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gpiolib: export descriptor-based GPIO interface

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This patch exports the gpiod_* family of API functions, a safer
alternative to the legacy GPIO interface. Differences between the gpiod
and legacy gpio APIs are:

- gpio works with integers, whereas gpiod operates on opaque handlers
  which cannot be forged or used before proper acquisition
- gpiod get/set functions are aware of the active low state of a GPIO
- gpio consumers should now include <linux/gpio/consumer.h> to access
  the new interface, whereas chips drivers will use
  <linux/gpio/driver.h>

The legacy gpio API is now built as inline functions on top of gpiod.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Alexandre Courbot 2013-10-17 10:21:36 -07:00 committed by Linus Walleij
parent b41fb43911
commit 79a9becda8
5 changed files with 662 additions and 366 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

428
drivers/gpio/gpiolib.c
View file

@ -16,16 +16,11 @@
#define CREATE_TRACE_POINTS #define CREATE_TRACE_POINTS
#include <trace/events/gpio.h> #include <trace/events/gpio.h>
/* Optional implementation infrastructure for GPIO interfaces. /* Implementation infrastructure for GPIO interfaces.
* *
* Platforms may want to use this if they tend to use very many GPIOs * The GPIO programming interface allows for inlining speed-critical
* that aren't part of a System-On-Chip core; or across I2C/SPI/etc. * get/set operations for common cases, so that access to SOC-integrated
* * GPIOs can sometimes cost only an instruction or two per bit.
* When kernel footprint or instruction count is an issue, simpler
* implementations may be preferred. The GPIO programming interface
* allows for inlining speed-critical get/set operations for common
* cases, so that access to SOC-integrated GPIOs can sometimes cost
* only an instruction or two per bit.
*/ */
@ -57,7 +52,7 @@ struct gpio_desc {
#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */ #define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
#define FLAG_TRIG_FALL 4 /* trigger on falling edge */ #define FLAG_TRIG_FALL 4 /* trigger on falling edge */
#define FLAG_TRIG_RISE 5 /* trigger on rising edge */ #define FLAG_TRIG_RISE 5 /* trigger on rising edge */
#define FLAG_ACTIVE_LOW 6 /* sysfs value has active low */ #define FLAG_ACTIVE_LOW 6 /* value has active low */
#define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */ #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
#define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */ #define FLAG_OPEN_SOURCE 8 /* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */ #define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
@ -81,29 +76,8 @@ static LIST_HEAD(gpio_chips);
static DEFINE_IDR(dirent_idr); static DEFINE_IDR(dirent_idr);
#endif #endif
/*
* Internal gpiod_* API using descriptors instead of the integer namespace.
* Most of this should eventually go public.
*/
static int gpiod_request(struct gpio_desc *desc, const char *label); static int gpiod_request(struct gpio_desc *desc, const char *label);
static void gpiod_free(struct gpio_desc *desc); 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(const struct gpio_desc *desc);
static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
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(const struct gpio_desc *desc);
static int gpiod_to_irq(const struct gpio_desc *desc);
static int gpiod_lock_as_irq(struct gpio_desc *desc);
static void gpiod_unlock_as_irq(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);
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
static void gpiod_unexport(struct gpio_desc *desc);
#ifdef CONFIG_DEBUG_FS #ifdef CONFIG_DEBUG_FS
#define gpiod_emerg(desc, fmt, ...) \ #define gpiod_emerg(desc, fmt, ...) \
@ -157,13 +131,14 @@ static int gpio_chip_hwgpio(const struct gpio_desc *desc)
/** /**
* Convert a GPIO number to its descriptor * Convert a GPIO number to its descriptor
*/ */
static struct gpio_desc *gpio_to_desc(unsigned gpio) struct gpio_desc *gpio_to_desc(unsigned gpio)
{ {
if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio)) if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
return NULL; return NULL;
else else
return &gpio_desc[gpio]; return &gpio_desc[gpio];
} }
EXPORT_SYMBOL_GPL(gpio_to_desc);
/** /**
* Convert an offset on a certain chip to a corresponding descriptor * Convert an offset on a certain chip to a corresponding descriptor
@ -181,10 +156,11 @@ static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip,
* This should disappear in the future but is needed since we still * This should disappear in the future but is needed since we still
* use GPIO numbers for error messages and sysfs nodes * use GPIO numbers for error messages and sysfs nodes
*/ */
static int desc_to_gpio(const struct gpio_desc *desc) int desc_to_gpio(const struct gpio_desc *desc)
{ {
return desc - &gpio_desc[0]; return desc - &gpio_desc[0];
} }
EXPORT_SYMBOL_GPL(desc_to_gpio);
/* Warn when drivers omit gpio_request() calls -- legal but ill-advised /* Warn when drivers omit gpio_request() calls -- legal but ill-advised
@ -219,16 +195,15 @@ static int gpio_ensure_requested(struct gpio_desc *desc)
return 0; return 0;
} }
static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) /**
* gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
* @desc: descriptor to return the chip of
*/
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
{ {
return desc ? desc->chip : NULL; return desc ? desc->chip : NULL;
} }
EXPORT_SYMBOL_GPL(gpiod_to_chip);
/* caller holds gpio_lock *OR* gpio is marked as requested */
struct gpio_chip *gpio_to_chip(unsigned gpio)
{
return gpiod_to_chip(gpio_to_desc(gpio));
}
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */ /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio) static int gpiochip_find_base(int ngpio)
@ -254,8 +229,15 @@ static int gpiochip_find_base(int ngpio)
} }
} }
/* caller ensures gpio is valid and requested, chip->get_direction may sleep */ /**
static int gpiod_get_direction(const struct gpio_desc *desc) * gpiod_get_direction - return the current direction of a GPIO
* @desc: GPIO to get the direction of
*
* Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
*
* This function may sleep if gpiod_cansleep() is true.
