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authorAlexandre Courbot <acourbot@nvidia.com>2013-02-15 09:46:15 +0400
committerGrant Likely <grant.likely@secretlab.ca>2013-03-02 17:20:19 +0400
commitdef634338d3ffb32fbe9b0a2d70cc24ef909cd4f (patch)
tree14da05000274ad6d6972d6c474d22362fa1b30e0 /drivers/gpio/gpiolib.c
parentbcabdef12da49878789464ad7239e97d83ea5ef5 (diff)
downloadlinux-def634338d3ffb32fbe9b0a2d70cc24ef909cd4f.tar.xz
gpiolib: use const parameters when possible
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> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r--drivers/gpio/gpiolib.c29
1 files changed, 16 insertions, 13 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 1a8a7a8f803f..a33bfc23e9f5 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);
@@ -1830,7 +1833,7 @@ 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;
@@ -1948,7 +1951,7 @@ 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;
@@ -1971,7 +1974,7 @@ 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;
@@ -1994,7 +1997,7 @@ 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;