* [PATCH v3 1/3] gpiolib: export descriptor-based GPIO interface
2013-10-17 17:21 [PATCH v3 0/3] New descriptor-based GPIO interface Alexandre Courbot
@ 2013-10-17 17:21 ` Alexandre Courbot
2013-10-17 17:21 ` [PATCH v3 2/3] gpiolib: port of_ functions to use gpiod Alexandre Courbot
` (2 subsequent siblings)
3 siblings, 0 replies; 9+ messages in thread
From: Alexandre Courbot @ 2013-10-17 17:21 UTC (permalink / raw)
To: Linus Walleij
Cc: Arnd Bergmann, Grant Likely, Mika Westerberg, gnurou,
Rafael J. Wysocki, Mathias Nyman, linux-gpio, linux-kernel,
linux-arch, devicetree, Alexandre Courbot
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>
---
drivers/gpio/gpiolib.c | 422 ++++++++++++++++++++++--------------------
include/asm-generic/gpio.h | 222 +++++++---------------
include/linux/gpio.h | 11 +-
include/linux/gpio/consumer.h | 238 ++++++++++++++++++++++++
include/linux/gpio/driver.h | 127 +++++++++++++
5 files changed, 658 insertions(+), 362 deletions(-)
create mode 100644 include/linux/gpio/consumer.h
create mode 100644 include/linux/gpio/driver.h
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 @@ struct gpio_desc {
#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 LIST_HEAD(gpio_chips);
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 @@ static int gpio_chip_hwgpio(const struct gpio_desc *desc)
/**
* 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 @@ static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip,
* 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 @@ static int gpio_ensure_requested(struct gpio_desc *desc)
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 @@ 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;
unsigned offset;
@@ -281,6 +263,7 @@ static int gpiod_get_direction(const struct gpio_desc *desc)
}
return status;
}
+EXPORT_SYMBOL_GPL(gpiod_get_direction);
#ifdef CONFIG_GPIO_SYSFS
@@ -365,17 +348,10 @@ static ssize_t gpio_value_show(struct device *dev,
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 @@ static ssize_t gpio_value_store(struct device *dev,
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 @@ 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
* @direction_may_change: true if userspace may change gpio direction
* Context: arch_initcall or later
@@ -804,7 +778,7 @@ static struct class gpio_class = {
*
* 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 @@ fail_unlock:
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 @@ 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
* @name: name of the symlink
* @gpio: gpio to create symlink to, already exported
@@ -905,8 +874,8 @@ static int match_export(struct device *dev, const void *data)
*
* 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 @@ static int gpiod_export_link(struct device *dev, const char *name,
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 @@ EXPORT_SYMBOL_GPL(gpio_export_link);
*
* 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 @@ unlock:
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 @@ static void gpiod_unexport(struct gpio_desc *desc)
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 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 */
/*
@@ -1677,7 +1610,16 @@ EXPORT_SYMBOL_GPL(gpiochip_is_requested);
* 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 @@ fail:
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 @@ fail:
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 @@ fail:
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 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce);
* 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 @@ static int _gpiod_get_value(const struct gpio_desc *desc)
}
/**
- * __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 @@ 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: 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 @@ static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
__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 @@ static void _gpiod_set_value(struct gpio_desc *desc, int value)
}
/**
- * __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);
}
+EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
-void __gpio_set_value(unsigned gpio, int value)
+/**
+ * gpiod_set_value() - 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 should be called from contexts where we cannot sleep, and will
+ * complain if the GPIO chip functions potentially sleep.
+ */
+void gpiod_set_value(struct gpio_desc *desc, int value)
{
- return gpiod_set_value(gpio_to_desc(gpio), 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(__gpio_set_value);
+EXPORT_SYMBOL_GPL(gpiod_set_value);
/**
- * __gpio_cansleep() - report whether gpio value access will sleep
- * @gpio: gpio in question
- * Context: any
+ * gpiod_cansleep() - report whether gpio value access may sleep
+ * @desc: gpio to check
*
- * This is used directly or indirectly to implement gpio_cansleep(). It
- * returns nonzero if access reading or writing the GPIO value can sleep.