*/
int gpiod_get_direction(const struct gpio_desc *desc)
{ {
struct gpio_chip *chip; struct gpio_chip *chip;
unsigned offset; unsigned offset;
@ -281,6 +263,7 @@ static int gpiod_get_direction(const struct gpio_desc *desc)
} }
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_get_direction);
#ifdef CONFIG_GPIO_SYSFS #ifdef CONFIG_GPIO_SYSFS
@ -365,17 +348,10 @@ static ssize_t gpio_value_show(struct device *dev,
mutex_lock(&sysfs_lock); mutex_lock(&sysfs_lock);
if (!test_bit(FLAG_EXPORT, &desc->flags)) { if (!test_bit(FLAG_EXPORT, &desc->flags))
status = -EIO; status = -EIO;
} else { else
int value; status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
value = !!gpiod_get_value_cansleep(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
status = sprintf(buf, "%d\n", value);
}
mutex_unlock(&sysfs_lock); mutex_unlock(&sysfs_lock);
return status; return status;
@ -398,9 +374,7 @@ static ssize_t gpio_value_store(struct device *dev,
status = kstrtol(buf, 0, &value); status = kstrtol(buf, 0, &value);
if (status == 0) { if (status == 0) {
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) gpiod_set_value_cansleep(desc, value);
value = !value;
gpiod_set_value_cansleep(desc, value != 0);
status = size; status = size;
} }
} }
@ -790,7 +764,7 @@ static struct class gpio_class = {
/** /**
* gpio_export - export a GPIO through sysfs * gpiod_export - export a GPIO through sysfs
* @gpio: gpio to make available, already requested * @gpio: gpio to make available, already requested
* @direction_may_change: true if userspace may change gpio direction * @direction_may_change: true if userspace may change gpio direction
* Context: arch_initcall or later * Context: arch_initcall or later
@ -804,7 +778,7 @@ static struct class gpio_class = {
* *
* Returns zero on success, else an error. * Returns zero on success, else an error.
*/ */
static int gpiod_export(struct gpio_desc *desc, bool direction_may_change) int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
{ {
unsigned long flags; unsigned long flags;
int status; int status;
@ -882,12 +856,7 @@ static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
status); status);
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_export);
int gpio_export(unsigned gpio, bool direction_may_change)
{
return gpiod_export(gpio_to_desc(gpio), direction_may_change);
}
EXPORT_SYMBOL_GPL(gpio_export);
static int match_export(struct device *dev, const void *data) static int match_export(struct device *dev, const void *data)
{ {
@ -895,7 +864,7 @@ static int match_export(struct device *dev, const void *data)
} }
/** /**
* gpio_export_link - create a sysfs link to an exported GPIO node * gpiod_export_link - create a sysfs link to an exported GPIO node
* @dev: device under which to create symlink * @dev: device under which to create symlink
* @name: name of the symlink * @name: name of the symlink
* @gpio: gpio to create symlink to, already exported * @gpio: gpio to create symlink to, already exported
@ -905,7 +874,7 @@ static int match_export(struct device *dev, const void *data)
* *
* Returns zero on success, else an error. * Returns zero on success, else an error.
*/ */
static int gpiod_export_link(struct device *dev, const char *name, int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc) struct gpio_desc *desc)
{ {
int status = -EINVAL; int status = -EINVAL;
@ -937,15 +906,10 @@ static int gpiod_export_link(struct device *dev, const char *name,
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_export_link);
int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
{
return gpiod_export_link(dev, name, gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_export_link);
/** /**
* gpio_sysfs_set_active_low - set the polarity of gpio sysfs value * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
* @gpio: gpio to change * @gpio: gpio to change
* @value: non-zero to use active low, i.e. inverted values * @value: non-zero to use active low, i.e. inverted values
* *
@ -956,7 +920,7 @@ EXPORT_SYMBOL_GPL(gpio_export_link);
* *
* Returns zero on success, else an error. * Returns zero on success, else an error.
*/ */
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{ {
struct device *dev = NULL; struct device *dev = NULL;
int status = -EINVAL; int status = -EINVAL;
@ -987,20 +951,15 @@ static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
/** /**
* gpio_unexport - reverse effect of gpio_export() * gpiod_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable * @gpio: gpio to make unavailable
* *
* This is implicit on gpio_free(). * This is implicit on gpio_free().
*/ */
static void gpiod_unexport(struct gpio_desc *desc) void gpiod_unexport(struct gpio_desc *desc)
{ {
int status = 0; int status = 0;
struct device *dev = NULL; struct device *dev = NULL;
@ -1033,12 +992,7 @@ static void gpiod_unexport(struct gpio_desc *desc)
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc), pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status); status);
} }
EXPORT_SYMBOL_GPL(gpiod_unexport);
void gpio_unexport(unsigned gpio)
{
gpiod_unexport(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_unexport);
static int gpiochip_export(struct gpio_chip *chip) static int gpiochip_export(struct gpio_chip *chip)
{ {
@ -1145,27 +1099,6 @@ static inline void gpiochip_unexport(struct gpio_chip *chip)
{ {
} }
static inline int gpiod_export(struct gpio_desc *desc,
bool direction_may_change)
{
return -ENOSYS;
}
static inline int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
return -ENOSYS;
}
static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
return -ENOSYS;
}
static inline void gpiod_unexport(struct gpio_desc *desc)
{
}
#endif /* CONFIG_GPIO_SYSFS */ #endif /* CONFIG_GPIO_SYSFS */
/* /*
@ -1677,7 +1610,16 @@ EXPORT_SYMBOL_GPL(gpiochip_is_requested);
* rely on gpio_request() having been called beforehand. * rely on gpio_request() having been called beforehand.
