1#ifndef _ASM_GENERIC_GPIO_H 2#define _ASM_GENERIC_GPIO_H 3 4#include <linux/types.h> 5#include <linux/errno.h> 6 7#ifdef CONFIG_GPIOLIB 8 9#include <linux/compiler.h> 10 11/* Platforms may implement their GPIO interface with library code, 12 * at a small performance cost for non-inlined operations and some 13 * extra memory (for code and for per-GPIO table entries). 14 * 15 * While the GPIO programming interface defines valid GPIO numbers 16 * to be in the range 0..MAX_INT, this library restricts them to the 17 * smaller range 0..ARCH_NR_GPIOS-1. 18 */ 19 20#ifndef ARCH_NR_GPIOS 21#define ARCH_NR_GPIOS 256 22#endif 23 24static inline int gpio_is_valid(int number) 25{ 26 /* only some non-negative numbers are valid */ 27 return ((unsigned)number) < ARCH_NR_GPIOS; 28} 29 30struct seq_file; 31struct module; 32 33/** 34 * struct gpio_chip - abstract a GPIO controller 35 * @label: for diagnostics 36 * @dev: optional device providing the GPIOs 37 * @owner: helps prevent removal of modules exporting active GPIOs 38 * @request: optional hook for chip-specific activation, such as 39 * enabling module power and clock; may sleep 40 * @free: optional hook for chip-specific deactivation, such as 41 * disabling module power and clock; may sleep 42 * @direction_input: configures signal "offset" as input, or returns error 43 * @get: returns value for signal "offset"; for output signals this 44 * returns either the value actually sensed, or zero 45 * @direction_output: configures signal "offset" as output, or returns error 46 * @set: assigns output value for signal "offset" 47 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings; 48 * implementation may not sleep 49 * @dbg_show: optional routine to show contents in debugfs; default code 50 * will be used when this is omitted, but custom code can show extra 51 * state (such as pullup/pulldown configuration). 52 * @base: identifies the first GPIO number handled by this chip; or, if 53 * negative during registration, requests dynamic ID allocation. 54 * @ngpio: the number of GPIOs handled by this controller; the last GPIO 55 * handled is (base + ngpio - 1). 56 * @can_sleep: flag must be set iff get()/set() methods sleep, as they 57 * must while accessing GPIO expander chips over I2C or SPI 58 * 59 * A gpio_chip can help platforms abstract various sources of GPIOs so 60 * they can all be accessed through a common programing interface. 61 * Example sources would be SOC controllers, FPGAs, multifunction 62 * chips, dedicated GPIO expanders, and so on. 63 * 64 * Each chip controls a number of signals, identified in method calls 65 * by "offset" values in the range 0..(@ngpio - 1). When those signals 66 * are referenced through calls like gpio_get_value(gpio), the offset 67 * is calculated by subtracting @base from the gpio number. 68 */ 69struct gpio_chip { 70 const char *label; 71 struct device *dev; 72 struct module *owner; 73 74 int (*request)(struct gpio_chip *chip, 75 unsigned offset); 76 void (*free)(struct gpio_chip *chip, 77 unsigned offset); 78 79 int (*direction_input)(struct gpio_chip *chip, 80 unsigned offset); 81 int (*get)(struct gpio_chip *chip, 82 unsigned offset); 83 int (*direction_output)(struct gpio_chip *chip, 84 unsigned offset, int value); 85 void (*set)(struct gpio_chip *chip, 86 unsigned offset, int value); 87 88 int (*to_irq)(struct gpio_chip *chip, 89 unsigned offset); 90 91 void (*dbg_show)(struct seq_file *s, 92 struct gpio_chip *chip); 93 int base; 94 u16 ngpio; 95 unsigned can_sleep:1; 96 unsigned exported:1; 97}; 98 99extern const char *gpiochip_is_requested(struct gpio_chip *chip, 100 unsigned offset); 101extern int __must_check gpiochip_reserve(int start, int ngpio); 102 103/* add/remove chips */ 104extern int gpiochip_add(struct gpio_chip *chip); 105extern int __must_check gpiochip_remove(struct gpio_chip *chip); 106 107 108/* Always use the library code for GPIO management calls, 109 * or when sleeping may be involved. 110 */ 111extern int gpio_request(unsigned gpio, const char *label); 112extern void gpio_free(unsigned gpio); 113 114extern int gpio_direction_input(unsigned gpio); 115extern int gpio_direction_output(unsigned gpio, int value); 116 117extern int gpio_get_value_cansleep(unsigned gpio); 118extern void gpio_set_value_cansleep(unsigned gpio, int value); 119 120 121/* A platform's <asm/gpio.h> code may want to inline the I/O calls when 122 * the GPIO is constant and refers to some always-present controller, 123 * giving direct access to chip registers and tight bitbanging loops. 124 */ 125extern int __gpio_get_value(unsigned gpio); 126extern void __gpio_set_value(unsigned gpio, int value); 127 128extern int __gpio_cansleep(unsigned gpio); 129 130extern int __gpio_to_irq(unsigned gpio); 131 132#ifdef CONFIG_GPIO_SYSFS 133 134/* 135 * A sysfs interface can be exported by individual drivers if they want, 136 * but more typically is configured entirely from userspace. 137 */ 138extern int gpio_export(unsigned gpio, bool direction_may_change); 139extern void gpio_unexport(unsigned gpio); 140 141#endif /* CONFIG_GPIO_SYSFS */ 142 143#else /* !CONFIG_HAVE_GPIO_LIB */ 144 145static inline int gpio_is_valid(int number) 146{ 147 /* only non-negative numbers are valid */ 148 return number >= 0; 149} 150 151/* platforms that don't directly support access to GPIOs through I2C, SPI, 152 * or other blocking infrastructure can use these wrappers. 153 */ 154 155static inline int gpio_cansleep(unsigned gpio) 156{ 157 return 0; 158} 159 160static inline int gpio_get_value_cansleep(unsigned gpio) 161{ 162 might_sleep(); 163 return gpio_get_value(gpio); 164} 165 166static inline void gpio_set_value_cansleep(unsigned gpio, int value) 167{ 168 might_sleep(); 169 gpio_set_value(gpio, value); 170} 171 172#endif /* !CONFIG_HAVE_GPIO_LIB */ 173 174#ifndef CONFIG_GPIO_SYSFS 175 176/* sysfs support is only available with gpiolib, where it's optional */ 177 178static inline int gpio_export(unsigned gpio, bool direction_may_change) 179{ 180 return -ENOSYS; 181} 182 183static inline void gpio_unexport(unsigned gpio) 184{ 185} 186#endif /* CONFIG_GPIO_SYSFS */ 187 188#endif /* _ASM_GENERIC_GPIO_H */ 189