Re: [PATCH 3/5] mfd: ti_am335x_tscadc: Don't read back REG_SE
From: Dmitry Torokhov
Date: Mon Jan 06 2014 - 13:10:52 EST
On Mon, Jan 06, 2014 at 09:35:25AM +0000, Lee Jones wrote:
> On Thu, 19 Dec 2013, Sebastian Andrzej Siewior wrote:
> > The purpose of reg_se_cache has been defeated. It should avoid the
> > read-back of the register to avoid the latency and the fact that the
> > bits are reset to 0 after the individual conversation took place.
> > The reason why this is required like this to work, is that read-back of
> > the register removes the bits of the ADC so they do not start another
> > conversation after the register is re-written from the TSC side for the
> > update.
> > To avoid the not required read-back I introduce a "set once" variant which
> > does not update the cache mask. After the conversation completes, the
> > bit is removed from the SE register anyway and we don't plan a new
> > conversation "any time soon". The current set function is renamed to
> > set_cache to distinguish the two operations.
> > This is a small preparation for a larger sync-rework.
> > Acked-by: Lee Jones <lee.jones@xxxxxxxxxx>
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> > ---
> > drivers/iio/adc/ti_am335x_adc.c | 4 ++--
> > drivers/input/touchscreen/ti_am335x_tsc.c | 4 ++--
> Just need Dmitry's Ack now.
Well, that has nothing to do with input per se but rather inner workings
of the device. But yes, FWIW:
Acked-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
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