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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - include/asm-generic/gpio.h
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>
10 #include <linux/compiler.h>
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).
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.
22 #define ARCH_NR_GPIOS 256
25 static inline int gpio_is_valid(int number
)
27 /* only some non-negative numbers are valid */
28 return ((unsigned)number
) < ARCH_NR_GPIOS
;
36 * struct gpio_chip - abstract a GPIO controller
37 * @label: for diagnostics
38 * @dev: optional device providing the GPIOs
39 * @owner: helps prevent removal of modules exporting active GPIOs
40 * @request: optional hook for chip-specific activation, such as
41 * enabling module power and clock; may sleep
42 * @free: optional hook for chip-specific deactivation, such as
43 * disabling module power and clock; may sleep
44 * @direction_input: configures signal "offset" as input, or returns error
45 * @get: returns value for signal "offset"; for output signals this
46 * returns either the value actually sensed, or zero
47 * @direction_output: configures signal "offset" as output, or returns error
48 * @set: assigns output value for signal "offset"
49 * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
50 * implementation may not sleep
51 * @dbg_show: optional routine to show contents in debugfs; default code
52 * will be used when this is omitted, but custom code can show extra
53 * state (such as pullup/pulldown configuration).
54 * @base: identifies the first GPIO number handled by this chip; or, if
55 * negative during registration, requests dynamic ID allocation.
56 * @ngpio: the number of GPIOs handled by this controller; the last GPIO
57 * handled is (base + ngpio - 1).
58 * @can_sleep: flag must be set iff get()/set() methods sleep, as they
59 * must while accessing GPIO expander chips over I2C or SPI
60 * @names: if set, must be an array of strings to use as alternative
61 * names for the GPIOs in this chip. Any entry in the array
62 * may be NULL if there is no alias for the GPIO, however the
63 * array must be @ngpio entries long.
65 * A gpio_chip can help platforms abstract various sources of GPIOs so
66 * they can all be accessed through a common programing interface.
67 * Example sources would be SOC controllers, FPGAs, multifunction
68 * chips, dedicated GPIO expanders, and so on.
70 * Each chip controls a number of signals, identified in method calls
71 * by "offset" values in the range 0..(@ngpio - 1). When those signals
72 * are referenced through calls like gpio_get_value(gpio), the offset
73 * is calculated by subtracting @base from the gpio number.
80 int (*request
)(struct gpio_chip
*chip
,
82 void (*free
)(struct gpio_chip
*chip
,
85 int (*direction_input
)(struct gpio_chip
*chip
,
87 int (*get
)(struct gpio_chip
*chip
,
89 int (*direction_output
)(struct gpio_chip
*chip
,
90 unsigned offset
, int value
);
91 void (*set
)(struct gpio_chip
*chip
,
92 unsigned offset
, int value
);
94 int (*to_irq
)(struct gpio_chip
*chip
,
97 void (*dbg_show
)(struct seq_file
*s
,
98 struct gpio_chip
*chip
);
102 unsigned can_sleep
:1;
106 extern const char *gpiochip_is_requested(struct gpio_chip
*chip
,
108 extern int __must_check
gpiochip_reserve(int start
, int ngpio
);
110 /* add/remove chips */
111 extern int gpiochip_add(struct gpio_chip
*chip
);
112 extern int __must_check
gpiochip_remove(struct gpio_chip
*chip
);
115 /* Always use the library code for GPIO management calls,
116 * or when sleeping may be involved.
118 extern int gpio_request(unsigned gpio
, const char *label
);
119 extern void gpio_free(unsigned gpio
);
121 extern int gpio_direction_input(unsigned gpio
);
122 extern int gpio_direction_output(unsigned gpio
, int value
);
124 extern int gpio_get_value_cansleep(unsigned gpio
);
125 extern void gpio_set_value_cansleep(unsigned gpio
, int value
);
128 /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
129 * the GPIO is constant and refers to some always-present controller,
130 * giving direct access to chip registers and tight bitbanging loops.
132 extern int __gpio_get_value(unsigned gpio
);
133 extern void __gpio_set_value(unsigned gpio
, int value
);
135 extern int __gpio_cansleep(unsigned gpio
);
137 extern int __gpio_to_irq(unsigned gpio
);
139 #ifdef CONFIG_GPIO_SYSFS
142 * A sysfs interface can be exported by individual drivers if they want,
143 * but more typically is configured entirely from userspace.
145 extern int gpio_export(unsigned gpio
, bool direction_may_change
);
146 extern int gpio_export_link(struct device
*dev
, const char *name
,
148 extern int gpio_sysfs_set_active_low(unsigned gpio
, int value
);
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
188 /* sysfs support is only available with gpiolib, where it's optional */
190 static inline int gpio_export(unsigned gpio
, bool direction_may_change
)
195 static inline int gpio_export_link(struct device
*dev
, const char *name
,
201 static inline int gpio_sysfs_set_active_low(unsigned gpio
, int value
)
206 static inline void gpio_unexport(unsigned gpio
)
209 #endif /* CONFIG_GPIO_SYSFS */
211 #endif /* _ASM_GENERIC_GPIO_H */