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-rw-r--r--Documentation/gpio.txt5
-rw-r--r--drivers/gpio/gpiolib.c18
-rw-r--r--include/asm-generic/gpio.h7
3 files changed, 28 insertions, 2 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 18022e249c5..8a7c45956d2 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -264,7 +264,7 @@ map between them using calls like:
/* map GPIO numbers to IRQ numbers */
int gpio_to_irq(unsigned gpio);
- /* map IRQ numbers to GPIO numbers */
+ /* map IRQ numbers to GPIO numbers (avoid using this) */
int irq_to_gpio(unsigned irq);
Those return either the corresponding number in the other namespace, or
@@ -284,7 +284,8 @@ system wakeup capabilities.
Non-error values returned from irq_to_gpio() would most commonly be used
with gpio_get_value(), for example to initialize or update driver state
-when the IRQ is edge-triggered.
+when the IRQ is edge-triggered. Note that some platforms don't support
+this reverse mapping, so you should avoid using it.
Emulating Open Drain Signals
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 317004fd94f..29a7e6b1be5 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1010,6 +1010,24 @@ int __gpio_cansleep(unsigned gpio)
}
EXPORT_SYMBOL_GPL(__gpio_cansleep);
+/**
+ * __gpio_to_irq() - return the IRQ corresponding to a GPIO
+ * @gpio: gpio whose IRQ will be returned (already requested)
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_to_irq().
+ * It returns the number of the IRQ signaled by this (input) GPIO,
+ * or a negative errno.
+ */
+int __gpio_to_irq(unsigned gpio)
+{
+ struct gpio_chip *chip;
+
+ chip = gpio_to_chip(gpio);
+ return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
+}
+EXPORT_SYMBOL_GPL(__gpio_to_irq);
+
/* There's no value in making it easy to inline GPIO calls that may sleep.
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 2c5744b66de..04cb1d175df 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -40,6 +40,8 @@ struct module;
* returns either the value actually sensed, or zero
* @direction_output: configures signal "offset" as output, or returns error
* @set: assigns output value for signal "offset"
+ * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
+ * implementation may not sleep
* @dbg_show: optional routine to show contents in debugfs; default code
* will be used when this is omitted, but custom code can show extra
* state (such as pullup/pulldown configuration).
@@ -73,6 +75,10 @@ struct gpio_chip {
unsigned offset, int value);
void (*set)(struct gpio_chip *chip,
unsigned offset, int value);
+
+ int (*to_irq)(struct gpio_chip *chip,
+ unsigned offset);
+
void (*dbg_show)(struct seq_file *s,
struct gpio_chip *chip);
int base;
@@ -112,6 +118,7 @@ extern void __gpio_set_value(unsigned gpio, int value);
extern int __gpio_cansleep(unsigned gpio);
+extern int __gpio_to_irq(unsigned gpio);
#ifdef CONFIG_GPIO_SYSFS