gpiolib: export descriptor-based GPIO interface
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>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index d66139d..224abdc 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -16,16 +16,11 @@
#define CREATE_TRACE_POINTS
#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
- * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
- *
- * 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.
+ * 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 @@
#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */
#define FLAG_TRIG_FALL 4 /* trigger on falling 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_SOURCE 8 /* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
@@ -81,29 +76,8 @@
static DEFINE_IDR(dirent_idr);
#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 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
#define gpiod_emerg(desc, fmt, ...) \
@@ -157,13 +131,14 @@
/**
* 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))
return NULL;
else
return &gpio_desc[gpio];
}
+EXPORT_SYMBOL_GPL(gpio_to_desc);
/**
* Convert an offset on a certain chip to a corresponding descriptor
@@ -181,10 +156,11 @@
* This should disappear in the future but is needed since we still
* 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];
}
+EXPORT_SYMBOL_GPL(desc_to_gpio);
/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
@@ -219,16 +195,15 @@
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;
}
-
-/* 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));
-}
+EXPORT_SYMBOL_GPL(gpiod_to_chip);
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
@@ -254,8 +229,15 @@
}
}
-/* 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;
unsigned offset;
@@ -281,6 +263,7 @@
}
return status;
}
+EXPORT_SYMBOL_GPL(gpiod_get_direction);
#ifdef CONFIG_GPIO_SYSFS
@@ -365,17 +348,10 @@
mutex_lock(&sysfs_lock);
- if (!test_bit(FLAG_EXPORT, &desc->flags)) {
+ if (!test_bit(FLAG_EXPORT, &desc->flags))
status = -EIO;
- } else {
- int value;
-
- value = !!gpiod_get_value_cansleep(desc);
- if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
- value = !value;
-
- status = sprintf(buf, "%d\n", value);
- }
+ else
+ status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
mutex_unlock(&sysfs_lock);
return status;
@@ -398,9 +374,7 @@
status = kstrtol(buf, 0, &value);
if (status == 0) {
- if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
- value = !value;
- gpiod_set_value_cansleep(desc, value != 0);
+ gpiod_set_value_cansleep(desc, value);
status = size;
}
}
@@ -790,7 +764,7 @@
/**
- * gpio_export - export a GPIO through sysfs
+ * gpiod_export - export a GPIO through sysfs
* @gpio: gpio to make available, already requested
* @direction_may_change: true if userspace may change gpio direction
* Context: arch_initcall or later
@@ -804,7 +778,7 @@
*
* 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;
int status;
@@ -882,12 +856,7 @@
status);
return status;
}
-
-int gpio_export(unsigned gpio, bool direction_may_change)
-{
- return gpiod_export(gpio_to_desc(gpio), direction_may_change);
-}
-EXPORT_SYMBOL_GPL(gpio_export);
+EXPORT_SYMBOL_GPL(gpiod_export);
static int match_export(struct device *dev, const void *data)
{
@@ -895,7 +864,7 @@
}
/**
- * 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
* @name: name of the symlink
* @gpio: gpio to create symlink to, already exported
@@ -905,8 +874,8 @@
*
* Returns zero on success, else an error.
*/
-static int gpiod_export_link(struct device *dev, const char *name,
- struct gpio_desc *desc)
+int gpiod_export_link(struct device *dev, const char *name,
+ struct gpio_desc *desc)
{
int status = -EINVAL;
@@ -937,15 +906,10 @@
return status;
}
-
-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);
+EXPORT_SYMBOL_GPL(gpiod_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
* @value: non-zero to use active low, i.e. inverted values
*
@@ -956,7 +920,7 @@
*
* 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;
int status = -EINVAL;
@@ -987,20 +951,15 @@
return status;
}
-
-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);
+EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
/**
- * gpio_unexport - reverse effect of gpio_export()
+ * gpiod_unexport - reverse effect of gpio_export()
* @gpio: gpio to make unavailable
*
* This is implicit on gpio_free().
