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authorLinus Walleij <linus.walleij@linaro.org>2013-09-24 11:54:38 +0200
committerLinus Walleij <linus.walleij@linaro.org>2013-10-16 09:59:54 +0200
commitd468bf9ecaabd3bf3a6134e5a369ced82b1d1ca1 (patch)
tree452eaf82c5c50a4673ccd5fccdc1407b1243d03d /include
parentgpio: ep93xx: get rid of bogus __raw* accessors (diff)
downloadlinux-d468bf9ecaabd3bf3a6134e5a369ced82b1d1ca1.tar.xz
linux-d468bf9ecaabd3bf3a6134e5a369ced82b1d1ca1.zip
gpio: add API to be strict about GPIO IRQ usage
It is currently often possible in many GPIO drivers to request a GPIO line to be used as IRQ after calling gpio_to_irq() and, as the gpiolib is not aware of this, set the same line to output and start driving it, with undesired side effects. As it is a bogus usage scenario to request a line flagged as output to used as IRQ, we introduce APIs to let gpiolib track the use of a line as IRQ, and also set this flag from the userspace ABI. The API is symmetric so that lines can also be flagged from .irq_enable() and unflagged from IRQ by .irq_disable(). The debugfs file is altered so that we see if a line is reserved for IRQ. Cc: Enric Balletbo i Serra <eballetbo@gmail.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include')
-rw-r--r--include/asm-generic/gpio.h3
-rw-r--r--include/linux/gpio.h12
2 files changed, 15 insertions, 0 deletions
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index bde646995d10..b309a5c0019e 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -192,6 +192,9 @@ extern int __gpio_cansleep(unsigned gpio);
extern int __gpio_to_irq(unsigned gpio);
+extern int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset);
+extern void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
+
extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
extern int gpio_request_array(const struct gpio *array, size_t num);
extern void gpio_free_array(const struct gpio *array, size_t num);
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 552e3f46e4a3..a06ec3e85ba3 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -204,6 +204,18 @@ static inline int gpio_to_irq(unsigned gpio)
return -EINVAL;
}
+static inline int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
+{
+ WARN_ON(1);
+ return -EINVAL;
+}
+
+static inline void gpio_unlock_as_irq(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ WARN_ON(1);
+}
+
static inline int irq_to_gpio(unsigned irq)
{
/* irq can never have been returned from gpio_to_irq() */