*/ */
static int gpiod_direction_input(struct gpio_desc *desc) /**
* gpiod_direction_input - set the GPIO direction to input
* @desc: GPIO to set to input
*
* Set the direction of the passed GPIO to input, such as gpiod_get_value() can
* be called safely on it.
*
* Return 0 in case of success, else an error code.
*/
int gpiod_direction_input(struct gpio_desc *desc)
{ {
unsigned long flags; unsigned long flags;
struct gpio_chip *chip; struct gpio_chip *chip;
@ -1734,14 +1676,19 @@ static int gpiod_direction_input(struct gpio_desc *desc)
gpiod_dbg(desc, "%s status %d\n", __func__, status); gpiod_dbg(desc, "%s status %d\n", __func__, status);
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_direction_input);
int gpio_direction_input(unsigned gpio) /**
{ * gpiod_direction_output - set the GPIO direction to input
return gpiod_direction_input(gpio_to_desc(gpio)); * @desc: GPIO to set to output
} * @value: initial output value of the GPIO
EXPORT_SYMBOL_GPL(gpio_direction_input); *
* Set the direction of the passed GPIO to output, such as gpiod_set_value() can
static int gpiod_direction_output(struct gpio_desc *desc, int value) * be called safely on it. The initial value of the output must be specified.
*
* Return 0 in case of success, else an error code.
*/
int gpiod_direction_output(struct gpio_desc *desc, int value)
{ {
unsigned long flags; unsigned long flags;
struct gpio_chip *chip; struct gpio_chip *chip;
@ -1814,22 +1761,17 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status); gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_direction_output);
int gpio_direction_output(unsigned gpio, int value)
{
return gpiod_direction_output(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_direction_output);
/** /**
* gpio_set_debounce - sets @debounce time for a @gpio * gpiod_set_debounce - sets @debounce time for a @gpio
* @gpio: the gpio to set debounce time * @gpio: the gpio to set debounce time
* @debounce: debounce time is microseconds * @debounce: debounce time is microseconds
* *
* returns -ENOTSUPP if the controller does not support setting * returns -ENOTSUPP if the controller does not support setting
* debounce. * debounce.
*/ */
static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{ {
unsigned long flags; unsigned long flags;
struct gpio_chip *chip; struct gpio_chip *chip;
@ -1871,12 +1813,19 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
return status; return status;
} }
EXPORT_SYMBOL_GPL(gpiod_set_debounce);
int gpio_set_debounce(unsigned gpio, unsigned debounce) /**
* gpiod_is_active_low - test whether a GPIO is active-low or not
* @desc: the gpio descriptor to test
*
* Returns 1 if the GPIO is active-low, 0 otherwise.
*/
int gpiod_is_active_low(const struct gpio_desc *desc)
{ {
return gpiod_set_debounce(gpio_to_desc(gpio), debounce); return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
} }
EXPORT_SYMBOL_GPL(gpio_set_debounce); EXPORT_SYMBOL_GPL(gpiod_is_active_low);
/* I/O calls are only valid after configuration completed; the relevant /* I/O calls are only valid after configuration completed; the relevant
* "is this a valid GPIO" error checks should already have been done. * "is this a valid GPIO" error checks should already have been done.
@ -1900,7 +1849,7 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce);
* that the GPIO was actually requested. * that the GPIO was actually requested.
*/ */
static int _gpiod_get_value(const struct gpio_desc *desc) static int _gpiod_get_raw_value(const struct gpio_desc *desc)
{ {
struct gpio_chip *chip; struct gpio_chip *chip;
int value; int value;
@ -1914,33 +1863,54 @@ static int _gpiod_get_value(const struct gpio_desc *desc)
} }
/** /**
* __gpio_get_value() - return a gpio's value * gpiod_get_raw_value() - return a gpio's raw value
* @gpio: gpio whose value will be returned * @desc: gpio whose value will be returned
* Context: any
* *
* This is used directly or indirectly to implement gpio_get_value(). * Return the GPIO's raw value, i.e. the value of the physical line disregarding
* It returns the zero or nonzero value provided by the associated * its ACTIVE_LOW status.
* gpio_chip.get() method; or zero if no such method is provided. *
* This function should be called from contexts where we cannot sleep, and will
* complain if the GPIO chip functions potentially sleep.
*/ */
static int gpiod_get_value(const struct gpio_desc *desc) int gpiod_get_raw_value(const struct gpio_desc *desc)
{ {
if (!desc) if (!desc)
return 0; return 0;
/* Should be using gpio_get_value_cansleep() */ /* Should be using gpio_get_value_cansleep() */
WARN_ON(desc->chip->can_sleep); WARN_ON(desc->chip->can_sleep);
return _gpiod_get_value(desc); return _gpiod_get_raw_value(desc);
} }
EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
int __gpio_get_value(unsigned gpio) /**
* gpiod_get_value() - return a gpio's value
* @desc: gpio whose value will be returned
*
* Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
* account.
