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 <avoront...@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);
return status;
}
EXPORT_SYMBOL_GPL(gpiochip_add);
@@ -1119,6 +1126,13 @@ int gpiochip_remove(struct gpio_chip *chip)
int status = 0;
unsigned id;
+ /* Ask external subsystems to release the chip. */
+ status = blocking_notifier_call_chain(&gpio_notifier,
+ GPIO_NOTIFY_CHIP_REMOVE, chip);
+ status = notifier_to_errno(status);
+ if (status)
+ return status;
+
spin_lock_irqsave(&gpio_lock, flags);
for (id = chip->base; id < chip->base + chip->ngpio; id++) {
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 485eeb6..84faae4 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -4,6 +4,7 @@
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
+#include <linux/notifier.h>
#ifdef CONFIG_GPIOLIB
@@ -208,4 +209,11 @@ static inline void gpio_unexport(unsigned gpio)
}
#endif /* CONFIG_GPIO_SYSFS */
+enum gpio_notify_msg {
+ GPIO_NOTIFY_CHIP_ADDED = 0,
+ GPIO_NOTIFY_CHIP_REMOVE = 1,
+};
+
+extern struct blocking_notifier_head gpio_notifier;
+
#endif /* _ASM_GENERIC_GPIO_H */
--
1.6.5.7
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