diff options
| author | David Brownell <dbrownell@users.sourceforge.net> | 2008-10-15 22:03:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-16 11:21:40 -0700 |
| commit | 0f6d504e73b49374c6093efe6aa60ab55058248a (patch) | |
| tree | 414c9e591ba23b2126bc9cad4e0efb1b60693b2d | |
| parent | 2f8d11971b9f54362437ce70f4d1911f0996d542 (diff) | |
gpiolib: gpio_to_irq() hooks
Add a new gpiolib mechanism: gpio_chip instances can provide mappings
between their (input) GPIOs and any associated IRQs. This makes it easier
for platforms to support IRQs that are provided by board-specific external
chips instead of as part of their core (such as SOC-integrated GPIOs).
Also update the irq_to_gpio() description, saying to avoid it because it's
not always supported.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | Documentation/gpio.txt | 5 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 18 | ||||
| -rw-r--r-- | include/asm-generic/gpio.h | 7 |
3 files changed, 28 insertions, 2 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index 18022e249c53..8a7c45956d24 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 317004fd94fb..29a7e6b1be5d 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 2c5744b66dec..04cb1d175df1 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 |