*
* This function should be called from contexts where we cannot sleep, and will
* complain if the GPIO chip functions potentially sleep.
*/
int gpiod_get_value(const struct gpio_desc *desc)
{ {
return gpiod_get_value(gpio_to_desc(gpio)); int value;
if (!desc)
return 0;
/* Should be using gpio_get_value_cansleep() */
WARN_ON(desc->chip->can_sleep);
value = _gpiod_get_raw_value(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
return value;
} }
EXPORT_SYMBOL_GPL(__gpio_get_value); EXPORT_SYMBOL_GPL(gpiod_get_value);
/* /*
* _gpio_set_open_drain_value() - Set the open drain gpio's value. * _gpio_set_open_drain_value() - Set the open drain gpio's value.
* @gpio: Gpio whose state need to be set. * @desc: gpio descriptor whose state need to be set.
* @chip: Gpio chip.
* @value: Non-zero for setting it HIGH otherise it will set to LOW. * @value: Non-zero for setting it HIGH otherise it will set to LOW.
*/ */
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value) static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
@ -1966,9 +1936,8 @@ static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
} }
/* /*
* _gpio_set_open_source() - Set the open source gpio's value. * _gpio_set_open_source_value() - Set the open source gpio's value.
* @gpio: Gpio whose state need to be set. * @desc: gpio descriptor whose state need to be set.
* @chip: Gpio chip.
* @value: Non-zero for setting it HIGH otherise it will set to LOW. * @value: Non-zero for setting it HIGH otherise it will set to LOW.
*/ */
static void _gpio_set_open_source_value(struct gpio_desc *desc, int value) static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
@ -1993,7 +1962,7 @@ static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
__func__, err); __func__, err);
} }
static void _gpiod_set_value(struct gpio_desc *desc, int value) static void _gpiod_set_raw_value(struct gpio_desc *desc, int value)
{ {
struct gpio_chip *chip; struct gpio_chip *chip;
@ -2008,62 +1977,70 @@ static void _gpiod_set_value(struct gpio_desc *desc, int value)
} }
/** /**
* __gpio_set_value() - assign a gpio's value * gpiod_set_raw_value() - assign a gpio's raw value
* @gpio: gpio whose value will be assigned * @desc: gpio whose value will be assigned
* @value: value to assign * @value: value to assign
* Context: any
* *
* This is used directly or indirectly to implement gpio_set_value(). * Set the raw value of the GPIO, i.e. the value of its physical line without
* It invokes the associated gpio_chip.set() method. * regard for its ACTIVE_LOW status.
*
* This function should be called from contexts where we cannot sleep, and will
* complain if the GPIO chip functions potentially sleep.
*/ */
static void gpiod_set_value(struct gpio_desc *desc, int value) void gpiod_set_raw_value(struct gpio_desc *desc, int value)
{ {
if (!desc) if (!desc)
return; return;
/* Should be using gpio_set_value_cansleep() */ /* Should be using gpio_set_value_cansleep() */
WARN_ON(desc->chip->can_sleep); WARN_ON(desc->chip->can_sleep);
_gpiod_set_value(desc, value); _gpiod_set_raw_value(desc, value);
} }
EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
void __gpio_set_value(unsigned gpio, int value)
{
return gpiod_set_value(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(__gpio_set_value);
/** /**
* __gpio_cansleep() - report whether gpio value access will sleep * gpiod_set_value() - assign a gpio's value
* @gpio: gpio in question * @desc: gpio whose value will be assigned
* Context: any * @value: value to assign
* *
* This is used directly or indirectly to implement gpio_cansleep(). It * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
* returns nonzero if access reading or writing the GPIO value can sleep. * account
*
* This function should be called from contexts where we cannot sleep, and will
* complain if the GPIO chip functions potentially sleep.
*/ */
static int gpiod_cansleep(const struct gpio_desc *desc) void gpiod_set_value(struct gpio_desc *desc, int value)
{
if (!desc)
return;
/* Should be using gpio_set_value_cansleep() */
WARN_ON(desc->chip->can_sleep);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
_gpiod_set_raw_value(desc, value);
}
EXPORT_SYMBOL_GPL(gpiod_set_value);
/**
* gpiod_cansleep() - report whether gpio value access may sleep
* @desc: gpio to check
*
*/
int gpiod_cansleep(const struct gpio_desc *desc)
{ {
if (!desc) if (!desc)
return 0; return 0;
/* only call this on GPIOs that are valid! */
return desc->chip->can_sleep; return desc->chip->can_sleep;
} }
EXPORT_SYMBOL_GPL(gpiod_cansleep);
int __gpio_cansleep(unsigned gpio)
{
return gpiod_cansleep(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_cansleep);
/** /**
* __gpio_to_irq() - return the IRQ corresponding to a GPIO * gpiod_to_irq() - return the IRQ corresponding to a GPIO
* @gpio: gpio whose IRQ will be returned (already requested) * @desc: gpio whose IRQ will be returned (already requested)
* Context: any
* *
* This is used directly or indirectly to implement gpio_to_irq(). * Return the IRQ corresponding to the passed GPIO, or an error code in case of
* It returns the number of the IRQ signaled by this (input) GPIO, * error.
* or a negative errno.
