| #ifndef _ASM_GENERIC_GPIO_H |
| #define _ASM_GENERIC_GPIO_H |
| |
| #include <linux/types.h> |
| |
| #ifdef CONFIG_GPIOLIB |
| |
| #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 |
| * @dev: optional device providing the GPIOs |
| * @owner: helps prevent removal of modules exporting active GPIOs |
| * @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 device *dev; |
| 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; |
| unsigned exported: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); |
| |
| |
| #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 void gpio_unexport(unsigned gpio); |
| |
| #endif /* CONFIG_GPIO_SYSFS */ |
| |
| #else /* !CONFIG_HAVE_GPIO_LIB */ |
| |
| 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 /* !CONFIG_HAVE_GPIO_LIB */ |
| |
| #ifndef CONFIG_GPIO_SYSFS |
| |
| /* 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 void gpio_unexport(unsigned gpio) |
| { |
| } |
| #endif /* CONFIG_GPIO_SYSFS */ |
| |
| #endif /* _ASM_GENERIC_GPIO_H */ |