blob: bde646995d10ab7c214b69fd818ae8328aa6b319 [file] [log] [blame]
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/of.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/compiler.h>
/* Platforms may implement their GPIO interface with library code,
* at a small performance cost for non-inlined operations and some
* extra memory (for code and for per-GPIO table entries).
* While the GPIO programming interface defines valid GPIO numbers
* to be in the range 0..MAX_INT, this library restricts them to the
* smaller range 0..ARCH_NR_GPIOS-1.
* ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
* builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
* actually an estimate of a board-specific value.
#define ARCH_NR_GPIOS 256
* "valid" GPIO numbers are nonnegative and may be passed to
* setup routines like gpio_request(). only some valid numbers
* can successfully be requested and used.
* Invalid GPIO numbers are useful for indicating no-such-GPIO in
* platform data and other tables.
static inline bool gpio_is_valid(int number)
return number >= 0 && number < ARCH_NR_GPIOS;
struct device;
struct gpio;
struct seq_file;
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);
* 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;
extern const char *gpiochip_is_requested(struct gpio_chip *chip,
unsigned offset);
extern struct gpio_chip *gpio_to_chip(unsigned gpio);
/* add/remove chips */
extern int gpiochip_add(struct gpio_chip *chip);
extern int __must_check gpiochip_remove(struct gpio_chip *chip);
extern struct gpio_chip *gpiochip_find(void *data,
int (*match)(struct gpio_chip *chip,
void *data));
/* Always use the library code for GPIO management calls,
* or when sleeping may be involved.
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);
extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
extern int gpio_get_value_cansleep(unsigned gpio);
extern void gpio_set_value_cansleep(unsigned gpio, int 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);
extern int __gpio_cansleep(unsigned gpio);
extern int __gpio_to_irq(unsigned gpio);
extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
extern int gpio_request_array(const struct gpio *array, size_t num);
extern void gpio_free_array(const struct gpio *array, size_t num);
* 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);
#endif /* CONFIG_GPIO_SYSFS */
* struct gpio_pin_range - pin range controlled by a gpio chip
* @head: 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
struct gpio_pin_range {
struct list_head node;
struct pinctrl_dev *pctldev;
struct pinctrl_gpio_range range;
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
unsigned int gpio_offset, unsigned int pin_offset,
unsigned int npins);
void gpiochip_remove_pin_ranges(struct gpio_chip *chip);
static inline int
gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
unsigned int gpio_offset, unsigned int pin_offset,
unsigned int npins)
return 0;
static inline void
gpiochip_remove_pin_ranges(struct gpio_chip *chip)
#endif /* CONFIG_PINCTRL */
#else /* !CONFIG_GPIOLIB */
static inline bool gpio_is_valid(int number)
/* only non-negative numbers are valid */
return number >= 0;
/* platforms that don't directly support access to GPIOs through I2C, SPI,
* or other blocking infrastructure can use these wrappers.
static inline int gpio_cansleep(unsigned gpio)
return 0;
static inline int gpio_get_value_cansleep(unsigned gpio)
return __gpio_get_value(gpio);
static inline void gpio_set_value_cansleep(unsigned gpio, int value)
__gpio_set_value(gpio, value);
#endif /* !CONFIG_GPIOLIB */
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 */