linux-kernel - Re: [PATCH 1/2] ACPI: reintroduce acpi_device

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Message-Id: <200906301711.34074.bjorn.helgaas@hp.com>
Date:	Tue, 30 Jun 2009 17:11:32 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	David Härdeman <david@...deman.nu>,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	linux-input@...r.kernel.org, jbarnes@...tuousgeek.org,
	Len Brown <lenb@...nel.org>
Subject: Re: [PATCH 1/2] ACPI: reintroduce acpi_device_ops .shutdown method

On Tuesday 30 June 2009 3:10:47 pm Andrew Morton wrote:
> On Sat, 27 Jun 2009 07:18:31 +0200
> David H__rdeman <david@...deman.nu> wrote:
> 
> > This reintroduces the .shutdown method which is used by the
> > winbond-cir driver. A normal revert wasn't possible since there
> > had been other changes to include/acpi/acpi_bus.h since.
> > 
> > Signed-off-by: David H__rdeman <david@...deman.nu>
> > ---
> >  drivers/acpi/scan.c     |   12 ++++++++++++
> >  include/acpi/acpi_bus.h |    2 ++
> >  2 files changed, 14 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > index 781435d..c94ab13 100644
> > --- a/drivers/acpi/scan.c
> > +++ b/drivers/acpi/scan.c
> > @@ -464,10 +464,22 @@ static int acpi_device_remove(struct device * dev)
> >  	return 0;
> >  }
> >  
> > +static void acpi_device_shutdown(struct device *dev)
> > +{
> > +	struct acpi_device *acpi_dev = to_acpi_device(dev);
> > +	struct acpi_driver *acpi_drv = acpi_dev->driver;
> > +
> > +	if (acpi_drv && acpi_drv->ops.shutdown)
> > +		acpi_drv->ops.shutdown(acpi_dev);
> > +
> > +	return ;
> > +}
> > +
> >  struct bus_type acpi_bus_type = {
> >  	.name		= "acpi",
> >  	.suspend	= acpi_device_suspend,
> >  	.resume		= acpi_device_resume,
> > +	.shutdown	= acpi_device_shutdown,
> >  	.match		= acpi_bus_match,
> >  	.probe		= acpi_device_probe,
> >  	.remove		= acpi_device_remove,
> > diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> > index c65e4ce..52da89a 100644
> > --- a/include/acpi/acpi_bus.h
> > +++ b/include/acpi/acpi_bus.h
> > @@ -96,6 +96,7 @@ typedef int (*acpi_op_resume) (struct acpi_device * device);
> >  typedef int (*acpi_op_bind) (struct acpi_device * device);
> >  typedef int (*acpi_op_unbind) (struct acpi_device * device);
> >  typedef void (*acpi_op_notify) (struct acpi_device * device, u32 event);
> > +typedef int (*acpi_op_shutdown) (struct acpi_device * device);
> >  
> >  struct acpi_bus_ops {
> >  	u32 acpi_op_add:1;
> > @@ -112,6 +113,7 @@ struct acpi_device_ops {
> >  	acpi_op_bind bind;
> >  	acpi_op_unbind unbind;
> >  	acpi_op_notify notify;
> > +	acpi_op_shutdown shutdown;
> >  };
> >  
> >  #define ACPI_DRIVER_ALL_NOTIFY_EVENTS	0x1	/* system AND device events */
> 
> Len, Bjorn: is this OK?  Or is there some other mechanism which the
> driver should have used?

I'm on vacation and don't have time to read the new winbond driver
right now, but maybe it could be changed so that wbcir_shutdown()
is an internal function called by wbcir_suspend() (as it is already)
and wbcir_remove().

I hate to re-introduce .shutdown when it's only used by a single
driver.  That makes me think either we have a bunch of drivers that
are buggy because they *should* have .shutdown methods but don't,
or the single user of .shutdown doesn't have a real dependency on it.

The winbond driver does not use any ACPI-specific functionality, so
it might be simpler to write it as a PNP driver (which would depend
on PNPACPI, of course).

Nice looking driver, by the way.  Even from a cursory glance it's
obvious that you've taken a lot of care with it.

Bjorn
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