General Purpose Input/Output (GPIO)¶
Contents:
Core¶
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struct gpio_irq_chip¶
GPIO interrupt controller
Definition:
struct gpio_irq_chip {
struct irq_chip *chip;
struct irq_domain *domain;
const struct irq_domain_ops *domain_ops;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY;
struct fwnode_handle *fwnode;
struct irq_domain *parent_domain;
int (*child_to_parent_hwirq)(struct gpio_chip *gc,unsigned int child_hwirq,unsigned int child_type,unsigned int *parent_hwirq, unsigned int *parent_type);
int (*populate_parent_alloc_arg)(struct gpio_chip *gc,union gpio_irq_fwspec *fwspec,unsigned int parent_hwirq, unsigned int parent_type);
unsigned int (*child_offset_to_irq)(struct gpio_chip *gc, unsigned int pin);
struct irq_domain_ops child_irq_domain_ops;
#endif;
irq_flow_handler_t handler;
unsigned int default_type;
struct lock_class_key *lock_key;
struct lock_class_key *request_key;
irq_flow_handler_t parent_handler;
union {
void *parent_handler_data;
void **parent_handler_data_array;
};
unsigned int num_parents;
unsigned int *parents;
unsigned int *map;
bool threaded;
bool per_parent_data;
bool initialized;
bool domain_is_allocated_externally;
int (*init_hw)(struct gpio_chip *gc);
void (*init_valid_mask)(struct gpio_chip *gc,unsigned long *valid_mask, unsigned int ngpios);
unsigned long *valid_mask;
unsigned int first;
void (*irq_enable)(struct irq_data *data);
void (*irq_disable)(struct irq_data *data);
void (*irq_unmask)(struct irq_data *data);
void (*irq_mask)(struct irq_data *data);
};
Members
chip
GPIO IRQ chip implementation, provided by GPIO driver.
domain
Interrupt translation domain; responsible for mapping between GPIO hwirq number and Linux IRQ number.
domain_ops
Table of interrupt domain operations for this IRQ chip.
fwnode
Firmware node corresponding to this gpiochip/irqchip, necessary for hierarchical irqdomain support.
parent_domain
If non-NULL, will be set as the parent of this GPIO interrupt controller's IRQ domain to establish a hierarchical interrupt domain. The presence of this will activate the hierarchical interrupt support.
child_to_parent_hwirq
This callback translates a child hardware IRQ offset to a parent hardware IRQ offset on a hierarchical interrupt chip. The child hardware IRQs correspond to the GPIO index 0..ngpio-1 (see the ngpio field of
struct gpio_chip
) and the corresponding parent hardware IRQ and type (such as IRQ_TYPE_*) shall be returned by the driver. The driver can calculate this from an offset or using a lookup table or whatever method is best for this chip. Return 0 on successful translation in the driver.If some ranges of hardware IRQs do not have a corresponding parent HWIRQ, return -EINVAL, but also make sure to fill in valid_mask and need_valid_mask to make these GPIO lines unavailable for translation.
populate_parent_alloc_arg
This optional callback allocates and populates the specific struct for the parent's IRQ domain. If this is not specified, then
gpiochip_populate_parent_fwspec_twocell
will be used. A four-cell variant namedgpiochip_populate_parent_fwspec_fourcell
is also available.child_offset_to_irq
This optional callback is used to translate the child's GPIO line offset on the GPIO chip to an IRQ number for the GPIO to_irq() callback. If this is not specified, then a default callback will be provided that returns the line offset.
child_irq_domain_ops
The IRQ domain operations that will be used for this GPIO IRQ chip. If no operations are provided, then default callbacks will be populated to setup the IRQ hierarchy. Some drivers need to supply their own translate function.
handler
The IRQ handler to use (often a predefined IRQ core function) for GPIO IRQs, provided by GPIO driver.
default_type
Default IRQ triggering type applied during GPIO driver initialization, provided by GPIO driver.
lock_key
Per GPIO IRQ chip lockdep class for IRQ lock.
request_key
Per GPIO IRQ chip lockdep class for IRQ request.
parent_handler
The interrupt handler for the GPIO chip's parent interrupts, may be NULL if the parent interrupts are nested rather than cascaded.
{unnamed_union}
anonymous
parent_handler_data
If per_parent_data is false, parent_handler_data is a single pointer used as the data associated with every parent interrupt.
parent_handler_data_array
If per_parent_data is true, parent_handler_data_array is an array of num_parents pointers, and is used to associate different data for each parent. This cannot be NULL if per_parent_data is true.
num_parents
The number of interrupt parents of a GPIO chip.
parents
A list of interrupt parents of a GPIO chip. This is owned by the driver, so the core will only reference this list, not modify it.
map
A list of interrupt parents for each line of a GPIO chip.
threaded
True if set the interrupt handling uses nested threads.
per_parent_data
True if parent_handler_data_array describes a num_parents sized array to be used as parent data.
initialized
Flag to track GPIO chip irq member's initialization. This flag will make sure GPIO chip irq members are not used before they are initialized.
domain_is_allocated_externally
True it the irq_domain was allocated outside of gpiolib, in which case gpiolib won't free the irq_domain itself.
init_hw
optional routine to initialize hardware before an IRQ chip will be added. This is quite useful when a particular driver wants to clear IRQ related registers in order to avoid undesired events.
init_valid_mask
optional routine to initialize valid_mask, to be used if not all GPIO lines are valid interrupts. Sometimes some lines just cannot fire interrupts, and this routine, when defined, is passed a bitmap in "valid_mask" and it will have ngpios bits from 0..(ngpios-1) set to "1" as in valid. The callback can then directly set some bits to "0" if they cannot be used for interrupts.