*/
-static int gpiod_cansleep(const struct gpio_desc *desc)
+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 @@ static int gpiod_to_irq(const struct gpio_desc *desc)
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 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq);
* 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 @@ static int gpiod_lock_as_irq(struct gpio_desc *desc)
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 @@ EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
* 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 @@ void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
}
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));
+ 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(gpio_get_value_cansleep);
+EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
-static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
+/**
+ * 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 module;
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 struct gpio_chip *gpiochip_find(void *data,
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_one(unsigned gpio, unsigned long flags, const char *labe
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 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
#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
--
1.8.4
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 2/3] gpiolib: port of_ functions to use gpiod
2013-10-17 17:21 [PATCH v3 0/3] New descriptor-based GPIO interface Alexandre Courbot
2013-10-17 17:21 ` [PATCH v3 1/3] gpiolib: export " Alexandre Courbot
@ 2013-10-17 17:21 ` Alexandre Courbot
2013-10-17 17:21 ` [PATCH v3 3/3] gpiolib: add gpiod_get() and gpiod_put() functions Alexandre Courbot
2013-10-18 11:23 ` [PATCH v3 0/3] New descriptor-based GPIO interface Linus Walleij
3 siblings, 0 replies; 9+ messages in thread
From: Alexandre Courbot @ 2013-10-17 17:21 UTC (permalink / raw)
To: Linus Walleij
Cc: Arnd Bergmann, Grant Likely, Mika Westerberg, gnurou,
Rafael J. Wysocki, Mathias Nyman, linux-gpio, linux-kernel,
linux-arch, devicetree, Alexandre Courbot
Refactor the of_ functions of gpiolib to use the now public gpiod
interface, and export of_get_named_gpiod_flags() and
of_get_gpiod_flags() functions.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpio/gpiolib-of.c | 28 +++++++++++++++++-----------
include/linux/of_gpio.h | 29 ++++++++++++++++++++++++-----
2 files changed, 41 insertions(+), 16 deletions(-)
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 0dfaf20..32a396d 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -15,19 +15,21 @@
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/io.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
+struct gpio_desc;
+
/* Private data structure for of_gpiochip_find_and_xlate */
struct gg_data {
enum of_gpio_flags *flags;
struct of_phandle_args gpiospec;
- int out_gpio;
+ struct gpio_desc *out_gpio;
};
/* Private function for resolving node pointer to gpio_chip */
@@ -45,28 +47,31 @@ static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
if (ret < 0)
return false;
- gg_data->out_gpio = ret + gc->base;
+ gg_data->out_gpio = gpio_to_desc(ret + gc->base);
return true;
}
/**
- * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
+ * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
* @np: device node to get GPIO from
* @propname: property name containing gpio specifier(s)
* @index: index of the GPIO
* @flags: a flags pointer to fill in
*
- * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
* value on the error condition. If @flags is not NULL the function also fills
* in flags for the GPIO.
