On Tue, 9 Feb 2010 10:16:44 -0700
Grant Likely [off-list ref] wrote:

On Fri, Feb 5, 2010 at 1:32 PM, Anton Vorontsov
[off-list ref] wrote:

quoted

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 <redacted>
---
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 <redacted>

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