valid_mask
If not
NULL
, holds bitmask of GPIOs which are valid to be included in IRQ domain of the chip.first
Required for static IRQ allocation. If set, irq_domain_add_simple() will allocate and map all IRQs during initialization.
irq_enable
Store old irq_chip irq_enable callback
irq_disable
Store old irq_chip irq_disable callback
irq_unmask
Store old irq_chip irq_unmask callback
irq_mask
Store old irq_chip irq_mask callback
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struct gpio_chip¶
abstract a GPIO controller
Definition:
struct gpio_chip {
const char *label;
struct gpio_device *gpiodev;
struct device *parent;
struct fwnode_handle *fwnode;
struct module *owner;
int (*request)(struct gpio_chip *gc, unsigned int offset);
void (*free)(struct gpio_chip *gc, unsigned int offset);
int (*get_direction)(struct gpio_chip *gc, unsigned int offset);
int (*direction_input)(struct gpio_chip *gc, unsigned int offset);
int (*direction_output)(struct gpio_chip *gc, unsigned int offset, int value);
int (*get)(struct gpio_chip *gc, unsigned int offset);
int (*get_multiple)(struct gpio_chip *gc,unsigned long *mask, unsigned long *bits);
void (*set)(struct gpio_chip *gc, unsigned int offset, int value);
void (*set_multiple)(struct gpio_chip *gc,unsigned long *mask, unsigned long *bits);
int (*set_config)(struct gpio_chip *gc,unsigned int offset, unsigned long config);
int (*to_irq)(struct gpio_chip *gc, unsigned int offset);
void (*dbg_show)(struct seq_file *s, struct gpio_chip *gc);
int (*init_valid_mask)(struct gpio_chip *gc,unsigned long *valid_mask, unsigned int ngpios);
int (*add_pin_ranges)(struct gpio_chip *gc);
int (*en_hw_timestamp)(struct gpio_chip *gc,u32 offset, unsigned long flags);
int (*dis_hw_timestamp)(struct gpio_chip *gc,u32 offset, unsigned long flags);
int base;
u16 ngpio;
u16 offset;
const char *const *names;
bool can_sleep;
#if IS_ENABLED(CONFIG_GPIO_GENERIC);
unsigned long (*read_reg)(void __iomem *reg);
void (*write_reg)(void __iomem *reg, unsigned long data);
bool be_bits;
void __iomem *reg_dat;
void __iomem *reg_set;
void __iomem *reg_clr;
void __iomem *reg_dir_out;
void __iomem *reg_dir_in;
bool bgpio_dir_unreadable;
int bgpio_bits;
raw_spinlock_t bgpio_lock;
unsigned long bgpio_data;
unsigned long bgpio_dir;
#endif ;
#ifdef CONFIG_GPIOLIB_IRQCHIP;
struct gpio_irq_chip irq;
#endif ;
unsigned long *valid_mask;
#if defined(CONFIG_OF_GPIO);
unsigned int of_gpio_n_cells;
int (*of_xlate)(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags);
#endif ;
};
Members
label
a functional name for the GPIO device, such as a part number or the name of the SoC IP-block implementing it.
gpiodev
the internal state holder, opaque struct
parent
optional parent device providing the GPIOs
fwnode
optional fwnode providing this controller's properties
owner
helps prevent removal of modules exporting active GPIOs
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 GPIO_LINE_DIRECTION_OUT / GPIO_LINE_DIRECTION_IN), or negative error. It is recommended to always implement this function, even on input-only or output-only gpio chips.
direction_input
configures signal "offset" as input, or returns error This can be omitted on input-only or output-only gpio chips.
direction_output
configures signal "offset" as output, or returns error This can be omitted on input-only or output-only gpio chips.
get
returns value for signal "offset", 0=low, 1=high, or negative error
get_multiple
reads values for multiple signals defined by "mask" and stores them in "bits", returns 0 on success or negative error
set
assigns output value for signal "offset"
set_multiple
assigns output values for multiple signals defined by "mask"
set_config
optional hook for all kinds of settings. Uses the same packed config format as generic pinconf.
to_irq
optional hook supporting non-static
gpiod_to_irq()
mappings; implementation may not sleepdbg_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).
init_valid_mask
optional routine to initialize valid_mask, to be used if not all GPIOs are valid.
add_pin_ranges
optional routine to initialize pin ranges, to be used when requires special mapping of the pins that provides GPIO functionality. It is called after adding GPIO chip and before adding IRQ chip.
en_hw_timestamp
Dependent on GPIO chip, an optional routine to enable hardware timestamp.
dis_hw_timestamp
Dependent on GPIO chip, an optional routine to disable hardware timestamp.
base
identifies the first GPIO number handled by this chip; or, if negative during registration, requests dynamic ID allocation. DEPRECATION: providing anything non-negative and nailing the base offset of GPIO chips is deprecated. Please pass -1 as base to let gpiolib select the chip base in all possible cases. We want to get rid of the static GPIO number space in the long run.
ngpio
the number of GPIOs handled by this controller; the last GPIO handled is (base + ngpio - 1).
offset
when multiple gpio chips belong to the same device this can be used as offset within the device so friendly names can be properly assigned.