*/ */
static int gpiod_to_irq(const struct gpio_desc *desc) int gpiod_to_irq(const struct gpio_desc *desc)
{ {
struct gpio_chip *chip; struct gpio_chip *chip;
int offset; int offset;
@ -2074,12 +2051,7 @@ static int gpiod_to_irq(const struct gpio_desc *desc)
offset = gpio_chip_hwgpio(desc); offset = gpio_chip_hwgpio(desc);
return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO; return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
} }
EXPORT_SYMBOL_GPL(gpiod_to_irq);
int __gpio_to_irq(unsigned gpio)
{
return gpiod_to_irq(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_to_irq);
/** /**
* gpiod_lock_as_irq() - lock a GPIO to be used as IRQ * gpiod_lock_as_irq() - lock a GPIO to be used as IRQ
@ -2091,7 +2063,7 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq);
* of its irq_chip implementation if the GPIO is known from that * of its irq_chip implementation if the GPIO is known from that
* code. * code.
*/ */
static int gpiod_lock_as_irq(struct gpio_desc *desc) int gpiod_lock_as_irq(struct gpio_desc *desc)
{ {
if (!desc) if (!desc)
return -EINVAL; return -EINVAL;
@ -2106,6 +2078,7 @@ static int gpiod_lock_as_irq(struct gpio_desc *desc)
set_bit(FLAG_USED_AS_IRQ, &desc->flags); set_bit(FLAG_USED_AS_IRQ, &desc->flags);
return 0; return 0;
} }
EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);
int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset) int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
{ {
@ -2120,13 +2093,14 @@ EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
* This is used directly by GPIO drivers that want to indicate * This is used directly by GPIO drivers that want to indicate
* that a certain GPIO is no longer used exclusively for IRQ. * that a certain GPIO is no longer used exclusively for IRQ.
*/ */
static void gpiod_unlock_as_irq(struct gpio_desc *desc) void gpiod_unlock_as_irq(struct gpio_desc *desc)
{ {
if (!desc) if (!desc)
return; return;
clear_bit(FLAG_USED_AS_IRQ, &desc->flags); clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
} }
EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);
void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset) void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
{ {
@ -2134,37 +2108,89 @@ void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
} }
EXPORT_SYMBOL_GPL(gpio_unlock_as_irq); EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
/* There's no value in making it easy to inline GPIO calls that may sleep. /**
* Common examples include ones connected to I2C or SPI chips. * gpiod_get_raw_value_cansleep() - return a gpio's raw value
* @desc: gpio whose value will be returned
*
* Return the GPIO's raw value, i.e. the value of the physical line disregarding
* its ACTIVE_LOW status.
*
* This function is to be called from contexts that can sleep.
*/ */
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{ {
might_sleep_if(extra_checks); might_sleep_if(extra_checks);
if (!desc) if (!desc)
return 0; return 0;
return _gpiod_get_value(desc); return _gpiod_get_raw_value(desc);
} }
EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
int gpio_get_value_cansleep(unsigned gpio) /**
* gpiod_get_value_cansleep() - return a gpio's value
* @desc: gpio whose value will be returned
*
* Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
* account.
*
* This function is to be called from contexts that can sleep.
*/
int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{ {
return gpiod_get_value_cansleep(gpio_to_desc(gpio)); int value;
}
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) might_sleep_if(extra_checks);
if (!desc)
return 0;
value = _gpiod_get_raw_value(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
return value;
}
EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
/**
* gpiod_set_raw_value_cansleep() - assign a gpio's raw value
* @desc: gpio whose value will be assigned
* @value: value to assign
*
* Set the raw value of the GPIO, i.e. the value of its physical line without
* regard for its ACTIVE_LOW status.
*
* This function is to be called from contexts that can sleep.
*/
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
{ {
might_sleep_if(extra_checks); might_sleep_if(extra_checks);
if (!desc) if (!desc)
return; return;
_gpiod_set_value(desc, value); _gpiod_set_raw_value(desc, value);
} }
EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
void gpio_set_value_cansleep(unsigned gpio, int value) /**
* gpiod_set_value_cansleep() - assign a gpio's value
* @desc: gpio whose value will be assigned
* @value: value to assign
*
* Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
* account
*
* This function is to be called from contexts that can sleep.
*/
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{ {
return gpiod_set_value_cansleep(gpio_to_desc(gpio), value); might_sleep_if(extra_checks);
if (!desc)
return;
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
value = !value;
_gpiod_set_raw_value(desc, value);
} }
EXPORT_SYMBOL_GPL(gpio_set_value_cansleep); EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
#ifdef CONFIG_DEBUG_FS #ifdef CONFIG_DEBUG_FS

222
include/asm-generic/gpio.h
View file

@ -10,6 +10,8 @@
#ifdef CONFIG_GPIOLIB #ifdef CONFIG_GPIOLIB
#include <linux/compiler.h> #include <linux/compiler.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/consumer.h>
/* Platforms may implement their GPIO interface with library code, /* Platforms may implement their GPIO interface with library code,
* at a small performance cost for non-inlined operations and some * at a small performance cost for non-inlined operations and some
@ -49,122 +51,11 @@ struct module;
struct device_node; struct device_node;
struct gpio_desc; struct gpio_desc;
/** /* caller holds gpio_lock *OR* gpio is marked as requested */
* struct gpio_chip - abstract a GPIO controller static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
* @label: for diagnostics {
* @dev: optional device providing the GPIOs return gpiod_to_chip(gpio_to_desc(gpio));
* @owner: helps prevent removal of modules exporting active GPIOs }
* @list: links gpio_chips together for traversal
* @request: optional hook for chip-specific activation, such as
* enabling module power and clock; may sleep
* @free: optional hook for chip-specific deactivation, such as
* disabling module power and clock; may sleep
* @get_direction: returns direction for signal "offset", 0=out, 1=in,
* (same as GPIOF_DIR_XXX), or negative error
* @direction_input: configures signal "offset" as input, or returns error
* @get: returns value for signal "offset"; for output signals this
* returns either the value actually sensed, or zero
* @direction_output: configures signal "offset" as output, or returns error
* @set_debounce: optional hook for setting debounce time for specified gpio in
* interrupt triggered gpio chips
* @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).
