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