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.
can_sleep
flag must be set iff get()/set() methods sleep, as they must while accessing GPIO expander chips over I2C or SPI. This implies that if the chip supports IRQs, these IRQs need to be threaded as the chip access may sleep when e.g. reading out the IRQ status registers.
read_reg
reader function for generic GPIO
write_reg
writer function for generic GPIO
be_bits
if the generic GPIO has big endian bit order (bit 31 is representing line 0, bit 30 is line 1 ... bit 0 is line 31) this is set to true by the generic GPIO core. It is for internal housekeeping only.
reg_dat
data (in) register for generic GPIO
reg_set
output set register (out=high) for generic GPIO
reg_clr
output clear register (out=low) for generic GPIO
reg_dir_out
direction out setting register for generic GPIO
reg_dir_in
direction in setting register for generic GPIO
bgpio_dir_unreadable
indicates that the direction register(s) cannot be read and we need to rely on out internal state tracking.
bgpio_bits
number of register bits used for a generic GPIO i.e. <register width> * 8
bgpio_lock
used to lock chip->bgpio_data. Also, this is needed to keep shadowed and real data registers writes together.
bgpio_data
shadowed data register for generic GPIO to clear/set bits safely.
bgpio_dir
shadowed direction register for generic GPIO to clear/set direction safely. A "1" in this word means the line is set as output.
irq
Integrates interrupt chip functionality with the GPIO chip. Can be used to handle IRQs for most practical cases.
valid_mask
If not
NULL
, holds bitmask of GPIOs which are valid to be used from the chip.of_gpio_n_cells
Number of cells used to form the GPIO specifier.
of_xlate
Callback to translate a device tree GPIO specifier into a chip- relative GPIO number and flags.
Description
A gpio_chip can help platforms abstract various sources of GPIOs so they can all be accessed through a common programming 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.
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for_each_requested_gpio_in_range¶
for_each_requested_gpio_in_range (chip, i, base, size, label)
iterates over requested GPIOs in a given range
Parameters
chip
the chip to query
i
loop variable
base
first GPIO in the range
size
amount of GPIOs to check starting from base
label
label of current GPIO
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gpiochip_add_data¶
gpiochip_add_data (gc, data)
register a gpio_chip
Parameters
gc
the chip to register, with gc->base initialized
data
driver-private data associated with this chip
Context
potentially before irqs will work
Description
When gpiochip_add_data()
is called very early during boot, so that GPIOs
can be freely used, the gc->parent device must be registered before
the gpio framework's arch_initcall(). Otherwise sysfs initialization
for GPIOs will fail rudely.
gpiochip_add_data()
must only be called after gpiolib initialization,
i.e. after core_initcall().
If gc->base is negative, this requests dynamic assignment of a range of valid GPIOs.
Return
A negative errno if the chip can't be registered, such as because the gc->base is invalid or already associated with a different chip. Otherwise it returns zero as a success code.
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struct gpio_pin_range¶
pin range controlled by a gpio chip
Definition:
struct gpio_pin_range {
struct list_head node;
struct pinctrl_dev *pctldev;
struct pinctrl_gpio_range range;
};
Members
node
list for maintaining set of pin ranges, used internally
pctldev
pinctrl device which handles corresponding pins
range
actual range of pins controlled by a gpio controller
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struct gpio_desc *gpio_to_desc(unsigned gpio)¶
Convert a GPIO number to its descriptor
Parameters
unsigned gpio
global GPIO number
Return
The GPIO descriptor associated with the given GPIO, or NULL
if no GPIO
with the given number exists in the system.
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struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum)¶
get the GPIO descriptor corresponding to the given hardware number for this chip
Parameters
struct gpio_chip *gc
GPIO chip
unsigned int hwnum
hardware number of the GPIO for this chip
Return
A pointer to the GPIO descriptor or ERR_PTR(-EINVAL)
if no GPIO exists
in the given chip for the specified hardware number.
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int desc_to_gpio(const struct gpio_desc *desc)¶
convert a GPIO descriptor to the integer namespace
Parameters
const struct gpio_desc *desc
GPIO descriptor
Description
This should disappear in the future but is needed since we still use GPIO numbers for error messages and sysfs nodes.
Return
The global GPIO number for the GPIO specified by its descriptor.
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struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)¶
Return the GPIO chip to which a GPIO descriptor belongs
Parameters
const struct gpio_desc *desc
descriptor to return the chip of
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int gpiod_get_direction(struct gpio_desc *desc)¶
return the current direction of a GPIO
Parameters
struct gpio_desc *desc
GPIO to get the direction of
Description
Returns 0 for output, 1 for input, or an error code in case of error.
This function may sleep if gpiod_cansleep()
is true.
Parameters
struct gpio_chip *gc
GPIO chip
Return
The per-subdriver data for the chip.
Parameters
struct gpio_chip *gc
the chip to unregister
Description
A gpio_chip with any GPIOs still requested may not be removed.
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struct gpio_chip *gpiochip_find(void *data, int (*match)(struct gpio_chip *gc, void *data))¶
iterator for locating a specific gpio_chip
Parameters
void *data
data to pass to match function
int (*match)(struct gpio_chip *gc, void *data)
Callback function to check gpio_chip
Description
Similar to bus_find_device. It returns a reference to a gpio_chip as determined by a user supplied match callback. The callback should return 0 if the device doesn't match and non-zero if it does. If the callback is non-zero, this function will return to the caller and not iterate over any more gpio_chips.
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int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)¶
maps an IRQ into a GPIO irqchip
Parameters
struct irq_domain *d
the irqdomain used by this irqchip
unsigned int irq
the global irq number used by this GPIO irqchip irq
irq_hw_number_t hwirq
the local IRQ/GPIO line offset on this gpiochip
Description
This function will set up the mapping for a certain IRQ line on a gpiochip by assigning the gpiochip as chip data, and using the irqchip stored inside the gpiochip.
