Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional
From: Mark Brown
Date: Thu Jan 21 2016 - 06:12:23 EST
On Thu, Jan 21, 2016 at 11:26:11AM +0100, Lothar Waßmann wrote:
> > On Thu, Jan 21, 2016 at 08:05:24AM +0100, Lothar Waßmann wrote:
> > > > On Wed, Jan 20, 2016 at 01:29:51PM +0100, Lothar Waßmann wrote:
> > > > > This pin is used as IRQ pin for the LTC3589 PMIC on the Ka-Ro
> > > > > electronics TX48 module. Make the IRQ optional in the driver and use a
> > > > > polling routine instead if no IRQ is specified in DT.
> > > > > Otherwise the driver will continuously generate interrupts and make
> > > > > the system unusable.
> > > > How will the driver generate interrupts if there is no interrupt
> > > > physically present in the system?
> > > It's using timer interrupts to poll the LTC3589 state.
> > I know that is what your patch does, my question is why you say in your
> > commit log that "Otherwise the driver will continuously generate
> > interrupts and make the system unusable".
> Because the interrupt is level triggered and the polarity of the
> EXTINT pin is inverted, the interrupt will be constantly active when
> the IRQ pin of the LTC3589 is inactive.
So, to repeat my original question, how will that generate interrupts if
there is no interrupt physically present in the system?
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