*/
-int of_get_named_gpio_flags(struct device_node *np, const char *propname,
- int index, enum of_gpio_flags *flags)
+struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
+ const char *propname, int index, enum of_gpio_flags *flags)
{
/* Return -EPROBE_DEFER to support probe() functions to be called
* later when the GPIO actually becomes available
*/
- struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
+ struct gg_data gg_data = {
+ .flags = flags,
+ .out_gpio = ERR_PTR(-EPROBE_DEFER)
+ };
int ret;
/* .of_xlate might decide to not fill in the flags, so clear it. */
@@ -78,16 +83,17 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
if (ret) {
pr_debug("%s: can't parse gpios property of node '%s[%d]'\n",
__func__, np->full_name, index);
- return ret;
+ return ERR_PTR(ret);
}
gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
of_node_put(gg_data.gpiospec.np);
- pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
+ pr_debug("%s exited with status %d\n", __func__,
+ PTR_RET(gg_data.out_gpio));
return gg_data.out_gpio;
}
-EXPORT_SYMBOL(of_get_named_gpio_flags);
+EXPORT_SYMBOL(of_get_named_gpiod_flags);
/**
* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index a83dc6f..d71f2cc 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -21,6 +21,7 @@
#include <linux/of.h>
struct device_node;
+struct gpio_desc;
/*
* This is Linux-specific flags. By default controllers' and Linux' mapping
@@ -47,7 +48,7 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
return container_of(gc, struct of_mm_gpio_chip, gc);
}
-extern int of_get_named_gpio_flags(struct device_node *np,
+extern struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
const char *list_name, int index, enum of_gpio_flags *flags);
extern int of_mm_gpiochip_add(struct device_node *np,
@@ -62,10 +63,10 @@ extern int of_gpio_simple_xlate(struct gpio_chip *gc,
#else /* CONFIG_OF_GPIO */
/* Drivers may not strictly depend on the GPIO support, so let them link. */
-static inline int of_get_named_gpio_flags(struct device_node *np,
+static inline struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
const char *list_name, int index, enum of_gpio_flags *flags)
{
- return -ENOSYS;
+ return ERR_PTR(-ENOSYS);
}
static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
@@ -80,6 +81,18 @@ static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
#endif /* CONFIG_OF_GPIO */
+static inline int of_get_named_gpio_flags(struct device_node *np,
+ const char *list_name, int index, enum of_gpio_flags *flags)
+{
+ struct gpio_desc *desc;
+ desc = of_get_named_gpiod_flags(np, list_name, index, flags);
+
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+ else
+ return desc_to_gpio(desc);
+}
+
/**
* of_gpio_named_count() - Count GPIOs for a device
* @np: device node to count GPIOs for
@@ -117,15 +130,21 @@ static inline int of_gpio_count(struct device_node *np)
}
/**
- * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
+ * of_get_gpiod_flags() - Get a GPIO descriptor and flags to use with GPIO API
* @np: device node to get GPIO from
* @index: index of the GPIO
* @flags: a flags pointer to fill in
*
- * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * Returns GPIO descriptor to use with Linux generic GPIO API, or a errno
* value on the error condition. If @flags is not NULL the function also fills
* in flags for the GPIO.
*/
+static inline struct gpio_desc *of_get_gpiod_flags(struct device_node *np,
+ int index, enum of_gpio_flags *flags)
+{
+ return of_get_named_gpiod_flags(np, "gpios", index, flags);
+}
+
static inline int of_get_gpio_flags(struct device_node *np, int index,
enum of_gpio_flags *flags)
{
--
1.8.4
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 3/3] gpiolib: add gpiod_get() and gpiod_put() functions
2013-10-17 17:21 [PATCH v3 0/3] New descriptor-based GPIO interface Alexandre Courbot
2013-10-17 17:21 ` [PATCH v3 1/3] gpiolib: export " Alexandre Courbot
2013-10-17 17:21 ` [PATCH v3 2/3] gpiolib: port of_ functions to use gpiod Alexandre Courbot
@ 2013-10-17 17:21 ` Alexandre Courbot
2013-10-18 11:23 ` [PATCH v3 0/3] New descriptor-based GPIO interface Linus Walleij
3 siblings, 0 replies; 9+ messages in thread
From: Alexandre Courbot @ 2013-10-17 17:21 UTC (permalink / raw)
To: Linus Walleij
Cc: Arnd Bergmann, Grant Likely, Mika Westerberg, gnurou,
Rafael J. Wysocki, Mathias Nyman, linux-gpio, linux-kernel,
linux-arch, devicetree, Alexandre Courbot
Add gpiod_get(), gpiod_get_index() and gpiod_put() functions that
provide safer management of GPIOs.