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int gpiochip_irq_domain_activate(struct irq_domain *domain, struct irq_data *data, bool reserve)¶
Lock a GPIO to be used as an IRQ
Parameters
struct irq_domain *domain
The IRQ domain used by this IRQ chip
struct irq_data *data
Outermost irq_data associated with the IRQ
bool reserve
If set, only reserve an interrupt vector instead of assigning one
Description
This function is a wrapper that calls gpiochip_lock_as_irq()
and is to be
used as the activate function for the struct irq_domain_ops
. The host_data
for the IRQ domain must be the struct gpio_chip
.
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void gpiochip_irq_domain_deactivate(struct irq_domain *domain, struct irq_data *data)¶
Unlock a GPIO used as an IRQ
Parameters
struct irq_domain *domain
The IRQ domain used by this IRQ chip
struct irq_data *data
Outermost irq_data associated with the IRQ
Description
This function is a wrapper that will call gpiochip_unlock_as_irq()
and is to
be used as the deactivate function for the struct irq_domain_ops
. The
host_data for the IRQ domain must be the struct gpio_chip
.
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int gpiochip_irqchip_add_domain(struct gpio_chip *gc, struct irq_domain *domain)¶
adds an irqdomain to a gpiochip
Parameters
struct gpio_chip *gc
the gpiochip to add the irqchip to
struct irq_domain *domain
the irqdomain to add to the gpiochip
Description
This function adds an IRQ domain to the gpiochip.
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int gpiochip_generic_request(struct gpio_chip *gc, unsigned int offset)¶
request the gpio function for a pin
Parameters
struct gpio_chip *gc
the gpiochip owning the GPIO
unsigned int offset
the offset of the GPIO to request for GPIO function
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void gpiochip_generic_free(struct gpio_chip *gc, unsigned int offset)¶
free the gpio function from a pin
Parameters
struct gpio_chip *gc
the gpiochip to request the gpio function for
unsigned int offset
the offset of the GPIO to free from GPIO function
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int gpiochip_generic_config(struct gpio_chip *gc, unsigned int offset, unsigned long config)¶
apply configuration for a pin
Parameters
struct gpio_chip *gc
the gpiochip owning the GPIO
unsigned int offset
the offset of the GPIO to apply the configuration
unsigned long config
the configuration to be applied
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int gpiochip_add_pingroup_range(struct gpio_chip *gc, struct pinctrl_dev *pctldev, unsigned int gpio_offset, const char *pin_group)¶
add a range for GPIO <-> pin mapping
Parameters
struct gpio_chip *gc
the gpiochip to add the range for
struct pinctrl_dev *pctldev
the pin controller to map to
unsigned int gpio_offset
the start offset in the current gpio_chip number space
const char *pin_group
name of the pin group inside the pin controller
Description
Calling this function directly from a DeviceTree-supported pinctrl driver is DEPRECATED. Please see Section 2.1 of Documentation/devicetree/bindings/gpio/gpio.txt on how to bind pinctrl and gpio drivers via the "gpio-ranges" property.
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int gpiochip_add_pin_range(struct gpio_chip *gc, const char *pinctl_name, unsigned int gpio_offset, unsigned int pin_offset, unsigned int npins)¶
add a range for GPIO <-> pin mapping
Parameters
struct gpio_chip *gc
the gpiochip to add the range for
const char *pinctl_name
the dev_name() of the pin controller to map to
unsigned int gpio_offset
the start offset in the current gpio_chip number space
unsigned int pin_offset
the start offset in the pin controller number space
unsigned int npins
the number of pins from the offset of each pin space (GPIO and pin controller) to accumulate in this range
Return
0 on success, or a negative error-code on failure.
Description
Calling this function directly from a DeviceTree-supported pinctrl driver is DEPRECATED. Please see Section 2.1 of Documentation/devicetree/bindings/gpio/gpio.txt on how to bind pinctrl and gpio drivers via the "gpio-ranges" property.
Parameters
struct gpio_chip *gc
the chip to remove all the mappings for
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const char *gpiochip_is_requested(struct gpio_chip *gc, unsigned int offset)¶
return string iff signal was requested
Parameters
struct gpio_chip *gc
controller managing the signal
unsigned int offset
of signal within controller's 0..(ngpio - 1) range
Description
Returns NULL if the GPIO is not currently requested, else a string. The string returned is the label passed to gpio_request(); if none has been passed it is a meaningless, non-NULL constant.
This function is for use by GPIO controller drivers. The label can help with diagnostics, and knowing that the signal is used as a GPIO can help avoid accidentally multiplexing it to another controller.
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struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc, unsigned int hwnum, const char *label, enum gpio_lookup_flags lflags, enum gpiod_flags dflags)¶
Allow GPIO chip to request its own descriptor
Parameters
struct gpio_chip *gc
GPIO chip
unsigned int hwnum
hardware number of the GPIO for which to request the descriptor
const char *label
label for the GPIO
enum gpio_lookup_flags lflags
lookup flags for this GPIO or 0 if default, this can be used to specify things like line inversion semantics with the machine flags such as GPIO_OUT_LOW
enum gpiod_flags dflags
descriptor request flags for this GPIO or 0 if default, this can be used to specify consumer semantics such as open drain
Description
Function allows GPIO chip drivers to request and use their own GPIO descriptors via gpiolib API. Difference to gpiod_request() is that this function will not increase reference count of the GPIO chip module. This allows the GPIO chip module to be unloaded as needed (we assume that the GPIO chip driver handles freeing the GPIOs it has requested).