* @base: identifies the first GPIO number handled by this chip; or, if
* negative during registration, requests dynamic ID allocation.
* @ngpio: the number of GPIOs handled by this controller; the last GPIO
* handled is (base + ngpio - 1).
* @desc: array of ngpio descriptors. Private.
* @can_sleep: flag must be set iff get()/set() methods sleep, as they
* must while accessing GPIO expander chips over I2C or SPI
* @names: if set, must be an array of strings to use as alternative
* names for the GPIOs in this chip. Any entry in the array
* may be NULL if there is no alias for the GPIO, however the
* array must be @ngpio entries long. A name can include a single printk
* format specifier for an unsigned int. It is substituted by the actual
* number of the gpio.
*
* A gpio_chip can help platforms abstract various sources of GPIOs so
* they can all be accessed through a common programing interface.
* Example sources would be SOC controllers, FPGAs, multifunction
* chips, dedicated GPIO expanders, and so on.
*
* Each chip controls a number of signals, identified in method calls
* by "offset" values in the range 0..(@ngpio - 1). When those signals
* are referenced through calls like gpio_get_value(gpio), the offset
* is calculated by subtracting @base from the gpio number.
*/
struct gpio_chip {
const char *label;
struct device *dev;
struct module *owner;
struct list_head list;
int (*request)(struct gpio_chip *chip,
unsigned offset);
void (*free)(struct gpio_chip *chip,
unsigned offset);
int (*get_direction)(struct gpio_chip *chip,
unsigned offset);
int (*direction_input)(struct gpio_chip *chip,
unsigned offset);
int (*get)(struct gpio_chip *chip,
unsigned offset);
int (*direction_output)(struct gpio_chip *chip,
unsigned offset, int value);
int (*set_debounce)(struct gpio_chip *chip,
unsigned offset, unsigned debounce);
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;
u16 ngpio;
struct gpio_desc *desc;
const char *const *names;
unsigned can_sleep:1;
unsigned exported:1;
#if defined(CONFIG_OF_GPIO)
/*
* If CONFIG_OF is enabled, then all GPIO controllers described in the
* device tree automatically may have an OF translation
*/
struct device_node *of_node;
int of_gpio_n_cells;
int (*of_xlate)(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags);
#endif
#ifdef CONFIG_PINCTRL
/*
* If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
* describe the actual pin range which they serve in an SoC. This
* information would be used by pinctrl subsystem to configure
* corresponding pins for gpio usage.
*/
struct list_head pin_ranges;
#endif
};
extern const char *gpiochip_is_requested(struct gpio_chip *chip,
unsigned offset);
extern struct gpio_chip *gpio_to_chip(unsigned gpio);
/* add/remove chips */
extern int gpiochip_add(struct gpio_chip *chip);
extern int __must_check gpiochip_remove(struct gpio_chip *chip);
extern struct gpio_chip *gpiochip_find(void *data,
int (*match)(struct gpio_chip *chip,
void *data));
/* Always use the library code for GPIO management calls, /* Always use the library code for GPIO management calls,
* or when sleeping may be involved. * or when sleeping may be involved.
@ -172,25 +63,52 @@ extern struct gpio_chip *gpiochip_find(void *data,
extern int gpio_request(unsigned gpio, const char *label); extern int gpio_request(unsigned gpio, const char *label);
extern void gpio_free(unsigned gpio); extern void gpio_free(unsigned gpio);
extern int gpio_direction_input(unsigned gpio); static inline int gpio_direction_input(unsigned gpio)
extern int gpio_direction_output(unsigned gpio, int value); {
return gpiod_direction_input(gpio_to_desc(gpio));
}
static inline int gpio_direction_output(unsigned gpio, int value)
{
return gpiod_direction_output(gpio_to_desc(gpio), value);
}
extern int gpio_set_debounce(unsigned gpio, unsigned debounce); static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
{
return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
}
extern int gpio_get_value_cansleep(unsigned gpio); static inline int gpio_get_value_cansleep(unsigned gpio)
extern void gpio_set_value_cansleep(unsigned gpio, int value); {
return gpiod_get_raw_value_cansleep(gpio_to_desc(gpio));
}
static inline void gpio_set_value_cansleep(unsigned gpio, int value)
{
return gpiod_set_raw_value_cansleep(gpio_to_desc(gpio), value);
}
/* A platform's <asm/gpio.h> code may want to inline the I/O calls when /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
* the GPIO is constant and refers to some always-present controller, * the GPIO is constant and refers to some always-present controller,
* giving direct access to chip registers and tight bitbanging loops. * giving direct access to chip registers and tight bitbanging loops.