These functions put the GPIO framework in line with the conventions of
other frameworks in the kernel, and help ensure every GPIO is declared
properly and valid while it is used.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpio/devres.c | 83 +++++++++++++++++
drivers/gpio/gpiolib.c | 203 ++++++++++++++++++++++++++++++++++++++++++
include/linux/gpio/consumer.h | 15 ++++
include/linux/gpio/driver.h | 56 ++++++++++++
4 files changed, 357 insertions(+)
diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
index 3e7812f..2caa257 100644
--- a/drivers/gpio/devres.c
+++ b/drivers/gpio/devres.c
@@ -19,6 +19,89 @@
#include <linux/device.h>
#include <linux/gfp.h>
+static void devm_gpiod_release(struct device *dev, void *res)
+{
+ struct gpio_desc **desc = res;
+
+ gpiod_put(*desc);
+}
+
+static int devm_gpiod_match(struct device *dev, void *res, void *data)
+{
+ struct gpio_desc **this = res, **gpio = data;
+
+ return *this == *gpio;
+}
+
+/**
+ * devm_gpiod_get - Resource-managed gpiod_get()
+ * @dev: GPIO consumer
+ * @con_id: function within the GPIO consumer
+ *
+ * Managed gpiod_get(). GPIO descriptors returned from this function are
+ * automatically disposed on driver detach. See gpiod_get() for detailed
+ * information about behavior and return values.
+ */
+struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
+ const char *con_id)
+{
+ return devm_gpiod_get_index(dev, con_id, 0);
+}
+EXPORT_SYMBOL(devm_gpiod_get);
+
+/**
+ * devm_gpiod_get_index - Resource-managed gpiod_get_index()
+ * @dev: GPIO consumer
+ * @con_id: function within the GPIO consumer
+ * @idx: index of the GPIO to obtain in the consumer
+ *
+ * Managed gpiod_get_index(). GPIO descriptors returned from this function are
+ * automatically disposed on driver detach. See gpiod_get_index() for detailed
+ * information about behavior and return values.
+ */
+struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx)
+{
+ struct gpio_desc **dr;
+ struct gpio_desc *desc;
+
+ dr = devres_alloc(devm_gpiod_release, sizeof(struct gpiod_desc *),
+ GFP_KERNEL);
+ if (!dr)
+ return ERR_PTR(-ENOMEM);
+
+ desc = gpiod_get_index(dev, con_id, idx);
+ if (IS_ERR(desc)) {
+ devres_free(dr);
+ return desc;
+ }
+
+ *dr = desc;
+ devres_add(dev, dr);
+
+ return 0;
+}
+EXPORT_SYMBOL(devm_gpiod_get_index);
+
+/**
+ * devm_gpiod_put - Resource-managed gpiod_put()
+ * @desc: GPIO descriptor to dispose of
+ *
+ * Dispose of a GPIO descriptor obtained with devm_gpiod_get() or
+ * devm_gpiod_get_index(). Normally this function will not be called as the GPIO
+ * will be disposed of by the resource management code.