Return
A pointer to the GPIO descriptor, or an ERR_PTR()-encoded negative error code on failure.
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void gpiochip_free_own_desc(struct gpio_desc *desc)¶
Free GPIO requested by the chip driver
Parameters
struct gpio_desc *desc
GPIO descriptor to free
Description
Function frees the given GPIO requested previously with
gpiochip_request_own_desc()
.
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int gpiod_direction_input(struct gpio_desc *desc)¶
set the GPIO direction to input
Parameters
struct gpio_desc *desc
GPIO to set to input
Description
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.
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int gpiod_direction_output_raw(struct gpio_desc *desc, int value)¶
set the GPIO direction to output
Parameters
struct gpio_desc *desc
GPIO to set to output
int value
initial output value of the GPIO
Description
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
as raw value on the physical line without regard for the ACTIVE_LOW status.
Return 0 in case of success, else an error code.
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int gpiod_direction_output(struct gpio_desc *desc, int value)¶
set the GPIO direction to output
Parameters
struct gpio_desc *desc
GPIO to set to output
int value
initial output value of the GPIO
Description
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
as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
account.
Return 0 in case of success, else an error code.
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int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)¶
Enable hardware timestamp in nanoseconds.
Parameters
struct gpio_desc *desc
GPIO to enable.
unsigned long flags
Flags related to GPIO edge.
Description
Return 0 in case of success, else negative error code.
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int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)¶
Disable hardware timestamp.
Parameters
struct gpio_desc *desc
GPIO to disable.
unsigned long flags
Flags related to GPIO edge, same value as used during enable call.
Description
Return 0 in case of success, else negative error code.
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int gpiod_set_config(struct gpio_desc *desc, unsigned long config)¶
sets config for a GPIO
Parameters
struct gpio_desc *desc
descriptor of the GPIO for which to set the configuration
unsigned long config
Same packed config format as generic pinconf
Return
0 on success, -ENOTSUPP
if the controller doesn't support setting the
configuration.
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int gpiod_set_debounce(struct gpio_desc *desc, unsigned int debounce)¶
sets debounce time for a GPIO
Parameters
struct gpio_desc *desc
descriptor of the GPIO for which to set debounce time
unsigned int debounce
debounce time in microseconds
Return
0 on success, -ENOTSUPP
if the controller doesn't support setting the
debounce time.
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int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)¶
Lose or retain GPIO state on suspend or reset
Parameters
struct gpio_desc *desc
descriptor of the GPIO for which to configure persistence
bool transitory
True to lose state on suspend or reset, false for persistence
Return
0 on success, otherwise a negative error code.
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int gpiod_is_active_low(const struct gpio_desc *desc)¶
test whether a GPIO is active-low or not
Parameters
const struct gpio_desc *desc
the gpio descriptor to test
Description
Returns 1 if the GPIO is active-low, 0 otherwise.
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void gpiod_toggle_active_low(struct gpio_desc *desc)¶
toggle whether a GPIO is active-low or not
Parameters
struct gpio_desc *desc
the gpio descriptor to change
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int gpiod_get_raw_value(const struct gpio_desc *desc)¶
return a gpio's raw value
Parameters
const struct gpio_desc *desc
gpio whose value will be returned
Description
Return the GPIO's raw value, i.e. the value of the physical line disregarding its ACTIVE_LOW status, or negative errno on failure.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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int gpiod_get_value(const struct gpio_desc *desc)¶
return a gpio's value
Parameters
const struct gpio_desc *desc
gpio whose value will be returned
Description
Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into account, or negative errno on failure.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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int gpiod_get_raw_array_value(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
read raw values from an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be read
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap to store the read values
Description
Read the raw values of the GPIOs, i.e. the values of the physical lines without regard for their ACTIVE_LOW status. Return 0 in case of success, else an error code.
This function can be called from contexts where we cannot sleep, and it will complain if the GPIO chip functions potentially sleep.
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int gpiod_get_array_value(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
read values from an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be read
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap to store the read values
Description
Read the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status into account. Return 0 in case of success, else an error code.
This function can be called from contexts where we cannot sleep, and it will complain if the GPIO chip functions potentially sleep.
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void gpiod_set_raw_value(struct gpio_desc *desc, int value)¶
assign a gpio's raw value
Parameters
struct gpio_desc *desc
gpio whose value will be assigned
int value
value to assign
Description
Set the raw value of the GPIO, i.e. the value of its physical line without regard for its ACTIVE_LOW status.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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void gpiod_set_value(struct gpio_desc *desc, int value)¶
assign a gpio's value
Parameters
struct gpio_desc *desc
gpio whose value will be assigned
int value
value to assign
Description
Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW, OPEN_DRAIN and OPEN_SOURCE flags into account.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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int gpiod_set_raw_array_value(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
assign values to an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be assigned
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap of values to assign
Description
Set the raw values of the GPIOs, i.e. the values of the physical lines without regard for their ACTIVE_LOW status.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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int gpiod_set_array_value(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
assign values to an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be assigned
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap of values to assign
Description
Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status into account.
This function can be called from contexts where we cannot sleep, and will complain if the GPIO chip functions potentially sleep.
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int gpiod_cansleep(const struct gpio_desc *desc)¶
report whether gpio value access may sleep
Parameters
const struct gpio_desc *desc
gpio to check
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int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name)¶
set the consumer name for the descriptor
Parameters
struct gpio_desc *desc
gpio to set the consumer name on
const char *name
the new consumer name
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int gpiod_to_irq(const struct gpio_desc *desc)¶
return the IRQ corresponding to a GPIO
Parameters
const struct gpio_desc *desc
gpio whose IRQ will be returned (already requested)
Description
Return the IRQ corresponding to the passed GPIO, or an error code in case of error.
