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Re: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg xfer

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  Re: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg xfer Shubhrajyoti Datta <shubhrajyoti.datta@gmail.com> - 2015-08-05 12:50 +0200
    Re: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg  xfer Vaibhav Hiremath <vaibhav.hiremath@linaro.org> - 2015-08-05 14:50 +0200

#1200641 — Re: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg xfer

hi ,
On Tue, Jul 21, 2015 at 6:11 PM, Vaibhav Hiremath
<vaibhav.hiremath@linaro.org> wrote:
> From: Yi Zhang <yizhang@marvell.com>
>
> Enable i2c module/unit before transmission and disable when it
> finishes.
>
> why?
> It's because the i2c bus may be disturbed if the slave device,
> typically a touch, powers on.

Why should that be an issue?
Is it an errata.

In which mode it is an issue slave / master or both?

>
> As we do not want to break slave mode support, this patch introduces
> DT property to control disable of the I2C module after xfer in master
> mode of operation.
>
> i2c-disable-after-xfer : If set, driver will disable I2C module after
> msg xfer
>
> Signed-off-by: Yi Zhang <yizhang@marvell.com>
> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
> ---
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#1200701 — Re: [PATCH-v5 2/5] i2c: pxa: enable/disable i2c module across msg xfer

On Wednesday 05 August 2015 04:16 PM, Shubhrajyoti Datta wrote:
> hi ,
> On Tue, Jul 21, 2015 at 6:11 PM, Vaibhav Hiremath
> <vaibhav.hiremath@linaro.org> wrote:
>> From: Yi Zhang <yizhang@marvell.com>
>>
>> Enable i2c module/unit before transmission and disable when it
>> finishes.
>>
>> why?
>> It's because the i2c bus may be disturbed if the slave device,
>> typically a touch, powers on.
>
> Why should that be an issue?
> Is it an errata.
>

Not I am aware of.

> In which mode it is an issue slave / master or both?
>

since it talks about touch, I expect it to be master mode.

Thanks,
Vaibhav
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