From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: [patch 2.6.27-rc8-omap 5/7] gpiolib to_irq() feature Date: Fri, 3 Oct 2008 09:02:55 -0700 Message-ID: <200810030902.55834.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp127.sbc.mail.sp1.yahoo.com ([69.147.65.186]:32646 "HELO smtp127.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753117AbYJCQbi (ORCPT ); Fri, 3 Oct 2008 12:31:38 -0400 Content-Disposition: inline Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org From: David Brownell 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 becuase it's not always supported. Signed-off-by: David Brownell Signed-off-by: Andrew Morton --- Preview of a 2.6.28 feature, taken from MM to let OMAP stage patches relying on this feature. Documentation/gpio.txt | 5 +++-- drivers/gpio/gpiolib.c | 18 ++++++++++++++++++ include/asm-generic/gpio.h | 7 +++++++ 3 files changed, 28 insertions(+), 2 deletions(-) --- 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 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1008,6 +1008,24 @@ 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. --- 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 gp extern int __gpio_cansleep(unsigned gpio); +extern int __gpio_to_irq(unsigned gpio); #ifdef CONFIG_GPIO_SYSFS