Parameters
struct gpio_chip *gc
the chip the GPIO to lock belongs to
unsigned int offset
the offset of the GPIO to lock as IRQ
Description
This is used directly by GPIO drivers that want to lock down a certain GPIO line to be used for IRQs.
Parameters
struct gpio_chip *gc
the chip the GPIO to lock belongs to
unsigned int offset
the offset of the GPIO to lock as IRQ
Description
This is used directly by GPIO drivers that want to indicate that a certain GPIO is no longer used exclusively for IRQ.
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int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)¶
return a gpio's raw value
Parameters
const struct gpio_desc *desc
gpio whose value will be returned
Description
Return the GPIO's raw value, i.e. the value of the physical line disregarding its ACTIVE_LOW status, or negative errno on failure.
This function is to be called from contexts that can sleep.
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int gpiod_get_value_cansleep(const struct gpio_desc *desc)¶
return a gpio's value
Parameters
const struct gpio_desc *desc
gpio whose value will be returned
Description
Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into account, or negative errno on failure.
This function is to be called from contexts that can sleep.
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int gpiod_get_raw_array_value_cansleep(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
read raw values from an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be read
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap to store the read values
Description
Read the raw values of the GPIOs, i.e. the values of the physical lines without regard for their ACTIVE_LOW status. Return 0 in case of success, else an error code.
This function is to be called from contexts that can sleep.
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int gpiod_get_array_value_cansleep(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
read values from an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be read
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap to store the read values
Description
Read the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status into account. Return 0 in case of success, else an error code.
This function is to be called from contexts that can sleep.
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void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)¶
assign a gpio's raw value
Parameters
struct gpio_desc *desc
gpio whose value will be assigned
int value
value to assign
Description
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.
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void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)¶
assign a gpio's value
Parameters
struct gpio_desc *desc
gpio whose value will be assigned
int value
value to assign
Description
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.
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int gpiod_set_raw_array_value_cansleep(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
assign values to an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be assigned
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap of values to assign
Description
Set the raw values of the GPIOs, i.e. the values of the physical lines without regard for their ACTIVE_LOW status.
This function is to be called from contexts that can sleep.
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int gpiod_set_array_value_cansleep(unsigned int array_size, struct gpio_desc **desc_array, struct gpio_array *array_info, unsigned long *value_bitmap)¶
assign values to an array of GPIOs
Parameters
unsigned int array_size
number of elements in the descriptor array / value bitmap
struct gpio_desc **desc_array
array of GPIO descriptors whose values will be assigned
struct gpio_array *array_info
information on applicability of fast bitmap processing path
unsigned long *value_bitmap
bitmap of values to assign
Description
Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status into account.
This function is to be called from contexts that can sleep.
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void gpiod_add_lookup_table(struct gpiod_lookup_table *table)¶
register GPIO device consumers
Parameters
struct gpiod_lookup_table *table
table of consumers to register
-
void gpiod_remove_lookup_table(struct gpiod_lookup_table *table)¶
unregister GPIO device consumers
Parameters
struct gpiod_lookup_table *table
table of consumers to unregister
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void gpiod_add_hogs(struct gpiod_hog *hogs)¶
register a set of GPIO hogs from machine code
Parameters
struct gpiod_hog *hogs
table of gpio hog entries with a zeroed sentinel at the end
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struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode, const char *con_id, int index, enum gpiod_flags flags, const char *label)¶
obtain a GPIO from firmware node
Parameters
struct fwnode_handle *fwnode
handle of the firmware node
const char *con_id
function within the GPIO consumer
int index
index of the GPIO to obtain for the consumer
enum gpiod_flags flags
GPIO initialization flags
const char *label
label to attach to the requested GPIO
Description
This function can be used for drivers that get their configuration from opaque firmware.
The function properly finds the corresponding GPIO using whatever is the underlying firmware interface and then makes sure that the GPIO descriptor is requested before it is returned to the caller.
In case of error an ERR_PTR() is returned.
Return
On successful request the GPIO pin is configured in accordance with provided flags.
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int gpiod_count(struct device *dev, const char *con_id)¶
return the number of GPIOs associated with a device / function or -ENOENT if no GPIO has been assigned to the requested function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
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struct gpio_desc *gpiod_get(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
obtain a GPIO for a given GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
Return the GPIO descriptor corresponding to the function con_id of device dev, -ENOENT if no GPIO has been assigned to the requested function, or another IS_ERR() code if an error occurred while trying to acquire the GPIO.
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struct gpio_desc *gpiod_get_optional(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
obtain an optional GPIO for a given GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
This is equivalent to gpiod_get()
, except that when no GPIO was assigned to
the requested function it will return NULL. This is convenient for drivers
that need to handle optional GPIOs.
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struct gpio_desc *gpiod_get_index(struct device *dev, const char *con_id, unsigned int idx, enum gpiod_flags flags)¶
obtain a GPIO from a multi-index GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
unsigned int idx
index of the GPIO to obtain in the consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
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, -ENOENT if no GPIO has been assigned to the requested function and/or index, or another IS_ERR() code if an error occurred while trying to acquire the GPIO.
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struct gpio_desc *gpiod_get_index_optional(struct device *dev, const char *con_id, unsigned int index, enum gpiod_flags flags)¶
obtain an optional GPIO from a multi-index GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
unsigned int index
index of the GPIO to obtain in the consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
This is equivalent to gpiod_get_index()
, except that when no GPIO with the
specified index was assigned to the requested function it will return NULL.