+ */
+void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
+{
+ WARN_ON(devres_release(dev, devm_gpiod_release, devm_gpiod_match,
+ &desc));
+}
+EXPORT_SYMBOL(devm_gpiod_put);
+
+
+
+
static void devm_gpio_release(struct device *dev, void *res)
{
unsigned *gpio = res;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 224abdc..9263c7b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -70,6 +70,8 @@ static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
+static DEFINE_MUTEX(gpio_lookup_lock);
+static LIST_HEAD(gpio_lookup_list);
static LIST_HEAD(gpio_chips);
#ifdef CONFIG_GPIO_SYSFS
@@ -2192,6 +2194,207 @@ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
}
EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
+/**
+ * gpiod_add_table() - register GPIO device consumers
+ * @table: array of consumers to register
+ * @num: number of consumers in table
+ */
+void gpiod_add_table(struct gpiod_lookup *table, size_t size)
+{
+ mutex_lock(&gpio_lookup_lock);
+
+ while (size--) {
+ list_add_tail(&table->list, &gpio_lookup_list);
+ table++;
+ }
+
+ mutex_unlock(&gpio_lookup_lock);
+}
+
+/*
+ * Caller must have a acquired gpio_lookup_lock
+ */
+static struct gpio_chip *find_chip_by_name(const char *name)
+{
+ struct gpio_chip *chip = NULL;
+
+ list_for_each_entry(chip, &gpio_lookup_list, list) {
+ if (chip->label == NULL)
+ continue;
+ if (!strcmp(chip->label, name))
+ break;
+ }
+
+ return chip;
+}
+
+#ifdef CONFIG_OF
+static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
+ unsigned int idx, unsigned long *flags)
+{
+ char prop_name[32]; /* 32 is max size of property name */
+ enum of_gpio_flags of_flags;
+ struct gpio_desc *desc;
+
+ if (con_id)
+ snprintf(prop_name, 32, "%s-gpios", con_id);
+ else
+ snprintf(prop_name, 32, "gpios");
+
+ desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
+ &of_flags);
+
+ if (IS_ERR(desc))
+ return desc;
+
+ if (of_flags & OF_GPIO_ACTIVE_LOW)
+ *flags |= GPIOF_ACTIVE_LOW;
+
+ return desc;
+}
+#else
+static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
+ unsigned int idx, unsigned long *flags)
+{
+ return ERR_PTR(-ENODEV);
+}
+#endif
+
+static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
+ unsigned int idx, unsigned long *flags)
+{
+ const char *dev_id = dev ? dev_name(dev) : NULL;
+ struct gpio_desc *desc = ERR_PTR(-ENODEV);
+ unsigned int match, best = 0;
+ struct gpiod_lookup *p;
+
+ mutex_lock(&gpio_lookup_lock);
+
+ list_for_each_entry(p, &gpio_lookup_list, list) {
+ match = 0;
+
+ if (p->dev_id) {
+ if (!dev_id || strcmp(p->dev_id, dev_id))
+ continue;
+
+ match += 2;
+ }
+
+ if (p->con_id) {
+ if (!con_id || strcmp(p->con_id, con_id))
+ continue;
+
+ match += 1;
+ }
+
+ if (p->idx != idx)
+ continue;
+
+ if (match > best) {
+ struct gpio_chip *chip;
+
+ chip = find_chip_by_name(p->chip_label);
+
+ if (!chip) {
+ dev_warn(dev, "cannot find GPIO chip %s\n",
+ p->chip_label);
+ continue;
+ }
+
+ if (chip->ngpio >= p->chip_hwnum) {
+ dev_warn(dev, "GPIO chip %s has %d GPIOs\n",
+ chip->label, chip->ngpio);
+ continue;
+ }
+
+ desc = gpio_to_desc(chip->base + p->chip_hwnum);
+ *flags = p->flags;
+
+ if (match != 3)
+ best = match;
+ else
+ break;
+ }
+ }
+
+ mutex_unlock(&gpio_lookup_lock);
+
+ return desc;
+}
+
+/**
+ * gpio_get - obtain a GPIO for a given GPIO function
+ * @dev: GPIO consumer
+ * @con_id: function within the GPIO consumer
+ *
+ * Return the GPIO descriptor corresponding to the function con_id of device
+ * dev, or an IS_ERR() condition if an error occured.
+ */
+struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id)
+{
+ return gpiod_get_index(dev, con_id, 0);
+}
+EXPORT_SYMBOL_GPL(gpiod_get);
+
+/**
+ * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
+ * @dev: GPIO consumer
+ * @con_id: function within the GPIO consumer
+ * @idx: index of the GPIO to obtain in the consumer
+ *
+ * This variant of gpiod_get() allows to access GPIOs other than the first
+ * defined one for functions that define several GPIOs.
