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Date: Fri, 5 Mar 2010 11:59:18 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH 1/4] gpiolib: Introduce chip addition/removal notifier
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Cc: David Brownell <dbrownell@users.sourceforge.net>,
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	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
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On Tue, 9 Feb 2010 10:16:44 -0700
Grant Likely <grant.likely@secretlab.ca> wrote:

> On Fri, Feb 5, 2010 at 1:32 PM, Anton Vorontsov
> <avorontsov@ru.mvista.com> wrote:
> > Some platforms (e.g. OpenFirmware) want to know when a particular chip
> > added or removed, so that the platforms could add their specifics for
> > non-platform devices, like I2C or SPI GPIO chips.
> >
> > This patch implements the notifier for chip addition and removal events.
> >
> > Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
> > ---
> > drivers/gpio/gpiolib.c   |  14 ++++++++++++++
> > include/asm-generic/gpio.h |  8 ++++++++
> > 2 files changed, 22 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index 350842a..375c03a 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -9,6 +9,7 @@
> > #include <linux/seq_file.h>
> > #include <linux/gpio.h>
> > #include <linux/idr.h>
> > +#include <linux/notifier.h>
> >
> >
> > /* Optional implementation infrastructure for GPIO interfaces.
> > @@ -1029,6 +1030,9 @@ static inline void gpiochip_unexport(struct gpio_chip *chip)
> >
> > #endif /* CONFIG_GPIO_SYSFS */
> >
> > +BLOCKING_NOTIFIER_HEAD(gpio_notifier);
> > +EXPORT_SYMBOL_GPL(gpio_notifier);
> > +
> > /**
> > * gpiochip_add() - register a gpio_chip
> > * @chip: the chip to register, with chip->base initialized
> > @@ -1103,6 +1107,9 @@ fail:
> >        pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n",
> >            chip->base, chip->base + chip->ngpio - 1,
> >            chip->label ? : "generic");
> > +    else
> > +        blocking_notifier_call_chain(&gpio_notifier,
> > +                      GPIO_NOTIFY_CHIP_ADDED, chip);
> 
> Rather than doing an else block which will need to be reworked if/when
> any additional code is added to the bottom of this routine, please
> rework the if() block to bail on failure instead of implicitly falling
> through to the return statement.

This still hasn't happened.

> Otherwise, this patch looks okay to me, so you can go ahead and add my:
> 
> Acked-by: Grant Likely <grant.likely@secretlab.ca>
> 

I'll merge it anyway and will ask you guys to keep track of this issue,
thanks.