This is convenient for drivers that need to handle optional GPIOs.
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struct gpio_descs *gpiod_get_array(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
obtain multiple GPIOs from a multi-index GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
This function acquires all the GPIOs defined under a given function.
Return a struct gpio_descs containing an array of descriptors, -ENOENT if no GPIO has been assigned to the requested function, or another IS_ERR() code if an error occurred while trying to acquire the GPIOs.
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struct gpio_descs *gpiod_get_array_optional(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
obtain multiple GPIOs from a multi-index GPIO function
Parameters
struct device *dev
GPIO consumer, can be NULL for system-global GPIOs
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
This is equivalent to gpiod_get_array()
, except that when no GPIO was
assigned to the requested function it will return NULL.
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void gpiod_put(struct gpio_desc *desc)¶
dispose of a GPIO descriptor
Parameters
struct gpio_desc *desc
GPIO descriptor to dispose of
Description
No descriptor can be used after gpiod_put()
has been called on it.
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void gpiod_put_array(struct gpio_descs *descs)¶
dispose of multiple GPIO descriptors
Parameters
struct gpio_descs *descs
struct gpio_descs containing an array of descriptors
ACPI support¶
-
struct gpio_desc *acpi_get_and_request_gpiod(char *path, unsigned int pin, char *label)¶
Translate ACPI GPIO pin to GPIO descriptor and hold a refcount to the GPIO device.
Parameters
char *path
ACPI GPIO controller full path name, (e.g. "\_SB.GPO1")
unsigned int pin
ACPI GPIO pin number (0-based, controller-relative)
char *label
Label to pass to gpiod_request()
Description
This function is a simple pass-through to acpi_get_gpiod(), except that
as it is intended for use outside of the GPIO layer (in a similar fashion to
gpiod_get_index()
for example) it also holds a reference to the GPIO device.
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bool acpi_gpio_get_io_resource(struct acpi_resource *ares, struct acpi_resource_gpio **agpio)¶
Fetch details of an ACPI resource if it is a GPIO I/O resource or return False if not.
Parameters
struct acpi_resource *ares
Pointer to the ACPI resource to fetch
struct acpi_resource_gpio **agpio
Pointer to a
struct acpi_resource_gpio
to store the output pointer
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void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)¶
Register isr for gpio chip ACPI events
Parameters
struct gpio_chip *chip
GPIO chip
Description
ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
handled by ACPI event methods which need to be called from the GPIO
chip's interrupt handler. acpi_gpiochip_request_interrupts()
finds out which
GPIO pins have ACPI event methods and assigns interrupt handlers that calls
the ACPI event methods for those pins.
Parameters
struct gpio_chip *chip
GPIO chip
Description
Free interrupts associated with GPIO ACPI event method for the given GPIO chip.
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int acpi_dev_gpio_irq_wake_get_by(struct acpi_device *adev, const char *name, int index, bool *wake_capable)¶
Find GpioInt and translate it to Linux IRQ number
Parameters
struct acpi_device *adev
pointer to a ACPI device to get IRQ from
const char *name
optional name of GpioInt resource
int index
index of GpioInt resource (starting from
0
)bool *wake_capable
Set to true if the IRQ is wake capable
Description
If the device has one or more GpioInt resources, this function can be used to translate from the GPIO offset in the resource to the Linux IRQ number.
The function is idempotent, though each time it runs it will configure GPIO pin direction according to the flags in GpioInt resource.
The function takes optional name parameter. If the resource has a property name, then only those will be taken into account.
The GPIO is considered wake capable if the GpioInt resource specifies SharedAndWake or ExclusiveAndWake.
Return
Linux IRQ number (> 0
) on success, negative errno on failure.
Device tree support¶
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int of_get_named_gpio(const struct device_node *np, const char *propname, int index)¶
Get a GPIO number to use with GPIO API
Parameters
const struct device_node *np
device node to get GPIO from
const char *propname
Name of property containing gpio specifier(s)
int index
index of the GPIO
Description
Returns GPIO number to use with Linux generic GPIO API, or one of the errno value on the error condition.
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int of_mm_gpiochip_add_data(struct device_node *np, struct of_mm_gpio_chip *mm_gc, void *data)¶
Add memory mapped GPIO chip (bank)
Parameters
struct device_node *np
device node of the GPIO chip
struct of_mm_gpio_chip *mm_gc
pointer to the of_mm_gpio_chip allocated structure
void *data
driver data to store in the
struct gpio_chip
Description
To use this function you should allocate and fill mm_gc with:
In the gpio_chip structure: - all the callbacks - of_gpio_n_cells - of_xlate callback (optional)
In the of_mm_gpio_chip structure: - save_regs callback (optional)
If succeeded, this function will map bank's memory and will do all necessary work for you. Then you'll able to use .regs to manage GPIOs from the callbacks.
-
void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)¶
Remove memory mapped GPIO chip (bank)
Parameters
struct of_mm_gpio_chip *mm_gc
pointer to the of_mm_gpio_chip allocated structure
Device-managed API¶
-
struct gpio_desc *devm_gpiod_get(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
Resource-managed
gpiod_get()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
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.
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struct gpio_desc *devm_gpiod_get_optional(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
Resource-managed
gpiod_get_optional()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
Managed gpiod_get_optional()
. GPIO descriptors returned from this function
are automatically disposed on driver detach. See gpiod_get_optional()
for
detailed information about behavior and return values.