+ *
+ * Return a valid GPIO descriptor, or an IS_ERR() condition in case of error.
+ */
+struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx)
+{
+ struct gpio_desc *desc;
+ int status;
+ unsigned long flags = 0;
+
+ dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
+
+ /* Using device tree? */
+ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
+ dev_dbg(dev, "using device tree for GPIO lookup\n");
+ desc = of_find_gpio(dev, con_id, idx, &flags);
+ } else {
+ dev_dbg(dev, "using lookup tables for GPIO lookup");
+ desc = gpiod_find(dev, con_id, idx, &flags);
+ }
+
+ if (IS_ERR(desc)) {
+ dev_warn(dev, "lookup for GPIO %s failed\n", con_id);
+ return desc;
+ }
+
+ status = gpiod_request(desc, con_id);
+
+ if (status < 0)
+ return ERR_PTR(status);
+
+ if (flags & GPIOF_ACTIVE_LOW)
+ set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
+ return desc;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_index);
+
+/**
+ * gpiod_put - dispose of a GPIO descriptor
+ * @desc: GPIO descriptor to dispose of
+ *
+ * No descriptor can be used after gpiod_put() has been called on it.
+ */
+void gpiod_put(struct gpio_desc *desc)
+{
+ gpiod_free(desc);
+}
+EXPORT_SYMBOL_GPL(gpiod_put);
+
#ifdef CONFIG_DEBUG_FS
static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 2088eb5..4d34dbb 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -18,6 +18,21 @@ struct gpio_chip;
*/
struct gpio_desc;
+/* Acquire and dispose GPIOs */
+struct gpio_desc *__must_check gpiod_get(struct device *dev,
+ const char *con_id);
+struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx);
+void gpiod_put(struct gpio_desc *desc);
+
+struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
+ const char *con_id);
+struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx);
+void devm_gpiod_put(struct device *dev, struct gpio_desc *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);
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 5dc172c..cd9da38 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -124,4 +124,60 @@ extern struct gpio_chip *gpiochip_find(void *data,
int gpiod_lock_as_irq(struct gpio_desc *desc);
void gpiod_unlock_as_irq(struct gpio_desc *desc);
+/**
+ * Lookup table for associating GPIOs to specific devices and functions using
+ * platform data.
+ */
+struct gpiod_lookup {
+ struct list_head list;
+ /*
+ * name of the chip the GPIO belongs to
+ */
+ const char *chip_label;
+ /*
+ * hardware number (i.e. relative to the chip) of the GPIO
+ */
+ u16 chip_hwnum;
+ /*
+ * name of device that can claim this GPIO
+ */
+ const char *dev_id;
+ /*
+ * name of the GPIO from the device's point of view
+ */
+ const char *con_id;
+ /*
+ * index of the GPIO in case several GPIOs share the same name
+ */
+ unsigned int idx;
+ /*
+ * mask of GPIOF_* values
+ */
+ unsigned long flags;
+};
+
+/*
+ * Simple definition of a single GPIO under a con_id
+ */
+#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _dev_id, _con_id, _flags) \
+ GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, 0, _flags)
+
+/*
+ * Use this macro if you need to have several GPIOs under the same con_id.
+ * Each GPIO needs to use a different index and can be accessed using
+ * gpiod_get_index()
+ */
+#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _dev_id, _con_id, _idx, \
+ _flags) \
+{ \
+ .chip_label = _chip_label, \
+ .chip_hwnum = _chip_hwnum, \
+ .dev_id = _dev_id, \
+ .con_id = _con_id, \
+ .idx = _idx, \
+ .flags = _flags, \
+}
+
+void gpiod_add_table(struct gpiod_lookup *table, size_t size);
+
#endif
--
1.8.4
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