#ifndef _ASM_GENERIC_GPIO_H #define _ASM_GENERIC_GPIO_H #include #include #include #include #ifdef CONFIG_GPIOLIB #include /* 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. */ #ifndef ARCH_NR_GPIOS #define ARCH_NR_GPIOS 256 #endif /* * "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_chip - abstract a GPIO controller * @label: for diagnostics * @dev: optional device providing the GPIOs * @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 * @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: 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). * @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; int (*request)(struct gpio_chip *chip, unsigned offset); void (*free)(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; 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 }; extern const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset); extern struct gpio_chip *gpio_to_chip(unsigned gpio); extern int __must_check gpiochip_reserve(int start, int ngpio); /* 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(const void *data, int (*match)(struct gpio_chip *chip, const 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_re_enabled(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 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); /* bindings for managed devices that want to request gpios */ int devm_gpio_request(struct device *dev, unsigned gpio, const char *label); void devm_gpio_free(struct device *dev, unsigned int gpio); #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); #endif /* CONFIG_GPIO_SYSFS */ #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) { might_sleep(); return __gpio_get_value(gpio); } static inline void gpio_set_value_cansleep(unsigned gpio, int value) { might_sleep(); __gpio_set_value(gpio, 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 */