1#ifndef _ASM_GENERIC_GPIO_H 2#define _ASM_GENERIC_GPIO_H 3 4#include <linux/kernel.h> 5#include <linux/types.h> 6#include <linux/errno.h> 7 8#ifdef CONFIG_GPIOLIB 9 10#include <linux/compiler.h> 11 12/* Platforms may implement their GPIO interface with library code, 13 * at a small performance cost for non-inlined operations and some 14 * extra memory (for code and for per-GPIO table entries). 15 * 16 * While the GPIO programming interface defines valid GPIO numbers 17 * to be in the range 0..MAX_INT, this library restricts them to the 18 * smaller range 0..ARCH_NR_GPIOS-1. 19 * 20 * ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of 21 * builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is 22 * actually an estimate of a board-specific value. 23 */ 24 25#ifndef ARCH_NR_GPIOS 26#define ARCH_NR_GPIOS 256 27#endif 28 29/* 30 * "valid" GPIO numbers are nonnegative and may be passed to 31 * setup routines like gpio_request(). only some valid numbers 32 * can successfully be requested and used. 33 * 34 * Invalid GPIO numbers are useful for indicating no-such-GPIO in 35 * platform data and other tables. 36 */ 37 38static inline int gpio_is_valid(int number) 39{ 40 return ((unsigned)number) < ARCH_NR_GPIOS; 41} 42 43struct device; 44struct seq_file; 45struct module; 46struct device_node; 47 48/** 49 * struct gpio_chip - abstract a GPIO controller 50 * @label: for diagnostics 51 * @dev: optional device providing the GPIOs 52 * @owner: helps prevent removal of modules exporting active GPIOs 53 * @request: optional hook for chip-specific activation, such as 54 * enabling module power and clock; may sleep 55 * @free: optional hook for chip-specific deactivation, such as 56 * disabling module power and clock; may sleep 57 * @direction_input: configures signal "offset" as input, or returns error 58 * @get: returns value for signal "offset"; for output signals this 59 * returns either the value actually sensed, or zero 60 * @direction_output: configures signal "offset" as output, or returns error 61 * @set: assigns output value for signal "offset" 62 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings; 63 * implementation may not sleep 64 * @dbg_show: optional routine to show contents in debugfs; default code 65 * will be used when this is omitted, but custom code can show extra 66 * state (such as pullup/pulldown configuration). 67 * @base: identifies the first GPIO number handled by this chip; or, if 68 * negative during registration, requests dynamic ID allocation. 69 * @ngpio: the number of GPIOs handled by this controller; the last GPIO 70 * handled is (base + ngpio - 1). 71 * @can_sleep: flag must be set iff get()/set() methods sleep, as they 72 * must while accessing GPIO expander chips over I2C or SPI 73 * @names: if set, must be an array of strings to use as alternative 74 * names for the GPIOs in this chip. Any entry in the array 75 * may be NULL if there is no alias for the GPIO, however the 76 * array must be @ngpio entries long. A name can include a single printk 77 * format specifier for an unsigned int. It is substituted by the actual 78 * number of the gpio. 79 * 80 * A gpio_chip can help platforms abstract various sources of GPIOs so 81 * they can all be accessed through a common programing interface. 82 * Example sources would be SOC controllers, FPGAs, multifunction 83 * chips, dedicated GPIO expanders, and so on. 84 * 85 * Each chip controls a number of signals, identified in method calls 86 * by "offset" values in the range 0..(@ngpio - 1). When those signals 87 * are referenced through calls like gpio_get_value(gpio), the offset 88 * is calculated by subtracting @base from the gpio number. 89 */ 90struct gpio_chip { 91 const char *label; 92 struct device *dev; 93 struct module *owner; 94 95 int (*request)(struct gpio_chip *chip, 96 unsigned offset); 97 void (*free)(struct gpio_chip *chip, 98 unsigned offset); 99 100 int (*direction_input)(struct gpio_chip *chip, 101 unsigned offset); 102 int (*get)(struct gpio_chip *chip, 103 unsigned offset); 104 int (*direction_output)(struct gpio_chip *chip, 105 unsigned offset, int value); 106 int (*set_debounce)(struct gpio_chip *chip, 107 unsigned offset, unsigned debounce); 108 109 void (*set)(struct gpio_chip *chip, 110 unsigned offset, int value); 111 112 int (*to_irq)(struct gpio_chip *chip, 113 unsigned offset); 114 115 void (*dbg_show)(struct seq_file *s, 116 struct gpio_chip *chip); 117 int base; 118 u16 ngpio; 119 const char *const *names; 120 unsigned can_sleep:1; 121 unsigned exported:1; 122 123#if defined(CONFIG_OF_GPIO) 124 /* 125 * If CONFIG_OF is enabled, then all GPIO controllers described in the 126 * device tree automatically may have an OF translation 127 */ 128 struct device_node *of_node; 129 int of_gpio_n_cells; 130 int (*of_xlate)(struct gpio_chip *gc, struct device_node *np, 131 const void *gpio_spec, u32 *flags); 132#endif 133}; 134 135extern const char *gpiochip_is_requested(struct gpio_chip *chip, 136 unsigned offset); 137extern int __must_check gpiochip_reserve(int start, int ngpio); 138 139/* add/remove chips */ 140extern int gpiochip_add(struct gpio_chip *chip); 141extern int __must_check gpiochip_remove(struct gpio_chip *chip); 142extern struct gpio_chip *gpiochip_find(void *data, 143 int (*match)(struct gpio_chip *chip, 144 void *data)); 145 146 147/* Always use the library code for GPIO management calls, 148 * or when sleeping may be involved. 149 */ 150extern int gpio_request(unsigned gpio, const char *label); 151extern void gpio_free(unsigned gpio); 152 153extern int gpio_direction_input(unsigned gpio); 154extern int gpio_direction_output(unsigned gpio, int value); 155 156extern int gpio_set_debounce(unsigned gpio, unsigned debounce); 157 158extern int gpio_get_value_cansleep(unsigned gpio); 159extern void gpio_set_value_cansleep(unsigned gpio, int value); 160 161 162/* A platform's <asm/gpio.h> code may want to inline the I/O calls when 163 * the GPIO is constant and refers to some always-present controller, 164 * giving direct access to chip registers and tight bitbanging loops. 165 */ 166extern int __gpio_get_value(unsigned gpio); 167extern void __gpio_set_value(unsigned gpio, int value); 168 169extern int __gpio_cansleep(unsigned gpio); 170 171extern int __gpio_to_irq(unsigned gpio); 172 173#define GPIOF_DIR_OUT (0 << 0) 174#define GPIOF_DIR_IN (1 << 0) 175 176#define GPIOF_INIT_LOW (0 << 1) 177#define GPIOF_INIT_HIGH (1 << 1) 178 179#define GPIOF_IN (GPIOF_DIR_IN) 180#define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW) 181#define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH) 182 183/** 184 * struct gpio - a structure describing a GPIO with configuration 185 * @gpio: the GPIO number 186 * @flags: GPIO configuration as specified by GPIOF_* 187 * @label: a literal description string of this GPIO 188 */ 189struct gpio { 190 unsigned gpio; 191 unsigned long flags; 192 const char *label; 193}; 194 195extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); 196extern int gpio_request_array(struct gpio *array, size_t num); 197extern void gpio_free_array(struct gpio *array, size_t num); 198 199#ifdef CONFIG_GPIO_SYSFS 200 201/* 202 * A sysfs interface can be exported by individual drivers if they want, 203 * but more typically is configured entirely from userspace. 204 */ 205extern int gpio_export(unsigned gpio, bool direction_may_change); 206extern int gpio_export_link(struct device *dev, const char *name, 207 unsigned gpio); 208extern int gpio_sysfs_set_active_low(unsigned gpio, int value); 209extern void gpio_unexport(unsigned gpio); 210 211#endif /* CONFIG_GPIO_SYSFS */ 212 213#else /* !CONFIG_HAVE_GPIO_LIB */ 214 215static inline int gpio_is_valid(int number) 216{ 217 /* only non-negative numbers are valid */ 218 return number >= 0; 219} 220 221/* platforms that don't directly support access to GPIOs through I2C, SPI, 222 * or other blocking infrastructure can use these wrappers. 223 */ 224 225static inline int gpio_cansleep(unsigned gpio) 226{ 227 return 0; 228} 229 230static inline int gpio_get_value_cansleep(unsigned gpio) 231{ 232 might_sleep(); 233 return gpio_get_value(gpio); 234} 235 236static inline void gpio_set_value_cansleep(unsigned gpio, int value) 237{ 238 might_sleep(); 239 gpio_set_value(gpio, value); 240} 241 242#endif /* !CONFIG_HAVE_GPIO_LIB */ 243 244#ifndef CONFIG_GPIO_SYSFS 245 246struct device; 247 248/* sysfs support is only available with gpiolib, where it's optional */ 249 250static inline int gpio_export(unsigned gpio, bool direction_may_change) 251{ 252 return -ENOSYS; 253} 254 255static inline int gpio_export_link(struct device *dev, const char *name, 256 unsigned gpio) 257{ 258 return -ENOSYS; 259} 260 261static inline int gpio_sysfs_set_active_low(unsigned gpio, int value) 262{ 263 return -ENOSYS; 264} 265 266static inline void gpio_unexport(unsigned gpio) 267{ 268} 269#endif /* CONFIG_GPIO_SYSFS */ 270 271#endif /* _ASM_GENERIC_GPIO_H */ 272