*/
-static void gpiod_unexport(struct gpio_desc *desc)
+void gpiod_unexport(struct gpio_desc *desc)
{
int status = 0;
struct device *dev = NULL;
@@ -1033,12 +992,7 @@
pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
status);
}
-
-void gpio_unexport(unsigned gpio)
-{
- gpiod_unexport(gpio_to_desc(gpio));
-}
-EXPORT_SYMBOL_GPL(gpio_unexport);
+EXPORT_SYMBOL_GPL(gpiod_unexport);
static int gpiochip_export(struct gpio_chip *chip)
{
@@ -1145,27 +1099,6 @@
{
}
-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 */
/*
@@ -1677,7 +1610,16 @@
* 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;
struct gpio_chip *chip;
@@ -1734,14 +1676,19 @@
gpiod_dbg(desc, "%s status %d\n", __func__, status);
return status;
}
+EXPORT_SYMBOL_GPL(gpiod_direction_input);
-int gpio_direction_input(unsigned gpio)
-{
- return gpiod_direction_input(gpio_to_desc(gpio));
-}
-EXPORT_SYMBOL_GPL(gpio_direction_input);
-
-static int gpiod_direction_output(struct gpio_desc *desc, int value)
+/**
+ * gpiod_direction_output - set the GPIO direction to input
+ * @desc: GPIO to set to output
+ * @value: initial output value of the GPIO
+ *
+ * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
+ * 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;
struct gpio_chip *chip;
@@ -1814,22 +1761,17 @@
gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
return status;
}
-
-int gpio_direction_output(unsigned gpio, int value)
-{
- return gpiod_direction_output(gpio_to_desc(gpio), value);
-}
-EXPORT_SYMBOL_GPL(gpio_direction_output);
+EXPORT_SYMBOL_GPL(gpiod_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
* @debounce: debounce time is microseconds
*
* returns -ENOTSUPP if the controller does not support setting
* 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;
struct gpio_chip *chip;
@@ -1871,12 +1813,19 @@
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
* "is this a valid GPIO" error checks should already have been done.
@@ -1900,7 +1849,7 @@
* 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;
int value;
@@ -1914,33 +1863,54 @@
}
/**
- * __gpio_get_value() - return a gpio's value
- * @gpio: gpio whose value will be returned
- * Context: any
+ * gpiod_get_raw_value() - return a gpio's raw value
+ * @desc: gpio whose value will be returned
*
- * This is used directly or indirectly to implement gpio_get_value().
- * It returns the zero or nonzero value provided by the associated
- * gpio_chip.get() method; or zero if no such method is provided.
+ * Return the GPIO's raw value, i.e. the value of the physical line disregarding
+ * 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 int gpiod_get_value(const struct gpio_desc *desc)
+int gpiod_get_raw_value(const struct gpio_desc *desc)
{
if (!desc)
return 0;
/* Should be using gpio_get_value_cansleep() */
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: Gpio whose state need to be set.
- * @chip: Gpio chip.
+ * @desc: gpio descriptor whose state need to be set.
* @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)
@@ -1966,9 +1936,8 @@
}
/*
- * _gpio_set_open_source() - Set the open source gpio's value.
- * @gpio: Gpio whose state need to be set.
- * @chip: Gpio chip.
+ * _gpio_set_open_source_value() - Set the open source gpio's value.
+ * @desc: gpio descriptor whose state need to be set.
* @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)
@@ -1993,7 +1962,7 @@
__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;
@@ -2008,62 +1977,70 @@
}
/**
- * __gpio_set_value() - assign a gpio's value
- * @gpio: gpio whose value will be assigned
+ * gpiod_set_raw_value() - assign a gpio's raw value
+ * @desc: gpio whose value will be assigned
* @value: value to assign
- * Context: any
*
- * This is used directly or indirectly to implement gpio_set_value().
- * It invokes the associated gpio_chip.set() method.
+ * Set the raw value of the GPIO, i.e. the value of its physical line without
+ * 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)
return;
/* Should be using gpio_set_value_cansleep() */
WARN_ON(desc->chip->can_sleep);
- _gpiod_set_value(desc, value);
+ _gpiod_set_raw_value(desc, value);
}
-
-void __gpio_set_value(unsigned gpio, int value)
-{
- return gpiod_set_value(gpio_to_desc(gpio), value);
-}
-EXPORT_SYMBOL_GPL(__gpio_set_value);
+EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
/**
- * __gpio_cansleep() - report whether gpio value access will sleep
- * @gpio: gpio in question
- * Context: any
+ * gpiod_set_value() - assign a gpio's value
+ * @desc: gpio whose value will be assigned
+ * @value: value to assign
*
- * This is used directly or indirectly to implement gpio_cansleep(). It
- * returns nonzero if access reading or writing the GPIO value can sleep.
+ * Set the logical value of the GPIO, i.e. taking its 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.
*/
-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)
return 0;
- /* only call this on GPIOs that are valid! */
return desc->chip->can_sleep;
}
-
-int __gpio_cansleep(unsigned gpio)
-{
- return gpiod_cansleep(gpio_to_desc(gpio));
-}
-EXPORT_SYMBOL_GPL(__gpio_cansleep);
+EXPORT_SYMBOL_GPL(gpiod_cansleep);
/**
- * __gpio_to_irq() - return the IRQ corresponding to a GPIO
- * @gpio: gpio whose IRQ will be returned (already requested)
- * Context: any
+ * gpiod_to_irq() - return the IRQ corresponding to a GPIO
+ * @desc: gpio whose IRQ will be returned (already requested)
*
- * This is used directly or indirectly to implement gpio_to_irq().
