Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1314757

Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional

Show all headers | View raw

Hi,

> On Thu, Jan 21, 2016 at 12:33:11PM +0100, Lothar Waßmann wrote:
> > > 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.
> 
> > It won't. That's the whole purpose of this patch.
> > I'm afraid, I don't quite understand what you want to say...
> 
> Your commit message (quoted above) claims that without this patch if no
> interrupt is supplied then the unsupplied interrupt will somehow be left
> screaming and make the system unusable.  This doesn't make sense, if
> there is no interrupt there is nothing to scream.
> 
"Otherwise" meant the case where the IRQ is specified in DT as is
currently required to get the driver loaded at all.

> > Without this patch there will be a constantly active interrupt, which
> > will stall the system because the nNMI interrupt (on the EXTINTn pin) is
> > level triggered.
> > Since the polarity of the interrupt input is fixed, there is no way to
> > use it in our HW.
> 
> So, contrary to what you've been saying, the interrupt is actually
> connected (and worse, connected to a NMI) but apparently not described
> in DT.  Why is it sensible to make the driver poll (which will affect
> all systems using this device, even those that don't care) and not just
> describe the interrupt in DT so it can be handled promptly in the normal
> fashion?  Presumably this will run into serious problems if the
> interrupt actually fires at runtime since the NMI will scream, it's not
> clear to me how the poll will manage to run successfully in that case.
> 
Currently the driver won't even load without an IRQ specified in DT.
My patch makes it possible to use the driver without requiring an IRQ!


Lothar Waßmann

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

PATCH [0/2] ARM: dts: am33xx: add support for Ka-Ro electronics TX48-7020 module Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-20 13:40 +0100
  [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-20 13:40 +0100
    Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-20 17:50 +0100
      Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-21 08:10 +0100
        Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-21 11:30 +0100
          Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-21 11:30 +0100
            Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-21 12:20 +0100
              Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-21 12:40 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-21 17:30 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-22 06:50 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-22 17:30 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-25 13:40 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-25 13:50 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Lothar Waßmann <LW@KARO-electronics.de> - 2016-01-25 14:00 +0100
                Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Mark Brown <broonie@kernel.org> - 2016-01-25 15:00 +0100
    Re: [PATCH 1/2] regulator: ltc3589: make IRQ optional Grygorii Strashko <grygorii.strashko@ti.com> - 2016-01-20 18:40 +0100

csiph-web