_adc: Adjust the closing bracket in tiadc_read_raw() Sebastian Andrzej Siewior
2013-12-22 16:55 ` Jonathan Cameron
2014-01-06 9:36 ` Lee Jones
2013-12-19 15:28 ` [PATCH 2/5] mfd: ti_am335x_tscadc: Make am335x_tsc_se_update() local Sebastian Andrzej Siewior
2013-12-19 17:16 ` Lee Jones
2013-12-19 15:28 ` [PATCH 3/5] mfd: ti_am335x_tscadc: Don't read back REG_SE Sebastian Andrzej Siewior
2013-12-22 17:46 ` Jonathan Cameron
2014-01-06 9:35 ` Lee Jones
2014-01-06 18:10 ` Dmitry Torokhov
2013-12-19 15:28 ` [PATCH 4/5] mfd: ti_am335x: Drop am335x_tsc_se_update() from resume path Sebastian Andrzej Siewior
2013-12-22 17:48 ` Jonathan Cameron
2013-12-19 15:28 ` [PATCH 5/5] mfd: input: iio: ti_amm335x: Rework TSC/ADC synchronization Sebastian Andrzej Siewior
2013-12-19 17:18 ` Lee Jones
2013-12-19 18:53 ` Sebastian Andrzej Siewior
2013-12-19 19:01 ` Zubair Lutfullah :
2013-12-20 8:14 ` Sebastian Andrzej Siewior
2013-12-20 3:36 ` Zubair Lutfullah :
2013-12-20 8:55 ` Sebastian Andrzej Siewior
2013-12-20 4:52 ` Zubair Lutfullah : [this message]
2013-12-22 18:03 ` Jonathan Cameron
2014-01-07 8:54 ` am335x: IIO/ADC fixes if used together with TSC, v2 Lee Jones
2014-01-08 8:03 ` Dmitry Torokhov
2014-01-08 8:08 ` Lee Jones
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