- * It returns the number of the IRQ signaled by this (input) GPIO,
- * or a negative errno.
+ * Return the IRQ corresponding to the passed GPIO, or an error code in case of
+ * error.
*/
-static int gpiod_to_irq(const struct gpio_desc *desc)
+int gpiod_to_irq(const struct gpio_desc *desc)
{
struct gpio_chip *chip;
int offset;
@@ -2074,12 +2051,7 @@
offset = gpio_chip_hwgpio(desc);
return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
}
-
-int __gpio_to_irq(unsigned gpio)
-{
- return gpiod_to_irq(gpio_to_desc(gpio));
-}
-EXPORT_SYMBOL_GPL(__gpio_to_irq);
+EXPORT_SYMBOL_GPL(gpiod_to_irq);
/**
* gpiod_lock_as_irq() - lock a GPIO to be used as IRQ
@@ -2091,7 +2063,7 @@
* of its irq_chip implementation if the GPIO is known from that
* code.
*/
-static int gpiod_lock_as_irq(struct gpio_desc *desc)
+int gpiod_lock_as_irq(struct gpio_desc *desc)
{
if (!desc)
return -EINVAL;
@@ -2106,6 +2078,7 @@
set_bit(FLAG_USED_AS_IRQ, &desc->flags);
return 0;
}
+EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);
int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
@@ -2120,13 +2093,14 @@
* This is used directly by GPIO drivers that want to indicate
* 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)
return;
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)
{
@@ -2134,37 +2108,89 @@
}
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.
*/
-
-static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
+int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
might_sleep_if(extra_checks);
if (!desc)
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));
-}
-EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
+ int value;
-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);
if (!desc)
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
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index b309a5c..00f8f0a 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -10,6 +10,8 @@
#ifdef CONFIG_GPIOLIB
#include <linux/compiler.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/consumer.h>
/* Platforms may implement their GPIO interface with library code,
* at a small performance cost for non-inlined operations and some
@@ -49,122 +51,11 @@
struct device_node;
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
- * @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));
-
+/* caller holds gpio_lock *OR* gpio is marked as requested */
+static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
+{
+ return gpiod_to_chip(gpio_to_desc(gpio));
+}
/* Always use the library code for GPIO management calls,
* or when sleeping may be involved.
@@ -172,25 +63,52 @@
extern int gpio_request(unsigned gpio, const char *label);
extern void gpio_free(unsigned gpio);
-extern int gpio_direction_input(unsigned gpio);
-extern int gpio_direction_output(unsigned gpio, int value);
+static inline int gpio_direction_input(unsigned gpio)
+{
+ 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);
-extern void gpio_set_value_cansleep(unsigned gpio, int value);
+static inline int gpio_get_value_cansleep(unsigned gpio)
+{
+ 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
* the GPIO is constant and refers to some always-present controller,
* giving direct access to chip registers and tight bitbanging loops.
*/
-extern int __gpio_get_value(unsigned gpio);
-extern void __gpio_set_value(unsigned gpio, int value);
+static inline int __gpio_get_value(unsigned gpio)
+{
+ 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 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
@@ -199,19 +117,30 @@
extern int gpio_request_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,
* but more typically is configured entirely from userspace.
*/
-extern int gpio_export(unsigned gpio, bool direction_may_change);
-extern int gpio_export_link(struct device *dev, const char *name,
- unsigned gpio);
-extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
-extern void gpio_unexport(unsigned gpio);
+static inline int gpio_export(unsigned gpio, bool direction_may_change)
+{
+ return gpiod_export(gpio_to_desc(gpio), direction_may_change);
+}
-#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
@@ -281,31 +210,4 @@
#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 */
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index a06ec3e..c691df0 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -16,14 +16,17 @@
#define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
#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 */
-#define GPIOF_OPEN_DRAIN (1 << 2)
+#define GPIOF_OPEN_DRAIN (1 << 3)
/* 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_CHANGEABLE (1 << 5)
+#define GPIOF_EXPORT (1 << 5)
+#define GPIOF_EXPORT_CHANGEABLE (1 << 6)
#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
new file mode 100644
index 0000000..2088eb5
--- /dev/null
+++ b/include/linux/gpio/consumer.h
@@ -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
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
new file mode 100644
index 0000000..5dc172c
--- /dev/null
+++ b/include/linux/gpio/driver.h
@@ -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