*/ */
extern int __gpio_get_value(unsigned gpio); static inline int __gpio_get_value(unsigned gpio)
extern void __gpio_set_value(unsigned gpio, int value); {
return gpiod_get_raw_value(gpio_to_desc(gpio));
}
static inline void __gpio_set_value(unsigned gpio, int value)
{
return gpiod_set_raw_value(gpio_to_desc(gpio), value);
}
extern int __gpio_cansleep(unsigned gpio); static inline int __gpio_cansleep(unsigned gpio)
{
return gpiod_cansleep(gpio_to_desc(gpio));
}
extern int __gpio_to_irq(unsigned gpio); static inline int __gpio_to_irq(unsigned gpio)
{
return gpiod_to_irq(gpio_to_desc(gpio));
}
extern int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset); 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 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
@ -199,19 +117,30 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe
extern int gpio_request_array(const struct gpio *array, size_t num); extern int gpio_request_array(const struct gpio *array, size_t num);
extern void gpio_free_array(const struct gpio *array, size_t num); extern void gpio_free_array(const struct gpio *array, size_t num);
#ifdef CONFIG_GPIO_SYSFS
/* /*
* A sysfs interface can be exported by individual drivers if they want, * A sysfs interface can be exported by individual drivers if they want,
* but more typically is configured entirely from userspace. * but more typically is configured entirely from userspace.
*/ */
extern int gpio_export(unsigned gpio, bool direction_may_change); static inline int gpio_export(unsigned gpio, bool direction_may_change)
extern int gpio_export_link(struct device *dev, const char *name, {
unsigned gpio); return gpiod_export(gpio_to_desc(gpio), direction_may_change);
extern int gpio_sysfs_set_active_low(unsigned gpio, int value); }
extern void gpio_unexport(unsigned gpio);
#endif /* CONFIG_GPIO_SYSFS */ static inline int gpio_export_link(struct device *dev, const char *name,
unsigned gpio)
{
return gpiod_export_link(dev, name, gpio_to_desc(gpio));
}
static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
}
static inline void gpio_unexport(unsigned gpio)
{
gpiod_unexport(gpio_to_desc(gpio));
}
#ifdef CONFIG_PINCTRL #ifdef CONFIG_PINCTRL
@ -281,31 +210,4 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
#endif /* !CONFIG_GPIOLIB */ #endif /* !CONFIG_GPIOLIB */
#ifndef CONFIG_GPIO_SYSFS
struct device;
/* sysfs support is only available with gpiolib, where it's optional */
static inline int gpio_export(unsigned gpio, bool direction_may_change)
{
return -ENOSYS;
}
static inline int gpio_export_link(struct device *dev, const char *name,
unsigned gpio)
{
return -ENOSYS;
}
static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
return -ENOSYS;
}
static inline void gpio_unexport(unsigned gpio)
{
}
#endif /* CONFIG_GPIO_SYSFS */
#endif /* _ASM_GENERIC_GPIO_H */ #endif /* _ASM_GENERIC_GPIO_H */

11
include/linux/gpio.h
View file

@ -16,14 +16,17 @@
#define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW) #define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
#define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH) #define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
/* Gpio pin is active-low */
#define GPIOF_ACTIVE_LOW (1 << 2)
/* Gpio pin is open drain */ /* Gpio pin is open drain */
#define GPIOF_OPEN_DRAIN (1 << 2) #define GPIOF_OPEN_DRAIN (1 << 3)
/* Gpio pin is open source */ /* Gpio pin is open source */
#define GPIOF_OPEN_SOURCE (1 << 3) #define GPIOF_OPEN_SOURCE (1 << 4)
#define GPIOF_EXPORT (1 << 4) #define GPIOF_EXPORT (1 << 5)
#define GPIOF_EXPORT_CHANGEABLE (1 << 5) #define GPIOF_EXPORT_CHANGEABLE (1 << 6)
#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT) #define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE) #define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)

238
include/linux/gpio/consumer.h Normal file
View file

@ -0,0 +1,238 @@
#ifndef __LINUX_GPIO_CONSUMER_H
#define __LINUX_GPIO_CONSUMER_H
#include <linux/err.h>
#include <linux/kernel.h>
#ifdef CONFIG_GPIOLIB
struct device;
struct gpio_chip;
/**
* Opaque descriptor for a GPIO. These are obtained using gpiod_get() and are
* preferable to the old integer-based handles.
*
* Contrary to integers, a pointer to a gpio_desc is guaranteed to be valid
* until the GPIO is released.
