Messages in this thread Patch in this message | | | From | Alexandre Courbot <> | Subject | [PATCH 2/4] gpiolib: use const parameters when possible | Date | Wed, 13 Feb 2013 16:03:00 +0900 |
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From: Alexandre Courbot <acourbot@nvidia.com>
Constify descriptor parameter of gpiod_* functions for those that should obviously not modify it. This includes value or direction get, cansleep, and IRQ number query.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> --- drivers/gpio/gpiolib.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 8a2cf9c..ad6df6b 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -88,13 +88,14 @@ static int gpiod_request(struct gpio_desc *desc, const char *label); static void gpiod_free(struct gpio_desc *desc); static int gpiod_direction_input(struct gpio_desc *desc); static int gpiod_direction_output(struct gpio_desc *desc, int value); +static int gpiod_get_direction(const struct gpio_desc *desc); static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce); -static int gpiod_get_value_cansleep(struct gpio_desc *desc); +static int gpiod_get_value_cansleep(const struct gpio_desc *desc); static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value); -static int gpiod_get_value(struct gpio_desc *desc); +static int gpiod_get_value(const struct gpio_desc *desc); static void gpiod_set_value(struct gpio_desc *desc, int value); -static int gpiod_cansleep(struct gpio_desc *desc); -static int gpiod_to_irq(struct gpio_desc *desc); +static int gpiod_cansleep(const struct gpio_desc *desc); +static int gpiod_to_irq(const struct gpio_desc *desc); static int gpiod_export(struct gpio_desc *desc, bool direction_may_change); static int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc); @@ -172,7 +173,7 @@ static int gpio_ensure_requested(struct gpio_desc *desc) } /* caller holds gpio_lock *OR* gpio is marked as requested */ -static struct gpio_chip *gpiod_to_chip(struct gpio_desc *desc) +static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) { return desc ? desc->chip : NULL; } @@ -207,7 +208,7 @@ static int gpiochip_find_base(int ngpio) } /* caller ensures gpio is valid and requested, chip->get_direction may sleep */ -static int gpiod_get_direction(struct gpio_desc *desc) +static int gpiod_get_direction(const struct gpio_desc *desc) { struct gpio_chip *chip; unsigned offset; @@ -223,11 +224,13 @@ static int gpiod_get_direction(struct gpio_desc *desc) if (status > 0) { /* GPIOF_DIR_IN, or other positive */ status = 1; - clear_bit(FLAG_IS_OUT, &desc->flags); + /* FLAG_IS_OUT is just a cache of the result of get_direction(), + * so it does not affect constness per se */ + clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); } if (status == 0) { /* GPIOF_DIR_OUT */ - set_bit(FLAG_IS_OUT, &desc->flags); + set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags); } return status; } @@ -263,7 +266,7 @@ static DEFINE_MUTEX(sysfs_lock); static ssize_t gpio_direction_show(struct device *dev, struct device_attribute *attr, char *buf) { - struct gpio_desc *desc = dev_get_drvdata(dev); + const struct gpio_desc *desc = dev_get_drvdata(dev); ssize_t status; mutex_lock(&sysfs_lock); @@ -1818,7 +1821,7 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce); * It returns the zero or nonzero value provided by the associated * gpio_chip.get() method; or zero if no such method is provided. */ -static int gpiod_get_value(struct gpio_desc *desc) +static int gpiod_get_value(const struct gpio_desc *desc) { struct gpio_chip *chip; int value; @@ -1936,7 +1939,7 @@ EXPORT_SYMBOL_GPL(__gpio_set_value); * This is used directly or indirectly to implement gpio_cansleep(). It * returns nonzero if access reading or writing the GPIO value can sleep. */ -static int gpiod_cansleep(struct gpio_desc *desc) +static int gpiod_cansleep(const struct gpio_desc *desc) { if (!desc) return 0; @@ -1959,7 +1962,7 @@ EXPORT_SYMBOL_GPL(__gpio_cansleep); * It returns the number of the IRQ signaled by this (input) GPIO, * or a negative errno. */ -static int gpiod_to_irq(struct gpio_desc *desc) +static int gpiod_to_irq(const struct gpio_desc *desc) { struct gpio_chip *chip; int offset; @@ -1982,7 +1985,7 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq); * Common examples include ones connected to I2C or SPI chips. */ -static int gpiod_get_value_cansleep(struct gpio_desc *desc) +static int gpiod_get_value_cansleep(const struct gpio_desc *desc) { struct gpio_chip *chip; int value; -- 1.8.1.3
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