#ifndef _ASM_GENERIC_GPIO_H #define _ASM_GENERIC_GPIO_H #include <linux/types.h> #ifdef CONFIG_HAVE_GPIO_LIB #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. */ #ifndef ARCH_NR_GPIOS #define ARCH_NR_GPIOS 256 #endif static inline int gpio_is_valid(int number) { /* only some non-negative numbers are valid */ return ((unsigned)number) < ARCH_NR_GPIOS; } struct seq_file; struct module; /** * struct gpio_chip - abstract a GPIO controller * @label: for diagnostics * @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" * @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 * * 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 { char *label; struct module *owner; 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); void (*set)(struct gpio_chip *chip, unsigned offset, int value); void (*dbg_show)(struct seq_file *s, struct gpio_chip *chip); int base; u16 ngpio; unsigned can_sleep:1; }; extern const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset); 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); /* 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_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); #else static inline int 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 #endif /* _ASM_GENERIC_GPIO_H */