1 #ifndef _ASM_GENERIC_GPIO_H
2 #define _ASM_GENERIC_GPIO_H
4 //#include <linux/kernel.h>
5 #include <linux/types.h>
6 //#include <linux/errno.h>
8 typedef enum{false, true} bool;
12 //#include <linux/compiler.h>
14 /* Platforms may implement their GPIO interface with library code,
15 * at a small performance cost for non-inlined operations and some
16 * extra memory (for code and for per-GPIO table entries).
18 * While the GPIO programming interface defines valid GPIO numbers
19 * to be in the range 0..MAX_INT, this library restricts them to the
20 * smaller range 0..ARCH_NR_GPIOS-1.
24 #define ARCH_NR_GPIOS 256
27 static inline int gpio_is_valid(int number)
29 /* only some non-negative numbers are valid */
30 return ((unsigned)number) < ARCH_NR_GPIOS;
37 * struct gpio_chip - abstract a GPIO controller
38 * @label: for diagnostics
39 * @dev: optional device providing the GPIOs
40 * @owner: helps prevent removal of modules exporting active GPIOs
41 * @request: optional hook for chip-specific activation, such as
42 * enabling module power and clock; may sleep
43 * @free: optional hook for chip-specific deactivation, such as
44 * disabling module power and clock; may sleep
45 * @direction_input: configures signal "offset" as input, or returns error
46 * @get: returns value for signal "offset"; for output signals this
47 * returns either the value actually sensed, or zero
48 * @direction_output: configures signal "offset" as output, or returns error
49 * @set: assigns output value for signal "offset"
50 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
51 * implementation may not sleep
52 * @dbg_show: optional routine to show contents in debugfs; default code
53 * will be used when this is omitted, but custom code can show extra
54 * state (such as pullup/pulldown configuration).
55 * @base: identifies the first GPIO number handled by this chip; or, if
56 * negative during registration, requests dynamic ID allocation.
57 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
58 * handled is (base + ngpio - 1).
59 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
60 * must while accessing GPIO expander chips over I2C or SPI
61 * @names: if set, must be an array of strings to use as alternative
62 * names for the GPIOs in this chip. Any entry in the array
63 * may be NULL if there is no alias for the GPIO, however the
64 * array must be @ngpio entries long.
66 * A gpio_chip can help platforms abstract various sources of GPIOs so
67 * they can all be accessed through a common programing interface.
68 * Example sources would be SOC controllers, FPGAs, multifunction
69 * chips, dedicated GPIO expanders, and so on.
71 * Each chip controls a number of signals, identified in method calls
72 * by "offset" values in the range 0..(@ngpio - 1). When those signals
73 * are referenced through calls like gpio_get_value(gpio), the offset
74 * is calculated by subtracting @base from the gpio number.
81 int (*request)(struct gpio_chip *chip,
83 void (*free)(struct gpio_chip *chip,
86 int (*direction_input)(struct gpio_chip *chip,
88 int (*get)(struct gpio_chip *chip,
90 int (*direction_output)(struct gpio_chip *chip,
91 unsigned offset, int value);
92 void (*set)(struct gpio_chip *chip,
93 unsigned offset, int value);
95 int (*to_irq)(struct gpio_chip *chip,
98 void (*dbg_show)(struct seq_file *s,
99 struct gpio_chip *chip);
103 unsigned can_sleep:1;
107 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
109 extern int gpiochip_reserve(int start, int ngpio);
111 /* add/remove chips */
112 extern int gpiochip_add(struct gpio_chip *chip);
113 extern int gpiochip_remove(struct gpio_chip *chip);
116 /* Always use the library code for GPIO management calls,
117 * or when sleeping may be involved.
119 extern int gpio_request(unsigned gpio, const char *label);
120 extern void gpio_free(unsigned gpio);
122 extern int gpio_direction_input(unsigned gpio);
123 extern int gpio_direction_output(unsigned gpio, int value);
125 extern int gpio_get_value_cansleep(unsigned gpio);
126 extern void gpio_set_value_cansleep(unsigned gpio, int value);
129 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
130 * the GPIO is constant and refers to some always-present controller,
131 * giving direct access to chip registers and tight bitbanging loops.
133 extern int __gpio_get_value(unsigned gpio);
134 extern void __gpio_set_value(unsigned gpio, int value);
136 extern int __gpio_cansleep(unsigned gpio);
138 extern int __gpio_to_irq(unsigned gpio);
140 #ifdef CONFIG_GPIO_SYSFS
143 * A sysfs interface can be exported by individual drivers if they want,
144 * but more typically is configured entirely from userspace.
146 extern int gpio_export(unsigned gpio, bool direction_may_change);
147 extern int gpio_export_link(struct device *dev, const char *name,
149 extern void gpio_unexport(unsigned gpio);
151 #endif /* CONFIG_GPIO_SYSFS */
153 #else /* !CONFIG_HAVE_GPIO_LIB */
155 static inline int gpio_is_valid(int number)
157 /* only non-negative numbers are valid */
161 /* platforms that don't directly support access to GPIOs through I2C, SPI,
162 * or other blocking infrastructure can use these wrappers.
165 static inline int gpio_cansleep(unsigned gpio)
170 static inline int gpio_get_value_cansleep(unsigned gpio)
173 return gpio_get_value(gpio);
176 static inline void gpio_set_value_cansleep(unsigned gpio, int value)
179 gpio_set_value(gpio, value);
182 #endif /* !CONFIG_HAVE_GPIO_LIB */
184 #ifndef CONFIG_GPIO_SYSFS
186 /* sysfs support is only available with gpiolib, where it's optional */
188 static inline int gpio_export(unsigned gpio, bool direction_may_change)
193 static inline int gpio_export_link(struct device *dev, const char *name,
199 static inline void gpio_unexport(unsigned gpio)
202 #endif /* CONFIG_GPIO_SYSFS */
204 #endif /* _ASM_GENERIC_GPIO_H */