-
struct gpio_desc *devm_gpiod_get_index(struct device *dev, const char *con_id, unsigned int idx, enum gpiod_flags flags)¶
Resource-managed
gpiod_get_index()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
unsigned int idx
index of the GPIO to obtain in the consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
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 *devm_fwnode_gpiod_get_index(struct device *dev, struct fwnode_handle *fwnode, const char *con_id, int index, enum gpiod_flags flags, const char *label)¶
get a GPIO descriptor from a given node
Parameters
struct device *dev
GPIO consumer
struct fwnode_handle *fwnode
firmware node containing GPIO reference
const char *con_id
function within the GPIO consumer
int index
index of the GPIO to obtain in the consumer
enum gpiod_flags flags
GPIO initialization flags
const char *label
label to attach to the requested GPIO
Description
GPIO descriptors returned from this function are automatically disposed on driver detach.
On successful request the GPIO pin is configured in accordance with provided flags.
-
struct gpio_desc *devm_gpiod_get_index_optional(struct device *dev, const char *con_id, unsigned int index, enum gpiod_flags flags)¶
Resource-managed
gpiod_get_index_optional()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
unsigned int index
index of the GPIO to obtain in the consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
Managed gpiod_get_index_optional()
. GPIO descriptors returned from this
function are automatically disposed on driver detach. See
gpiod_get_index_optional()
for detailed information about behavior and
return values.
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struct gpio_descs *devm_gpiod_get_array(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
Resource-managed
gpiod_get_array()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
Managed gpiod_get_array()
. GPIO descriptors returned from this function are
automatically disposed on driver detach. See gpiod_get_array()
for detailed
information about behavior and return values.
-
struct gpio_descs *devm_gpiod_get_array_optional(struct device *dev, const char *con_id, enum gpiod_flags flags)¶
Resource-managed
gpiod_get_array_optional()
Parameters
struct device *dev
GPIO consumer
const char *con_id
function within the GPIO consumer
enum gpiod_flags flags
optional GPIO initialization flags
Description
Managed gpiod_get_array_optional()
. GPIO descriptors returned from this
function are automatically disposed on driver detach.
See gpiod_get_array_optional()
for detailed information about behavior and
return values.
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void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)¶
Resource-managed
gpiod_put()
Parameters
struct device *dev
GPIO consumer
struct gpio_desc *desc
GPIO descriptor to dispose of
Description
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.
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void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc)¶
Remove resource management from a gpio descriptor
Parameters
struct device *dev
GPIO consumer
struct gpio_desc *desc
GPIO descriptor to remove resource management from
Description
Remove resource management from a GPIO descriptor. This is needed when you want to hand over lifecycle management of a descriptor to another mechanism.
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void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs)¶
Resource-managed
gpiod_put_array()
Parameters
struct device *dev
GPIO consumer
struct gpio_descs *descs
GPIO descriptor array to dispose of
Description
Dispose of an array of GPIO descriptors obtained with devm_gpiod_get_array()
.
Normally this function will not be called as the GPIOs will be disposed of
by the resource management code.
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int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)¶
request a GPIO for a managed device
Parameters
struct device *dev
device to request the GPIO for
unsigned gpio
GPIO to allocate
const char *label
the name of the requested GPIO
Except for the extra dev argument, this function takes the same arguments and performs the same function as gpio_request(). GPIOs requested with this function will be automatically freed on driver detach.
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int devm_gpio_request_one(struct device *dev, unsigned gpio, unsigned long flags, const char *label)¶
request a single GPIO with initial setup
Parameters
struct device *dev
device to request for
unsigned gpio
the GPIO number
unsigned long flags
GPIO configuration as specified by GPIOF_*
const char *label
a literal description string of this GPIO
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int devm_gpiochip_add_data_with_key(struct device *dev, struct gpio_chip *gc, void *data, struct lock_class_key *lock_key, struct lock_class_key *request_key)¶
Resource managed gpiochip_add_data_with_key()
Parameters
struct device *dev
pointer to the device that gpio_chip belongs to.
struct gpio_chip *gc
the GPIO chip to register
void *data
driver-private data associated with this chip
struct lock_class_key *lock_key
lockdep class for IRQ lock
struct lock_class_key *request_key
lockdep class for IRQ request
Context
potentially before irqs will work
Description
The gpio chip automatically be released when the device is unbound.
Return
A negative errno if the chip can't be registered, such as because the gc->base is invalid or already associated with a different chip. Otherwise it returns zero as a success code.
sysfs helpers¶
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int gpiod_export(struct gpio_desc *desc, bool direction_may_change)¶
export a GPIO through sysfs
Parameters
struct gpio_desc *desc
GPIO to make available, already requested
bool direction_may_change
true if userspace may change GPIO direction
Context
arch_initcall or later
Description
When drivers want to make a GPIO accessible to userspace after they have requested it -- perhaps while debugging, or as part of their public interface -- they may use this routine. If the GPIO can change direction (some can't) and the caller allows it, userspace will see "direction" sysfs attribute which may be used to change the gpio's direction. A "value" attribute will always be provided.
Returns zero on success, else an error.
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int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc)¶
create a sysfs link to an exported GPIO node
Parameters
struct device *dev
device under which to create symlink
const char *name
name of the symlink
struct gpio_desc *desc
GPIO to create symlink to, already exported
Description
Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN node. Caller is responsible for unlinking.
Returns zero on success, else an error.
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void gpiod_unexport(struct gpio_desc *desc)¶
reverse effect of
gpiod_export()
Parameters
struct gpio_desc *desc
GPIO to make unavailable
Description
This is implicit on gpiod_free().