From 0f6d504e73b49374c6093efe6aa60ab55058248a Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 15 Oct 2008 22:03:14 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/gpio.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'Documentation/gpio.txt') 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 -- cgit v1.2.3-58-ga151