*/
struct gpio_desc;
int gpiod_get_direction(const struct gpio_desc *desc);
int gpiod_direction_input(struct gpio_desc *desc);
int gpiod_direction_output(struct gpio_desc *desc, int value);
/* Value get/set from non-sleeping context */
int gpiod_get_value(const struct gpio_desc *desc);
void gpiod_set_value(struct gpio_desc *desc, int value);
int gpiod_get_raw_value(const struct gpio_desc *desc);
void gpiod_set_raw_value(struct gpio_desc *desc, int value);
/* Value get/set from sleeping context */
int gpiod_get_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value);
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
int gpiod_is_active_low(const struct gpio_desc *desc);
int gpiod_cansleep(const struct gpio_desc *desc);
int gpiod_to_irq(const struct gpio_desc *desc);
/* Convert between the old gpio_ and new gpiod_ interfaces */
struct gpio_desc *gpio_to_desc(unsigned gpio);
int desc_to_gpio(const struct gpio_desc *desc);
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
#else /* CONFIG_GPIOLIB */
static inline struct gpio_desc *__must_check gpiod_get(struct device *dev,
const char *con_id)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx)
{
return ERR_PTR(-ENOSYS);
}
static inline void gpiod_put(struct gpio_desc *desc)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
const char *con_id)
{
return ERR_PTR(-ENOSYS);
}
static inline
struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx)
{
return ERR_PTR(-ENOSYS);
}
static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_direction(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_direction_input(struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_direction_output(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_get_value(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_value(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_raw_value(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_raw_value(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_raw_value_cansleep(struct gpio_desc *desc,
int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_is_active_low(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline int gpiod_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline int gpiod_to_irq(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -EINVAL;
}
static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
{
return ERR_PTR(-EINVAL);
}
static inline int desc_to_gpio(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -EINVAL;
}
static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return ERR_PTR(-ENODEV);
}
#endif /* CONFIG_GPIOLIB */
#if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_GPIO_SYSFS)
int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc);
int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
void gpiod_unexport(struct gpio_desc *desc);
#else /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
static inline int gpiod_export(struct gpio_desc *desc,
bool direction_may_change)
{
return -ENOSYS;
}
static inline int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
return -ENOSYS;
}
static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
return -ENOSYS;
}
static inline void gpiod_unexport(struct gpio_desc *desc)
{
}
#endif /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
#endif

127
include/linux/gpio/driver.h Normal file
View file

@ -0,0 +1,127 @@
#ifndef __LINUX_GPIO_DRIVER_H
#define __LINUX_GPIO_DRIVER_H
#include <linux/types.h>
struct device;
struct gpio_desc;
/**
* struct gpio_chip - abstract a GPIO controller
* @label: for diagnostics
* @dev: optional device providing the GPIOs
* @owner: helps prevent removal of modules exporting active GPIOs
* @list: links gpio_chips together for traversal
* @request: optional hook for chip-specific activation, such as
* enabling module power and clock; may sleep
* @free: optional hook for chip-specific deactivation, such as
* disabling module power and clock; may sleep
* @get_direction: returns direction for signal "offset", 0=out, 1=in,
* (same as GPIOF_DIR_XXX), or negative error
* @direction_input: configures signal "offset" as input, or returns error
* @direction_output: configures signal "offset" as output, or returns error
* @get: returns value for signal "offset"; for output signals this
* returns either the value actually sensed, or zero
* @set: assigns output value for signal "offset"
* @set_debounce: optional hook for setting debounce time for specified gpio in
* interrupt triggered gpio chips
* @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).
* @base: identifies the first GPIO number handled by this chip; or, if
* negative during registration, requests dynamic ID allocation.
* @ngpio: the number of GPIOs handled by this controller; the last GPIO
* handled is (base + ngpio - 1).
* @desc: array of ngpio descriptors. Private.
* @can_sleep: flag must be set iff get()/set() methods sleep, as they
* must while accessing GPIO expander chips over I2C or SPI
* @names: if set, must be an array of strings to use as alternative
* names for the GPIOs in this chip. Any entry in the array
* may be NULL if there is no alias for the GPIO, however the
* array must be @ngpio entries long. A name can include a single printk
* format specifier for an unsigned int. It is substituted by the actual
* number of the gpio.
*
* A gpio_chip can help platforms abstract various sources of GPIOs so
* they can all be accessed through a common programing interface.
* Example sources would be SOC controllers, FPGAs, multifunction
* chips, dedicated GPIO expanders, and so on.
*
* Each chip controls a number of signals, identified in method calls
* by "offset" values in the range 0..(@ngpio - 1). When those signals
* are referenced through calls like gpio_get_value(gpio), the offset
* is calculated by subtracting @base from the gpio number.
*/
struct gpio_chip {
const char *label;
struct device *dev;
struct module *owner;
struct list_head list;
int (*request)(struct gpio_chip *chip,
unsigned offset);
void (*free)(struct gpio_chip *chip,
unsigned offset);
int (*get_direction)(struct gpio_chip *chip,
unsigned offset);
int (*direction_input)(struct gpio_chip *chip,
unsigned offset);
int (*direction_output)(struct gpio_chip *chip,
unsigned offset, int value);
int (*get)(struct gpio_chip *chip,
unsigned offset);
void (*set)(struct gpio_chip *chip,
unsigned offset, int value);
int (*set_debounce)(struct gpio_chip *chip,
unsigned offset,
unsigned debounce);
int (*to_irq)(struct gpio_chip *chip,
unsigned offset);
void (*dbg_show)(struct seq_file *s,
struct gpio_chip *chip);
int base;
u16 ngpio;
struct gpio_desc *desc;
const char *const *names;
unsigned can_sleep:1;
unsigned exported:1;
#if defined(CONFIG_OF_GPIO)
/*
* If CONFIG_OF is enabled, then all GPIO controllers described in the
* device tree automatically may have an OF translation
*/
struct device_node *of_node;
int of_gpio_n_cells;
int (*of_xlate)(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags);
#endif
#ifdef CONFIG_PINCTRL
/*
* If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
* describe the actual pin range which they serve in an SoC. This
* information would be used by pinctrl subsystem to configure
* corresponding pins for gpio usage.
*/
struct list_head pin_ranges;
#endif
};
extern const char *gpiochip_is_requested(struct gpio_chip *chip,
unsigned offset);
/* add/remove chips */
extern int gpiochip_add(struct gpio_chip *chip);
extern int __must_check gpiochip_remove(struct gpio_chip *chip);
extern struct gpio_chip *gpiochip_find(void *data,
int (*match)(struct gpio_chip *chip, void *data));
/* lock/unlock as IRQ */
int gpiod_lock_as_irq(struct gpio_desc *desc);
void gpiod_unlock_as_irq(struct gpio_desc *desc);
#endif